Crude terephthalic acid composition and method of obtaining said composition

FIELD: chemistry.

SUBSTANCE: invention relates to liquid-phase catalytic oxidation of an aromatic compound and to the obtained crude terephthalic acid. Oxidation is carried out in a bubble column reactor which ensures a highly efficient process at relatively low temperature. Particles of the obtained terephthalic acid, which contains approximately less than 100 parts weight/million of 2,6-dicarboxyfluorenone, have transmission factor at 340 nm (%T340) greater than approximately 25%, additionally contains approximately less than 12 parts weight/million of 4,4-dicarboxystilbene and/or contains approximately less than 400 parts weight/million of isophthalic acid. Particles of the obtained terephthalic acid, characterised by average size ranging from approximately 20 to approximately 150 micrometres, are dissolved in tetrahydrofuran for one minute to concentration of a least approximately 500 parts/million and/or is characterised by average BET surface area greater than approximately 0.6 m2/g.

EFFECT: product can be extracted and purified using methods which are cheaper than those which can be used if the acid is obtained via a high-temperature oxidation method.

37 cl, 36 dwg, 5 tbl, 1 ex

 

The technical field to which the invention relates.

The present invention relates mainly to a method of liquid-phase catalytic oxidation of aromatic compounds. One aspect of the present invention relates to a partial oxidation dialkylamino aromatic compounds (in particular, para-xylene) to obtain the crude aromatic dicarboxylic acids (in particular, crude terephthalic acid), which is then subjected to purification and separation. Another aspect of the present invention relates to an improved bubble column reactor type, which ensures the implementation of more efficient and cost-effective way of liquid-phase oxidation.

The level of technology

The reaction liquid-phase oxidation is used in different existing industrial methods. For example, liquid-phase oxidation of currently used for the oxidation of aldehydes into acids (in particular, oxidation of propionic aldehyde in propionic acid)oxidation of cyclohexane to adipic acid and oxidation of alkyl substituted aromatic compounds to alcohols, acids or decollate. The most important industrial method for the oxidation in the latter category (the oxidation of alkyl substituted aromatic compounds) is the liquid-phase catalytic partial oxidation of para-xylene with images is of terephthalic acid. Terephthalic acid is an important compound that is widely used. The main application of terephthalic acid is used as starting material for the production of polyethylene terephthalate (PET, PET). PAT is a well-known plastic material, which is worldwide in large quantities used in the manufacture of such products as bottles, fibers and packaging materials.

In a typical method of liquid-phase oxidation, including partial oxidation of para-xylene with the formation of terephthalic acid, liquid-phase stream of the original connection and the gas-phase oxidant stream is introduced into the reactor and they form in the reactor multiphase reaction medium. Fed to the reactor liquid phase stream starting compound contains at least one is able to oxidize organic compound (in particular, para-xylene), and gas-phase oxidant stream contains molecular oxygen. At least part of the molecular oxygen which is introduced into the reactor in the form of gas dissolved in the liquid phase reaction medium and ensures the availability of oxygen for the implementation of liquid-phase reactions. If the liquid phase of the multiphase reaction medium has an insufficient concentration of molecular oxygen (i.e., if certain portions of the reaction medium “experience is with the lack of oxygen”), the undesirable side reactions may lead to the formation of impurities and/or may slow down the flow of the required reactions. If the liquid phase reaction medium contains too few are able to oxidize compounds, the reaction rate may be undesirable low. In addition, if the liquid phase reaction medium contains excess concentration is able to oxidize compounds, additional undesirable side reactions may lead to the formation of impurities.

Conventional reactors for carrying out liquid-phase oxidation is supplied by means of mixing contained in a multiphase reaction medium. Stirring of the reaction medium is carried out with the aim to facilitate the dissolution of molecular oxygen in the liquid phase reaction medium, to maintain a relatively uniform concentration of dissolved oxygen in the liquid phase reaction medium and to maintain a relatively uniform concentration is able to oxidize organic compounds in the liquid phase reaction medium.

Stirring of the reaction medium in which the liquid-phase oxidation, often carried out with the use of mechanical means of mixing in such reactors, as, for example, flow-through reactors mixing (CSTR). Despite the fact that CSTR is able to provide thorough mixing of the PE klonoa environment, CSTR have a number of disadvantages. CSTR have a relatively high capital cost, because they, for example, require the use of expensive engines, isolated from contact with fluid bearings and drive shafts and/or the use of complex mixing devices. In addition, rotating and/or oscillating mechanical components of the conventional CSTR require regular maintenance. Labor costs and downtime associated with carrying out specified maintenance, increase operating costs CSTR. However, even with regular maintenance, used in the CSTR mechanical mixing system are subject to mechanical failure and may require replacement in a relatively short period of time.

Bubble column reactor types represent an attractive alternative to the CSTR and the other is provided with a mechanical stirring reactors for carrying out processes of oxidation. Bubble column reactor type provide mixing of the reaction medium, without requiring the use of expensive and unreliable mechanical equipment. Typically, a bubble column reactor type include an elongated vertical reaction zone in which the reaction medium. Peremesherve.naruzhno environment in the reaction zone supplied mainly due to the natural buoyancy of gas bubbles, which rise up through the liquid phase reaction medium. The specified mixing due to the natural buoyancy, which is provided in bubble columns reactor type, reduces capital and operating costs compared to the reactor with mechanical stirring. In addition, the almost complete absence of moving mechanical parts in bubble columns reactor type allows to obtain a system for carrying out the oxidation, which is less prone to mechanical failure than the reactor with mechanical agitation.

In the case where the liquid-phase partial oxidation of para-xylene is carried out in a conventional reactor for oxidation (CSTR or a bubble column reactor type), then discharged from the reactor product, as a rule, is a suspension containing crude terephthalic acid (CTA) and the mother liquor. One HUNDRED contains relatively high levels of impurities (in particular, contains 4-carboxybenzene, paratoluidine acid, fluorenone and other coloured compounds)that make it unsuitable for use as raw materials for the production of PET. Therefore, one HUNDRED obtained in conventional reactors for carrying out processes of oxidation, as a rule, treated, which turns a HUNDRED in purified therephtale the th acid (MOUTH), suitable for PET.

Typical cleaning method, with the aim of turning a HUNDRED in the MOUTH, includes the following stages: (1) the replacement of the mother liquor HUNDRED-containing suspension in water, (2) heating the suspension HUNDRED/water with the aim of dissolving a HUNDRED in water, (3) catalytic hydrogenation of a solution of a HUNDRED/water to transform impurities in a more convenient and/or easily detachable connection, (4) precipitation received his MOUTH from the solution after hydrogenation by multistage crystallization and (5) separating the crystals of the MOUTH from the remaining liquids. Despite the fact that the conventional cleaning method is effective, it can be very expensive. Individual factors that contribute to the high cost of conventional cleaning methods one HUNDRED, are, for example, the heat required to facilitate the dissolution of a HUNDRED in the water, the catalyst required for carrying out the hydrogenation, the supply of hydrogen required for hydrogenation, the loss of yield caused by hydrogenation parts of terephthalic acid, and numerous vessels, necessary for carrying out multi-stage crystallization. So, you want to get a HUNDRED in a product that could be cleaned without requiring use of the heat of dissolution in water, hydrogenation and/or multi-stage crystallize the AI.

The objects of the invention

Thus, an object of the present invention is more efficient and economical reactor for liquid-phase oxidation and a method of liquid-phase oxidation.

Another object of the present invention is more efficient and economical reactor and method of liquid-phase catalytic partial oxidation of para-xylene with the formation of terephthalic acid.

Another object of the present invention is a bubble column reactor type, which provides superior holding reactions liquid-phase oxidation with the formation of smaller amounts of impurities.

Another object of the present invention is more efficient and economical system for producing purified terephthalic acid (MOUTH) by liquid phase oxidation of para-xylene with the formation of crude terephthalic acid (CTA) and subsequent treatment of a HUNDRED with the obtain of the MOUTH.

Another object of the present invention is a bubble column reactor for oxidation of para-xylene and get a HUNDRED in a product that does not require for its purification using heat, accelerating the dissolution of a HUNDRED in the water, hydrogenation of dissolved HUNDRED and/or carry out multi-stage crystallization of the MOUTH after hydrogenation.

It should be noted that this volume is about invention, defined in the attached claims is not limited to methods and devices that can implement all of the above objects. Moreover, the scope of the claimed invention may include various systems that do not provide all or any of the above objects. Additional objects and advantages of the present invention will be readily understood by a person skilled in the art after reviewing the following detailed description of the invention and the attached drawings.

The invention

One of the embodiments of the present invention relates to the composition of the crude terephthalic acid (CTA), which represents many HUNDRED particles extracted from the reactor for oxidation, which is at least partially formed of particles of a HUNDRED, while a typical sample of a HUNDRED particles has one or more of these properties: (a) contains less than about 6 ppm wt. 4,4-decarboxilase (4,4-DCS), (b) contains less than about 400 ppm wt. isophthalic acid (IPA), (c) contains less than about 25 ppm by weight. 2,6-dicarboxylate (2,6-DCF), (d) has a percent transmittance at 340 nm (%T340more than about 60.

Another variant of implementation of the present invention Casa is tsya composition of the suspension, extracted from the reactor for oxidation, the composition of the suspension includes making a solution and solids crude terephthalic acid (CTA), and particles of a HUNDRED, at least partially formed in the reactor for carrying out processes of oxidation, while a typical sample of the suspension has one or more of these properties that are generic for solid and liquid components of the suspension: (a) contains less than about 1500 ppm by weight. isophthalic acid (IPA), (b) contains less than about 500 ppm wt. phthalic acid (PA), (C) contains less than about 500 ppm wt. trimellitic acid (TMA), (d) contains less than about 2000 ppm wt. benzoic acid (BA).

Another variant implementation of the present invention relates to a method, which comprises the following stages: (a) oxidizing para-xylene in the liquid phase, multi-phase reaction medium contained in a reaction zone, at least one primary reactor for oxidation; and (b) removing the suspension containing mother liquor and solids crude terephthalic acid (CTA), from the reaction zone, while a typical sample of a HUNDRED particles has one or more of these properties: (i) contains less than about 6 ppm wt. 4,4-decarboxilase (4,4-DCS),(ii) contains less than about 400 ppm wt. isophthalic acid (IPA), (iii) contains less than about 25 ppm by weight. 2,6-dicarboxylate (2,6-DCF), (iv) has a percent transmittance at 340 nm (%T340more than about 60.

Another variant of implementation of the present invention relates to a method, which comprises the following stages: (a) the filing of the original recycled solvent, at least one reactor for oxidation; (b) oxidation is able to oxidize compounds in the liquid phase, multi-phase reaction medium contained in the reaction zone of the reactor for oxidation; and (C) removing the suspension containing mother liquor and solids crude terephthalic acid (CTA), from the reaction zone, while a typical sample of a HUNDRED particles contains less than about 5 ppm wt. 2,7-dicarboxylate (2,7-DCF).

Another variant implementation of the present invention relates to a method, which comprises the following stages: (a) oxidizing para-xylene in the liquid phase, multi-phase reaction medium contained in a reaction zone, at least one reactor for carrying out processes of oxidation; and (b) removing the suspension containing making solution and solid particles of crude terephthalic acid (CTA), from the reaction zone, while a typical sample of a HUNDRED particles has one or more of oksanakost, which are generic for solid and liquid components of the suspension: (i) contains less than about 1500 ppm by weight. isophthalic acid (IPA), (ii) contains less than about 500 ppm wt. phthalic acid (PA), (iii) contains less than about 500 ppm wt. trimellitic acid (TMA), (iv) contains less than about 2000 ppm wt. benzoic acid (BA).

Brief description of drawings

Preferred embodiments of the present invention are described in detail hereinafter with reference to the following drawings

which figure 1 presents a side view of a reactor for carrying out processes of oxidation, which is constructed in accordance with one embodiments of the present invention, and, in particular, the drawing explains the flow of streams of initial substances, oxidizing agent and phlegmy in the reactor, the presence of multi-phase reaction medium in the reactor and the gas outlet and the suspension of the upper and lower parts of the reactor, respectively;

figure 2 presented in section along the line 2-2 in figure 3 an enlarged side view of the bottom of the bubble column reactor type, and, in particular, the drawing illustrates the location and configuration of the bubbler to enter the oxidizer, which is used for flow of oxidant into the reactor;

figure 3 presents a top view of the bubbler to enter oxidizer shown in figure 2, and, in particular, erti explains holes for the supply of oxidant, located at the top of the bubbler to enter oxidant;

4 shows the bottom view of the bubbler to enter oxidizer shown in figure 2, in particular the drawing explains holes for the supply of oxidant, located at the bottom of the bubbler to enter oxidant;

figure 5 presents in cross-section on line 5-5, figure 3 is a side view of the bubbler to enter oxidant, and, in particular, the drawing explains the orientation of the openings for supplying oxidant, located at the top and bottom of the bubbler to enter oxidant;

figure 6 presents an enlarged side view of the lower part of the bubble column reactor type, and, in particular, the drawing explains the delivery system of the original substances inside the reactor at multiple height positions;

figure 7 presents a top view in section along the line 7-7 figure 6, in particular the drawing explains, as shown in Fig.6 supply system of the original substance distributes the flow of the original substances in the preferred radial feed area of the original substances (FZ) and more than one azimuthal quadrant (Q1, Q2, Q3, Q4);

on Fig presented in the context of a top view similar to Fig.7, which explains an alternative device for feeding starting materials in the reactor by means of bayonet tubes, each of which has many small holes to feed the original substances;

figure 9 presents an isometric projection of an alternative system for supplying starting materials in the reaction zone in multiple height positions, which does not require a large number of penetrations in the reactor, in particular, the drawing shows that the distribution system of the source material may at least partially be based on the bubbler to enter oxidant;

figure 10 presents a side view of the distribution system of the original substances with one sidebar and bubbler to enter the oxidizer, which is shown in Fig.9;

figure 11 presents a top view in section along the line 11-11 in figure 10, further explaining the distribution system of the original substances with one sidebar, which is based on the bubbler to enter oxidant;

on Fig presents an isometric projection of an alternative bubbler to enter oxidant, in which all the holes for the supply of the oxidant is located at the bottom of the annular element;

on Fig presents a top view of an alternative bubbler to enter oxidizer shown in Fig;

on Fig presents a bottom view of an alternative bubbler to enter oxidizer shown in Fig, in particular the drawing explains the location of the bottom holes for the flow of oxidant in the reaction zone;

on Fig presented in section along the line 15-15 on Fig side view of the bubbler dawodu oxidant, in particular, the drawing explains the orientation of the lower insertion openings oxidant;

on Fig presents a side view of a bubble column reactor type has an internal reservoir for deaeration, which is located near the bottom outlet of the reactor;

on Fig presented in section along the line 17-17 on Fig enlarged view of the lower part of the bubble column reactor of the type shown in Fig, and, in particular, the drawing explains the configuration of the inner tank deaeration, which is located at the lower outlet bubble column reactor type;

on Fig presents a top view in section along the line 18-18 in Fig, which, in particular, explains the flow conditioner placed in the tank deaeration;

on Fig presents a side view of a bubble column reactor type, equipped with an external reservoir for deaeration, which explains how part of the suspension after deaeration, leaving the lower part of the tank deaeration can be used for flushing the line of discharge of the reaction products attached to the bottom of the reactor;

on Fig presents a side view of a bubble column reactor type, equipped with a hybrid internal/external tank deaeration designed to separate the gas phase from the reaction medium, to which I displayed on the side of the reactor at a certain altitude mark;

on Fig presents a side view of a bubble column reactor of the type provided with an alternative hybrid tank deaeration, which is located near the bottom of the reactor;

on Fig presented in the context of an enlarged side view of the lower part of the bubble column reactor of the type shown in Fig, and, in particular, the drawing illustrates the use of alternative bubbler to enter oxidant having input connections, in which the oxidant stream enters through the bottom of the reactor;

on Fig presented in the context of an enlarged side view, similar Fig, and, in particular, the drawing explains alternative device for entering a flow of oxidant to the reactor through the many holes in the bottom plate of the reactor and the optional use of reflective plates designed to more evenly distribute the flow of the oxidant in the reactor;

on Fig presents a side view of a bubble column reactor of the type in which the applied internal pressure pipeline, designed to improve the dispersion is able to oxidize compounds due to the recirculation of the reaction medium from the upper part of the reactor in the lower part of the reactor;

on Fig presents a side view of a bubble column reactor of the type in which the applied external pressure pipeline, designed the La improve dispersion is able to oxidize compounds due to the recirculation of the reaction medium from the upper part of the reactor in the lower part of the reactor;

on Fig presented in section side view of the horizontal ejector, which can be used to improve the dispersion is able to oxidize compounds in the reactor for carrying out the processes of oxidation and, in particular, the drawing explains the ejector, in which the fluid flow is used to enter the reaction medium in the ejector and which with great speed delivers the mixture of starting compounds and reaction medium in the reaction zone;

on Fig presented in section side view of a vertical ejector, which can be used to improve the dispersion is able to oxidize compounds in the oxidation reactor, and, in particular, the drawing explains the ejector, which mixes the liquid starting material and the feed gas, uses the combined two-phase fluid for introducing the reaction medium in the ejector and high speed directs the mixture of liquid starting substances of the injected gas and the reaction medium in the reaction zone;

on Fig presents a side view of a bubble column reactor of the type containing a multiphase reaction medium, and, in particular, the drawing explains the reaction medium, which is theoretically divided into 30 horizontal layers of equal volume in order to quantify certain gradients in the reaction environment;

on Fig presents a side view of a bubble column is accornero type, containing multiphase reaction medium, and, in particular, the drawing explains the first and second discrete 20%continuous volume of the reaction medium, which have significantly different concentrations of oxygen and/or the rate of consumption of oxygen;

on Fig presents a side view of two spaced one above the other reactors, equipped or not equipped with an optional mechanical agitation, which contain multi-phase reaction medium, in particular drawing explains that the reactors include discrete 20%continuous volume of the reaction medium, which have significantly different concentrations of oxygen and/or the rate of oxygen consumption;

on Fig presents a side view of three adjacent to each other reactors, equipped or not equipped with an optional mechanical agitation, which contain multi-phase reaction medium, and, in particular, the drawing explains that the reactors include discrete 20%continuous volume of the reaction medium, which have significantly different concentrations of oxygen and/or the rate of oxygen consumption;

on figa and 32V shows the magnified view of particles of crude terephthalic acid (CTA), obtained in accordance with one embodiments of the present invention, and, in particular, the pictures show that each particle has a HUNDRED nor the kind of density, large surface area of the particles formed by many loosely coupled with each other subparticles of a HUNDRED;

on figa and 33B shows the magnified view of particles of crude terephthalic acid (CTA), obtained in the usual way, and, in particular, the pictures indicate that you have received the usual way particle HUNDRED has a larger particle size, lighter in weight and smaller size compared with the particle HUNDRED, obtained in accordance with the present invention, which is shown in figa and 32V;

on Fig in simplified form shows streaming chart known method of producing purified terephthalic acid (MOUTH);

on Fig in simplified form shows streaming chart of a method of obtaining a MOUTH in accordance with one embodiments of the present invention; and

on Fig the results of the test for dissolution for a certain period of time, which is described in the examples and, in particular, it explains that the crystals of one HUNDRED for the present invention are dissolved faster than the crystals HUNDRED, obtained in the usual way.

Detailed description of the invention

One of the embodiments of the present invention relates to liquid-phase partial oxidation is able to oxidize compounds. Specified the oxidation is preferably carried out in the liquid phase of the multiphase reaction medium, of which the traveler is contained in one or more reactors mixing. Suitable equipped with a stirring reactors include, for example, a reactor with stirring using a sparging (in particular, a bubble column reactor type reactor with mechanical stirring (in particular, housing the reactors continuous stirring and the reactor with stirring using a stream (in particular, gas-jet reactors). In one of the embodiments of the present invention the liquid-phase oxidation is carried out in a bubble column reactor type.

In this description, the term “bubble column reactor type” refers to a reactor for carrying out chemical reactions in multiphase reaction medium, while stirring the reaction medium is mainly due to the motion of gas bubbles up through the reaction medium. In this description, the term “mixing” refers to the power that is dissipated in the reaction medium and causes the flow and/or mixing liquids. In this description, the terms “most”, “mostly” and “primarily” means more than 50%. In this description, the term “mechanical mixing” refers to mixing of the reaction medium caused by the physical movement of the hard(them) or flexible(their) item(s) relative to the reaction medium or within the reaction medium. For example, a mechanical pen is eshiwani can be done by rotation, fluctuations and/or vibrations inside agitators, paddles, vibrators or acoustic diaphragms, which are placed in the reaction medium. In this description, the term “mixing flow” refers to the mixing of the reaction medium caused by injection with high speed and/or recirculation of one or more liquids in the reaction medium. For example, the mixing flow can be performed using nozzles, ejectors and/or ejection devices.

In a preferred embodiment of the present invention is less than about 40% of stirring the reaction medium in a bubble column reactor type in the oxidation process is carried out by mechanical stirring and/or mixing flow, more preferably, less than about 20% mixing is carried out by mechanical stirring and/or mixing flow and, most preferably, less than 5% mixing is carried out by mechanical stirring and/or mixing flow. The amount of mechanical mixing and/or mixing of the stream, which is carried out in a multiphase reaction medium in the oxidation process, is preferably less than approximately

3 kW/cm3reaction medium, more preferably, is less than listello 2 kW/cm 3and, most preferably, is less than 1 kW/cm3.

If we now turn to figure 1, the preferred bubble column reactor type 20 can be described as a bubble column reactor type 20, which consists of a casing of the reactor 22, which includes a section of the reaction 24 and the separating section 26. Partition the reaction 24 restricts the inner reaction zone 28, while section division 26 limits the internal separation zone 30. Mainly the flow of liquid starting substances is introduced into the reaction zone 28 through the inlet openings for the filing of the original substances 32a,b,c,d. Predominately gas-phase oxidant stream is introduced into reaction zone 28 through the bubbler to enter oxidizer 34 located in the lower part of the reaction zone 28. The flow of liquid starting substances and the gas-phase oxidant stream together form a multiphase reaction medium 36 within the reaction zone 28. Multiphase reaction medium 36 includes a liquid phase and a gas phase. More preferably, the multiphase reaction medium 36 is a three-phase environment, which contains a solid phase, liquid phase and gas phase components. Solid-phase component of the reaction medium 36 is mainly deposited in the reaction zone 28 in the oxidation reaction, which proceeds in the liquid phase of the reactions is authorized environment 36. Bubble column reactor type 20 has an outlet opening for discharging the suspension 38, which is located near the bottom of the reaction zone 28, and the hole for the gas outlet 40, which is located near the upper part of the separation zone 30. The flow of suspension containing liquid-phase and solid-phase components of the reaction medium 36, the output from the reaction zone 28 through the opening for discharge of the suspension 38, while a predominantly gaseous stream of exhaust gases is withdrawn from the separation zone 30 via the outlet port for gas 40.

The flow of liquid starting substances, which is served in a bubble column reactor type 20 through the inlet openings for the filing of the original substances 32a,b,c,d, mainly contains is able to oxidize the compound, the solvent and the catalytic system.

Able to oxidize a compound that is present in the stream of liquid starting substances, mainly contains at least one hydrocarbon group. More preferably, able to oxidize the compound is an aromatic compound. Even more preferably, is able to oxidize the compound is an aromatic compound containing as a substituent at least one attached hydrocarbon group, or at least one attached zameshano the hydrocarbon group, or at least one heteroatom attached, or at least one attached carboxyl functional group (-COOH). Even more preferably, is able to oxidize the compound is an aromatic compound that contains at least one attached hydrocarbon group, or at least one attached substituted hydrocarbon group, each attached group contains from 1 to 5 carbon atoms. Finally, even more preferably, is able to oxidize the compound is an aromatic compound that contains exactly two connected groups, each attached group contains exactly one carbon atom and includes a methyl group and/or substituted by a methyl group and/or not more than one carboxyl group. Even more preferably, is able to oxidize the compound is a para-xylene, meta-xylene, para-tolualdehyde, meta tolualdehyde, para-Truelove acid, meta-Truelove acid and/or acetaldehyde. Most preferably, is able to oxidize the compound is a para-xylene.

“Hydrocarbon group” in this description means, at least one carbon atom, which is connected to hydrogen atoms or other atoms of carbon. “Substituted hydrocarbon group” in the description means, at least one carbon atom, which is connected at least one heteroatom and at least one hydrogen atom. “Heteroatoms” in this description means all atoms other than carbon atoms and hydrogen atoms. Aromatic compounds herein include aromatic cycle, which contains at least 6 carbon atoms and, more preferably, in the cycle contains only carbon atoms. Suitable examples of such aromatic cycles include, but not limited to, benzene, biphenyl, terphenyl, naphthalene, and other carbon-containing condensed aromatic cycles.

Suitable examples are able to oxidize compounds include aliphatic hydrocarbons, in particular alkanes, branched alkanes, cyclic alkanes, aliphatic alkenes, branched alkenes and cyclic alkenes); aliphatic aldehydes (in particular, acetaldehyde, propionic aldehyde, somerley aldehyde and N.-butyric aldehyde); aliphatic alcohols (in particular, ethanol, isopropanol, N.-propanol, N.-butanol and Isobutanol); aliphatic ketones (in particular, dimethylketone, ethylmethylketone, diethylketone and isopropylethylene); aliphatic esters (in particular, methylformate, methyl acetate, ethyl acetate); aliphatic peroxides, nagkalat and hydroperoxides (in particular, hydroperoxide tert-butyl, peracetic acid and hydroperoxide, di-tert-butyl); aliphatic compounds with groups that represent a combination of the above aliphatic compounds plus other heteroatoms (in particular, aliphatic compounds comprising one or more molecular segments of hydrocarbons, aldehydes, alcohols, ketones, esters, peroxides, nakilat and/or hydroperoxides in combination with sodium, bromine, cobalt, manganese and zirconium); various benzene cycles, naphthalene cycles, biphenyls, terphenyls, and other aromatic groups containing one or more hydrocarbon groups attached (in particular, toluene, ethylbenzene, isopropylbenzene, N.-propylbenzoyl, neopentylene, para-xylene, meta-xylene, ortho-xylene, all isomers of trimethylbenzene, all isomers of tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, all isomers of utilitybase, all isomers of diethylbenzene, all isomers of ethyldimethylamine, all isomers of dimethylnaphthalene, all isomers of ethylmethylketone, all isomers of diethylketone, all isomers of dimethylbiphenyl, all isomers of ethylmethylamine, all isomers of diethylsilane, stilbene and stilbene with one or more attached hydrocarbon groups, fluorene and fluorene with one or more attached hydrocarbon groups, ntrace, and anthracene with one or more attached hydrocarbon groups and diphenylethan and diphenylethan with one or more attached hydrocarbon groups); various benzene cycles, naphthalene cycles, biphenyls, terphenyls, and other aromatic groups containing one or more attached hydrocarbon groups and/or one or more attached heteroatoms, which may be linked to other atoms or groups of atoms (in particular, phenol, all isomers of METHYLPHENOL, all isomers of dimethylphenols, all isomers napolov, benzylmethylamine ether, all isomers of bromophenols, Brabanthal, all isomers of brontallo, including alpha-broncolor, debrabant, naphtalene cobalt, and all isomers of bromobiphenyl); various benzene cycles, naphthalene cycles, biphenyls, terphenyls, and other aromatic groups containing one or more attached hydrocarbon groups and/or one or more attached heteroatoms, and/or one or more attached substituted hydrocarbon groups (in particular, benzaldehyde, all isomers of bromobenzaldehyde, all isomers bromodomain Truelove aldehydes, including isomers of alpha-bromeliae aldehydes, all isomers of hydroxybenzaldehyde, all isomers of bromhidrosisbacterial, all isomers

benzene is carboxaldehyde, all isomers

benzotrichloride, para-Truelove aldehyde,

meta-Truelove aldehyde, ortho-Truelove aldehyde, all isomers of colordialog1.showdialog, all isomers

toluoldiisocyanates, all isomers

colormatrixfilter, all isomers

dimethylaminobenzaldehyde, all isomers

dimethylaminobenzaldehyde, all isomers

dimethylaminobenzaldehyde, all isomers

trimethylbenzaldehyde, all isomers ethylcellulose aldehydes, all isomers of trimethylbenzaldehyde, tetramethyldisiloxane, hydroxymethylbenzene, all isomers of hydroxymethylcellulose, all isomers of hydroxymethylbutyrate, all isomers hydroxymethylcellulose aldehydes, all isomers hydroxymethylbutyrate aldehydes, the hydroperoxide of benzyl, benzoyl hydroperoxide, all isomers of trimethylhydroquinone and all isomers of methylphenyldichlorosilane); various benzene cycles, naphthalene cycles, biphenyls, terphenyls, and other aromatic groups containing one or more attached selected hydrocarbon groups, with selected groups means a hydrocarbon group, and/or attached heteroatoms, and/or substituted hydrocarbon groups and/or groups of carboxylic acids, and/or groups of Narciso is (in particular, benzoic acid, para-Truelove acid, meta-Truelove acid, ortho-Truelove acid, all isomers ethylbenzene acids, all isomers propylbenzene acids, all isomers butylbenzoic acids, all isomers pentylbenzoic acids, all isomers dimethylbenzoic acids, all isomers ethylmethylamine acids, all isomers trimethylbenzoic acids, all isomers tetramethylbenzene acids, pentamethylbenzene acid, all isomers diethylbenzene acids, all isomers benzylcarbamoyl acids, all isomers benzotriazole acids, all isomers methylbenzeneboronic acids, all isomers dimethylphenylcarbinol acids, all isomers methylbenzotriazole acids, all isomers brombenzoic acids, all isomers of acids dibromobenzoic all isomers bromeliae acids, including alpha-Bromeliaceae acid, tolyloxy acid, all isomers of hydroxybenzoic acids, all isomers hydroxymethylbenzene acids, all isomers hydroxytoluene acids, all isomers hydroxymethylcellulose acids, all isomers hydroxyethylmethylcellulose acids, all isomers hydroxypropanoic acids, all isomers hydroxyprolisilane acids, all isomers hydroxymethylbenzene acids, all isomers of carboxybenzaldehydes, all Isom the ditch of dicarboxaldehyde, adventurou acid, all isomers hydroperoxidation acids, all isomers hydroperoxidation acids, all isomers hydroperoxidation acids, all isomers of hydroperoxyalkyl, all isomers methylpiperidino acids, all isomers dimethylphenylcarbinol acids, all isomers methylpiperidino acids, all isomers biphenyldicarboxylic acids, all isomers of stilbene with one or more attached selected groups, all isomers of fluorenone with one or more attached selected groups, all isomers naphthalene with one or more attached selected groups, benzyl, and all isomers of benzyl with one or more attached selected groups, benzophenone, all isomers of benzophenone with one or more attached selected groups, anthraquinone, all isomers of anthraquinone with one or more attached selected groups, all isomers of diphenylethane with one or more attached selected groups, benzocoumarin, all isomers of benzocoumarin with one or more attached selected groups).

If you are able to oxidize the compound contained in the liquid-phase stream of the original substance, is a normally solid joint is m (i.e. is a solid at standard temperature and pressure), preferably able to oxidize connection with the introduction into the reaction zone 28 is almost completely dissolved in the solvent. The boiling point is able to oxidize compounds at atmospheric pressure preferably should be at least about 50°C. More preferably, the boiling point is able to oxidize the compound is from about 80 to about 400°C. and, most preferably, is from 125 to 155°C. the Number able to oxidize compounds in the liquid phase of the original substance is preferably from about 2 to about 40 wt.%, more preferably ranges from about 4 to about 20% wt. and, most preferably, is from 6 to 15 wt.%.

It should also be noted that it is able to oxidize the compound contained in the liquid-phase stream of the original substances, can include a combination of two or more different are able to oxidize compounds. The two or more different chemical compounds can be mixed with each other in the form of liquid-phase stream of the original substance, or may be submitted separately in the form of multiple threads of the original substances. For example, is able to oxidize connected to the e, containing para-xylene, meta-xylene, para-Truelove aldehyde, para-Truelove acid and acetaldehyde, can be fed into the reactor through one entrance or through several separate inputs.

The solvent, which is present in the liquid-phase stream of the original substances, mainly contains an acid component and water component. The solvent is preferably present in the liquid-phase stream of the original substance in a concentration of from about 60 to about 98 wt.%, more preferably, from about 80 to about 96 wt.%. and, most preferably, from 85 to 94% by weight. The acid component of the solvent is primarily mainly low molecular weight organic monocarboxylic acid containing 1-6 carbon atoms, and more preferably, contains 2 carbon atoms. The most preferred component of the solvent is mainly acetic acid. The acid component preferably is at least about 75% wt. from the total quantity of solvent, more preferably is at least about 80% wt. from the total quantity of solvent, and most preferably ranges from 85 to 98 wt.%. from the total quantity of solvent, and the remaining amount is mainly water. The solvent which is introduced into BA is botany column reactor type 20, may include small amounts of impurities, such as, for example, para-tolualdehyde, terephthalaldehyde, 4-carboxybenzene (4-CBA), benzoic acid, para-tolarova acid, para-Truelove aldehyde, alpha-bromo-para-tolarova acid, isophthalic acid, phthalic acid, trimellitate acid, polyaromatic compounds and/or suspended particles. The total number of impurities in the solvent, which is introduced into bubble column reactor type 20, mostly, does not exceed about 3% wt.

Catalytic system, which is contained in the liquid-phase stream of the original substances, mainly, is a homogeneous liquid-phase catalytic system, which can accelerate the oxidation (including partial oxidation) is able to oxidize compounds. More preferably, the catalytic system contains at least one transition metal of variable valence. Even more preferably, the transition metal of variable valence is a cobalt. Even more preferably, the catalyst system comprises cobalt and bromine. Most preferably, the catalyst system comprises cobalt, bromine and manganese.

If cobalt is present in the catalytic system, the amount of cobalt contained in the liquid-phase stream of the original substances, p is edocfile, should be such that the cobalt concentration in the liquid phase of reaction medium 36 is maintained from about 300 to about 6000 weight parts per million (ppm wt.), more preferably, from about 700 to about 4200 ppm wt. and, most preferably, from 1200 to 3000 ppm wt. If bromine is present in the catalytic system, the amount of bromine contained in the liquid-phase stream of the original substances, preferably, should be such that the concentration of bromine in the liquid phase of reaction medium 36 is maintained from about 300 to about 5000 ppm wt., more preferably, from about 600 to about 4000 ppm by weight. and, most preferably, from 900 to 3000 ppm wt. If manganese is present in the catalytic system, the amount of manganese contained in the liquid-phase stream of the original substances, preferably, should be such that the manganese concentration in the liquid phase of reaction medium 36 is maintained from about 20 to about 1000 ppm wt., more preferably, from about 40 to about 500 ppm wt. and, most preferably, from 50 to 200 ppm wt.

Above concentrations of cobalt, bromine and/or manganese in the liquid phase of reaction medium 36 is expressed in the time-averaged and volume units. In this description, the term “userdn the config time” means the average value, at least 10 measurements, which in the same way be held for a continuous period of at least 100 sec. In this description, the term “average volume” means the average value of at least 10 measurements, which are performed in a homogeneous 3-dimensional spatial environment within a given volume.

The mass ratio of cobalt to bromine (Co:Br) in the catalytic system, which is introduced into the reaction zone 28, preferably, is between approximately 0.25:1 to about 4:1, more preferably, is from about 0.5:1 to about 3:1 and, most preferably, is from 0.75:1 to 2:1. The mass ratio of cobalt to manganese (Co:Mn) in the catalytic system, which is introduced into the reaction zone 28, preferably, is approximately 0.3:1 to about 40:1, more preferably, is from about 5:1 to about 30:1 and, most preferably, is from 10:1 to 25:1.

The flow of liquid starting substances, which is served in a bubble column reactor type 20, may include small amounts of impurities, such as, for example, toluene, ethylbenzene, para-tolualdehyde, terephthalaldehyde, 4-carboxybenzene (4-CBA), benzoic acid, para-tolarova acid, para-Truelove aldehyde, alpha-bromo-para-toluyl the Wai acid, isophthalic acid, phthalic acid, trimellitate acid, polyaromatic compounds and/or suspended particles. If obtaining terephthalic acid is used in bubble column reactor type 20, the impurities are also meta-xylene and ortho-xylene. The total number of impurities in the liquid-phase stream of the original substance, which is served in a bubble column reactor type 20, mostly, does not exceed about 3% wt.

Although figure 1 explains the variant of implementation of the present invention, which is able to oxidize compound, solvent and catalyst system are mixed together and served in a bubble column reactor type 20 in the form of a single thread, in an alternative embodiment, the present invention is able to oxidize compound, solvent and catalyst system can be introduced into bubble column reactor type 20 separately. For example, you can apply a stream of para-xylene in a bubble column reactor type 20 through the entrance, located separately from the entrance(s) for supply of solvent and catalyst.

Gas-phase oxidant stream, which is served in a bubble column reactor type 20 through the bubbler to enter oxidizer 34, predominantly contains molecular oxygen (O2). The flow of oxidant, pre is respectfully, contains from about 5 to about 40 mol%. molecular oxygen, more preferably, contains from about 15 to about 30 mol%. molecular oxygen, and most preferably contains from about 18 to about 24 mol%. molecular oxygen. Remaining in the oxidant stream mainly consists of gas or gases, such as nitrogen, which is inert in the reaction of oxidation. More preferably, the flow of the oxidizer consists essentially of molecular oxygen and nitrogen. Most preferably, the oxidant stream is a dry air, which contains approximately 21% mol. molecular oxygen and from about 78 to about 81 mol%. of nitrogen. In an alternative embodiment of the present invention, the oxidant stream may represent an almost pure oxygen.

Returning again to figure 1, it should be noted that the bubble column reactor of the type 20 is preferably provided with a dispenser phlegmy 42, which is located above the upper surface 44 of the reaction medium 36. The dispenser phlegmy 42 is designed to introduce drops predominately liquid-phase stream phlegmy in separation zone 30 using any known from the technical field of devices to generate droplets. More preferably, the distribution is elitel phlegmy 42 to form a stream of droplets of the sprayed liquid, fed down toward the upper surface 44 of the reaction medium 36. Specified downward flow of droplets of the sprayed liquid preferably has an impact (i.e. engages and covers), at least 50% of the maximum square horizontal cross-section of the separation zone 30. More preferably, the droplets of the spray effect, at least 75% of the maximum square horizontal cross-section of the separation zone 30. Most preferably, the droplets of the spray effect, at least 90% of the maximum square horizontal cross-section of the separation zone 30. Specified downward flow of the aerosol phlegmy can help prevent foaming on the surface or over the top surface 44 of the reaction medium 36, and may also assist in the separation of any liquid or droplets of suspensions that are fond of moving up the gas going to the hole for the gas outlet 40. In addition, phlegm can be used to reduce the number of particles and potentially precipitating compounds (in particular, dissolved benzoic acid, para-Truelove acid, 4-CBA, terephthalic acid and salts of the metal catalyst contained in the gases discharged from the separation zone 30 via the outlet port 40. Additionally, the introduction of drops of phlegmy in separation zone 30 by distilleries actions be used to control the composition of gases exhaust through the opening to the gas outlet 40.

Flow phlegmy served in the bubble column reactor type 20 through the dispenser phlegmy 42, mainly has the same composition, as the component of the solvent in the liquid-phase stream of the original substance, which is served in a bubble column reactor type 20 through the entrances to the filing of the original substance 32a, b, c, d. Thus, the flow phlegmy preferably contains an acid component and water. The acid component of the flow phlegmy mainly represents a low-molecular organic monocarboxylic acid containing 1-6 carbon atoms, and more preferably, contains 2 carbon atoms. The acid component of phlegmy, the most preferred is acetic acid. The acid component preferably is at least about 75% wt. of the total number of flow phlegmy, more preferably is at least about 80% wt. of the total number of flow phlegmy, and most preferably ranges from 85 to 98 wt.%. of the total number of flow phlegmy, and the rest is water. Because the flow phlegmy has almost the same composition as the solvent in the liquid-phase stream of the original substances, when in the present description refers to “the total amount of solvent”, is which is fed into the reactor, in the “total amount of solvent” should be included as a flow phlegmy, and the proportion of solvent in the flow of the starting materials.

In the process of liquid-phase oxidation bubble column reactor type 20, preferably, the threads of the original substances, the oxidizer flow phlegmy almost continuously introduced into the reaction zone 28, while the exhaust gases and suspensions were continuously removed from the reaction zone 28. In this description, the term “continuously” means interrupted less than 10 min period of time, the duration of which is at least 10 hours. In the oxidation process is able to oxidize the compound (in particular, para-xylene), preferably continuously introduced into the reaction zone 28 in the amount of at least about 8000 kg/h, more preferably from about 13000 kg/hour to about 80000 kg/h, more preferably from about 18000 kg/h to approximately 50,000 kg/hour and, most preferably, from 22,000 kg/h up to 30,000 kg/h. Despite the fact that the speed of the feed entering the reaction of threads of original substances, the oxidizer flow phlegmy, preferably, should be almost stable, in this case, it should be noted that in one of the embodiments of the present invention assumes the use the use the pulsating delivery of initial substances, oxidant and/or phlegmy to improve the processes of mixing and mass transfer. In the case where the filing of the original substances, oxidizing agent and/or flow phlegmy is in pulse mode, flow rate, preferably in the range from approximately 0 to approximately 500% of specified in this description of the flow rates at steady state operation, more preferably, from about 30 to about 200% of specified in this description of the flow rates at steady state operation and, most preferably, from 80 to 120% of the specified in this description of the flow rates at steady state.

The average spatio-temporal rate of the reaction (STR) in the bubble column reactor of the type 20 is defined as the mass of the source is able to oxidize compounds per unit volume of reaction medium 36 per unit time (in particular determined by the number of kilograms of the original para-xylene in a cubic meter per hour). In the normal approach, before carrying out the calculation of values of STR, you generally deduct the amount able to oxidize compounds, which have not turned into the product of the number able to oxidize compounds contained in the flow of the starting materials. However, the degree of conversion and outputs the product, as a rule, are high for many PR is pactically the present invention is able to oxidize compounds (in particular, para-xylene), and therefore in this description it is convenient to define the following term, as described above. Taking into account, among other capital expenditures and current work in process, it is generally preferable to conduct the reaction with large values of STR. However, carrying out the reaction using all large values of STR may affect the quality or yield of the product by the partial oxidation. Bubble column reactor type 20 is particularly suitable in the case when STR is able to oxidize compounds (in particular, para-xylene) is from about 25 kg/m3·h to about 400 kg/m3·hours, more preferably, from about 30 kg/m3·h to about 250 kg/m3·h, even more preferably from about 35 kg/m3·h to about 150 kg/m3·hours and, most preferably, from 40 kg/m3·h to 100 kg/m3·h.

STR for oxygen in the bubble column reactor of the type 20 is defined as the molecular mass of oxygen consumed per unit volume of reaction medium 36 per unit time (in particular, is determined by the number of kilograms of molecular oxygen, which is consumed per cubic meter per hour). Taking into account, among other things, capital expenditures and is caused by oxidation consumption of solvent, the reaction is predpochtitelno, should be done with large values of STR for oxygen. However, carrying out reactions using increasing values of STR for oxygen eventually reduces the quality or yield of the product by the partial oxidation. If not to be bound by any theory, it is possible to assume that this phenomenon is probably related to the transfer rate of molecular oxygen from the gas phase into the liquid phase at the boundary surface of the partition and from there to the volume of liquid. Too much STR value for oxygen, possibly leading to a too low content of dissolved oxygen in the liquid phase reaction medium.

Final average STR value for oxygen in this description is defined as the mass of the total amount of oxygen absorbed in the entire volume of reaction medium 36 per unit time (in particular, it is determined by the number of kilograms of molecular oxygen, which is consumed per cubic meter per hour). Bubble column reactor type 20 is particularly suitable in the case when the total average value of STR to oxygen is from about 25 kg/m3·h to about 400 kg/m3·hours, more preferably, from about 30 kg/m3·h to about 250 kg/m3·h, even more preferably from about 35 kg/m3 ·h to about 150 kg/m3·hours and, most preferably, from 40 kg/m3·h to 100 kg/m3·h.

In the process of oxidation bubble column reactor type 20 the ratio of the velocity of the mass flow to the total quantity of solvent (as in the original thread connections and flow phlegmy) to the mass flow rate is able to oxidize compounds entering the reaction zone 28, preferably, should be maintained from about 2:1 to about 50:1, more preferably from about 5:1 to about 40:1 and most preferably from 7.5:1 to 25:1. The ratio of the mass flow rate of the solvent, which comes as part of the flow of the original substance to the mass flow rate of the solvent, which comes as part of the flow phlegmy, supported from about 0.5:1 to the lack of any flow phlegmy, more preferably from about 0.5:1 to about 4:1, even more preferably from about 1:1 to about 2:1 and most preferably from 1.25:1 to 1.5:1.

In the process of liquid-phase oxidation bubble column reactor type 20, the flow of oxidant, preferably, should be in the bubble column reactor type 20 in number, which provides a number of molecular oxygen, several what about the excess amount of oxygen, is required by stoichiometry. An excessive amount of molecular oxygen required for obtaining the best results for a particular is able to oxidize compounds that affect the overall economy of the liquid-phase oxidation. In the process of liquid-phase oxidation bubble column reactor type 20 the ratio of the mass flow rate of the oxidizer mass flow rate is able to oxidize organic compounds (in particular, para-xylene)entering the reactor 20 preferably maintained from about 0.5:1 to about 20:1, more preferably from about 1:1 to about 10:1 and most preferably from 2:1 to 6:1.

If you refer back to figure 1, the threads of the original substances, oxidant and phlegmy, served in a bubble column reactor type 20 together form at least part of a multiphase reaction medium 36. The reaction medium 36, predominantly, is a three-phase environment, which includes the solid phase, liquid phase and gas phase. As indicated above, the oxidation is able to oxidize compounds (in particular, para-xylene) mainly occurs in the liquid phase of reaction medium 36. Thus, the liquid phase of reaction medium 36 includes dissolved oxygen and is able to oxidize the connection. Exothermic nature of R. the action of oxidation, which flows in a bubble column reactor type 20, causes the boiling/evaporation of part of the solvent (in particular, acetic acid and water), which is introduced through the feed holes of the original substance 32a, b, c, d. Thus, the gas phase reaction medium 36 in the reactor 20 is formed mostly evaporated solvent and undissolved, unreacted portion of the source of oxidant. In some known from the technical field of reactors for carrying out the oxidation using heat-exchange tubes/fins for heating or cooling the reaction medium. However, such a design of the heat exchanger may be desirable for the reactor of the present invention and described in this method. Thus, the bubble column reactor type 20 preferably has virtually no surfaces that come into contact with the reaction medium 36, and allocates time-averaged heat flux more than 30000 W/m2.

The concentration of dissolved oxygen in the liquid phase of reaction medium 36 is in dynamic equilibrium between the rate of mass transfer from the gas phase and the consumption rate of the exothermic reaction within the liquid phase (i.e. it is not determined simply partial pressure of molecular oxygen in the incoming gas phase, although partial dilleniales one of the factors affecting the rate of dissolved oxygen, and it really affects the upper boundary concentration of dissolved oxygen). The amount of dissolved oxygen has local variations, while it is higher near the interface of the bubbles. In General, the amount of dissolved oxygen depends on the balance of supply and factors affecting consumption, in different parts of reaction medium 36. Depending on time, the amount of dissolved oxygen depends on the homogeneity of mixing gas and liquid relative to the speed of consumption during chemical reactions. In order to achieve a consistent supply and consumption of dissolved oxygen in the liquid phase of reaction medium 36, averaged in time and volume concentration of oxygen in the liquid phase of reaction medium 36, preferably should be maintained at a level greater than approximately 1 ppm, molar, more preferably, from about 4 to about 1000 ppm mol., even more preferably, from about 8 to about 500 ppm mol., and most preferably, from 12 to 120 ppm mol.

The reaction liquid-phase oxidation, which is carried out in a bubble column reactor type 20, mostly, is a reaction which is accompanied by precipitation of the formed solid is exist. More preferably, the reaction liquid-phase oxidation, which is carried out in a bubble column reactor type 20, causes at least about 10% wt. able to oxidize compounds (in particular, para-xylene), which enters the reaction zone 28, forms a solid connection (in particular, the particles of crude terephthalic acid in the reaction medium 36. Even more preferably, the reaction liquid-phase oxidation leads to the fact that at least approximately 50 wt.%. able to oxidize compounds forms a solid compound in the reaction medium 36. Most preferably, the reaction liquid-phase oxidation leads to the fact that at least about 90% wt. able to oxidize compounds forms a solid compound in the reaction medium 36. The total amount of solids in the reaction medium 36, preferably, should be greater than about 3% wt. in terms of time-averaged and volume value. More preferably, the total amount of solids in the reaction medium 36 is supported from about 5 to about 40 wt.%, even more preferably, from about 10 to about 35% wt. and, most preferably, from 15 to 30% wt. A significant portion of the product of the oxidation reaction (in particular, terephthalic acid), forming the I in the bubble column reactor type 20, is mostly in reaction medium 36 in the form of solid substances in contrast to the other compounds, which remain dissolved in the liquid phase of reaction medium 36. The number of solid-phase reaction product of oxidation present in the reaction medium 36, preferably, is at least 25% wt. from the total mass of the reaction product of oxidation (solid and liquid)contained in the reaction medium 36, more preferably, is at least 75% wt. from the total mass of the reaction product of the oxidation contained in the reaction medium 36, and, most preferably, is at least 95% wt. from the total mass of the reaction product of the oxidation contained in the reaction medium 36. The above numerical bounds for the number of solids in the reaction medium 36 are considered practically stationary mode of operation of a bubble column reactor type 20 for almost a continuous period of time and does not relate to the stages of start, stop, or to non-optimal operation of the bubble column reactor of the type 20. The amount of solids in the reaction medium 36 is determined by the gravimetric method. In the analysis, gravimetric method separate part of the suspension stands out from the reaction medium and weighed. The conditions under which effectively about specials division of all solid and liquid phases within the reaction medium, free liquid is separated from the portion of solids by sedimentation or filtration thus, in order to avoid losses precipitated in the sludge solids in the portion of the solids is less than 10% of the initial mass of the liquid. Remaining in the solids of the liquid is evaporated to dryness so as to avoid sublimation of solids. The remaining portion of the solids weighed. The ratio of the mass of the portion of solids to the mass of the original portion of the suspension represents the largest fraction of solids, which is usually expressed in percent.

Accompanied by the precipitation of solids reaction, which flows in a bubble column reactor type 20, can cause a blockage (i.e. sediment) surface some hard structures in contact with the reaction medium 36. So, in one of the embodiments of the present invention bubble column reactor type 20, preferably, has almost no in the reaction zone 28 internal structural elements for performing heat exchange, mixing or reject stream, as these structural elements are susceptible to clogging. If in the reaction zone 28 are internal structural elements, it is desirable to avoid the application of interior design is a separate estimate, a significant proportion of the external surface which is facing up, flat surface, such as facing up to the flat surface more prone to clogging. Thus, if the reaction zone 28 includes one or more internal structures, preferably not more than approximately 20% of the total number facing up and exposed to the outer surface of such inner structures should be an almost flat surface, the deviation from the horizontal is less than approximately 15°.

If we return again to figure 1, the physical configuration of the bubble column reactor type 20 facilitates optimized oxidation process is able to oxidize compounds (in particular, para-xylene), which leads to the formation of minimal amounts of impurities. Elongated reactor section 24 inside the casing of the reactor 22 preferably includes almost cylindrical housing 46 and bottom 48. The upper boundary of the reaction zone 28 outlines the horizontal plane 50, which crosses the top of the cylindrical body 46. The lower boundary 52 of reaction zone 28 outlines the most low located to the inner surface of the bottom 48. As a rule, the lower boundary 52 of reaction zone 28 is located n is directly next to the opening for discharging the suspension 38. Thus, elongated reaction zone 28 defined within the bubble column reactor type 20 has a maximum length “L”measured from the top 50 to the bottom edge 52 of reaction zone 28 along the long axis of the cylindrical body 46. The length L of the reaction zone 28, preferably, is from about 10 to about 100 m, more preferably, is from about 20 to about 75 m, and most preferably is from 25 to 50 meters the reaction Zone 28 has a maximum diameter (width) D, which is usually equal to the maximum inner diameter of the cylindrical body 46. The maximum diameter D of the reaction zone 28, preferably, is from about 1 to about 12 m, more preferably, is from about 2 to about 10 m, more preferably, is from about 3.1 to about 9 m, and most preferably is from 4 to 8 PM In the preferred embodiment of the present invention, the reaction zone 28 has a ratio of length to diameter L:D is from about 6:1 to about 30:1. Even more preferably, the reaction zone 28 has a ratio of L:D is from about 8:1 to about 20:1. Most preferably, the reaction zone 28 has a ratio L:D from 9:1 to 15:1.

As described above, in the reaction zone 28 bubbling Colo is by reactor type 20 is formed multiphase reaction medium 36. The reaction medium 36 has a lower bound coincides with the lower boundary 52 of reaction zone 28, and an upper boundary that is located on the top surface 44. The upper surface 44 of the reaction medium 36 outlines the horizontal plane, which cuts off part of the upper level of the reaction zone 28, where the contents of the reaction zone 28 is transferred from the continuous gas-phase state in a continuous liquid-phase state. The top surface 44, preferably, is located on the altitude mark, where the time-average ability to retain gas in a thin horizontal slice of the contents of the reaction zone 28 is 0.9.

The reaction medium 36 has a maximum height H, measured between its upper and lower ends. The maximum width W of the reaction medium 36 is generally equal to the maximum diameter D of the cylindrical body 46. When carrying out liquid-phase oxidation bubble column reactor type 20 value N, preferably maintained at from about 60 to about 120% of the value L, more preferably at a level from about 80 to about 110% of the value of L and, most preferably, from 85 to 100% of the value of L. In the preferred embodiment of the present invention, the reaction medium 36 has a ratio of height to width (H:W excess will bring the flax 3:1. More preferably, the reaction medium 36 has a ratio H:W from about 7:1 to about 25:1. Even more preferably, the reaction medium 36 has a ratio H:W from about 8:1 to about 20:1. Most preferably, the reaction medium 36 has a ratio H:W from 9:1 to 15:1. In one of the embodiments of the present invention L=H and D=W, so that different sizes or relationship described in this description for L and D also apply to H and W, and Vice versa.

Relatively large values of the ratios of L:D and H:W, given in accordance with one embodiment of the present invention can provide a system of the present invention several important advantages. As discussed below, it was found that higher values of the ratios of L:D and H:W and some others discussed below are the features that contribute to the formation of favorable gradients in the concentration of molecular oxygen and/or is able to oxidize compounds (in particular, para-xylene) in height in reaction medium 36. Contrary to usual practice, according to which the preference should be given well-mixed reaction medium, concentration of reagents which are distributed more or less evenly, it was found that the vertical speed distribution of the concentrations CI is the oxygen and/or is able to oxidize compounds contributes to flow more efficient oxidation reactions. To minimize the concentrations of oxygen and is able to oxidize compounds near the top of reaction medium 36 can help to avoid losses unreacted oxygen and unreacted able to oxidize compounds through the top hole for the gas outlet 40. However, if the concentration is able to oxidize compounds and unreacted oxygen within the reaction medium 36 is low, then the rate and/or selectivity of the oxidation are reduced. Thus, the concentration of molecular oxygen and/or is able to oxidize compounds, preferably, should be higher close to the lower boundary of the reaction medium 36, than near the top of reaction medium 36.

In addition, large values of the ratios of L:D and H:W lead to the fact that in the lower portion of reaction medium 36 set much more pressure than the pressure in the upper portion of reaction medium 36. The specified pressure gradient height is the height and density of the reaction medium 36. One of the advantages of such a pressure gradient height is that the increased pressure at the bottom of the reactor provides the best solubility of oxygen and better mass transfer, in contrast to the solubility of oxygen and mass transfer, which would be established at values of temperature and pressure, comparable to values and in the upper part of smaller reactors. As a result, the oxidation reaction can be conducted at lower temperatures than the temperature that would be required in the smaller reactor. In the case when the bubble column reactor of the type 20 is used for the partial oxidation of para-xylene with the formation of crude terephthalic acid (CTA), the ability to carry out the process at lower temperatures the reaction with the same or better rates of mass transfer of oxygen provides several advantages. For example, low temperature oxidation of para-xylene reduces the amount of solvent that is burned in the reaction. As further discussed below, the low temperature oxidation also contributes to the formation of small, having a large surface area, loosely coupled with each other and easily dissolving particles of a HUNDRED, which can be subjected to purification using a more cost effective way, compared to large, with a small surface area and particle density HUNDRED, which are obtained in a conventional oxidation processes carried out at high temperature.

In the process of oxidation in the reactor 20 time-averaged and volume the temperature of the reaction medium 36, preferably, is maintained from about 125 to about 200°C., more preferably, from about 140 to CA is approximately 180°C and most preferably, from 150 to 170°C. the Top pressure in the reaction medium 36 is preferably maintained from about 1 to about 20 bar overpressure (bar), more preferably, from about 2 to about 12 bar and, most preferably, from 4 to 8 bar. The difference in pressure between the upper part of the reaction medium 36 and the lower part of the reaction medium 36, preferably, is from about 0.4 bar to about 5 bar, more preferably, the difference in pressure ranges from approximately 0.7 bar to about 3 bar and, most preferably, the difference in pressure ranges from 1 bar to 2 bar. Despite the fact that usually the pressure in the upper portion of reaction medium 36 is preferably maintained at a relatively constant level, one of the embodiments of the present invention involves the use of pulsed upper pressure with the aim of providing a more thorough mixing and/or better mass transfer in the reaction medium 36. In the case when the higher pressure is pulsed, then the magnitude of the pulsating pressure preferably ranges from about 60 to about 140% of the above pressure values under steady-state conditions, more preferably, is from about 85 to about 15% of the above pressure values under steady-state conditions and, most preferably, ranges from 95 to 105% of the above pressure values under steady-state conditions.

Another advantage of the great values of the relations L:D in the reaction zone 28 is that it can increase the average given speed in reaction medium 36. The term “speed” and “speed strip” in this description with reference to the reaction medium 36 means the volume flow rate of the gas phase in the reaction medium 36 at a certain point height in the reactor divided by the area of a horizontal section of the reactor at this altitude mark. The increased value of a given speed, which provides a large value of the ratio of L:D in the reaction zone 28 can promote local mixing and increasing the ability to retain gas in the reaction medium 36. Time-averaged reduced speed in reaction medium 36 at one quarter of the height, half height and/or three-quarters the height of reaction medium 36, preferably exceeds about 0.3 m/sec, more preferably, ranges from about 0.8 to about 5 m/sec, even more preferably in the range from approximately 0.9 to approximately 4 m/sec, and most preferably ranges from 1 to 3 m/sec.

Returning again to figure 1, it should mark the th the dividing section 26 of the bubble column reactor of the type 20 is just an extended part of the casing of the reactor 22, which is located immediately above the reactor section 24. The separating section 26 reduces the speed of the upward flow of the gas phase in a bubble column reactor type 20 as the gas phase rises above the upper surface 44 of the reaction medium 36 and close to the outlet for gas 40. The specified speed reduction is facing upward flow of the gas phase helps to remove liquids and/or solids that are captured by an ascending stream of gas phase and thereby reduces undesirable loss of specific components contained in the liquid phase of reaction medium 36.

The separating section 26 preferably includes a transition wall 54, usually having the shape of a truncated cone, wide side wall 56, typically having a cylindrical shape, and the cover 58. The narrow lower end of the transition wall 54 connected to the upper part of the cylindrical body 46 of the reactor section 24. The wider upper end of the transition wall 54 connected to the lower part of the side wall 56. Transition wall 54 extends upward and laterally from its narrow lower end at an angle, preferably comprising from approximately 10 to approximately 70° from the vertical, the more predpochtitelno, components from approximately 15 to approximately 50° from the vertical, and most preferably comprising from 15 to 45° from the vertical. Wide side wall 56 has a maximum diameter of X, which is usually larger than the maximum diameter D of the reactor section 24, however, in the case when the upper part of the reactor section 24 has a smaller diameter than the maximum diameter of the reactor section 24, then X may actually be less than D. In the preferred embodiment of the present invention the ratio of X:D the diameter of the wide side wall 56 to the maximum diameter of the reactor section 24 is from about 0.8:1 to about 4:1 and, most preferably, is from 1:1 to 2:1. The cover 58 is connected to the upper part of the side wall 56. Cover 58 preferably is an element, usually elliptical in shape, in the centre of which is a hole that allows gas to come out of the separation zone 30 through the opening to the gas outlet 40. Alternatively, the cover 58 may be of any shape, including conical. The separation zone 30 has a maximum height Y, which is measured from the top 50 of the reaction zone 28 to the upper part of the separation zone 30. The ratio of L:Y the length of the reaction zone 28 to the height of the separation zone 30 preferably ranges from approx the flax 2:1 to about 24:1, more preferably, ranges from about 3:1 to about 20:1 and, most preferably, is from 4:1 to 16:1.

Refer now to figure 1-5 and in detail discuss the location and configuration of the bubbler 34 to enter the oxidizer. Figure 2 and 3 shows that the bubbler 34 to enter the oxidizer may include an annular element 60, the transverse element 62 and a pair of pipes 64a, b for supplying oxidant. These pipes 64a, b for supplying oxidant, predominantly, can enter into the reactor above the elevation at which is located the annular element 60, and then is directed downward, as shown in figure 2 and 3. Alternatively, the pipe 64a, b for supplying oxidant can log into the reactor below the elevation at which is located the annular element 60, or to lie in the same horizontal plane as the annular element 60. Each of the pipes 64a, b for supplying oxidant includes a first end connected with the respective inlet 66a, b for supplying oxidant, which is made in the reactor vessel 22, and a second end that is fluidly connected to the annular element 60. The annular element 60, preferably formed of tubing, preferably, is formed of multiple sections of straight tubing and, most preferably, many sections of straight tubes, rigidly soedinennykh other to form a polygonal tubular ring. The annular element 60, preferably formed of at least three sections of straight tubing, more preferably, formed 6-10 sections of the tubes and, most preferably, is formed of 8 sections of the tubes. Thus, when the annular element 60 is formed of 8 sections of tubes, he in General has an octagonal configuration. The transverse element 62 mainly formed almost straight sections of pipe that are joined smoothly with the opposite sections of the tubes of the ring element 60 and continue in a diagonal direction between the sections of tubing annular element 60. Section tubes, which are used for control element 62 preferably have almost the same diameter as the section of the tubes, which are used for the manufacture of annular element 60. Section tubes, which form the pipes 64a, b for supplying oxidant, the annular element 60 and the transverse element 62 preferably have a nominal diameter of greater than about 0.1 m, more preferably have a nominal diameter of from about 0.2 to about 2 m, and most preferably, have a diameter of from 0.25 to 1 m As probably best shown in figure 3, and the annular element 60, and the transverse element 62 contain many available above open the th 68 for supplying oxidant order to direct the flow of oxidant upward into the reaction zone 28. As probably best shown in figure 4, the annular element 60 and/or the transverse element 62 may have one or more located at the bottom of the holes 70 for supplying oxidant order to direct the flow of oxidant down into the reaction zone 28. Located at the bottom of the hole 70 for supplying oxidant can also be used to load liquids and/or solids that may enter through the annular element 60 and/or the transverse element 62. To prevent the formation of solids within the bubbler 34 to enter the oxidizer, the fluid flow may be continuously or periodically be sent through the bubbler 34 to enter the oxidizer in order to wash away any accumulated solids.

If you refer back to figure 1 to 4, in the process of conducting oxidation bubble column reactor type 20 streams of oxidizer under pressure is directed through the inputs 66a, b of the oxidant into the input pipes 64a, b for oxidant, respectively. Then the oxidant streams are routed through the pipes 64a, b for supplying oxidant in the annular element 60. As soon as the oxidant stream enters annular element 60, the flow of oxidant is distributed over the internal volume of the ring element 60 and the cross member 62. Then, the oxidant stream is ejected from the bubbler 34 to enter the oxidizer enters the zone of reactions is 28 through upper and lower holes 68, 70 for supplying oxidant in the annular element 60 and the transverse element 62.

The outputs of the upper holes 68 for supplying oxidant spatially separated from each other in the horizontal direction and are located at almost the same height in the reaction zone 28. Thus, the outputs of the upper holes 68 for supplying oxidant in the General case found along almost horizontal plane, which is defined by the top part of the bubbler 34 to enter the oxidizer. The outputs of the lower holes 70 for supplying oxidant spatially separated from each other in the horizontal direction and are located at almost the same height in the reaction zone 28. Thus, the outputs of the lower holes 70 to enter the oxidant in the General case found along almost horizontal plane, which is defined by the lower part of the bubbler 34 to enter the oxidizer.

In one of the embodiments of the present invention bubbler 34 to enter the oxidant is at least approximately 20 formed therein upper holes 68 for supplying oxidant. More preferably, the bubbler 34 to enter the oxidizer is from about 40 to about 800 formed therein upper holes for supplying oxidant. Most preferably, the bubbler 34 to enter the oxidizer is from 60 to 400 is obrazovannyh it top holes 68 for supplying oxidant. Bubbler 34 to enter the oxidant preferably is at least about 1 formed therein, the bottom hole 70 to enter the oxidizer. More preferably, the bubbler 34 to enter the oxidizer is from about 2 to about 40 formed therein the lower holes 70 for supplying oxidant. Most preferably, the bubbler 34 to enter the oxidizer is from 8 to approximately 20 formed therein the lower holes 70 for supplying oxidant. The ratio of the number of upper holes 68 for supplying oxidant to the lower number of holes 70 for supplying oxidant in the bubbler 34 to enter oxidant, preferably, is from about 2:1 to about 100:1, more preferably, is from about 5:1 to about 25:1 and, most preferably, is from 8:1 to 15:1. The diameters of almost all upper and lower openings 68, 70 for supplying oxygen, preferably almost the same, so that the ratio of the volumetric flow rate of the oxidizer from the upper and lower openings 68, 70 are aligned with the above relations for the relative amounts of the upper and lower openings 68, 70 to the input of oxygen.

Figure 5 shows the flow of oxidant from the upper and lower openings 68, 70 for supplying oxidant. As for the top holes 68 the La feed oxidant, then, at least part of the upper holes 68 for supplying oxygen, preferably directs the flow of oxidant at an angle A, which is deflected from the vertical. The percentage of upper holes 68 for supplying oxygen, which are deflected from the vertical by an angle A, preferably, is from about 30 to about 90%, more preferably, is from about 35 to about 80%, even more preferably, is from about 60 to about 75% and, most preferably, is approximately 67%. The magnitude of the angle A, preferably, is from about 5 to about 60°, more preferably, ranges from approximately 10 to approximately 45° and, most preferably, is from 15 to 30°. As for the bottom holes 70 for supplying an oxidant, preferably, almost all the lower holes 70 for supplying oxidant to be located near the closest to the bottom part of the annular element 60 and/or cross member 62. Thus, any fluid and/or any solid substances that happen to fall into the bubbler 34 to enter oxidant, can be easily removed from the bubbler 34 to enter the oxidizer through the lower holes 70 for supplying oxidant. The lower holes 70 for supplying an oxidant, preferably, direct the flow of ocil the index down almost vertical angle. In this description of the upper hole to enter the oxidant can be any opening that directs the flow of oxidant mostly up (i.e. at an angle more horizontal), and the lower hole to enter the oxidant can be any opening that directs the flow of oxidant mainly down (i.e. at an angle below the horizontal).

In many conventional bubble columns reactor type, containing a multiphase environment, virtually all of the reaction medium, which is located below the bubbler to enter oxidant (or other device for flow of oxidant in the reaction zone), has a very low ability to retain gas. As is known from the field of technology, the ability to retain gas” is simply the volumetric fraction of a multiphase environment, which is in the gaseous state. Areas where the ability to retain gas in the environment is low, can also be described as “neurorubine” zone. In many conventional containing slurry bubble columns reactor type a significant part of the total volume of the reaction medium is located below the bubbler to enter oxidant (or other device for flow of oxidant in the reaction zone). Thus, a significant portion of the reaction medium, which is at the bottom of a conventional bubble columns reactor type, neuronova.

It was found that minimizing the number of nearisogenic areas subjected to oxidation reaction medium in a bubble column reactor type can minimize the formation of a particular type of undesirable impurities. Neurorubine zone of the reaction medium contain relatively little bubbles of oxidizing agent. Specified low volume of bubbles of oxidizing agent reduces the amount of molecular oxygen that is available for dissolution in the liquid phase reaction medium. Thus, the liquid phase in nearisogenic zone of the reaction medium has a relatively small concentration of molecular oxygen. These oxygen-depleted neurorubine zone of the reaction medium tend to accelerate unwanted side reactions, and not the desired oxidation reaction. For example, in the case when para-xylene is partially oxidized with the formation of terephthalic acid, the lack of availability of oxygen in the liquid phase reaction medium can lead to the formation of undesirable large amounts of benzoic acid and condensed aromatic cycles, including, in particular, is extremely undesirable colored molecules, known as fluorenone and anthraquinones.

In accordance with one embodiments of the present invention the liquid-phase oxidation is carried out in bubble number is nna reactor type, which is configured and operates in such a way that the volume fraction of the reaction medium with low held by the volumes of gas are minimized. The above minimization nearisogenic zones it is possible to quantify theoretically breaking the entire volume of the reaction medium 2,000 discrete horizontal layers of constant volume. Except for the very top and the very bottom of horizontal layers, each horizontal layer has a discrete volume, which is laterally limited by the reactor wall, and top and bottom limited imaginary horizontal planes. The top horizontal layer is limited below an imaginary horizontal plane, and the top is limited to the upper surface of the reaction medium. The bottom-most horizontal layer is limited from above an imaginary horizontal plane, and the bottom is limited to the lower end of the reactor. After the reaction medium is theoretically divided by 2,000 discrete horizontal layers of equal volume, you can define a time-averaged and volume ability to retain gas for each horizontal layer. When using this method to quantify the number nearisogenic zones number of horizontal layers in which the time-averaged and volume ability to retain gas is less than ,1, preferably, should be less than 30, more preferably, should be less than 15, even more preferably, should be less than 6, even more preferably, should be less than 4 and, most preferably, should be less than 2. The number of horizontal layers in which the ability to retain gas is less than 0.2, preferably, should be less than 80, more preferably, should be less than 40, even more preferably, should be less than 20, even more preferably, should be less than 12 and, most preferably, should be less than 5. The number of horizontal layers, in which the value retention of gas is less than 0.3, preferably, should be less than 120, more preferably, should be less than 80, more preferably, should be less than 40, even more preferably, should be less than 20 and, most preferably, should be less than 15.

Returning again to figure 2, it should be noted that the authors found that lower accommodation bubbler 34 to enter the oxidant in the reaction zone 28 provides several benefits, including reducing the number nearisogenic zones in reaction medium 36. At given values of H the height of reaction medium 36, the length L of the reaction zone 28, the maximum diameter D of the ons response 28 the most part (i.e. >50 wt.%) flow of an oxidant, preferably, should be introduced into the reaction zone 28 within approximately 0,N, 0,022L and/or 0,25D from the bottom 52 of reaction zone 28. More preferably, a large portion of the oxidant stream is introduced into reaction zone 28 within approximately 0,N, 0,018L and/or 0,2D from the bottom 52 of reaction zone 28. Most preferably, a large portion of the oxidant stream is introduced into reaction zone 28 within 0,N, 0,013L

and/or 0,15D from the bottom 52 of reaction zone 28.

In the design shown in figure 2, the distance along the height Y1between the bottom 52 of reaction zone 28 and the output of the upper holes 68 for supplying oxidant in the bubbler 34 to enter the oxidant is less than approximately 0,N, 0,022L and/or 0,25D, so that practically the entire flow of the oxidant enters the reaction zone within about 0,N, 0,022L and/or 0,25D from the bottom 52 of reaction zone 28. More preferably, Y1is less than approximately 0,N, 0,018L and/or 0,2D. Most preferably, Y1is less than 0,N, 0,013L and/or 0,15D, but greater than 0,N, 0,004L and/or 0 06D. Figure 2 shows the tangential line 72 in the place where the bottom edge of the cylindrical body 46 of the casing of the reactor 22 is connected with the upper end of the elliptical bottom 48 of the casing of the reactor 22. Alternatively, the plate 48 may be of any shape, t is the number of conical shape, and the tangential line, still, is defined by the lower edge of the cylindrical body 46. Distance height-Y2between the tangential line 72 and the top of the bubbler 34 to enter the oxidant preferably is at least about 0,N, 0,001L and/or 0,01D; more preferably, is at least approximately 0,N, 0,004L and/or 0,05D; and most preferably, is at least 0,01H, 0,008L and/or 0,1D. Distance height-Y3between the bottom 52 of reaction zone 28 and the output of the lower feed holes of the oxidant 70 bubbler 34 to enter the oxidant preferably is less than approximately 0,N, 0,013L and/or 0,15D; more preferably, is less than approximately 0,N, 0,01L and/or 0,1D; and, most preferably, is less than 0,01H, 0,008L and/or 0,075D, but greater than 0,N, 0,002L and/or 0,025D.

In a preferred embodiment of the present invention, the openings through which the oxidant stream and the flow of the original substance is directed into the reaction zone, configure so that the quantity (by weight) of the oxidant or the original substances supplied through the hole was directly proportional to the open area of the holes. For example, if 50% of the total open area defined by all the holes for the supply of oxidant is in the range of 0,15D on the lower level of the reaction zone, there is a 50% wt. the oxidant stream enters the reaction zone in the range of 0,15D from the lower level of the reaction zone, and Vice versa.

In addition to the benefits provided by the minimization nearisogenic areas (i.e. areas with low ability to retain gas in the reaction medium, it has been shown that the oxidation can be accelerated by maximizing the ability to hold gas throughout the reaction medium 36. Time-averaged and volume capacity of the reaction medium 36 to hold the gas preferably is at least, to 0.4, more preferably, is from about 0.6 to about 0.9, and most preferably, is from 0.65 to 0.85. The above-mentioned values the ability to keep the gas contributes to several physical and functional characteristics of bubble column reactor type 20. For example, for a given size of reactor and flow of oxidizer large ratio L:D in the reaction zone 28 leads to a smaller value of the diameter, which increases given speed in reaction medium 36, which, in turn, increases the ability to retain gas. In addition, it is known that the actual diameter of the bubble column reactor type and the ratio of L:D affect the average value of the ability to keep the gas even for a given constant given speed. In addition, minimizing NEAERA avannah zones, especially in the lower part of the reaction zone 28, increases the ability to retain gas. In addition, the pressure in the upper part and the configuration of the bubble column reactor type can influence the sustainability of its work when specified in this description large given speed and high capacity to hold gas.

Further, the authors of the present invention have found that to achieve a high capacity to hold gas and large values of mass transfer, it is important to carry out the process with the optimized value of the pressure in the upper part of the reactor. One would expect that the process with the lowest value of the upper pressure according to Henry's law reduces the solubility of molecular oxygen, should lead to a decrease in the rate of mass transfer of molecular oxygen from the gas phase into the liquid phase. In the reactor with mechanical agitation that is exactly what happens, since the levels of aeration and mass transfer rate are determined by the design of the mixing device and the value of the upper pressure. However, for the bubble column reactor of the type in accordance with a preferred embodiment of the present invention, the authors of the present invention have determined how you can use a smaller amount of verhnesadovoe, to make this mass of source gas-phase oxidant to occupy a larger volume and thus to increase the speed in reaction medium 36, which, in turn, will lead to increased ability to hold gas and to increase the rate of mass transfer of molecular oxygen.

The balance between merging and destruction of drops is an extremely complex phenomenon, which, on the one hand, can cause foaming, which reduces the internal rate of circulation in the liquid phase and may require a very large separation zones, and on the other hand, can lead to the formation of a small number of very large drops, which reduces the ability to retain gas and reduces the rate of mass transfer from the flow of oxidant in the liquid phase. As for the liquid phase, it is known that its composition, density, viscosity and surface tension, among other factors, are in a very complex relationship with each other and produce very complex results even in the absence of the solid phase. For example, laboratory studies show that in the preparation of messages and in the evaluation of observations even for simple containing water and an air bubble columns, you must specify whether “water” tap water, distilled water or deionized water. For Konigssee in the liquid phase and adding the solid phase the degree of complexity increases even more. Surface heterogeneity of individual solid particles, the average size of the solids, the distribution of particle sizes, the amount of solids relative to the liquid phase and the ability of the liquid to moisten the surface of solids, among others, are important for their interaction with the liquid phase and the flow of oxidizer and should be considered when establishing the final behavior bubbling and when establishing a picture of the distribution of convection currents.

Thus, the ability of the bubble column reactor type to function properly specified in this description provides high speed and high values the ability to keep the gas depends on a suitable choice of: (1) the composition of the liquid phase reaction medium; (2) the number and type of deposited solids, both of these parameter can be controlled by reaction conditions; (3) fed to the reactor number source of oxidant; (4) top pressure, which affects the volume flow of the oxidizer, the stability of the bubbles and by energy balance on the reaction temperature; (5) the reaction temperature, which affects the fluid properties, the properties of deposited solids and specific volume flow of the oxidizer; and (6) design and mechanical design of the reactor, in the including attitude L:D.

If we return again to figure 1, it should be noted that it has been shown that the best distribution is able to oxidize compounds (in particular, para-xylene) in reaction medium 36 can be provided by introducing a stream of liquid starting materials in the reaction zone 28 in multiple height positions. The flow of liquid starting substances, preferably, is introduced into the reaction zone 28 at least through the 3 holes for the filing of the original substances, more preferably, through the 4 holes for the filing of the original substances. In this description, the term “hole for the filing of the original substances” means openings through which liquid source materials are received in the reaction zone 28 to be mixed with the reaction medium 36. Preferably, at least 2 holes for input substances must be separated from each other in height by a distance equal to at least approximately 0,5D, more preferably equal to at least about 1,5D and most preferably equal to at least 3D. However, most upland hole for the filing of the original substances, preferably, should be separated in height from the lowest set of holes for supplying oxidant distance not exceeding approximately 0,75H, 0,65L and/or 8D; more preferably, not exceed ishushim approximately 0,5H, 0,4L and/or 5D; and, most preferably, not greater than 0,4H, 0,35L and/or 4D.

Although it is desirable to introduce a stream of liquid starting materials in multiple locations at different levels of height, it was also found that the best distribution is able to oxidize compounds in the reaction medium 36 is provided in the case, if most of the initial liquid-phase substances introduced into the lower half of the reaction medium 36 and/or the reaction zone 28. Preferably, at least about 75% wt. the initial liquid-phase substances served in the lower half of the reaction medium 36 and/or the reaction zone 28. Most preferably, at least 90% wt. the initial liquid-phase substances served in the lower half of the reaction medium 36 and/or the reaction zone 28. In addition, at least about 30 wt.%. the source of liquid substances should be introduced into the reaction zone 28 within about 1,5D from the lowest located at the height where in the reaction zone 28 is introduced a stream of oxidizer. The specified most low-placed, where the reaction zone 28 is introduced a stream of oxidant, usually located at the bottom of the bubbler to enter oxidant; however, in the preferred embodiment structure of the present invention examined various alternative configurations for the Chi source of oxidant in the reaction zone 28. At least about 50% wt. liquid starting substances, preferably, is introduced within approximately 2,5D from the lowest located at the height where the oxidant stream is introduced into reaction zone 28. At least about 75% wt. flow of liquid starting substances, preferably, is introduced within approximately 5D from being located at the lowest altitude where the oxidant stream is introduced into reaction zone 28.

Each of the holes for the filing of the original substances defines an exposed surface through which the filing of the original substances. At least about 30% of the total open area of all the holes for the filing of the original substances, preferably located within 1,5D from the lowest located at the height where the oxidant stream is introduced into reaction zone 28. At least about 50% of the total open area of all the holes for the filing of the original substances, preferably, is introduced within approximately 2,5D from the lowest located at the height where the oxidant stream is introduced into reaction zone 28. At least about 75% of the total open area of all the holes for the filing of the original substances, preferably, is introduced within approximately 5D from the lowest p is spokoinogo height space where the oxidant stream is introduced into reaction zone 28.

If you return to figure 1, in one of the embodiments of the present invention, the inlet 32a, b, c, d for the filing of the original substances are simply a series of vertically spaced holes along one side of the casing of the reactor 22. These feed holes of the original substances preferably have almost the same diameter, which is less than approximately 7 cm, more preferably ranges from about 0.25 to about 5 cm, and most preferably ranges from 0.4 to 2 cm Bubble column reactor type 20, preferably equipped with a system for controlling flow rate of liquid starting substances, which comes out of each hole. Such a system of control flow, preferably, includes an individual valves for controlling the flow 74a, b, c, d for each respective input 32a, b, c, d for the filing of the original substances. In addition, a bubble column reactor type 20, preferably equipped with a system of flow control, which allows you to submit at least part of the flow of liquid starting materials in the reaction zone 28 with increased the speed on the input component, at least about 2 meters per second, more predpochtite is) component, at least about 5 m/sec, even more preferably constituting at least about 6 m/sec, and most preferably comprising from 8 to 20 m/sec. In this description, the term “given velocity at the inlet” means the time-averaged volumetric flow rate of liquid starting substances, leaving holes for the filing of the original substance divided by the square holes for the filing of the original substances. At least about 50% wt. flow of the original substances, preferably, is fed into the reaction zone 28 with increased the speed at the entrance. Most preferably, the entire flow of the original substance is fed into the reaction zone 28 with increased the speed at the entrance.

Let us turn now to Fig.6-7, which presents an alternative system for flow of liquid starting materials in the reaction zone 28. In the specified embodiment of the present invention the flow of the original substance is fed into the reaction zone 28 at four different levels. Each level is fitted with the respective distribution system of the original substances 76a, b, c, d. Each of the distribution systems of the original substances 76 includes a base pipe 78 to the filing of the original substances and pipe 80. Each nozzle 80 has at least two outputs 82, 84, United correspond with what their input pipes 86, 88, which penetrate into the reaction zone 28 through the reactor vessel 22. Each of the input pipes 86, 88 contains the corresponding holes 87, 89 to the filing of the original substances, intended for input stream starting materials in the reaction zone 28. Holes 87, 89 to the filing of the original substances preferably have the same diameter, which is less than approximately 7 cm, more preferably, ranges from 0.25 to about 5 cm, and most preferably ranges from 0.4 to 2 cm Holes 87, 89 to the filing of the original substances of each of the distribution systems 76a, b, c, d starting compounds preferably are diametrically opposed so that you can enter the stream of starting materials in the reaction zone 28 in opposite directions. In addition, located diametrically opposite the inputs 86, 88 for the filing of the original substances neighboring distribution systems starting compounds 76, preferably oriented with a turn of 90° relative to each other. When carrying out the process flow of liquid starting substances is served in the main pipe 78 to the filing of the original substances and then into the pipe 80. The nozzle 80 controls the flow of the original substances evenly with simultaneous submission to the opposite sides of the reactor 20 through the openings 87, 89 to the filing of the original substances.

Phose alternative design, where each distribution system of the original substances 76 provided with a bayonet tubes 90, 92 and not the input pipes 86, 88 (see figure 7). Bayonet tubes 90, 92 juts into the reaction zone 28 and contain numerous small feeding holes 94, 96 for the filing of the original substances intended for input of liquid starting substances the reaction zone 28. Small holes 94, 96 for the filing of the original substances in the bayonet tubes 90, 92 preferably has the same diameter, which is less than approximately 50 mm, more preferably approximately 2 to approximately 25 mm and, most preferably, is from 4 to 15 mm

Fig.9-11 explain alternative distribution system 100 of the original substances. The distribution system 100 of the original substance enters the stream of liquid starting substances in lots divided by height divided by the horizontal positions without requiring multiple taps in the side wall of the bubble column reactor of the type 20. The distribution system 100 of the original substances usually includes a single inlet pipe 102, the collector 104, a lot of vertical distribution tubes 106, the horizontal support device 108 and a vertical reference device 110. The inlet pipe 102 penetrates through the side wall of the housing 46 of the casing of the reactor 22. The input line is the gadfly 102 fluidly connected to the manifold 104. The collector 104 distributes the flow of the original substances coming from the inlet pipe 102, the vertical distribution tubes 106. Each of the vertical distribution tube 106 has a lot divided by the height of the openings 112a, b, c, d for the filing of the original substances intended for input stream starting materials in the reaction zone 28. The horizontal support device 108 is connected to each of the distribution tubes 106 and prevents relative lateral movement of the distribution tubes 106. Vertical reference device 110 mainly attached to the horizontal support device 108 and to the top of the bubbler 34 to enter the oxidizer. Vertical reference device 110 substantially prevents relative vertical movement of the distribution tubes 106 in the reaction zone 28. Holes 112 for the filing of the original substances preferably have almost the same diameter, which is less than approximately 50 mm, more preferably, is from about 2 to about 25 mm and, most preferably, is from 4 to 15 mm, the Distance in height between the holes 112 for the filing of the original substances distribution system 100 of the original substance, which explain Fig.9-11, can be almost the same as and make the creation, described above when considering the distribution of the original substance, which is shown in figure 1.

It was found that the distribution of flows in the reaction medium many bubble columns reactor type may allow you to create uneven azimuthal distribution is able to oxidize compounds in the reaction medium, especially when able to oxidize the connection is mostly served with one side of the reaction medium. In the present description, the term “azimuth” refers to the angle or distance around turned up the axis along which extends the reaction zone. In the present description, the term “facing up” means having the deviation from the vertical in the range of 45°. In one of the embodiments of the present invention, the flow source containing substance is able to oxidize the compound (in particular, para-xylene is injected into the reaction zone through a lot of azimuthal separated holes for the filing of the original substances. These azimuthal separated holes for the filing of the original substances can help in eliminating areas in the reaction environment with excessively high and excessively low concentrations is able to oxidize compounds. Various systems for the filing of the original substances, is shown in Fig.6-11, are examples of systems that provide going is its azimuthal separation of the feed holes of the original substances.

If you go back to 7, with the purpose of quantitative evaluation of the azimuthal separate introduction of flow of liquid starting substances in the reaction medium, the reaction medium can theoretically be divided into four facing up azimuthal quadrant Q1, Q2, Q3, Q4”with approximately equal volumes. These azimuthal quadrants Q1, Q2, Q3, Q4“ are determined by a pair of imaginary intersecting perpendicular vertical planes “P1P2”that stretch for maximum vertical dimensions and the maximum size of the reaction medium. In the case when the reaction medium is contained in a cylindrical reactor, the line of intersection of the imaginary intersecting vertical planes P1P2approximately coincides with the vertical centerline of the cylinder, and each of the azimuthal quadrants Q1, Q2, Q3, Q4in the General case is a wedge-shaped vertical volume, the height of which is equal to the height of the reaction medium. A significant portion is able to oxidize compounds, preferably, should act in a reactionary environment through the feed holes of the parent compounds, which are located at least at two different azimuthal quadrants.

In predpochtitel the om embodiment of the present invention is not more than about 80% wt. able to oxidize compounds fed to the reaction medium through the feed holes of the original substances, which may be located in a single azimuthal quadrant. More preferably, not more than about 60 wt.%. able to oxidize compounds fed to the reaction medium through the feed holes of the original substances, which may be located in a single azimuthal quadrant. Most preferably, no more than about 40% wt. able to oxidize compounds fed to the reaction medium through the feed holes of the original substances, which may be located in a single azimuthal quadrant. The specified parameters of the azimuthal distribution is able to oxidize compounds determine when the azimuthal azimuthal quadrants are oriented so that the maximum number able to oxidize connection comes in one azimuthal quadrants. For example, if the entire flow of the original substance is supplied into the reaction medium through the two holes for the filing of the original substances that azimuthal separated from each other at 89°, when determining the azimuthal distribution in four azimuthal quadrants, 100% wt. flow of the original substance enters the reaction medium in one only the azimuthal quadrant, because of the azimuthal quadrants can be azimuthally oriented so that the two holes for the filing of the original substances are in the same azimuthal quadrant.

In addition to the benefits associated with the correct azimuthal separation of the holes for the filing of the original substances, it was also shown that important can be a suitable radial separation of the holes for the filing of the original substances in the bubble column reactor type. A significant portion is able to oxidize compounds, which is served in a reaction medium, preferably, should flow through the feed holes of the original substances, radially separated inside from the side wall of the reactor. So, in one of the embodiments of the present invention, a significant portion is able to oxidize compounds fed to the reaction zone through the feed holes of the original substances located in the “preferred radial feed area of the original substance”, which is separated from inside facing up side, limiting the reaction zone.

Returning again to Fig.7, it should be noted that the preferred radial feed area of the original substances FZ may take the form of theoretical facing up cylinder placed in the center of the reaction zone 28, the outer diameter of Do is 0,9D, where D means the diameter of the reaction zone 28. Thus, among the preferred radial feed area of the original substances FZ and the inner wall surrounding the reaction zone 28 is formed of the outer annular gap OA, the thickness of which is 0,05D. Preferably, only a small portion is able to oxidize compounds can be reached or does not fit into the reaction zone 28 through the feed holes of the original substances, which are located in the specified external annular gap OA.

In another embodiment, the present invention is only a small part is able to oxidize compounds can be reached or does not fit into the Central reaction zone 28. Thus, as shown in Fig, the preferred radial feed area of the original substances FZ may take the form of theoretical facing up ring with a Central reaction zone 28, the outer diameter of Dois 0,9D, and an inner diameter of DIis 0,2D. Thus, in this embodiment of the present invention from the center of the preferred radial feed area of the original substances FZ “cut” the inner cylinder IC, the diameter of which is 0,2D. Preferably, only a small portion is able to oxidize compounds can be reached or does not fit into the reaction zone 28 through a hole n the villas of the original substances, located in the specified inner cylinder IC.

In a preferred embodiment of the present invention, a significant portion is able to oxidize compounds fed to the reaction medium 36 through the feed holes of the original substances, which are located in the preferred radial feed area of the original substances, regardless of whether the preferred radial feed area of the original substances described above, a cylindrical or annular shape. More preferably, at least about 25% wt. able to oxidize compounds fed to the reaction medium 36 through the feed holes of the original substances, which are located in the preferred radial feed area of the original substances. Even more preferably, at least about 50% wt. able to oxidize compounds fed to the reaction medium 36 through the feed holes of the original substances, which are located in the preferred radial feed area of the original substances. Most preferably, at least 75% wt. able to oxidize compounds fed to the reaction medium 36 through the feed holes of the original substances, which are located in the preferred radial feed area of the original substances.

Despite the fact that theoretical azimuthal quadrants and t is eroticheska preferred radial feed area of the original substances, see figure 7 and 8 are described with reference to the flow of liquid starting substances, it has been shown that certain advantages are provided by the corresponding azimuthal and radial flow gas-phase oxidant. So, in one of the embodiments of the present invention the above description of the azimuthal and radial distribution of the flow of liquid starting substances can also be used to describe how the flow of gaseous oxidant is fed to the reaction medium 36.

Let us now turn to Fig-15, which is illustrated an alternative bubbler 200 to enter oxidant, which includes a ring element 202 and a pair of pipelines 204, 206 for supplying oxidant. Shown in Fig-15 bubbler 200 to enter oxidant similar to the bubbler 34 to enter the oxidizer, which is shown in Fig.1-11, however, has the following three main differences: (1) the bubbler 200 to enter the oxidizer does not contain diagonal transverse element; (2) the upper part of the annular element 202 has no holes for receiving the oxidant in the upward direction; and (3) the bubbler 200 to enter the oxidizer has a lot of extra holes in the lower part of the annular element 202.

As probably best shown in Fig and 15, the lower part of the ring 202 bubbler to enter ocil the body contains many holes 208 for supplying oxidant. Holes 208 for supplying oxidant is preferably configured so that at least about 1% of the total open surface defined by the holes 208 for supplying oxidant, is located below the centerline 210 (Fig) annular element 202, while the axial line 210 is at the level of the volumetric centroid of the ring element 202. More preferably, at least about 5% of the total open area defined by all holes 208 for supplying oxidant, is located below the axial line 210, in this case, at least approximately 2% of the total open surface define openings 208, through which the oxidant stream flows mainly in a downward direction at an angle components within approximately 30° from the vertical. Even more preferably, at least about 20% of the total open area defined by all holes 208 for supplying oxidant, is located below the axial line 210, in this case, at least approximately 10% of the total open surface define openings 208, through which the oxidant stream flows mainly in a downward direction at an angle components within approximately 30° from the vertical. Most preferably, at least about 75% of the total open area defined by all the holes is 208 to enter oxidant, is located below the axial line 210, in this case, at least approximately 40% of the total open surface define openings 208, through which the oxidant stream flows mainly in a downward direction at an angle components within approximately 30° from the vertical. The fraction of the total surface defined by all holes 208 to enter the oxidizer, which are located above the centerline 210 preferably is less than about 75%, more preferably less than about 50%, even more preferably less than about 25% and, most preferably, less than 5%.

As shown in Fig and 15, the openings 208 to enter the oxidant include facing down holes 208a and beveled openings 208b. Facing down the hole 208a is configured so that the flow of oxidant through them comes mainly in a downward direction at an angle components within approximately 30° from the vertical, more preferably, components within approximately 15° from the vertical and, most preferably, components within 5° from the vertical. Beveled openings 208b configured in such a way that the flow of oxidant through them flows mainly in the direction and in the downward direction at an angle A, the value of which is from about 15 to about 75° from the articale, more preferably the angle a is from about 30 to about 60° from the vertical and, most preferably, angle a is from 40 to 50° from the vertical.

Almost all holes 208 for supplying an oxidant, preferably have approximately the same diameter. The diameter of holes 208 for supplying oxidant, preferably, is from about 2 to about 300 mm, more preferably, ranges from approximately 4 to approximately 120 mm and, most preferably, is from 8 to 60 mm, the Total number of holes 208 for supplying oxidant in the annular element 202 is selected in such a way that meets the criteria for low pressure drop, which are described in detail below. The total number of holes 208 for supplying oxidant formed in the annular element 202 preferably is at least about 10, more preferably, the total number of holes 208 for supplying oxidant is from about 20 to about 200 and most preferably, the total number of holes 208 for supplying oxidant ranges from 40 to 100.

Despite the fact that Fig-15 shows a very specific form of the bubbler 200 to enter oxidant, it should be noted that to achieve a given in this description of benefits can be and is used many forms of bubblers to enter oxidant. For example, the bubbler to enter oxidant need not take the form of an octagonal ring element shown in Fig-13. Moreover, the bubbler to enter the oxidizer can be formed in any configuration of the pressure(s) of the pipeline(s), with(their) many spatially separated apertures, through which flows the stream of the oxidant. The size, number and orientation of holes for supplying oxidant in pressure pipeline, preferably, is in the above range. In addition, the shape of the bubbler to enter oxidant, preferably, is such as to ensure the above azimuthal and radial distribution of molecular oxygen.

Regardless of the specific form of the bubbler to enter oxidant bubbler to enter oxidant, preferably, has the same configuration and operates in such a way as to minimize the pressure drop associated with the flow of the oxidant stream through the openings of the pressure(s) of the pipeline(s). This pressure drop is calculated as time-averaged static pressure of the stream of oxidant within the discharge pipe at the exit of the holes 66a, b bubbler to enter oxidant minus the time-averaged static pressure in the reaction zone at the height where half of the flow of the oxidant wodis is above a given elevation, and half of the oxidant stream is introduced below the specified elevation. In a preferred embodiment of the present invention time-averaged pressure drop associated with the flow of the oxidant stream from the bubbler to enter the oxidant is less than approximately 0.3 megapascals (MPa), more preferably is less than about 0.2 MPa, more preferably is less than about 0.1 MPa, and most preferably, is less than 0.05 MPa. In the preferred conditions described in this description of the bubble column reactor type flow pressure of the oxidizer inside the pressure(s) of the pipeline(s) of the bubbler to enter oxidant, preferably, is from about 0.35 to about 1 MPa, more preferably, is from about 0.45 to about 0.85 MPa, and most preferably is from 0.5 to 0.7 MPa.

If you go back to the previously considered the form of a bubbler to enter oxidant, is shown in figure 2-5, preferably continuously or periodically rinse the bubbler to enter oxidizer high-pressure fluid (in particular, acetic acid, water and/or para-xylene) in order to prevent the clogging of the bubbler to enter oxidizer solids. If used is similar to the strong pressure of the fluid, the effective amount of liquid (i.e., not just a small number of drops of liquid, which naturally can be in the flow of the oxidant preferably is passed through a bubbler to enter oxidant and through holes for supplying oxidant for more than one minute daily. If the liquid is continuously or intermittently fed through the bubbler to enter oxidant, the time-averaged ratio of the mass flow of the fluid passing through the bubbler to enter oxidant mass flow of molecular oxygen passing through the bubbler to enter oxidant, preferably should be from about 0.05:1 to about 30:1, or from about 0.1:1 to about 2:1 or even of 0.2:1 to 1:1.

In one of the embodiments of the present invention, a significant portion is able to oxidize compounds (in particular, para-xylene) can be fed into the reaction zone through the bubbler to enter oxidant. When using this form of the bubbler to enter oxidant can oxidize compound and molecular oxygen, preferably come from the bubbler to enter oxidant through the same hole in the bubbler to enter oxidant. As stated previously, you are able to oxidize the connection is typically a liquid at set the Ohm value of STP. Thus, in this embodiment the design of the bubbler to enter the oxidant can flow two-phase flow, while the liquid phase contains is able to oxidize the connection, and the gas phase contains molecular oxygen. However, it should be understood that when the flow through the bubbler to enter oxidant, at least, the part is able to oxidize compounds can be in the gaseous state. In one of the embodiments of the present invention the liquid phase flowing through the bubbler to enter oxidant formed mainly able to oxidize connection. In another embodiment of the present invention the liquid phase flowing through the bubbler to enter oxidant, has almost the same composition as the stream source of the substances listed above. In the case where the liquid phase flowing through the bubbler to enter oxidant, has almost the same composition as the stream of initial substances, such liquid may contain a solvent and/or catalyst system in quantities and ratios that were described above for the composition of the flow of the starting materials.

In one of the embodiments of the present invention, preferably, at least about 10% wt. able to oxidize compounds introduced into the area R of the shares, passes through the bubbler to enter oxidant, more preferably at least about 40 wt.%. able to oxidize compounds is fed into the reaction zone through the bubbler to enter oxidant and, most preferably, at least 80% wt. able to oxidize compounds is fed into the reaction zone through the bubbler to enter oxidant. In that case, if all or part of the number able to oxidize compounds is fed into the reaction zone through the bubbler to enter oxidant, preferably at least about 10% wt. the total number of molecular oxygen supplied to the reaction zone passes through the same bubbler to enter oxidant, more preferably at least about 40 wt.%. able to oxidize compounds is fed into the reaction zone through the same bubbler to enter oxidant and, most preferably, at least 80% masspeople to oxidize compounds is fed into the reaction zone through the same bubbler to enter oxidant. In that case, if a significant portion is able to oxidize compounds is fed into the reaction zone through the bubbler to enter oxidant, the bubbler to enter oxidant, preferably, is provided with one or more temperature sensors (such as thermocouples). These temperature sensors can when enetica for to provide an environment in which the temperature in the bubbler to enter the oxidizer does not become dangerously high.

If we now turn to Fig-18, that are given to them in bubble column reactor type 20, which includes an internal reservoir for deaeration 300, which is located at the bottom of the reaction zone 28 near the outlet 38. It was found that side reactions leading to the formation of impurities occur with a relatively high speed in the process of deaeration of the reaction medium 36. In this description, “deaeration” indicates the selection of the gas phase of the multiphase reaction medium. In that case, if the reaction medium 36 highly aerated (the ability to retain gas is >0,3), the formation of impurities is minimal. When the reaction medium 36 substantially neuronova (the ability to retain gas is <0.01), and the formation of impurities is also minimal. However, if the reaction medium is partially aerated (the ability to retain gas is 0.01 to 0.3), then activated the adverse reactions, and produces an increased amount of impurities. The tank deaeration 300 solves this problem and other problems by minimizing the volume of reaction medium 36, which is partially aerated condition, as well as by mini is Itachi time to perform deaeration of reaction medium 36. Substantially deaerated slurry is formed in the bottom of the tank deaeration 300 and leaves the reactor 20 through the opening for discharge of the suspension 38. Substantially deaerated slurry preferably contains less than about 5 vol.% the gas phase, more preferably contains less than about 2 vol.% gas phase and, most preferably, contains less than 1% vol. the gas phase.

On Fig given bubble column reactor type 20, which includes a level controller 302 and the valve flow control 304. The level regulator 302 and the valve flow control 304 are coordinated in such a way as to maintain a nearly constant level of reaction medium 36 in the reaction zone 28. The level regulator 302 is able to determine (in particular, on the principle of determining the level of differential pressure or level detection using radioisotope labels), the level of the upper surface 44 of the reaction medium 36 and to generate the control signal 306, which corresponds to the level of reaction medium 36. Valve flow control 304 receives the control signal 306 and regulates the flow rate of the suspension through line 308 to unload the suspension. Thus, the speed of withdrawal suspe the Ziya through hole for discharging the slurry 38 can vary between the maximum volumetric flow rate (F maxwhen the level of the reaction medium 36 is too high, and the minimum volumetric flow rate (Fminwhen the level of the reaction medium 36 is too low.

Removal of solid-phase oxidation products from the reaction zone 28 part it must first pass through the tank deaeration 300. The tank deaeration 300 generates an internal volume with a low degree of turbulence, in which the gas phase reaction medium 36 can naturally stand out from the liquid and solid phases of the reaction medium 36 as liquid and solids move down towards the hole for discharging the suspension 38. The selection of the gas phase from the liquid and solid phases is called the natural emergence of the gas phase in the liquid and solid phases. When using tank deaeration 300 transition reaction medium 36 from fully aerated three-phase environment to fully deaerated two phase medium is carried out quickly and efficiently.

As for Fig and 18, it should be noted that the tank deaeration 300 includes generally drawn up the side wall 308, which determines the deaeration zone 312. The side wall 308 extends upward, and its deviation from the vertical, preferably, is in the range of about 30°, more preferably, is within approximately 10° from the vertical is Ali. Most preferably, the side wall 308 is almost vertical. The deaeration zone 312 is separated from the reaction zone 28 and has a height h and diameter d. The upper end 310 of the side wall 308 is open, so that the reaction medium can flow from the reaction zone 28 into the inner volume 312. The lower end of the side wall 308 is fluidly connected to the opening for discharging the suspension 38 through the transition section 314. In some cases, for example, when the size of the hole for discharging the suspension 38 is large, and the diameter d of the side wall 308 is small, the transition section 314 can be removed. As probably best shown in Fig, tank deaeration 300 may also include a flow conditioner 316, which is located in the deaeration zone 312. The stabilizer stream 316 may be of any design capable of preventing the formation of vortices as solid and liquid phases move down towards the hole for discharging the suspension 38.

In order to ensure proper separation of the gas phase from the solid and liquid phases in the vessel for deaeration 300 carefully selected height h and the area of the horizontal cross section of the internal deaeration zone 312. The height h and the area of the horizontal cross section of the internal deaeration zone 312 must provide sufficient distance and time, so that even in the case when the extracted maximum to the number of suspension (i.e. when the suspension is extracted with a speed of Fmaxalmost the entire volume of the gas bubbles could stand out from the solid and liquid phases before the gas bubbles reach the outlet at the bottom of the tank deaeration 300. Thus, the cross-sectional area of deaeration zone 312, preferably, should be such that the maximum speed of the down (Vdmaxthe liquid and solid phases through the deaeration zone 312 was much less than the natural rate of rise (Vu) bubbles of the gas phase through the liquid and solid phase. The maximum speed of the down (Vdmaxthe liquid and solid phases through the deaeration zone 312 is achieved when the maximum flow rate of the suspension (Fmax), which has already been discussed above. The natural rate of rise (Vu) bubbles of the gas phase through the liquid and solid phase varies depending on the size of the bubbles; however, the natural rate of rise (Vu0,5) gas bubbles with a diameter of 0.5 cm through the liquid and the solid phase can be used as values of the cutoff, because the initial diameter of almost all of the bubbles in the volume of reaction medium 36 exceeds 0.5, see the cross-sectional Area of deaeration zone 312, preferably, is such that the value of Vdmaxis less than approximately 75% of the values of Vu0,5more preferably, the value of Vdmaxis less than about 40% on the value of Vu0,5and, most preferably, the value of Vdmaxis less than 20% of the value of Vu0,5.

The speed of moving down the liquid and solid phases in the deaeration zone 312 tank deaeration 300 is calculated as the rate of volumetric flow of deaerated suspension through hole for discharging the suspension 38 divided by the minimum value of the sectional area of deaeration zone 312. The speed of moving down the liquid and solid phases in the deaeration zone 312 tank deaeration 300, preferably less than about 50 cm/sec, more preferably, is less than approximately 30 cm/sec, and most preferably less than 10 cm/sec.

It should be noted that despite the fact that facing up the side wall 308 of the tank deaeration 300, as mentioned, has a cylindrical shape, the side wall 308 may consist of multiple side walls, which form a variety of forms (in particular, can have a triangular, square and oval), provided that the walls limit the internal volume, which has a corresponding volume, the cross-sectional area, the width d and height h. In a preferred embodiment of the present invention, the value of d ranges from approximately 0.2 to when listello 2 m, more preferably ranges from about 0.3 to about 1.5 m, and most preferably, is from 0.4 to 1.2 m In the preferred embodiment of the present invention, the value of h ranges from about 0.3 to about 5 m, more preferably, is from about 0.5 to about 3 m, and most preferably, ranges from 0.75 to 2 m

In a preferred embodiment of the present invention, the side wall 308 is almost vertical, so that the area of a horizontal section of deaeration zone 312 is practically constant along the entire height h of deaeration zone 312. The maximum area of a horizontal section of deaeration zone 312 is less than approximately 25% of the maximum square horizontal cross-section of reaction zone 28. More preferably, the maximum area of a horizontal section of deaeration zone 312 is from approximately 0.1 to approximately 10% of the maximum square horizontal cross-section of reaction zone 28. Most preferably, the maximum area of a horizontal section of deaeration zone 312 is from 0.25 to 4% of the maximum square horizontal cross-section of reaction zone 28. The maximum area of a horizontal section of deaeration zone 312, preferably, is from about 0.02 to about 3 m 2more preferably, from about 0.05 to about 2 m2and most preferably is from 0.1 to 1.2 m2. The amount of deaeration zone 312, preferably less than about 5% of the total volume of reaction medium 36 or the reaction zone 28. More preferably, the amount of deaeration zone 312 is from about 0.01 to about 2% of the total volume of reaction medium 36 or the reaction zone 28. Most preferably, the amount of deaeration zone 312 is from 0.05 to about 1% of the total volume of reaction medium 36 or the reaction zone 28. The amount of deaeration zone 312, preferably, is less than approximately 2 m3more preferably, ranges from approximately 0.01 to approximately 1 m3and, most preferably, is from 0.05 to 0.5 m3.

As for Fig, it presents bubble column reactor type 20, which comprises an outer tank deaeration 400. In this construction aerated reaction medium 36 is withdrawn from the reaction zone 28 via is located at a certain height, the hole in the side wall of the casing of the reactor 22. With the aim of separating the gas phase from the solid and liquid phases paged aerated medium enters into the external tank for carrying out deaeration 400 through the discharge pipe 402. The Department is owned by the gas phase leaves the tank deaeration 400 pipeline 404, while almost deaerated slurry withdrawn from the tank deaeration 400 pipeline 406.

On Fig discharge pipe 402 is shown as approximately a straight horizontal line, which is orthogonal with respect to the reactor vessel 22. It's just one of convenient configurations; the discharge pipe 402 may be any other in all respects, provided that it is an acceptable way connects the bubble column reactor type 20 with the external tank deaeration 400. As for the pipeline 404, it is mainly attached to the top or near the top of the tank deaeration 400 so that it was possible to reliably solve the safety problems associated with the formation of stagnant pockets, capable of containing oxidized compound and an oxidant. In addition, for the convenience of the pipes 402 and 404 may include shut-off devices, such as valves.

In the case when the reaction medium 36 is removed from reactor 20 through the exit located at a certain altitude mark, as shown in Fig, the bubble column reactor type 20, preferably, provided with a bottom outlet 408 located at the lower level 52 of reaction zone 28. The lower outlet port 408 and the associated lower pipe 410 may be used to vigr the conditions (i.e. the for emptying) of the reactor 20 at the time of the stop process. One or more output apertures 408 are preferably in the lower part, corresponding to one third of the height of reaction medium 36, more preferably, are in the lower part corresponding to one quarter of the height of reaction medium 36, and, most preferably, are located at the lowest point of the reaction zone 28.

In the case of extraction of the suspension at a certain altitude mark and systems, deaeration, shown in Fig, the lower pipe 410 and the lower outlet port 408 is not used for discharging the suspension from the reaction zone in the oxidation process. From the field of technology it is known that solids tend to settle under the action of gravity from nearisogenic and for any other reasons not mix parts of the suspension, including pipelines with stagnant flow. In addition, the deposited solids (in particular, terephthalic acid) can harden with the formation of large conglomerates at the expense of leakage of a continuous deposition process and/or reorganization of the crystal structure. Thus, to prevent clogging the bottom line 410, a portion of the deaerated slurry from the bottom of the tank deaeration 400 can be used to rent the main or periodic washing the bottom line 410 during normal operation of the reactor 20. Preferably, such a washing pipe 410 head suspension is carried out by periodically opening valve 412 in the pipeline 410, so that the portion of the deaerated suspension could hit the pipe 410 into the reaction zone 28 through the lower outlet port 408. Even in the case when the valve 412 is fully or partially open, only part of the deaerated suspension flows through the lower pipe 410 and comes back into the reaction zone 28. The remaining portion of the deaerated suspension, which is not used for washing the bottom line 410, is shown through line 414 from the reactor 20 and is fed to the subsequent processing (in particular, cleaning).

During normal operation of the bubble column reactor type 20 for a considerable period of time (in particular, more than 100 hours) number of deaerated slurry, which is used to flush the bottom line 410, preferably, is less than 50% wt. of the total number of deaerated suspension obtained at the bottom of the tank deaeration 400, more preferably less than about 20% wt. and, most preferably, is less than 5% wt. In addition, for a considerable period of time, the average rate of mass transfer deaerated suspension, which uses the La wash the bottom line 410, preferably, less than 4 times the average rate of mass transfer is able to oxidize compounds in the reaction zone 28, more preferably less than 2 times the average rate of mass transfer is able to oxidize compounds in the reaction zone 28, still more preferably it is less than the average rate of mass transfer is able to oxidize compounds in the reaction zone 28 and, most preferably, it is less than 0.5 times the average rate of mass transfer is able to oxidize compounds in the reaction zone 28.

If you return to Fig, the tank deaeration 400 includes directed almost vertically, mainly cylindrical side wall 416 that defines the deaeration zone 418. The deaeration zone 418 has a diameter d and height h. The height h is measured by the distance in height between the level where aerated reaction medium enters the tank deaeration 400, and the lower part of the side wall 416. The height h diameter d, the area and volume of a deaeration zone 418, mostly the same as described above for the deaeration zone 312 tank deaeration 300, which is shown in Fig-18. In addition, the tank deaeration 400 includes an upper section 420 formed by the continuation of the side wall 416 outside the deaeration zone 418. The top section 420 of the tank deaeration 400 can they the be any height, however, preferably, it extends up to the level or above the level of reaction medium 36 in the reaction zone 28. The top section 420 provides the gas phase sufficient space so that she could be separated from the liquid and solid phases before the gas phase leaves the tank deaeration 400 through line 404. It should be noted that although it is shown that the pipeline 404 returns the separated gas phase in the separation zone of the reactor 20, in the alternative, the pipeline 404 may be connected to the reactor vessel 20 at any point height above the level at which is output pipeline 402. Pipe 404 may not necessarily be connected with tubing to the gas outlet 40 so that the separated gas phase of the tank deaeration 400 is combined with the output from the upper part of the vapor stream in the pipe 40 and is sent for further processing.

If we now turn to Fig, here is a bubble column reactor type 20, which includes a hybrid external internal tank deaeration 500. In this configuration, the portion of reaction medium 36 is withdrawn from the reaction zone 28 via is located at a sufficiently high altitude hole 502 in the side wall of the casing of the reactor 22. Extracted the reaction medium 36 then flows into the crank socket 504 from siteline larger diameter and into the upper part of the tank deaeration 500. On Fig shown that cranked tube 504 is connected orthogonal to the side wall of the casing of the reactor 22 and represents a steady turn at an angle of approximately 90°. This is just one of the convenient configurations, and cranked tube 504 may be any other in all respects, provided that it is an acceptable way connects the bubble column reactor type 20 with the external tank deaeration 500. In addition, for the convenience of a bent pipe 504 may include shut-off devices, such as valves.

Reservoir deaeration 500 gas phase moves upward, while the solid and liquid phases move down. Moving up the gas phase can again get into a cranked tube 504 and return through the opening 502 in the reaction zone 28. Thus, in the hole 502 may be countercurrent flowing reaction medium 36 and output the separated gas. Deaerated suspension leaves the tank deaeration 500 through line 506. The tank deaeration 500 includes directed almost vertically, mainly cylindrical side wall 508, which limits the deaeration zone 510. The deaeration zone 510 has a height h and diameter d. Located at a certain altitude mark the hole 502 and cranked pipe 504 preferably have the same diameter as the diameter d of the zone is eaerly 510. The height h diameter d, the area and volume of a deaeration zone 510, mostly the same as described above for the deaeration zone 312 tank deaeration 300, which is shown in Fig-18.

Fig and 20 explain the design bubble column reactor type 20, where the solid product (in particular, the crude terephthalic acid from the reaction zone 28, the output from the reaction zone 28 via is located at a certain altitude mark the hole. Discharging aerated reaction medium 36 through situated at a certain height level, which is above the bottom of the bubble column reactor type 20, can help to avoid the accumulation and stagnation poorly aerated reaction medium 36 in the lower part 52 of reaction zone 28. In accordance with other aspects of the present invention, the oxygen concentration and is able to oxidize compounds (in particular, para-xylene) in reaction medium 36 near the top of reaction medium 36, predominantly lower than near the bottom. Thus, the discharge reaction medium 36 through which at a certain height level can increase output by reducing the amount of unreacted reagents are removed from the reactor 20. In addition, the temperature of the reaction medium 36 varies significantly in the vertical direction in the case, to the GDS bubble column reactor type 20 works with large values of STR and gradients of chemical composition, as indicated in the present description. In these conditions, the temperature of reaction medium 36 typically has a local minimum near the top and bottom of the reaction zone 28. At the bottom of the zone education minimum is caused by evaporation of the solvent near the place where comes all the amount of oxidant or a portion of the oxidant. At the top of the zone education minimum connected again with the evaporation of the solvent, but in this case it is caused by reducing the pressure inside the reaction medium. In addition, can produce additional local minima between the top and bottom in the same place in the reaction zone receives an additional amount of the original substance and the oxidizer. Between the top and bottom of the reaction zone 28 also has one or more temperature peaks caused by the heat released during the course of the exothermic oxidation reaction. Discharging the reaction medium 36 through which at a certain height level with a higher temperature can provide special advantages in the case when a subsequent stage of processing flow at a higher temperature, because it reduces the loss of energy associated with heating paged reaction medium, which is sent for trials later processing.

Thus, in the preferred embodiment, this image is etenia and especially in the case when subsequent processes occur at higher temperatures, the reaction medium 36 is unloaded from the bubble column reactor type 20 through the set(s) at a certain height output(s) hole(s)that(s) is(are) higher level(s), where in the reaction zone 28 includes at least 50 wt.%. flow of liquid starting substances and/or flow of gas-phase oxidant. More preferably, the reaction medium 36 is removed from bubble column reactor type 20 through the set(s) at a certain height output(s) hole(s)that(s) is(are) higher level(s), where in the reaction zone 28 includes almost all the amount of flow of liquid starting substances and/or flow of gas-phase oxidant. Preferably, at least 50% wt. components of the solid phase and the liquid phase extracted from the bubble column reactor type 20, deduced from the bubble column reactor type 20 through the set(s) at a certain height output(s) hole(s). More preferably, almost all components of the solid phase and the liquid phase extracted from the bubble column reactor type 20, are derived from the bubble column reactor type 20 through the set(s) at a certain height output(s) hole(s). Preferably, the set(s) defined on the th height of the output(s) hole(s) is(are), at least approximately 1D above the lower end 52 of reaction zone 28. More preferably, the set(s) at a certain height output(s) hole(s) is(are)at least approximately 2D above the lower end 52 of reaction zone 28. Most preferably, the set(s) at a certain height output(s) hole(s) is(are)at least on the 3D distance above the lower end 52 of reaction zone 28. At a given height H of reaction medium 36 set(s) at a certain height output(s) hole(s) is(are)preferably, a height of from about 0.2 n to about 0,8H, more preferably, a height of from approximately 0,3N to about 0,7N and, most preferably, a height of 0,4N and 0,6N. In addition, the temperature of the reaction medium 36 at a level located at a certain height of the outlet from the reaction zone 28, preferably at least 1°C higher than the temperature of the reaction medium 36 at the lower level 52 of reaction zone 28. More preferably, the temperature of the reaction medium 36 at the level of the outlet from the reaction zone 28, which is located at a certain height from approximately 1.5 to approximately 16°C higher than the temperature of the reaction medium 36 at the lower level 52 of reaction zone 28. Most PR is doctitle, the temperature of the reaction medium 36 at the level of the outlet from the reaction zone 28, which is located at a certain height in the range from 2 to 12°C higher than the temperature of the reaction medium 36 at the lower level 52 of reaction zone 28.

As for Fig, here presents bubble column reactor type 20, which includes alternative hybrid tank deaeration 600, located at the bottom of the reactor 20. In this configuration, aerated reaction medium 36 is unloaded from the reaction zone 28 through a relatively large hole 602 in the bottom 52 of the casing of the reactor 22. Hole 602 denotes an open upper end of the tank deaeration 600. Reservoir deaeration 600 gas phase moves upward, while the solid and liquid phases move down. Rising gas phase can re-enter into the reaction zone 28 through the opening 602. Thus, in the opening 602 may be countercurrent flowing reaction medium 36 and output the separated gas. Deaerated suspension leaves the tank deaeration 600 through line 604. The tank deaeration 600 includes directed almost vertically, mainly cylindrical side wall 606, which indicates the deaeration zone 608. The deaeration zone 608 has a height h and diameter d. Hole 602 preferably has a diameter that matches the diameter or larger than the diameter d of the deaeration zone 608. The height h diameter d, the area and volume of a deaeration zone 608, mostly the same as described above for the deaeration zone 312 tank deaeration 300, which is shown in Fig-18.

As for Fig, here it is shown that the bubble column reactor type 20 presented on Fig includes alternative bubbler 602 to enter oxidant. Bubbler 602 for entering the oxidizer includes an annular element 622 and a pair of intake pipelines 624, 626. The annular element 622 has almost the same shape that the annular element 202 discussed above with reference to Fig-15. Input pipelines 624,626 directed up through the holes in the bottom 48 of the casing of the reactor 22 and serves the flow of oxidant in the annular element 622.

As for Fig, here it is shown that the bubble column reactor type 20 presented on Fig includes not containing bubbler device for flow of oxidant in the reaction zone 28. In configuration Fig the flow of oxidant fed into the reactor 20 through the pipes 630, 632 to enter oxidant. Pipelines 630, 632 to enter oxidizer connected with the corresponding holes 634, 636 to enter oxidant in the bottom 48 of the casing of the reactor 22. The flow of oxidant is directly credited into the reaction zone 28 through the holes 634, 636 to enter oxidant. Can be set as optional is trogatelnye plate 638, 640 order to deflect the flow of oxidant, when he first enters the reaction zone 28.

As indicated previously, the reactor for oxidation, preferably, should have the same configuration and function so that in him in the reaction medium did not form a high concentration can oxidize compounds, because such zones may lead to the formation of impurities. One way to improve the initial dispersion is able to oxidize compounds (in particular, para-xylene) in the reaction medium is diluted able to oxidize compounds liquid. The liquid used to dilute able to oxidize compounds may be emitted from a portion of the reaction medium, which is located at a considerable distance below the height where able to oxidize the compound is introduced into the reaction zone. Specified fluid from a remote part of the reaction medium can circulate to the level of height, which is close to the mark the height where able to oxidize the compound is transferred through the pipeline, which is located inside and/or outside of the main reactor.

On Fig and 25 illustrate two preferred method for receiving fluid from a remote part of the reaction medium to elevation near the entrance to the filing of the JV is capable to oxidize compounds using the internal (Fig) and external (Fig) pipeline. The length of the discharge pipe from its input (i.e. holes(th), where the liquid enters the pipe) to its output (i.e. holes(th), where the liquid comes out of the pipeline) is greater than approximately 1 m, more preferably greater than approximately 3 m, even more preferably greater than approximately 6 m, and most preferably, greater than, 9 m However, the actual length of the reactor becomes insignificant in the case when the fluid is supplied from a separate reservoir, which may be located directly above the reactor or near the reactor, in which the original falls are able to oxidize the connection. Fluid from a single reservoir that contains at least some amount of the reaction medium, is the preferred source for initial dilution is able to oxidize the connection.

Regardless of its source, the fluid flow through the pipeline, preferably, has a lower constant concentration is able to oxidize compounds than the reaction medium, which is directly adjacent at least one of the outputs of the pipeline. In addition, the liquid flowing through the pipeline, preferably, is in the liquid phase concentration is able to oxidize compounds, which is less than h is m approximately 100,000 ppm wt., more preferably is less than about 10000 ppm wt., even more preferably, is less than approximately 1000 ppm wt. and, most preferably, is less than 100 ppm wt., when this concentration is measured before adding to the pipeline increment source is able to oxidize compound and any optional separate source of solvent. When the measurement is carried out after adding the increment source is able to oxidize compounds and an optional source of solvent, the combined stream of liquid entering the reaction medium, preferably, is in the liquid phase concentration is able to oxidize compounds, which is less than approximately 300,000 ppm wt., more preferably, is less than approximately 50,000 ppm wt. and, most preferably, is less than 10,000 ppm wt.

It is desirable to maintain a fairly low flow rate through the pipeline so that the circulating fluid is really limited to a desired maximum gradient is able to oxidize compounds in the reaction medium. In this regard, the ratio of the weight of the liquid phase in the reaction zone, where initially increment is able to oxidize the connection to the mass transfer rate of fluid that pass the t through the pipeline, preferably should be greater than approximately 0.3 min, more preferably should be greater than approximately 1 min, even more preferably should be from about 2 min to about 120 min, and most preferably should be from 3 minutes to 60 minutes

There are many ways to force the liquid through the pipeline. Preferred means are gravity, the ejectors of all types, in which a liquid medium is used, the gas or liquid or a combination thereof, as well as mechanical pumps of all types. In that case, when using the ejector, in one of the embodiments of the present invention as a liquid carrier is used, at least one liquid selected from the group which includes able to oxidize the original connection (liquid or gas), the initial oxidizing agent (gas), the original solvent (liquid) and supplied by a pump reaction medium (suspension). In another embodiment of the present invention as a liquid carrier is used, at least two fluid selected from the group that includes able to oxidize the original connection, the source of the oxidizing agent and the original solvent. In yet another embodiment of the present invention as Idaho media uses a combination of the source is able to oxidize compounds the source of oxidant and a source of solvent.

Suitable diameter or diameters of the pipeline, through which the circulation can vary depending on the number and properties of the supplied substances, energy, which can cause movement of the fluid flow, and capital outlays. The minimum diameter of such tubing, preferably, is greater than approximately 0.02 m, more preferably, is from about 0.06 to m to about 2 m, and most preferably ranges from 0.12 m to 0.8 m

As indicated previously, it is desirable to control the flow through the pipeline in certain specified limits. From the field of technology there are many resources to implement such control by choosing an appropriate set configuration during the design pressure of the pipeline. Another preferred design is the use of structural elements, which may vary during the process, namely include valves of all types and with any characteristics, including valves, managed not only manually, but also driven by an actuator, using a variety of devices, including loop-back flow control using sensors or without the aid of sensors. Other preferred means to which toleromune flow of liquid diluent is a variation of the energy input between the inlet and outlet of the pipeline. Preferred means include changing the feed speed of one or more liquid carriers allocated to the ejector, the change in energy supplied to the pump drive, the change in the difference in density or change of the difference in levels, if you use the force of gravity. Can also be applied to any combination of these preferred resources.

The pipeline, which is used to implement the circulation of fluid from the reaction medium, can be a pipeline from any known technology type. In one of the embodiments of the present invention, the pipeline design in whole or in part, using conventional materials for piping. In another embodiment of the present invention, the pipeline design in whole or in part, using the wall of the reactor as one of the parts of the pipeline. The pipeline can be constructed in such a way that it is entirely located within the boundaries of the reactor (Fig), or the pipeline can be constructed in such a way that it is entirely located outside of the reactor (Fig), or the pipeline may contain sections that are located both inside and outside of the reactor.

The authors of the present invention believe that especially in large reactors, it is desirable to have multiple speaker is the delivery and use various schemes of the fluid through the pipeline. In addition, it may be desirable to make the number of output holes in different places of one of the pipelines or all pipelines. Design features, in accordance with other aspects of the present invention, will provide the balance of the required General gradient between the stationary concentrations are able to oxidize compounds with the desired initial dilution is able to oxidize the original connection.

Both Fig and 25 explain the designs that use the reservoir for deaeration, coupled with the pipeline. The specified tank deaeration ensures that part of the reaction medium, which is used to dilute the incoming able to oxidize compounds will represents almost deaerated suspension. It should however be noted that the liquid or slurry, which is used to dilute the incoming able to oxidize compounds may be in aerated form and deaerated form.

Using passing through the pipeline fluid to effect the dilution source is able to oxidize compounds most useful in bubble columns reactor type. Moreover, in bubble columns reactor type benefits associated with the initial dilution of the original ways the tion to oxidize compounds can be achieved without adding the source is able to oxidize compounds directly into the pipeline, provided that the outlet pipe is located close enough to the place where the supply is able to oxidize compounds. In this embodiment of the present invention the outlet of the pipeline, preferably located at a distance which is within about 27 diameters of the outlet pipeline from the nearest place, which served are able to oxidize compounds, more preferably, is located at a distance within approximately 9 diameters of the outlet pipe, more preferably, is located at a distance within approximately 3 diameter of the outlet pipe and, most preferably, is located at a distance within 1 diameter of the outlet pipe.

It was also found that for the initial dilution of the source is able to oxidize compounds in bubble columns reactor type, in accordance with one embodiments of the present invention can be used ejectors flow, even without the use of pipelines, designed to get used for diluting liquid is C remote part of the reaction medium. In such cases, the ejector is located inside the reaction medium and has an open channel directed from the reaction medium in the neck of the ejection device, where the low pressure draws the neighboring reaction medium. Examples of two possible forms of ejectors shown in Fig and 27. In a preferred embodiment, the design of said ejectors nearest place of supply is able to oxidize compounds is at a distance within approximately 4 m, more preferably, is at a distance within approximately 1 m, and most preferably, is at a distance of 0.3 m from the mouth of the ejector. In another embodiment, the present invention is able to oxidize the connection is supplied under pressure as a liquid medium. In yet another embodiment of the present invention, or the solvent, or the oxidizer is fed under pressure as an additional liquid carrier, together with is able to oxidize connection. Finally, in yet another embodiment of the present invention and a solvent and an oxidant at the same time served under pressure as an additional liquid carrier, together with is able to oxidize the connection.

The authors of the present invention believe that especially in large reactors may be desirable COI is whether the set of ejectors of different shapes, set in different locations within the reaction medium. Design features, in accordance with other aspects of the present invention, will provide the balance of the required General gradient between the stationary concentrations are able to oxidize compounds with the desired initial dilution is able to oxidize the parent compound. In addition, the authors of the present invention believe that the jet at the outlet of the ejector can be oriented in any direction. If you use a lot of ejectors, each of them can be focused individually and in any direction.

As indicated above, certain physical and operational characteristics of bubble column reactor type 20, which was described above with reference to figure 1-27 ensure the formation of vertical gradients of pressure, temperature and concentrations of reactants (i.e. oxygen and is able to oxidize compounds) in reaction medium 36. As discussed above, these vertical gradients contribute to the flow, more efficient oxidation process, compared to conventional oxidation processes, in which is formed a well-mixed reaction medium with a relatively uniform pressure, temperature and concentrations of reagents in the entire volume of reactio the Noah environment. Education gradients for oxygen that can oxidize compounds (in particular, para-xylene) and temperature height allows the use of an oxidizing system, in accordance with the embodiment of the present invention, which will be hereinafter described in more detail.

If we turn now to Fig, to quantify the concentration gradients of reagents that exist in the reaction medium 36 at carrying out oxidation bubble column reactor type 20, the entire volume of reaction medium 36 can theoretically be divided into 30 discrete horizontal layers of equal volume. Fig explains the concept of a fission reaction medium 36 30 discrete horizontal layers of equal volume. With the exception of the upper and the lower horizontal layers, each horizontal layer is a discrete volume, which is limited above and below the imaginary horizontal plane and laterally limited by the wall of the reactor 20. The top horizontal layer is limited below an imaginary horizontal plane, and the top is limited to the upper surface of the reaction medium 36. The bottom-most horizontal layer is limited from above an imaginary horizontal plane, and the bottom is limited by the bottom casing of the vessel. After the reaction medium 36 theoretically, once the ITA 30 discrete horizontal layers of equal volume, you can define a time-averaged and volume concentration in each horizontal layer. Individual horizontal layer having the maximum concentration of all 30 horizontal layers, can be described as “C-max horizontal layer. Individual horizontal layer located above the C-max horizontal layer and having the lowest concentration of all the horizontal layers located above the C-max horizontal layer, can be described as “C-min horizontal layer. Now the concentration gradient along the height can be calculated as the ratio of the concentration of C-max horizontal layer to the concentration of C-min horizontal layer.

As regards the quantitative evaluation of the concentration gradient of oxygen, after the reaction medium 36 is theoretically divided into 30 discrete horizontal layers of equal volume, O2-max horizontal layer identifies as the layer having the maximum oxygen concentration of all 30 horizontal layers, and About2-min horizontal layer identify as a layer having a minimum oxygen concentration of horizontal layers above About2-max horizontal layer. The oxygen concentration in horizontal layers measured in the gas phase of reaction medium 36 and is expressed as the time-averaged and volume molar values of the relative liquid phase. The ratio of the oxygen concentration Of2-max horizontal layer to the oxygen concentration Of2-min horizontal layer, preferably, is from about 2:1 to about 25:1, more preferably is from about 3:1 to about 15:1 and most preferably is from 4:1 to 10:1.

Typically, About2-max horizontal layer is located near the lower portion of reaction medium 36, while the O2-min horizontal layer is located near the top of reaction medium 36. Preferably, O2-min horizontal layer is one of the 5 most highly placed in horizontal layers from all of the 30 discrete horizontal layers. Most preferably, About2-min horizontal layer represents the top of the 30 discrete horizontal layers, as shown in Fig. Preferably, O2-max horizontal layer is one of the 10 most low-lying horizontal layers of all the 30 discrete horizontal layers. Most preferably, About2-max horizontal layer represents one of the 5 most low-elevation 30 discrete horizontal layers. For example, on Fig About2-max horizontal layer designated as the third horizontal layer from the bottom of reactor 20. The distance in height between About 2-min and2-max horizontal layers, preferably, is at least approximately 2W, more preferably, is at least approximately 4W and, most preferably, is at least 6W. The distance in height between the O2-min and2-max horizontal layers, preferably, is at least approximately 0,2N, more preferably, is at least approximately 0,4H and, most preferably, is at least 0,6N.

Time-averaged and volume concentration of oxygen relative to the liquid phase in O2-min horizontal layer, preferably, is from about 0.1 to about 3 mol%, more preferably, ranges from about 0.3 to about 2 mol%. and, most preferably, is from 0.5 to 1.5 mol%. Time-averaged and volume concentration of oxygen in the O2-max horizontal layer, preferably, is from about 4 to about 20 mol%, more preferably, ranges from about 5 to about 15 mol%. and, most preferably, is from 6 to 12 mol%. Time-averaged oxygen concentration relative to the dry product in the exhaust gas stream which is removed from the reactor 20 through the outlet 40, before occhialino, is from about 0.5 to about 9 mol%, more preferably, ranges from about 1 to about 7 mol%. and, most preferably, is from 1.5 to 5 mol%.

Since the oxygen concentration rapidly decreases toward the upper portion of reaction medium 36, it is desirable that the oxygen demand decreased in the upper portion of reaction medium 36. This decrease oxygen demand near the upper boundary of the reaction medium 36 can be achieved by creating a vertical concentration gradient is able to oxidize compounds (in particular, para-xylene), while the minimum concentration capable to oxidize compounds is near the top of reaction medium 36.

As regards the quantitative evaluation of the concentration gradient is able to oxidize compounds (in particular, para-xylene), then after the reaction medium 36 is theoretically partitioned into 30 discrete horizontal layers of equal volume, identify OC-max horizontal layer as the layer in which the concentration is able to oxidize compounds maximum of 30 horizontal layers, and identify OS-min horizontal layer as the layer in which the concentration is able to oxidize compounds minimum of horizontal layers that are located above the OS-ma horizontal layer. Concentration is able to oxidize compounds in horizontal layers is determined in the liquid phase and is expressed as the time-averaged and volume values for the mass fraction. The ratio of concentrations is able to oxidize compounds in OC-max horizontal layer of concentration is able to oxidize compounds in OS-min horizontal layer, preferably, is greater than approximately 5:1, more preferably is greater than approximately 10:1, even more preferably is greater than approximately 20:1 and, most preferably, is from 40:1 to 1000:1.

As a rule, OC-max horizontal layer is located near the lower portion of reaction medium 36, while the OS-min horizontal layer is located near the top of reaction medium 36. Preferably, OS-min horizontal layer represents one of the 5 most upper horizontal layers of all the 30 discrete horizontal layers. Most preferably, OS-min horizontal layer is on top of the 30 discrete horizontal layers, as shown in Fig. Preferably, OC-max horizontal layer represents one of the 10 most bottom horizontal layers of all the 30 discrete horizontal layers. Most preferably, OC-max horizontal layer represents one of the 5 most bottom Horiz is Talnah layers among the 30 discrete horizontal layers. For example, on Fig shown that OC-max horizontal layer is the fifth horizontal layer from the bottom of reactor 20. The distance in height between the OS-min and OC-max horizontal layers, preferably, is at least approximately 2W, where W denotes the maximum width of the reaction medium 36. More preferably, the distance in height between the OS-min and OC-max horizontal layers is at least approximately 4W and, most preferably, is at least 6W. For a given value of the height H of the reaction medium 36, the distance in height between the OS-min and OC-max horizontal layers, preferably, is at least approximately 0,2N, more preferably, is at least approximately 0,4H and, most preferably, is at least 0,6N.

Time-averaged and volume concentration are able to oxidize compounds (in particular, para-xylene) in the liquid phase OS-min horizontal layer preferably is less than about 5000 ppm wt., more preferably, is less than approximately 2000 ppm wt., even more preferably, less than about 400 ppm wt. and, most preferably, is from 1 ppm wt. to 100 ppm wt. Time-averaged and volume concentration are able to oxidize connection is tion in the liquid phase OC-max horizontal layer, preferably, ranges from about 100 ppm wt. up to approximately 10,000 ppm wt., more preferably, ranges from about 200 ppm wt. to about 5000 ppm wt., and, most preferably, from 500 ppm wt. up to 3000 ppm wt.

Despite the fact that in the bubble column reactor type 20 preferably generates concentration gradients can oxidize compounds in height, the volume percent of the reaction medium 36, containing the concentration is able to oxidize compounds in the liquid phase is greater than 1000 ppm wt., preferably, should be minimal. Time-averaged volumetric percentage of reaction medium 36, containing the concentration is able to oxidize compounds in the liquid phase is greater than 1000 ppm wt., preferably, less than about 9%, more preferably less than about 6% and, most preferably, is less than 3%. Time-averaged volumetric percentage of reaction medium 36, the concentration is able to oxidize compounds in the liquid phase of which exceeds 2500 ppm wt., preferably, less than about 1.5%, more preferably less than about 1% and, most preferably, is less than 0.5%. Time-averaged volumetric percentage of reaction medium 36,the concentration is able to oxidize compounds in the liquid phase which exceeds 10000 ppm wt., preferably, is less than approximately 0.3%, more preferably less than about 0.1% and, most preferably, is less than 0.03%. Time-averaged volumetric percentage of reaction medium 36, the concentration is able to oxidize compounds in the liquid phase which exceeds 25000 ppm wt., preferably, less than about 0.03%, more preferably less than about 0.015 percent and, most preferably, is less than 0,007%. The authors of the present invention noted that the volume of reaction medium 36, containing elevated levels can oxidize compounds do not necessarily have to be in one continuous volume. In many cases chaotic pattern of flows in a bubble column reactor type form two or more continuous, but isolated from other portions of the reaction medium 36, which have elevated levels can oxidize compounds. In each moment of time, when spending averaged over time, all such continuous, but isolated from other volumes in excess of 0.0001% vol. from the total amount of the reaction medium, add together to determine the total volume, which contains elevated levels of concentrations is able to oxidize compounds in the liquid phase.

Typically, the T-max horizontal layer will be located near the Central part of the reaction medium 36, while the T-min horizontal layer will be located near the lower portion of reaction medium 36. T-min horizontal layer, preferably, is one of the 10 most bottom horizontal layers of the 15 most low-lying horizontal layers. More preferably, the T-min horizontal layer is one of the 5 most bottom horizontal layers of the 15 most low-lying horizontal layers. For example, on Fig T-min horizontal layer is shown as the second horizontal layer from the bottom of reactor 20. T-max horizontal layer, preferably, is one of 20 middle horizontal layers from all 30 horizontal layers. More preferably, the T-max horizontal layer, is one of 14 middle horizontal layers from all 30 horizontal layers. For example, on Fig T-max horizontal layer is shown as the twentieth layer from the bottom of reactor 20 (i.e. one of 10 middle horizontal layers). The distance in height between the T-min and T-max horizontal layers, preferably, is at least approximately 2W, more preferably, is, Myung is our least approximately 4W and, most preferably, is at least 6W. The distance in height between the T-min and T-max horizontal layers, preferably, is at least approximately 0,2N, more preferably, is at least approximately 0,4H and, most preferably, is at least 0,6N.

As described above, in the case when the reaction medium 36 there is a temperature gradient along the height, then the reaction medium 36 mostly unloaded at a certain point height where the temperature of the reaction medium is greatest, especially in the case when the extractable product in the following steps, is subjected to processing at higher temperatures. Thus, in the case when the reaction medium 36 is unloaded from the reaction zone 28 via one or more located at a certain elevation height of the outlet openings, as shown in Fig and 20, set(s) at a certain point height of the output(s) hole(s) has(s) be located near the T-max horizontal layer. Located at a certain altitude mark the outlet, preferably, is within 10 horizontal layers from the T-max horizontal layer, more preferably, is within 5 horizontal layers from the T-max horizontal layer and, the most the e preferably is within 2 horizontal layers from the T-max horizontal layer.

Further it should be noted that many of the discussed in this description of the features of the present invention can be used in various reactor systems for oxidative processes, not only in systems that use a single reactor for oxidation. In addition, some of the features of the present invention can be used in reactors with mechanical agitation and/or reactors with flow mixing, and not just in a bubbling reactor (i.e. bubble columns reactor type). For example, the authors of the present invention discovered a number of benefits associated with step distribution/change of oxygen concentration and/or the rate of consumption of oxygen within the reaction medium. The benefits of speed distribution of the concentration/consumption of oxygen in the reaction medium, can be implemented regardless of whether the full amount of the reaction medium in a single reactor or in multiple reactors. In addition, the benefits of speed distribution of the concentration/consumption of oxygen in the reaction medium, can be implemented regardless of whether it is(are) whether the reactor(the) reactor(s) with mechanical stirring, flow-through mixing and/or with bubbling stirring.

One way to quantify the formation of a stepped distribution of oxygen concentration and/or the rate of consumption of oxygen in the reaction environment is to compare two or more separate 20%continuous volume of the reaction medium. These 20%continuous volumes do not have to have a certain shape. However, each of the 20%continuous volumes should be formed adjacent volume of the reaction medium (i.e. each volume must be “continuous”) and 20%continuous quantities should not overlap (i.e. volumes are “separate”). On Fig-31 it was shown that these individual 20%continuous volumes can reside in the same reactor (Fig) or in multiple reactors (Fig and 31). It should be noted that the rectors shown in Fig-31, can be a reactor with mechanical stirring, with flow mixing and/or bubble mixing. In one of the embodiments of the present invention the reactor is shown in Fig-31 preferably are bubbling reactor (i.e. bubbling reactor columns).

As for Fig, here presents the reactor 20, which contains the reaction medium 36. The reaction medium 36 includes a first separate the first 20%continuous volume 37 and the second separate 20-percent continuous volume of 39.

As for Fig, here presents mnogofaktornaya system, which includes the first reactor a and second reactor 720b. Reactors a,b together contain the full volume of the reaction medium 736. The first reactor a contains the first portion of the reaction medium a, while the second reactor 720b contains the second portion of the reaction medium 736b. First separate 20%continuous volume 737 reaction medium 736 depicted as the volume enclosed in the first reactor a, while the second individual 20%continuous volume 739 reaction medium 736 depicted as the volume enclosed in the second reactor 720b.

As for Fig, here presents mnogofaktornaya system, which includes the first reactor a, the second reactor 820b and the third reactor s. Reactors a, b, C together contain the full volume of the reaction medium 836. The first reactor a contains the first portion of the reaction medium a; the second reactor 820b contains the second portion of the reaction medium 836b; and the third reactor 820 contains a third portion of the reaction medium 836 S. First separate 20-percent continuous volume 837 reaction medium 836 depicted as the volume enclosed in the first reactor a, the second separate 20-percent continuous volume 839 of the reaction medium 836 depicted as the volume enclosed in the second reactor 820b; and the third, a separate 20-percent continuous volume 841 of the reaction medium 836 and OBrien as volume, the prisoner in the third reactor s.

Speed distribution of available oxygen in the reaction medium can be quantified by considering 20%continuous volume of the reaction medium, which contains the richest fraction of oxygen in the gas phase, as well as considering 20%continuous volume of the reaction medium, which contains the most depleted molar fraction of oxygen in the gas phase. In the gas phase separate 20-percent continuous volume of the reaction medium containing the highest concentration of oxygen in the gas phase, time-averaged and volume concentration of oxygen relative to the liquid phase, preferably, is from about 3 to about 18 mol%, more preferably, ranges from about 3.5 to about 14 mol%. and, most preferably, is from 4 to 10 mol%. In the gas phase separate 20-percent continuous volume of the reaction medium containing the lowest concentration of oxygen in the gas phase, time-averaged and volume concentration of oxygen relative to the liquid phase, preferably, is from about 0.3 to about 5 mol%, more preferably, ranges from about 0.6 to about 4 mol%. and, most preferably, ranges from 0.9 to 3 mol%. Moreover, the ratio of time-averaged and volume of the mu oxygen concentration relative to the liquid phase the most enriched to 20 percent continuous volume of the reaction medium to the most depleted 20%continuous volume of the reaction medium, preferably, ranges from about 1.5:1 to about 20:1, more preferably, is from about 2:1 to about 12:1 and, most preferably, is from 3:1 to 9:1.

Speed velocity of oxygen consumption in the reaction medium can be quantified in terms of STR for oxygen, which is already discussed above. STR for oxygen was previously considered in a General sense (i.e. from the point of view of the average values of STR for oxygen throughout the reaction medium); however, STR for oxygen can also be seen in the local sense (i.e. for a portion of the reaction medium) in order to quantify the speed distribution speed of consumption of oxygen throughout the reaction medium.

The authors of the present invention found that it is advisable to get STR for oxygen coordinated to vary throughout the reaction environment considered in this description gradients related to the pressure in the reaction medium and the molar fraction of molecular oxygen in the gas phase reaction medium. The ratio of STR for oxygen in the first separate 20 percent continuous volume of the reaction medium to respect STR for oxygen in the second separate 20-percent continuous volume of the reaction medium, preferably, is from about 1.5:1 to about 20:1, more pre is respectfully, is from about 2:1 to about 12:1 and, most preferably, is from 3:1 to 9:1. In one of the embodiments of the present invention, “the first single 20-percent continuous volume” is closer than “the second single 20-percent continuous volume” to the place where molecular oxygen is initially fed into the reaction environment. These large gradients STR for oxygen desirable if the environment for carrying out the partial oxidation reaction is contained in a bubbler oxidation reactor column or in any other reactor type, which creates pressure gradients and/or mole fraction of molecular oxygen in the gas phase of the reaction medium (in particular, in the reactor with mechanical agitation produced several vertically spaced zones of mixing that is achieved by using a variety of blades, forming a strong radial flow, which could increase, mainly through the system of horizontal separation walls, and the stream of the oxidant is usually rises up from the supply point located in the lower part reactor, regardless of what's inside each vertical mixed zone may occur countercurrent mixing of oxidizer and a reverse mixing of the oxidant stream may be going on the t between adjacent vertical mixing zones). Thus, the authors of the present invention have found that if there is a pressure gradient and/or mole fraction of molecular oxygen in the gas phase of the reaction medium, it is desirable to create a similar gradients in need of dissolved oxygen for the chemical reaction with the help given in this description methods.

Preferred ways to cause local variations STR for oxygen are controlling supply is able to oxidize compounds and control mixing of the liquid phase in the reaction medium, to control the concentration gradients are able to oxidize compounds in accordance with the description of the present invention. Other suitable ways to cause local variations STR for oxygen include forced changes in the activity of the reaction by varying the local temperature and by changing the local mixture of catalyst and components of the solvent (in particular through the gas, causing the cooling due to the evaporation of a certain part of the reaction medium, and by filing a stream of solvent containing more water, in order to reduce the activity of a specific part of the reaction medium).

As discussed above with reference to Fig and 31, it may be desirable to conduct the reaction partial about what islene in several reactors, thus, at least part, preferably at least 25%, more preferably at least 50% and most preferably at least 75% of molecular oxygen, leaving the first reactor is sent in one or more subsequent reactors to consumption of additional amounts, preferably of more than 10%, more preferably in excess of 20% and, most preferably, in excess of 40% of the number of molecular oxygen, leaving the first/located upstream of the reactor. When using such a sequential flow of molecular oxygen from one reactor to the other, it is desirable that the reaction in the first reactor was carried out with greater intensity than at least one subsequent reactor, the ratio averaged over the reactor STR values for oxygen in a first reactor to the average reactor the STR value for oxygen in the subsequent reactor, preferably, is from about 1.5:1 to about 20:1, more preferably, is from about 2:1 to about 12:1 and, most preferably, is from 3:1 to 9:1.

As mentioned above, to create a consistent flow of molecular oxygen in the subsequent reactors, in accordance with us is oasim invention, suitable for all types used in the first stage reactor (in particular, they can be a bubble column reactor with mechanical stirring, the reactor with a back-mixing reactor with internal redistribution reactor plunger type etc) and all types of subsequent reactors, which may differ or do not differ from the type of reactor used in the first stage of the process. Means enabling the reduction averaged over the reactor STR values for oxygen in the subsequent reactors are generally decreasing temperatures, lower concentrations can oxidize compounds and the decrease in the specific activity of the mixture of catalyst components and solvent (in particular, the decrease of the concentration of cobalt, increasing the water content and the introduction of inhibitors of the catalyst in the form of small additives of copper ions).

In the process of moving from the first reactor to the next reactor oxidant stream may be subjected to any well-known from the technical field effects, such as compression or pressure reduction, cooling or heating, removing the weight or add weight in any number or any type. However, the decline averaged across the reactor STR values for oxygen in the subsequent reactors is particularly useful in the case where the absolute is the t in the upper part of the first reactor is less than about 2.0 MPa, more preferably is less than about 1.6 MPa, and most preferably, is less than 1.2 MPa. In addition, the decline averaged across the reactor STR values for oxygen in the subsequent reactors is particularly useful in the case when the ratio of the absolute value of the pressure in the upper part of the first reactor to the absolute value of the pressure in the upper part, at least one subsequent reactor is from about 0.5:1 to 6:1, more preferably, ranges from approximately 0.6:1 to about 4:1 and, most preferably, is from 0.7:1 to 2:1. The reduction of pressure in the subsequent reactors following boundary values leads to an excessive decrease in the availability of molecular oxygen, and the pressure increases beyond the specified boundary values leads to additional costs, compared to using a fresh portion of the oxidizer.

In that case, when you apply a sequential stream of molecular oxygen in the subsequent reactors with lower average STR for oxygen, fresh portions of the source is able to oxidize compounds, solvent and oxidant can be fed into the subsequent reactor and/or into the first reactor. The flow of the liquid phase and the solid phase, if they are present in the reaction medium, can LW is to rely in any direction between the reactors. All gas phase or part of the gas phase leaving the first reactor and into the subsequent reactor, can be moved separately or in a mixture with portions of the liquid phase and the solid phase, if they are present in the reaction medium coming from the first reactor. The product stream comprising a liquid phase and a solid phase, if present, can be extracted from the reaction medium in any reactor system.

If you return to figure 1-29, the oxidation is preferably carried out in a bubble column reactor type 20 in conditions that differ markedly in accordance with the described in this description of the preferred embodiment of the present invention, conditions in conventional reactors for carrying out processes of oxidation. In the case when carrying out liquid-phase partial oxidation of para-xylene in the crude terephthalic acid (CTA), in accordance with described in this description of the preferred embodiment of the present invention, use bubble column reactor type 20, the spatial profiles of the local intensity of the reaction, the local evaporation rates and local temperature in combination with the modes of the flow of liquid substances in the reaction medium and the preferred, relatively low temperature oxidation contribute is the education of particles of a HUNDRED, who have unique and preferred properties.

Figa and 32V illustrate the basic particles of a HUNDRED, obtained in accordance with one embodiments of the present invention. On figa shows the basic particles HUNDRED at 500-fold magnification, and when receiving image Fig In the camera “zooms in” inside one of the basic particles and shows that particle at 2000-fold increase. As probably best illustrates pig In each basic particle HUNDRED, usually formed by a large number of small agglomerate of subparticles of a HUNDRED, as a result of the underlying HUNDRED particles have a relatively large surface area, high porosity, low density and good solubility. Unless otherwise noted below various properties HUNDRED according to the present invention is measured for a typical sample of a HUNDRED, the mass of a typical sample is at least 1 g and/or it includes at least 10000 individual particles HUNDRED. Basic HUNDRED particles usually have an average particle size of from about 20 to about 150 microns, more preferably, from about 30 to about 120 microns and, most preferably, from 40 to 90 μm. Subunit HUNDRED usually have an average particle size of from about 0.5 to about 30 microns, more preferably, from when listello 1 to about 15 microns, and, most preferably, from 2 to 5 μm. The relatively large surface area of the base particles HUNDRED, which illustrate figa and 32V, can be quantitatively evaluated by measuring the surface area method Braunauer-Emmett-teller (BET). Basic HUNDRED particles preferably have an average surface area BET, equal to at least 0.6 m2/, More preferably, the base particles HUNDRED have an average surface area BET, which ranges from approximately 0.8 to approximately 4 m2/, Most preferably, the base particles HUNDRED have an average surface area BET, which ranges from 0.9 to 2 m2/, Physical properties (in particular, particle size, surface area BET, porosity and solubility) of the base particles HUNDRED, obtained by the optimized method of oxidation, in accordance with the preferred embodiment of the present invention, allow a clearance of particles HUNDRED using more efficient and/or economical methods, as further specified in Fig.

The above values of average particle sizes determined by microscopy in polarized light with subsequent image analysis. In the analysis of particle sizes used optical microscope Nikon AI lens 4× Plan Flour N.A. 0.13, a digital camera (Spot RT™ and persons the local computer with the software Image Pro Plus™ V4.5.0.19 for image analysis. A method of analyzing particle size includes the following basic stages: (1) dispersing powders HUNDRED in mineral oil; (2) placement of the sample variance between the object glass microscope cover glass; (3) study of the slides by microscopy in polarized light (when crossed Polaroid - particles appear as bright objects on a black background); (4) obtaining different images for each sample preparation (field size = 3×2.25 mm; pixel size = 1,84 µm/pixel); (5) conducting image analysis using the software Pro Plus™; (6) preparation of the summary table of the parameters measuring particles; and (7) carrying out statistical processing of the data in the PivotTable. Stage (5) “analysis of an image using software Pro Plus™includes the following sub-phases: (a) determining a threshold detection of white particles on a dark background; (b) obtaining a two-level image; (C) a single application of the open filter to filter out distorted pixels; (d) measurement of all particles in the image; and (e) record the average measured diameter for each particle. Software Pro Plus™ determines the average diameter of individual particles as srednecenovogo the length of the diameters of the particles, which is measured at intervals of 2 degrees and which passage is t through the centroid of the particle. Stage (7) “conducting statistical data summary table includes the calculation of the volume-weighted average particle size in the following way. Calculate the volume of each of the n particles in the sample as if it had a spherical shape by the formula π/6*di3; multiply the volume of each particle to its diameter, to obtain the value of π/6*di4; sum values π/6*di4for all particles in the sample; summarize the volumes of all particles in the sample; calculate the volume-weighted diameter of the particle by dividing the sum of (π/6*di4for all particles in the sample to the amount of (π/6*di3for all particles in the sample. In this specification, “average particle size” means the volume-weighted average particle size, which is determined by the above method; it is also designated as D(4,3).

In addition, the stage 7 includes the determination of particle sizes for which different fractions of the total sample are smaller. For example, D(v, 0,1) denotes the particle size for which 10% of the total sample contains particles of a smaller size, and 90% contains particles of larger size; D(v, 0.5) is denotes the particle size for which half the volume of the sample contains particles of a smaller size, and half the volume of the sample contains particles of larger size; D(v 0,9) denotes the size of the particles, for which 90% of the total volume contains particles of a smaller size; and so on in Addition, the stage 7 includes the calculation of D(v, 0,9) minus D(v, 0,1), which in this description is defined as “the distribution of particle sizes; and stage 7 includes the calculation of the distribution of particle sizes divided by D(4, 3), which in this description referred to as the relative size distribution of particles”.

Further, the value D(v, 0,1) for particles of a HUNDRED, the measurement method given above, preferably, is from about 5 to about 65 μm, more preferably, is from about 15 to about 55 microns and, most preferably, from 25 to 45 μm. The value D(v, 0.5) is for particles of a HUNDRED, the measurement method given above, preferably, is from about 10 to about 90 μm, more preferably, is from about 20 to about 80 microns and, most preferably, is from 30 to 70 μm. The value D(v, 0,9) for particles of a HUNDRED, the measurement method given above, preferably, is from about 30 to about 150 microns, more preferably, is from about 40 to about 130 microns and, most preferably, ranges from 50 to 110 μm. The relative distribution of particle sizes, preferably, the composition is yet from approximately 0.5 to approximately 2.0, more preferably, ranges from about 0.6 to about 1.5 and most preferably ranges from 0.7 to 1.3.

The above values of the surface area of the BET is measured on a Micromeritics instrument ASAP2000 (produced by the company Micromeritics Instrument Corporation of Norcross, GA). In the first stage measurements weigh from 2 to 4 g of sample particles and dried in vacuum at 50°C. the sample was Then placed in a gas system analysis device and cooled to a temperature of 77 K. Measure the adsorption isotherms of nitrogen, at least at the 5 equilibrium values of pressure, placing the sample in a known volume of gaseous nitrogen and measuring the decrease in pressure. The equilibrium pressure values are approximately in the range of R/R0=0,01-0,20, where P denotes the equilibrium pressure, and R0denotes the vapor pressure of liquid nitrogen at 77 K. Then build the graph obtained isotherms in accordance with the following equation BET:

where Vathis refers to the amount of gas absorbed by the sample when the value of P, Vmdenotes the volume of gas required to cover the entire sample surface by a monolayer of gas, and s is a constant. From the obtained graph to determine the values of Vmand C. Then the value of Vmtransferred to the surface area, using the value of the sectional area of azo is and at 77 K by the equation:

where σ is the cross-sectional area of nitrogen at 77 K, the value of T corresponds to 77 K, and R is the gas constant.

As indicated above, a HUNDRED, obtained in accordance with one embodiments of the present invention, has a better ability to dissolve in comparison with the usual one HUNDRED obtained in other ways. The specified high speed of dissolution can more efficiently clean a HUNDRED and/or to use more effective methods of cleaning. Hereinafter in the description discusses how quantitative evaluation of the dissolution rate of a HUNDRED.

The dissolution rate of a known quantity of solids in a known amount of solvent to stir the mixture can be measured using various techniques. Used in this description of the method, which is called the “test of dissolution for a certain period of time”, is the following. If the test is normal ambient pressure of approximately 0.1 MPa. Ambient temperature, which is used when testing dissolution for a certain period of time is 22°C. in Addition, before conducting the test, the solids, the solvent and all used to dissolve the snap fully thermally balanced when the specified rate is the atur, therefore significant heating or cooling chemical glass or the content within a specified period of dissolution does not occur. Portion of fresh solvent, which represents tetrahydrofuran, suitable for carrying out HPLC (purity is 99.9%), hereinafter referred to as THF, in the amount of 250 g is placed in a clean glass of high chemical from KIMAX capacity 400 ml (room 14020 catalog Kimble®, Kimble/Kontes, Finland, new Jersey) without a lid, which has a smooth wall and a generally cylindrical shape. The glass is placed is covered with a Teflon magnetic razmeshivali (number 58948-230 VWR catalog, its length is approximately 1 inch, 3/8 inch, it has an octagonal cross-section; VWR International, West Chester, PA 19380), where it settles to the bottom. The sample is stirred with a multi-position magnetic stirrer Variomag®15 (H&P Labortechnik AG, Oberkochen, Germany)installed on the mode of rotation of 800 rpm Stirring begin not more than 5 min before adding solids and continue without interruption for at least 30 min after addition of solids. A solid sample particles crude or purified TRA total weight of up to 250 mg weighed into the Cup for weighing samples, the walls of which the particles do not stick. At the initial time, denoted as t=0, weighed a solid substance p is thus poured into the stirred THF and at the same time include a timer. If done correctly, THF quickly wets the solids and within 5 sec forms a dilute, mix well the suspension. Then get samples of this mixture in the following periods, measured in minutes from t=0: 0,08; 0,25; 0,50; 0,75; 1,00; 1,50; 2,00; 2,50; 3,00; 4,00; 5,00; 6,00; 8,00; 10,00; 15,00 and 30,00. Each take a small sample of the diluted mix well suspension using a new disposable syringe (Becton, Dickinson and Co., 5 ml, REF 30163, Franklin Lakes, NJ 07417). Immediately after extraction of man-made glass approximately 2 ml of pure fluid sample quickly passed through new unused syringe filter (25 mm diameter, 0.45 μm, Gelman GHP Acrodisc FG®, Pall Corporation, Easter Hills, NY 11548) in new equipped with RFID glass tube. The length of the time period for each operation of the filling syringe, transfer the filter and transfer to a test tube should be less than approximately 5 seconds, and the specified interval, respectively, begins and ends within about ±3 seconds from the time of preparation each required sample. Within about five minutes after each filling tube is stoppered and maintained at approximately a constant temperature before the next chemical analysis. After taking the last sample 30 minutes after BP is the times t=0, all 16 samples analyzed for dissolved TCA using the method of HPLC-DAD (HPLC detector diode matrix) as broadly indicated in the present description. In this test the calibration standards and the results are shown in the number of milligrams of dissolved TRA per gram of solvent THF (hereinafter referred to as ppm in THF”). For example, if all 250 mg solids are very clean TRA and all the specified number of fully dissolved in 250 g of THF used as solvent, before being selected for a particular sample, correct the measured concentration of approximately 1000 ppm in THF.

When a HUNDRED, obtained according to the present invention, experience using the above test dissolution for a certain period of time, the sample taken after one minute after t=0, preferably dissolved to a concentration equal to at least about 500 ppm in THF, more preferably to a concentration equal to at least about 600 ppm in THF. In the sample, which was taken two minutes after t=0, a HUNDRED of the present invention, preferably, will be dissolved to a concentration equal to at least about 700 ppm in THF, more preferably to a concentration equal to at least PR is approximately 750 ppm in THF. In the sample, which is taken through four minutes after t=0, a HUNDRED of the present invention, preferably, will be dissolved to a concentration equal to at least approximately 840 ppm in THF, more preferably to a concentration equal to at least approximately 880 ppm in THF.

The authors of the present invention have found that regardless of the complexity of the composition of the sample particles and the dissolution process, to describe the time dependence of the full data set obtained using the test for dissolution for a certain period of time, can be applied relatively simple negative exponential growth model. Type of equation, which is hereinafter referred to as the model of dissolution for a certain period of time, can be represented as follows:

S=A+B*(1-exp(-C*t)),

where t = time, measured in minutes;

S = solubility, expressed in ppm in THF, at time t;

exp = exponential function natural logarithm base 2;

A, b = regression constants, expressed in ppm in THF, And this applies mainly to the rapid dissolution of smaller particles for very short periods of time, and the sum a+b mainly refers to the total dissolution time near the end of the specified test period; and

C = time constant regression, is expressed in inverse minutes (min -1).

The regression constants are selected so as to minimize the sum of squares of deviations of the actually received data from the corresponding values obtained from simulation, and this method is called the method of “least squares”. The preferred software package to conduct the regression analysis of the obtained data is JMP Release 5.1.2 (SAS Institute Inc., JMP Software, SAS Campus Drive, Cary, NC 27513).

When a HUNDRED received in accordance with the present invention, are examined with a test for dissolution for a certain period of time, and then carry out the analysis on the model of dissolution for a certain period of time, as described above, then a HUNDRED, preferably has a time constant “C” is greater than approximately 0.5 min-1more preferably, greater than approximately 0.6 min-1and, most preferably, greater than 0.7 min-1.

Figa and 33B illustrate the usual HUNDRED particles obtained in the conventional high-temperature oxidation process in the hull reactor continuous mixing (CSTR). On figa shows the usual HUNDRED particles at 500-fold magnification, and when receiving the image figv camera “zooms” into the particles and shows a typical particle HUNDRED at 2000-fold increase. Visual comparison of ASTEC HUNDRED according to the present invention, shown in figa and 32V, and the usual HUNDRED particles shown in figa and 33B shows that ordinary particles have a greater density, less surface area, less porosity and greater particle size than the particles of one HUNDRED for the present invention. Indeed, the usual HUNDRED listed on figa and 33B, has an average particle size of about 205 μm, and the surface area BET for them is about 0,57 m2/year

On Fig explains the usual method of obtaining a purified terephthalic acid (MOUTH). In the usual method of obtaining the mouth of the para-xylene is partially oxidized in the high temperature reactor 700 with stirring. The suspension, containing one HUNDRED, is unloaded from the reactor 700 and then cleaned in the cleaning system 702. The product from the purification system 702 in the form of the MOUTH is injected into the separation system 706 for the separation and drying of the particles of the MOUTH. Cleaning system 702 makes a major contribution to the cost of obtaining particles of the MOUTH in the usual ways. Cleaning system 702 typically includes an add/water exchange 708, the system dissolving 710, the system hydrogenation 712 and three separate reactor for carrying out crystallization 704a, b, c. In the system add/water exchange 708 a large part of the mother liquor is replaced by water. After adding water, the water/slurry HUNDRED is fed in dissolving 710, where the mixture HUNDRED water Naga is eveda until while particles HUNDRED is completely dissolved in the water. After the dissolution of a HUNDRED, a HUNDRED solution in water is subjected to hydrogenation in a hydrogenation system 712. Stream is hydrogenated product after hydrogenation system 712 then subjected to crystallization in three stages in the reactor for carrying out crystallization 704a,b, and then is separated in the separation system 706.

On Fig is illustrated an improved method of obtaining a MOUTH using a bubble column reactor type 800 constructed in accordance with the embodiment of the present invention. The original suspension containing solid particles HUNDRED and mother liquor, is unloaded from the reactor 800. Typically, the initial slurry may contain solid particles HUNDRED from about 10 to about 50 wt.%, and the rest is the mother solution. Solid particles of a HUNDRED, which are contained in the initial suspension, usually contain at least about 400 ppm Mas-carboxyanhydride (4-CBA), more typically contain at least about 800 ppm Mas-IAS and most typically contain 4-CBA from 1000 to 15000 ppm wt. The original suspension, which is output from the reactor 800, is fed into the purification system 802 to reduce the concentration of 4-CBA and other impurities contained in a HUNDRED. More pure/purified suspension obtained in the purification system 802 is subjected to separation and drying in the separation system 804, and thus are more pure solid particles of terephthalic acid containing less than about 400 ppm Mas-IAS, more preferably, less than about 250 ppm Mas-CBA and, most preferably, from 10 to 200 ppm Mac-IAS.

Cleaning system 802 system receiving MOUTH, shown in Fig, provides several advantages compared to the cleaning system 802, known from the field of engineering systems, which is shown in Fig. Cleaning system 802, preferably, as a rule, contains a system replacement stock solution 806, evaporated boiler 808 and one mold 810. In the system replace the mother liquor 806, at least 50% wt. the mother liquor contained in the initial suspension, replaced used to replace fresh replacement solvent and the thus formed suspension in the replacement solvent, which contains particles of a HUNDRED and used to replace the solvent. The suspension in the replacement solvent, which leaves the system replace the mother liquor 806, comes evaporated in the boiler (or the second oxidation reactor) 808. In common boiler 808 secondary oxidation reaction is carried out at somewhat higher temperatures than those used during the original/primary oxidation reaction, which is carried out in a bubble column reactor is wow type 800. As indicated above, a large surface area, the smaller the particle size and low density of particles HUNDRED, obtained in the reactor 800, leads to the fact that certain impurities trapped particles HUNDRED are available for oxidation of evaporated in the boiler 808, without requiring the complete dissolution of the particles HUNDRED evaporated in the boiler 808. Thus, the temperature evaporated in the boiler 808 may be lower than in many similar processes known from the technical field. In the process of secondary oxidation, which is evaporated in the boiler 808, the content of 4-CBA in a HUNDRED, preferably, reduced by at least 200 ppm wt., more preferably, reduced by at least 400 ppm wt. and, most preferably, is reduced in the range from 600 to 6000 ppm wt. The temperature of the secondary oxidation reactions evaporated in the boiler 808, preferably about 10°C higher than the temperature of the primary oxidation reaction in bubble column reactor type 800, more preferably from about 20°to about 80°C. higher than the temperature of the primary oxidation reaction in bubble column reactor type 800 and, most preferably, from 30°C to 50°C higher than the temperature of the primary oxidation reaction in bubble column reactor type 800. The temperature of the secondary oxidation reaction preferably ranges from approx the tion 160 to about 240°C, more preferably, ranges from about 180 to about 220°C. and, most preferably, ranges from 190 to 210°C. the Purified product after evaporated boiler 808 requires only one stage in the mold 810 before separation in the separation system 804. Suitable methods for secondary oxidation/vyvarki are discussed in detail in the patent application U.S. No. 2005/0065373, the full content of which is expressly incorporated into this description by reference.

Terephthalic acid (in particular of the MOUTH), obtained in the system shown in Fig mainly formed by particles, the average size of which is at least approximately 40 μm, more preferably, is from about 50 to about 2000 microns and, most preferably, is from 60 to 200 microns. Particles of the MOUTH, preferably, have an average surface area BET less than approximately 0.25 m2/g, more preferably, this amount ranges from approximately 0.005 to approximately 0.2 m2/g and, most preferably, is from 0.01 to 0.18 m2/, MOUTH, get in the system shown in Fig, suitable as a feedstock for the production of the PET. Typically, PET obtained by esterification of terephthalic acid with ethylene glycol, followed by polycondensation. There is aleva acid, obtained in accordance with the embodiment of the present invention, preferably used as a raw material in the method of obtaining a PET in a tubular reactor, which is described in patent application U.S. No. 10/013318, filed December 7, 2001, the full contents of which are incorporated into this description by reference.

In the present description, the particles HUNDRED with the preferred morphology is particularly suitable for use in the above oxidation of evaporated process to reduce the content of 4-CBA. In addition, these preferred particles HUNDRED provide benefits for a wide range of subsequent treatments, including the dissolution and/or chemical reactions with the participation of these particles. These additional subsequent processing include, but not limited to, interaction with at least one hydroxyl-containing compound with the formation of esters, in particular the interaction of one HUNDRED with methanol to form terephthalate and impurity esters; the interaction of at least one diola with the formation of the ester monomer and/or polymer compounds, in particular the interaction of one HUNDRED with ethylene glycol to form polyethylene terephthalate (PET); and full or partial dissolution in the solvent, including the I, but not limited to, water, acetic acid and N-methyl-2-pyrrolidone, which may include further processing, including, but not limited to, pereosazhdeniya purer terephthalic acid and/or selective chemical reduction of carbonyl groups other than carboxyl groups. Particularly noteworthy is the almost complete dissolution of a HUNDRED in a solvent containing water, in combination with partial hydrogenation, which reduces the amount of aldehydes, in particular 4-CBA, fluorenone, phenonom and/or anthraquinones.

The authors of the present invention believe that the particles of a HUNDRED, has disclosed in this description of preferred properties, can be obtained from particles of a HUNDRED that do not correspond to those disclosed in this description of preferred properties (nekotorye particles HUNDRED) using methods including, but not limited to, mechanical grinding reconforming particles HUNDRED and full or partial dissolution reconforming particles HUNDRED with subsequent complete or partial presidenial.

In accordance with one embodiments of the present invention, it is proposed a method of partial oxidation is able to oxidize aromatic compounds with one or more types of aromatic carboxylic acids, in which h is the purity of the solvent as an integral part of the original substances (i.e. “the original solvent”) and the purity is able to oxidize compounds as an integral part of the original substances (i.e. source is able to oxidize compounds”) control in certain lower limits. Together with other variants of implementation of the present invention that allows you to control the purity of the liquid phase and the solid phase, if it is present, and the joint phase of the suspension (i.e. the solid phase plus liquid phase reaction medium in certain preferred limits, which are listed below.

As for the source of the solvent, a method of oxidation is able(s) to oxidize aromatic(s) connection(s) with the formation of aromatic carboxylic acids, where the original solvent, served in the reaction medium is a mixture of analytical grade acetic acid and water, which is often used both in laboratory scale and pilot plant. Also known mode for carrying out the oxidation is able to oxidize aromatic compounds to aromatic carboxylic acids, where the solvent leaving the reaction medium is separated from the resulting aromatic carboxylic acid and then recycled to the reaction medium in the form of the original solvent, mainly with the aim of reducing production costs. Specified recycler is of the solvent causes some impurities present in the original substance, and formed in the process by-products over time accumulate in the recycled solvent. Of the techniques known to a large number of ways to clean recycled solvent before it is reintroduced into the reaction environment. In General, higher degree of purification of recycled solvent leads to significantly higher production costs than a smaller degree of purification using similar methods of cleaning. One of the embodiments of the present invention is concerned with identifying and establishing preferred within the content of a large number of impurities in the original solvent, many of which until now was considered pretty harmless, with the aim to find the optimal balance between the total production costs and total purity of the product.

“Recycled original solvent” refers to in this description as the original solvent containing at least about 5% wt. substances that have already passed through the reaction medium containing one or more are able to oxidize aromatic compounds, which are subjected to partial oxidation. Taking into account the generated supply of solvent and lifespan and the business cycle in industrial setting, the portion of the recycled solvent, preferably, should pass through the reaction medium at least once during the day of the trial, more preferably at least once a day for at least seven consecutive days of the process and, most preferably, at least once a day for at least 30 consecutive days during the process. For economic reasons, preferably at least 20 wt.%. the original solvent in the reaction medium of the present invention is recycled solvent, more preferably at least 40 wt.%, even more preferably, at least 80% wt. and, most preferably, at least 90% wt. the original solvent is recycled solvent.

The authors of the present invention have found that taking into account the activity of the reaction and metallic impurities that remain in the product of oxidation, the concentration of selected metals of variable valence in the stream recycled to the source of the solvent, preferably, are within the following limits. Iron concentration in the recycled solvent, preferably, less than about 150 ppm wt., more preferably, less than about 40 ppm wt. and, most preferably, is from 0 to 8 ppm wt. The Nickel concentration in the recycled solvent, preferably, less than about 150 ppm wt., more preferably, less than about 40 ppm wt. and, most preferably, is from 0 to 8 ppm wt. The chromium concentration in the recycled solvent, preferably, less than about 150 ppm wt., more preferably, less than about 40 ppm wt. and, most preferably, is from 0 to 8 ppm wt. The concentration of molybdenum in the recycled solvent, preferably, less than about 75 ppm wt., more preferably, less than about 20 ppm by weight. and, most preferably, is from 0 to 4 ppm wt. The concentration of titanium in the recycled solvent, preferably, less than about 75 ppm wt., more preferably, less than about 20 ppm by weight. and, most preferably, is from 0 to 4 ppm wt. Copper concentration in the recycled solvent, preferably, less than about 20 ppm wt., more preferably, less than about 4 ppm wt. and, most preferably, ranges from 0 to 1 ppm wt. In recycled solvent, as a rule, prisutstvie who have other metal impurities, the content of which usually varies in low proportions in relation to one or more of the above metals. Maintaining the concentrations of the above metals in the above preferred boundaries will be maintained at the appropriate level and other metal impurities.

These metals may occur as impurities in any of the applicants in the process of starting compounds (i.e. able to oxidize compounds, solvent, oxidant and catalyst components). In addition, metals can appear as corrosion products of any unit in contact with the reaction medium and/or in contact with recycled solvent. Controls of metals detected above the limits of concentration include the appropriate technical requirements and monitoring of the purity of different starting compounds and the appropriate selection of construction materials, including, but not limited to, many industrial grade titanium and stainless steels, including varieties such as steel, smelted the duplex process, and a steel with a high content of molybdenum.

The authors present invention also established a preferred boundary for the selected aromatic compounds in the recycled solvent. They include both precipitated and dissolved aromatic connection is to be placed, contained in the recycled solvent.

Suddenly found that he besieged the product (in particular, TRA) partial oxidation of para-xylene is a pollutant, which also need to be tackled in the recycled solvent. Because suddenly there are preferred the boundaries of the content of solids in the reaction medium, any precipitated product contained in the original solvent, directly reduces the number able to oxidize compounds that can be consistently introduced into the reaction. In addition, it was found that the ingestion of large quantities of precipitated solid TRA in recycled solvent has a negative impact on the properties of the particles, which are formed in the deposition process of oxidative environment, which leads to the manifestation of undesirable properties when conducting subsequent operations (in particular, during the filtration of the product, washing with a solvent, oxidative digestion of the crude product, dissolving the crude product, for further processing, and so on). Another undesirable feature of the precipitated substances are fed into the process the recycled solvent is that they often contain a very large quantity of precipitated impurities in comparison with the concentration of impurities in the volume of solid substances is involved in suspensions TRA, of which devote a greater portion of the recycled solvent. The high content of impurities, which is observed in solids suspended in the recycled filtrate is likely to be associated with times of nucleation in the deposition of certain impurities from the recycled solvent and/or cooling of the recycled solvent both intentional and caused losses to the environment. For example, significantly higher levels of concentration are strongly colored and unwanted 2,6-dicarboxylate detected in the solids present in the recycled solvent at a temperature of 80°C, than in the solid TRA separated from the recycled solvent at a temperature of 160°C. Similarly, significantly higher levels of isophthalic acid are observed in the solid substances present in the recycled solvent, in comparison with the levels observed in the solid TPA from the reaction environment. The specific the specific behavior of precipitated impurities captured recycled solvent, when their re-introduction into the reaction environment, obviously, may vary. It probably depends on the relative solubility of the impurity in the liquid phase reaction medium, it is possible that precipitated impurity is distributed in aside the different substances, and possibly from the local deposition rate TRA in that place, where the solid substance for the first time comes back into the reaction environment. Thus, the authors of the present invention found that it is important to control the levels of certain impurities in the recycled solvent, as described below, irrespective of whether contained these impurities in the recycled solvent in dissolved form or represent particles that are captured recycled solvent.

The amount of precipitated solids contained in the recycled filtrate determine gravimetric method according to the following method. Take a separate sample supplied into the reaction mixture solvent as the solvent is sent through a pipeline to the reaction medium. Acceptable sample size of approximately 100 g, which is placed in a glass container, the internal volume of approximately 250 ml Before the pressure of the recycled filtrate beats with atmospheric and before the sample of the filtrate is placed in the container, recycled filtrate is cooled to a temperature less than 100°C.; cooling is necessary in order to minimize the evaporation of the solvent in a short amount of time until the sample is sealed in the container is. After the sample is selected at atmospheric pressure, the glass container tightly closed immediately. Then the sample is allowed to cool down to approximately 20°C at an ambient temperature of approximately 20°With and without forced convection. After the sample temperature reaches approximately 20°C, it can withstand under specified conditions, at least within 2 hours. Then sealed container vigorously shaken until then, until a visually homogeneous distribution of the solid particles. Immediately after that, the container with the sample placed in a magnetic stirrer and rotate it at a speed sufficient to maintain a homogeneous distribution of the solid particles. An aliquot of 10 ml of a mixture of liquids with suspended solid substances are taken using a pipette and weighed. Then a large part of the liquid phase from the specified aliquots, still at a temperature of 20°C, remove vacuum filtration thus, to avoid loss of solids. Selected from the specified aliquot of wet solids are then dried so as to avoid sublimation of solids, and the resulting dried solids weighed. The ratio of the weight of the dried solids to the mass of the original aliquot of the suspension is the fraction of solid is exist, which is usually expressed in percentages and refer to in this description as the content of solid substances deposited at a temperature of 20°C from the original solvent.

The authors of the present invention have discovered that aromatic compounds dissolved in the liquid phase reaction medium, which are aromatic carboxylic acids that do not contain non-aromatic hydrocarbon group (in particular, isophthalic acid, benzoic acid, phthalic acid, 2,5,4'-tricarboxymethyl), unexpectedly harmful components. Despite the fact that the chemical activity of these compounds is significantly reduced in this reaction medium in comparison with are able to oxidize a compound containing non-aromatic hydrocarbon group, the authors of the present invention have found that these compounds, however, suffer a number of undesirable transformations. Thus, it is necessary to control the content of these substances in the liquid phase reaction medium in the acceptable range. Thus, there are preferred boundary for the selected compounds in the feed to the process is recycled to the solvent, and the preferred boundary for the selected precursors in the source is able to oxidize aromatic compounds.

For example, the authors present asego invention installed, while carrying out liquid-phase partial oxidation of para-xylene with the formation of terephthalic acid (TPA) are strongly colored and undesirable impurity 2,7-dicarboxylate (2,7-DCF) is almost impossible to detect in the reaction medium and paged the product, if the content of the meta-substituted aromatic compounds in the reaction medium is at very low levels. The authors of the present invention found that when a mixture of isophthalic acid is present in increasing amounts in the original solvent, the formation of 2,7-DCF increases almost in direct proportion. The authors present invention also found that, when in the original para-xylene is a mixture of meta-xylene, the formation of 2,7-DCF again increases almost in direct proportion. Moreover, the authors of the present invention have found that even in the case when the original solvent and the source is able to oxidize the compound does not contain meta-substituted aromatic compounds, some amount of isophthalic acid is formed in the process of a typical partial oxidation of very pure para-xylene, especially when in the liquid phase reaction medium is benzoic acid. Specified independently formed isophthalic acid, due to its great is th, than TRA, solubility in a solvent comprising acetic acid and water that can accumulate in sites of industrial plants that use recycled solvent. Thus, the amount of isophthalic acid in a solvent, the amount of meta-xylene in the source is able to oxidize aromatic compounds and speed independent education isophthalic acid in the reaction medium accordingly should be considered in balance with each other and in balance with any reactions that consumed isophthalic acid. It was found that isophthalic acid, in addition to the above education 2,7-DCF, shall enter into additional reactions, which are discussed below. In addition, the authors of the present invention found that when establishing appropriate boundaries for the meta-substituted aromatic compounds by the partial oxidation of para-xylene with the formation of the TRA should consider other problems. It turned out that other highly colored and undesirable compounds such as 2,6-dicarboxylate (2,6-DCF), largely refer to the dissolved vapor-replaced aromatic compounds, which are always present in the original para-xylene used in the reaction of liquid-phase oxidation. Thus, the suppression of the formation of 2,7-DCF should Rass is atrevete in perspective with the other formed of the colored impurities.

For example, the authors of the present invention found that when the liquid-phase partial oxidation of para-xylene with obtaining TRA education trimellitic acid increases with increasing levels of isophthalic acid and phthalic acid in the reaction medium. Trimellitate acid is trehosnovnoy carboxylic acid, which causes branching of the polymer chain in the process of getting a PET from TRA. In many applications of PET levels of branching of the polymer chain must be controlled low, and thus in purified TPA levels trimellitic acid must be controlled low. In addition to education trimellitic acid, the presence of meta-substituted and ortho-substituted compounds in the reaction medium leads to the formation of other trekhosnovnykh acids (in particular, 1,3,5-tricarboxylate). In addition, the increase in the content trekhosnovnykh acids in the reaction medium leads to an increase in the number formed by tetracarbonyl acid (in particular, 1,2,4,5-tetracarboxylate). In accordance with the present invention, controlling the total education of aromatic acids containing more than two carboxyl groups, is one of the factors in setting the preferred levels of meta-substituted and ortho-substituted compounds in the feed to the process rezic the new solvent, in the source is able to oxidize the compound in the reaction medium.

For example, the authors of the present invention found that when the liquid-phase partial oxidation of para-xylene with obtaining TRA elevated levels in the liquid phase reaction medium short dissolved aromatic carboxylic acids that do not contain non-aromatic hydrocarbon group, directly leading to increased formation of carbon monoxide and carbon dioxide. Specified increased formation of carbon oxides leads to a decrease of the product yield in terms of the oxidizer, and in terms of the ability to oxidize connection, in the latter case, because many of the jointly produced aromatic carboxylic acids, which, on the one hand, can be considered as impurities, on the other hand, also have commercial value. Thus, the proper removal of relatively soluble carboxylic acids that do not contain non-aromatic hydrocarbon group of the recycled solvent is of economic importance from the point of view of prevention of loss can oxidize aromatic compounds and oxidant, in addition to suppressing the formation of highly undesirable compounds, such as various fluorenone and trimellitate acid.

For example, the authors of this izopet the deposits found when the liquid-phase partial oxidation of para-xylene with obtaining TRA probably cannot avoid the formation of 2,5,4'-tricarboxymethyl. 2,5,4'-Tricarboxymethyl is trehosnovnoy aromatic acid, which is formed by condensation of two aromatic rings, probably due to condensation of dissolved para-substituted aromatic compounds with aryl radical, with aryl radical, probably formed during the decarboxylation or decarbonylation para-substituted aromatic compounds. Fortunately, 2,5,4'-tricarboxymethyl usually produced in smaller quantities than trimellitate acid and usually does not lead to a significant increase in branching of polymer molecules in the process of getting a PET. However, the authors of the present invention have found that elevated levels of 2,5,4'-tricarboxymethyl in the reaction medium in the oxidation of alkyl substituted aromatic compounds, in accordance with a preferred variant implementation of the present invention, lead to higher levels of the highly colored and unwanted 2,6-DCF. An increased amount of 2,6-DCF, probably formed of 2,5,4'-tricarboxymethyl by closing the loop with loss of a water molecule, however, the exact reaction mechanism is not known. If 2,5,4'-tricarboxymethyl, which is better than TRA, Rast is areeda in the solvent, containing acetic acid and water, allow to accumulate in the recycled solvent in too large quantities, the rate of conversion of 2,6-DCF may be unacceptably high.

For example, the authors of the present invention found that when the liquid-phase partial oxidation of para-xylene with obtaining TRA aromatic carboxylic acid, not containing non-aromatic hydrocarbon group (in particular, isophthalic acid, if present in the liquid phase in sufficient concentration, usually lead to a moderate suppression of the chemical activity of the reaction medium.

For example, the authors of the present invention found that when the liquid-phase partial oxidation of para-xylene with obtaining TRA deposition often occurs imperfectly (i.e. high) in relation to the relative concentrations of various chemical compounds in the solid phase and in the liquid phase. This is probably due to the fact that the deposition rate is too high for the preferred spatial-temporal velocity according to the present invention, which leads to imperfect coprecipitation of impurities and even clogging. Thus, in the case where it is desirable to limit the concentration of certain impurities (in particular, trimellitic acid and 2,6-DCF) in crude TPA due to the organization's operations in subsequent stages of the process of, it is desirable to control the concentration of impurities in the original solvent, and the speed of their formation in the reaction medium.

For example, the authors of the present invention have found that derivatives of benzophenone compounds (in particular, 4,4'-dicarbocyanine and 2,5,4'-tricarbocyanine), which are formed by liquid-phase partial oxidation of para-xylene, have an undesirable effect on the reaction medium, in which the PET, even though benzophenone derivatives themselves are not so much coloring TRA compounds, as fluorenone and anthraquinones. Thus, it is desirable to minimize the presence of benzophenone and their respective predecessors in recycled solvent and the source, is able to oxidize the connection. In addition, the authors of the present invention have found that the presence of high amounts of benzoic acid, regardless of whether they came together with recycled solvent or formed in the reaction medium leads to increased rates of formation of 4,4'-dicarbocyanine.

To summarize the above, the authors of the present invention discovered and conduct a meaningful quantitative assessment of unexpected chain reactions, characteristic of aromatic compounds not containing non-aromatic pleva Horodnya group, present when carrying out liquid-phase partial oxidation of para-xylene with the formation of TRA. Summing up the above for only one case of benzoic acid, it can be noted that the authors of the present invention have found that elevated levels of benzoic acid in the reaction medium in some embodiments, implementation of the present invention result in a significant increase in the formation of highly colored and unwanted 9-fluorenone-2-carboxylic acid, significantly increased levels of 4,4'-dicarboxyethyl to higher levels of 4,4'-dicarbocyanine to moderate suppression of the chemical activity of para-xylene during its oxidation to elevated levels of carbon oxides and associated loss of product yield. The authors of the present invention have found that elevated levels of benzoic acid in the reaction medium also lead to the formation of isophthalic acid and phthalic acid levels which, in accordance with other aspects of the present invention, it is desirable to control in a narrow range. The number and importance of reactions in which it participates benzoic acid, seems even more surprising, as some researchers suggest using benzoic acid instead of acetic acid as a component of the solvent (see, in particular, U.S. patent is the 6562997). In addition, the authors of the present invention have observed that benzoic acid is formed by oxidation of para-xylene with speeds that appear to be very important in comparison with its formation of impurities, such as toluene and ethylbenzene, which are usually contained in the source is able to oxidize the connection representing a commercially pure para-xylene.

On the other hand, the authors of the present invention have found little benefit from additional regulation of the composition of the recycled solvent in the presence relationship is able to oxidize aromatic compounds and in relation to the intermediate aromatic compounds, which remain non-aromatic hydrocarbon group, and at the same time have a relatively high solubility in recycled solvent. In General, these compounds or act in a reactionary environment, or formed in the reaction medium with velocities that lead to the fact that their number is significantly higher than their presence in recycled solvent; the rate of consumption of these compounds in the reaction medium is high enough, if they maintain one or more non-aromatic hydrocarbon groups, which consequently limits their accumulation in the recycled solvent. E.g. the measures during partial oxidation of para-xylene in a multiphase reaction medium para-xylene is evaporated to a limited extent compared to the large quantities of solvent. When the specified evaporated the solvent leaves the reactor as part of the exhaust gas and condensed to extract for use as a recycled solvent, a significant portion of the evaporated para-xylene is also condensed. There is no need to limit the concentration specified para-xylene in the recycled solvent. For example, if the solvent is separated from the solid substances in suspension, which is derived from the reaction medium, which is the oxidation of para-xylene, the concentration of para-Truelove acid extracted in the specified solvent will be comparable with the concentration of para-Truelove acid at the point of removal of the suspension from the reaction medium. Despite the fact that may be important, as described below, limit established the concentration of para-Truelove acid in the liquid phase reaction medium, there is no need to separately regulate the content of para-Truelove acid in the specified portion of the recycled solvent due to the relatively good solubility and relatively low mass transfer rate pair-Truelove acid compared with the formation of p is RA-Truelove acid in the reaction medium. By analogy, the authors of the present invention found that, in accordance with a preferred variant implementation of the present invention there is no need to limit the recycled solvent concentration of aromatic compounds with methyl groups (in particular, Truelove acids), aromatic aldehyde (in particular, terephthalic aldehyde, aromatic compounds with hydroxymethylene substituents (in particular, 4-hydroxymethylbenzene acid) and Poslednij aromatic compounds, while retaining at least one non-aromatic hydrocarbon group (in particular, alpha-bromo-para-Truelove acid) lower than that naturally present in the liquid phase, withdrawn from the reaction medium formed by partial oxidation of xylene. The authors of the present invention unexpectedly found that there is also no need to adjust in recycled solvent concentration of individual phenols which are usually formed during the partial oxidation of xylene, because the rate of formation and decay of these compounds in the reaction environment are more important than the content in the recycled solvent. For example, the authors of the present invention have found that 4-hydroxybenzoic acid has a relatively small effect for the e on the chemical activity in preferred embodiments, the implementation of the present invention, when it is introduced into the reactor in the amount of about 2 g of 4-hydroxybenzoic acid per 1 kg of para-xylene, which is much higher than its natural presence in recycled solvent, despite the fact that, as reported by other authors, she has a significant toxic effect in such reaction media (see, in particular, W.Partenheimer, Catalysis Today 23 (1995) p.81).

Thus, as disclosed herein, there are many reactions, and when establishing the preferred boundaries for various aromatic compounds it is necessary to take into account many factors. The identified patterns are expressed in terms of the total average weight of the composition of all streams of solvent, which enter into the reaction medium for a certain period of time, preferably within one day, more preferably within one hour, and most preferably within one minute. For example, if one stream of solvent is fed continuously with a speed of 7 kg per minute, while the content of isophthalic acid in it is 40 ppm wt., and the second stream of solvent is fed continuously at a rate of 10 kg per minute, while the content of isophthalic acid in it is 2000 ppm wt., and other threads of the solvent in the reaction medium is no longer supplied,the total average weight of the composition of the incoming solvent is calculated as(40*7+2000*10)/(7+10)=1193 ppm wt. isophthalic acid. It should be noted that the weight of any source is able to oxidize compounds or any source of oxidizer, which can be mixed with the original solvent before they enter the reaction medium, is not taken into account when calculating the total average weight of the composition of the solvent.

In the following table 1 shows preferred values for some of the components in the original solvent, which is fed into the reaction environment. Table 1 shows the following components of the original solvent: 4-carboxybenzene (4-CBA), 4,4'-dicarbonitrile (4,4'-DCS), 2,6-dicarboxaldehyde (2,6-DCA), 2,6-dicarboxylate (2,6-DCF), 2,7-dicarboxylate (2,7-DCF), 3,5-dicarboxylate (3,5-DCF), 9-fluorenone-2-carboxylic acid (9F-SA), 9-fluorenone-4-carboxylic acid (9F-SA), the total number of fluorenone, including other fluorenone not included in the list of individual fluorenone (total content of fluorenone), 4,4'-dicarboxyethyl (4,4'-DCB), 2,5,4'-tricarboxymethyl (2,5,4'-TCB), phthalic acid (RA), isophthalic acid (IPA), benzoic acid (BA), trimellitate acid (TMA), 2,6-dicarboxylicacid (2,6-DCBC), 4,4'-dicarboxyethyl (4,4'-DCBZ), 4,4'-dicarbocyanine (4,4'-DCBP), 2,5,4'-tricarbocyanine (2,5,4'-TSWR), terephthalic acid (TPA), settled solids in temp is the temperature of 20°C and the total content of aromatic carboxylic acids, lacking non-aromatic hydrocarbon group. The following table 1 shows a preferable amount of these impurities in a HUNDRED, obtained in accordance with the embodiment of the present invention.

Table 1
Components of the initial solvent, supplied in a reaction medium
Designation connectionThe preferred quantity (ppm wt.)A more preferred amount (ppm wt.)The most preferred amount (ppm wt.)
4-CBA<120030-60060-300
4,4'-DCS<3<2<1
2,6-DCA<60,1-30,2-1
2,6-DCF<200,1-100,5-5
2,7-DCF<10 0,1-50,5-2
3,5-DCF<10<5<2
9F-SA<100,1-50,5-2
9F-SA<5<3<1
The total content of fluorenone<40<201-8
4,4'-DCB<45<150,5-5
2,5,4'-TCB<450.1 to 150,5-5
RA<100015-40040-150
IPA250040-1200120-400
BA<450050-1500150-500
TMA<100015-400 40-150
2,6-DCBC<40<20<5
4,4'-DCBZ<40<20<5
4,4'-DCBP<40<20<5
2,5,4'-DVR<40<200,5-5
TRA<9000200-6000400-2000
Settled solids at 20°C<9000200-6000600-2000
The total content of aromatic carboxylic acids, lacking non-aromatic hydrocarbon group<18000300-9000450-3000

Many other aromatic impurities usually present in the recycled solvent, and their levels usually vary in much smaller proportions relative to one or more of the disclosed aroma is of soedinenii. Methods of controlling aromatic compounds disclosed in the preferred boundaries, as a rule, allow you to support other aromatic impurities to acceptable levels.

It is known that in the case when the reaction medium is applied bromine, in dynamic equilibrium can exist many ionic and organic forms of bromine. After they leave the reaction medium into different installation sites associated with the recycling of the solvent, these different forms of bromine show different levels of stability. For example, alpha-bromo-para-tolarova acid can under certain conditions be maintained in the form of molecules, and other conditions can quickly be either hydrolyzed with the formation of 4-hydroxymethylbenzene acid and hydrogen bromide. In the present invention, preferably, at least about 40 wt.%, more preferably, at least about 60% wt. and, most preferably, at least about 80% wt. from the total amount of bromine present in the common source solvent supplied to the reaction medium contains one or more of the following forms: ions, bromide, alpha-bromo-para-tolarova acid and brooksyne acid.

Although the importance and value of monitoring the overall average weight of the purity of the original rest is rites disclosed in the present invention the extent necessary not previously been detected and/or disclosed, appropriate ways of controlling the purity of the original solvent can be grouped from different methods which are already known from the technical field. First, any solvent evaporated from the reaction medium, as a rule, has a suitable purity, provided that the liquid or solid substances from the reaction environment is not captured evaporated solvent. Applying droplets of the solvent for irrigation above the reaction medium space used to separate exhaust gas, as disclosed in the present invention, allows, respectively, to reduce such grasping; from the specified exhaust gas can be condensed recycled solvent, which has a suitable purity relative to aromatic compounds. Secondly, more complex and costly cleanup entering the reactor recycled solvent, usually refers to a solvent which is removed from the reaction medium in liquid form, and to the solvent, which is substantially in contact with liquid and/or solid phases of the reaction medium to be extracted from the reaction medium (in particular, this applies to the recycled solvent obtained after the filter where the solids are concentrated and/or washed, recycled solvent, the floor is UEMOA after centrifuge, where the solids are concentrated and/or washed, recycled solvent, separated after the operations of crystallization, and the like). However, from the field of engineering known means to carry out the necessary cleaning of the flows of recycled solvent using one or more of the previously disclosed methods. Appropriate means of controlling precipitated substances in recycled solvent within the specified limits are, but not limited to, gravity sedimentation, mechanical filtration using a filter cloth on a rotating belt filters or rotary drum filters, mechanical filtration using fixed filter medium in the pressure vessels, hydrocyclones and centrifuges. Means controlling the dissolved aromatic compounds in the recycled solvent in these limits are, however, not limited to the means disclosed in U.S. patent No. 4939297, and application for U.S. patent No. 2005-0038288, which is incorporated into this description by reference. However, none of these known inventions are not found and are not disclosed preferred levels of purity common source of solvent, as disclosed in the present invention. In azannyh known inventions only available cleaning methods selected and the partial flows of recycled solvent, of which cannot be inferred in the present description, the optimum values for the total average weight of the composition of the solvent supplied into the reaction environment.

As for the purity of the source is able to oxidize compounds, it is known that it contains a certain amount of isophthalic acid, phthalic acid and benzoic acid, low levels of which are valid in the purified TPA used in the production of polymers. Moreover, it is known that these substances are relatively better soluble in many solvents, and therefore can easily be removed from the purified TPA using crystallization processes. However disclosed in this description of the preferred alternative implementation of the present invention it is now known that controlling the level of a few relatively easily soluble aromatic substances, namely comprising isophthalic acid, phthalic acid and benzoic acid in the liquid phase reaction medium was suddenly important to control the level of polycyclic and painted aromatic compounds formed in the reaction medium, for controlling compounds containing more than two carboxyl groups in the molecule, for controlling reactivity in the environment, which is partial oxidation, and to whom toleromune affecting the product yield losses oxidant and aromatic compounds.

From the field of technology it is known that isophthalic acid, phthalic acid and benzoic acid formed in the reaction medium as follows. The mixture of meta-xylene feedstock with a good yield of oxidized with the formation of the IPA. The mixture of ortho-xylene feedstock with a good yield of oxidized with the formation of phthalic acid. Admixture of benzene and toluene feedstock with a good yield of oxidized with the formation of benzoic acid. However, the authors of the present invention found that a significant number of isophthalic acid, phthalic acid and benzoic acid formed in the reaction medium containing para-xylene, as a result of processes other than oxidation of meta-xylene, ortho-xylene, ethylbenzene and toluene. These specific chemical reaction may include decarbonylation, decarboxylation, transformation, transition States and the inclusion of the methyl and carbonyl radicals in the aromatic cycles.

When determining the preferred limits for impurities in the source is able to oxidize the connection, you must consider many factors. Any impurity in the feedstock would result in direct losses in yield and cost of cleaning product, if the requirements for the purity of the product of oxidation are quite hard (in particular, in the reaction with the food, where is the partial oxidation of para-xylene, toluene and ethylbenzene, which are typically found in commercially pure para-xylene, lead to the formation of benzoic acid and the benzoic acid is substantially removed in most cases produced in an industrial scale TRA). In the case when the product of partial oxidation of impurities, received together with the raw material, participate in additional reactions, when determining cleanup costs of raw materials should take into account not only the loss of product yield, but also to consider and address other factors (in particular, in the reaction medium, which is a partial oxidation of para-xylene, ethylbenzene results, along with other things, to the formation of benzoic acid, and benzoic acid, in turn, leads to a highly colored 9-fluorenone-2-carboxylic acid, isophthalic acid, to phthalic acid and high amounts of carbon oxides). In that case, when the reaction medium forms an additional amount of impurities due to the chemical reactions that are not directly related to the available feedstock impurities, then the analysis becomes even more complicated (in particular, in the reaction medium, which is a partial oxidation of para-xylene, benzoic acid is formed and also the para-xylene). In addition, requirements for the preferred purity of the feedstock may be affected and further processing of the crude oxidation product. For example, the cost of removal to acceptable levels direct additives (benzoic acid) and derivatives of impurities (isophthalic acid, phthalic acid, 9-fluorenone-2-carboxylic acid and the like) can be the same, may differ from each other and may be different from the requirements for removal mostly not relevant to this category of impurities (in particular, 4-CBA - product of incomplete oxidation in the oxidation of para-xylene with the formation of TRA).

Disclosed below ranges of original purity para-xylene are preferred in the case when para-xylene together with the solvent and oxidant is fed into the reaction environment for partial oxidation with the formation of TRA. These ranges are preferred for the process of receiving TRA, which implies Oleochemicals stages, aimed at the removal of impurities other than the oxidant and solvent (in particular, metal catalyst). These ranges even more preferred ways of receiving TRA, which is the removal of the additional amount of 4-CBA from a HUNDRED (in particular, by turning one HUNDRED per terephthalate plus primany the esters and subsequent separation of methyl ester of 4-CBA by distillation, using the methods of oxidative degirolami, with the aim of turning the 4-CBA TPA, using the methods of hydrogenation, with the aim of turning the 4-CBA in the para-Truelove acid, which is then separated by the methods of fractional crystallization). These ranges are preferred for production TRA, which is the removal of the additional amount of 4-CBA from a HUNDRED using the methods of oxidative deliriouse to transform 4-CBA TPA.

On the basis of new data on the preferred ranges recycling of aromatic compounds and the relative amounts of aromatic compounds, which are formed directly contained in the feedstock impurities, in comparison with other possible ways of proceeding chemical reactions, installed improved ranges for impurities in the crude para-xylene, which is used for carrying out the partial oxidation process when receiving TPA. In the following table 2 shows the preferred values for the number of meta-xylene, ortho-xylene and ethyl benzene + toluene in the original para-xylene.

Table 2
Components of the crude para-xylene
The name of the component The preferred quantity (ppm wt.)A more preferred amount (ppm wt.)The most preferred amount (ppm wt.)
meta-xylene20-80050-600100-400
ortho-xylene10-30020-20030-100
the benzene + toluene*20-70050-500100-300
the total number of50-900100-800200-700
* Specification for mixture benzene + toluene is given for each connection separately and the total amount

Professionals should be clear that the above impurities in the crude para-xylene can have the greatest impact on the reaction medium after the products of their partial oxidation accumulate in the recycled solvent. For example, the receipt of meta-xylene in an amount corresponding to the upper level of the most preferred range, i.e. 400 ppm wt., non the Lenna leads to the formation of approximately 200 ppm masisilaw acid in the liquid phase reaction medium in the case when the content of solids in the reaction medium is approximately 33% wt. This is comparable with the number corresponding to the upper limit, the component 400 ppm wt., the most preferred range for isophthalic acid in the recycled solvent, which after a typical evaporation of the solvent, carried out for the purpose of cooling the reaction medium, leads to the formation of approximately 1200 ppm wt. isophthalic acid in the liquid phase reaction medium. Thus, the most likely effect meta-xylene, ortho-xylene, ethylbenzene and toluene contained in the original crude para-xylene, is the accumulation over time of products of partial oxidation in the recycled solvent. Thus, the above ranges for impurities in the original crude para-xylene, preferably, should be maintained for at least half of each day of the process in any reaction medium for carrying out partial oxidation in a specific industrial setting, more preferably, at least within three quarters of each day, for at least seven consecutive days of the process and, most preferably, in the case to the da average mass values of the composition of the crude para-xylene are in the preferred range, for at least 30 days of continuous operation.

Methods of obtaining containing impurities para-xylene is the preferred purity is known from the field of machinery and shall include, but not limited to, distillation, methods of fractional crystallization at temperatures below room temperature, and methods of using molecular sieves, including selective adsorption depending on the size of the pores. However, the maximum requirements described in this description of the preferred ranges of purity, are too high and expensive compared to those that are usually provided by commercial suppliers of para-xylene; at the same time, the minimum requirements regarding the preferred ranges of purity, thus avoiding unnecessary costly purification of para-xylene fed to the reaction medium for carrying out partial oxidation, as established and disclosed, where the combined effects of self-education impurities from the para-xylene and reactions consumption impurities in the reaction medium becomes more important than the levels of impurities introduced with the crude para-xylene.

In that case, when containing para-xylene stream source includes substances selected impurities such as benzene and/or toluene, OK is slena these impurities can lead to the formation of benzoic acid. In this description, the term “formed from impurities benzoic acid” refers benzoic acid obtained from a source other than xylene by oxidation of xylene.

As disclosed in the present invention, part of the benzoic acid from the oxidation of xylene, is formed from the xylene. This benzoic acid is formed from xylene explicitly advanced in respect of any fraction resulting benzoic acid, which can be a benzoic acid obtained from impurities. Not to commit himself to any theory, the authors present invention believe that benzoic acid is formed from xylene in the reaction medium in the case when various intermediate oxidation products of xylene undergo spontaneous carbonyliron (loss of carbon monoxide) or decarboxylation (loss of carbon dioxide) with the formation of aryl radicals. These aryl radicals can be hydrogen atoms from one or more sources available in the reaction environment, and lead to self-generated benzoic acid. Regardless of the mechanism of occurrence of a chemical reaction, the term “self-generated benzoic acid” refers to benzoic acid, which is obtained from the xylene in the oxidation process.

As well as the aperture is raised in the present invention, in that case, when para-xylene is oxidized with the formation of terephthalic acid (TPA), the accumulation of self-generated benzoic acid leads to a decrease of the product yield in terms of para-xylene and in terms of the oxidant. In addition, the presence of self-generated benzoic acid in the liquid phase reaction medium correlates with the increase of many adverse reactions, including, in particular, the formation of a strongly colored compounds, called monocarboxylates. Self-generated benzoic acid also leads to undesirable accumulation of benzoic acid in the recycled filtrate, which leads to a further increase in the concentration of benzoic acid in the liquid phase reaction medium. Thus, the formation of self-generated benzoic acid, it is desirable to minimize, however, it is necessary to take into account, respectively, formed from the admixture of benzoic acid, the factors influencing the intake of benzoic acid, the factors that are associated with other problems of selectivity of reactions, General issues of economic development.

The authors of the present invention found that the independent formation of benzoic acid can be controlled at low levels by the appropriate selection voltage is emer, temperature, flow, xylene and the availability of oxygen in the reaction medium in the oxidation process. Not to commit himself to any theory, the authors present invention is believed that the low temperature and improved availability of oxygen, probably inhibit decarbonylation and/or decarboxylation and thereby avoids the problems associated with the independent formation of benzoic acid. Sufficient availability of oxygen directs aryl radicals towards the formation of less harmful products, in particular hydroxybenzoic acids. The distribution of xylene in the reaction medium can also affect the balance between the conversion of aryl radicals in benzoic acid or hydroxybenzoic acid. Regardless of the mechanism of occurrence of a chemical reaction, the authors present invention has determined the conditions of the reaction, which, despite the fact that they are soft enough to reduce the formation of benzoic acid at the same time are tough enough to oxidize a significant fraction formed hydroxybenzoic acids with getting monoxide and/or carbon dioxide, which are easily removed from the reaction product.

In a preferred embodiment of the present invention the oxidation reactor configured and operated so about what atom, to the formation of self-generated benzoic acid was minimized, and the oxidation of hydroxybenzoic acid with the formation of the monoxide and/or carbon dioxide was maximum. In the case when for oxidation of para-xylene with the formation of terephthalic acid using a reactor for carrying out the processes of oxidation of para-xylene, preferably, should be at least about 50% wt. from the total amount of xylene in the flow of raw materials fed to the reactor. More preferably, the para-xylene is at least about 75% wt. from the total amount of xylene in the flow of the parent compounds. Even more preferably, the para-xylene is at least about 95% wt. from the total amount of xylene in the flow of the parent compounds. Most preferably, the para-xylene is almost all the amount of xylene in the original thread connections.

If the reactor is the oxidation of para-xylene with the formation of terephthalic acid, the rate of receipt of terephthalic acid, preferably, should be the maximum, and the speed of obtaining self-generated benzoic acid should be minimal. The ratio of the speed (by weight) of terephthalic acid to speed (by weight) alone is obrazovavsheisya benzoic acid, preferably is at least about 500:1, more preferably is at least about 1000:1 and, most preferably, is at least 1500:1. As will be shown below, the speed of receiving self-generated benzoic acid, mainly measured when the concentration of benzoic acid in the liquid phase reaction medium is less than 2000 ppm wt., more preferably, less than 1000 ppm wt. and, most preferably, less than 500 ppm wt., as these low concentrations reduce to an acceptable low rate of reactions, in which benzoic acid is transformed into other compounds.

If you combine self-generated benzoic acid and formed from impurities benzoic acid, the ratio of the speed (by weight) of terephthalic acid to speed (by weight) of the total benzoic acid preferably is at least about 400:1, more preferably is at least about 700:1 and, most preferably, is at least 1100:1. As will be shown below, the total speed of obtaining self-generated benzoic acid plus formed from the admixture of benzoic acid, the benefits of the natural enemy, measured when the concentration of benzoic acid in the liquid phase reaction medium is less than 500 ppm wt., as these low concentrations reduce to an acceptable low rate of reactions, in which benzoic acid is transformed into other compounds.

As disclosed in the present invention, higher concentrations of benzoic acid in the liquid phase reaction medium lead to higher education many other aromatic compounds, several of which are harmful impurities in ENGLAND; and, as disclosed in the present invention, higher concentrations of benzoic acid in the liquid phase reaction medium lead to increased formation of gaseous oxides of carbon, and their formation leads to loss of yield in terms of the oxidant or aromatic compounds and/or loss of solvent. In addition, as disclosed in the present invention, the authors of the present invention found that a significant part of the specified increased formation of other aromatic compounds and oxides of carbon caused by reactions that transform a number of the molecules of benzoic acid, in contrast to benzoic acid, which catalyzes the occurrence of other reactions, in which she is not consumed. Thus, the sum of the Noah education benzoic acid” is defined herein as the time-averaged mass of benzoic acid, which leaves the reaction medium, minus the time-averaged mass of the entire benzoic acid, which enters the reaction medium during the same time period. Specified total education benzoic acid often has a positive value that is determined by the rate of receipt formed from impurities benzoic acid and self-generated benzoic acid. However, the authors of the present invention found that the rate of conversion of benzoic acid to carbon dioxide and some other compounds increases almost linearly with increasing concentration of benzoic acid in the liquid phase reaction medium, if the measurements are conducted when other conditions of the reaction, including temperature, oxygen availability, STR and activity of the reaction are maintained approximately constant. So, in that case, when the concentration of benzoic acid in the liquid phase reaction medium is large enough, possibly due to the high concentration of benzoic acid in the recycled solvent, then the transformation of molecules of benzoic acid to other compounds, including oxides of carbon, can match or even surpass the chemical formation of new molecules of benzoic acid. In this case, the size of the total education benzoic acid can balance near zero is or even become negative. The authors of the present invention found that in the case when the sum of the formation of benzoic acid has a positive value, the ratio of the rate of production (by weight) of terephthalic acid in the reaction medium speed total education of benzoic acid in the reaction medium, preferably, is greater than approximately 700:1, more preferably is greater than approximately 1100:1 and, most preferably, is greater than 4000:1. The authors of the present invention found that in the case when the value of the total education benzoic acid has a negative value, the ratio of the rate of production (by weight) of terephthalic acid in the reaction medium speed total education of benzoic acid in the reaction medium, preferably, is greater than about 200:(-1), more preferably is greater than about 100:(-1) and, most preferably, is greater than 5000:(-1).

The authors of the present invention have discovered the preferred ranges for the composition of a suspension (liquid + solid), which is unloaded from the reaction medium, and composition portions HUNDRED in suspension. It was unexpectedly found that the preferred composition of the suspension and the preferred composition of the HUNDRED are of great practical importance. Nab is emer, purified TRA obtained from the specified preferred one HUNDRED by oxidative degirolami, contains a fairly low level of impurities and colored impurities, so that the purified TPA suitable without further hydrogenation of 4-CBA and/or colored impurities for a wide range of applications of PET in the manufacture of fibers and packaging materials. For example, a preferred composition of the suspension, as indicated in the description, allows to obtain a liquid phase reaction medium, which contains a relatively low number of important impurities and thereby significantly reduces the formation of other, even more undesirable impurities, as specified in this description. In addition, the preferred composition of the suspension, in accordance with the preferred embodiment of the present invention greatly facilitates subsequent processing liquid contained in the suspension, in order to obtain enough clean recycled solvent.

One HUNDRED and obtained in accordance with the embodiment of the present invention, contains less impurities specified type than a HUNDRED obtained using conventional methods and systems, in particular those where the use of recycled solvent. Impurities that may be present in a HUNDRED, include the following: 4-carboxybenzene (4-CBA), 44'-dicarbonitrile (4,4'-DCS), 2,6-dicarboxaldehyde (2,6-DCA), 2,6-dicarboxylate (2,6-DCF), 2,7-dicarboxylate (2,7-DCF), 3,5-dicarboxylate (3,5-DCF), 9-fluorenone-2-carboxylic acid (9F-SA), 9-fluorenone-4-carboxylic acid (9F-SA), 4,4'-dicarboxyethyl (4,4'-DCB), 2,5,4'-tricarboxymethyl (2,5,4'-TCB), phthalic acid (RA), isophthalic acid (IPA), benzoic acid (VA), trimellitate acid (TMA), para-tolarova acid (RTAS), 2,6-dicarboxylicacid (2,6-DCBC), 4,4'-dicarboxyethyl (4,4'-DCBZ), 4,4'-dicarbocyanine (4,4'-DCBP), 2,5,4'-tricarbocyanine (2,5,4'-TSWR). The following table 3 presents the preferred amounts of these impurities in a HUNDRED, obtained in accordance with the embodiment of the present invention.

Table 3
Impurities in a HUNDRED
Designation connectionThe preferred quantity (ppm wt.)A more preferred amount (ppm wt.)The most preferred amount (ppm wt.)
4-CBA<15000100-8000400-2000
4,4'-DCS <12<6<3
2,6-DCA<9<6<2
2,6-DCF<1002-505-25
2,7-DCF<30<15<5
3,5-DCF<16<8<2
9F-SA<16<8<4
9F-SA<8<4<2
The total content of fluorenone<1002-604-35
4,4'-DCB<641-322-8
2,5,4'-TCB<24<12<8
RA<20 3-1005-50
IPA<80010-40020-200
BA<6005 are 30015-100
TMA<80010-40020-200
RTAS<200010-100050-500
2,6-DCBC<64<32<8
4,4'-DCBZ<12<8<4
4,4'-DCBP<40<30<20
2,5,4'-DVR<32<16<4

In addition, one HUNDRED, obtained in accordance with the embodiment of the present invention, preferably, less colored in comparison with a HUNDRED, obtained using conventional methods and systems, in which lastnosti those where to use the recycled solvent. So, a HUNDRED, obtained in accordance with one embodiments of the present invention, preferably has a percent transmittance at 340 nm, is equal to at least about 25%, more preferably at least about 50% and most preferably at least 60%. Next, a HUNDRED, obtained in accordance with one embodiments of the present invention preferably has a percent transmittance at 400 nm, is equal to at least about 88%, more preferably at least about 90% and most preferably at least 92%.

Test on the percent transmittance is a measure of the contents colored, light-absorbing impurities in TRA or a HUNDRED. In this description, is the test measurements, which are performed for portions of a solution obtained by dissolving 2.00 g of dry solid TPA or a HUNDRED in of 20.0 ml of dimethyl sulfoxide (DMSO), with the qualification of “pure for analysis” or better. A portion of the specified solution is then placed in palomacrataceous the Hellma cell, PN 176700, which is made of quartz and has a light path of 1.0 cm and a volume of 0.39 ml (Hellma USA, 80 Skyline Drive, Plainview, NY 11803). To determine the transmission through the specified filled flow cell at a different wavelength of light used spectrophotometers diode matrix Agilent 8453 Diode Array Spectrophotometer (Agilent Technologies, 395 Page Mill Road, Palo Alto, CA 94303). After an appropriate correction for background absorption, including absorption of the specified cell and the used solvent, data on the percentage of bandwidth that characterizes the fraction of the incident light, which has passed through the solution, directly to the specified device. Data on the percentage of light transmittance at wavelengths of 340 and 400 nm are most suitable for separating pure TRA from many impurities, which, as a rule, are in it.

The following table 4 presents the preferred boundaries for various aromatic impurities in the phase of the suspension (solid + liquid) reaction medium.

<1
Table 4
Impurities in suspension
Designation connectionThe preferred quantity (ppm wt.)A more preferred amount (ppm wt.)The most preferred amount (ppm wt.)
4-CBA<8000<5000<2500
4,4'-DCS<4<2
2,6-DCA<6<3<1
2,6-DCF<702-404-20
2,7-DCF<12<8<4
3,5-DCF<12<8<4
9F-SA<12<8<4
9F-SA<8<4<2
The total content of fluorenone<902-605-30
4,4'-DCB<641-162-4
2,5,4'-TCB<602-404-20
RA<300025-150075-500
IPA<900075-4500225-1500
BA<15000100-6000300-2000
TMA<300025-150075-500
RTAS<8000100-4000200-2000
4,4'-DCBZ<5<4<3
4,4'-DCBP<240<160<80
2,5,4'-DVR<120<80<40

These preferred compositions suspension include the preferred composition of the liquid phase reaction medium and to avoid experimental difficulties caused by the deposition of additional components of the liquid phase of reaction medium on the components of the solid phase in the selection process of the sample from the reaction medium, the separation of liquids and solids and changes directed by the Dom analysis.

Many other aromatic impurities, as a rule, are also present in the phase of the suspension in the reaction medium contained in the reaction medium HUNDRED and usually vary less with levels and/or proportions relative to one or more disclosed aromatic compounds. Controlling aromatic compounds disclosed in the preferred boundaries allows you to maintain acceptable levels and other aromatic impurities. These preferred compounds for phase suspension in the reaction medium and the solid of one HUNDRED, which define directly in suspension, are achieved through the implementation described in this description of embodiments of the present invention for the partial oxidation of para-xylene with the formation of TRA.

The measurement of the concentration of the components present in low levels, in a solvent, recycled solvent, a HUNDRED, of the suspension from the reaction medium and the MOUTH is done using methods of liquid chromatography. The following are two equivalent variants of implementation of the present invention.

The method, which in this description referred to as HPLC-DAD, includes liquid chromatography high resolution (HPLC) in conjunction with detection by diode array (DAD), to conduct a separate quantification of molecules is of hypoxia substances in the selected sample. To conduct these measurements use the model 1100 HPLC equipped with a detector diode matrix, which produces the company Agilent Technologies (Palo Alto, California), although suitable analytical instruments commercially available from other manufacturers. As is known from the field of technology, as the time of elution, and the output signal of the detector is calibrated using known compounds, which are present in known quantities, while compounds and their quantities correspond to those found in real unknown specimens.

The method, which in this description referred to as HPLC-MS, includes liquid chromatography high resolution (HPLC)coupled with mass spectrometry (MS)for separation, identification and quantification of molecules of different substances in the sample. For measurements using analytical instruments Alliance HPLC and ZQ MS, which manufactures the company Waters Corp. (Milford, Massachusetts), although suitable analytical instruments commercially available from other manufacturers. As is known from the field of technology, as the time of elution, and the output signal of the mass spectrometer is calibrated using known compounds, which are present in known quantities, while compounds and their quantities correspond to those found in the real unknown is STN samples.

Another variant of implementation of the present invention relates to the partial oxidation is able to oxidize aromatic compounds with appropriate balance between the suppression of harmful aromatic impurities, on the one hand, and between carbon dioxide and carbon monoxide, which indicate a General term carbon oxides (SoH), on the other hand. Typically, these oxides of carbon leave the reactor together with the exhaust gases, and they correspond to the destructive loss of solvent and able to oxidize compounds, including, ultimately, the preferred oxidized derivatives (in particular, acetic acid, para-xylene and TRA). The authors of the present invention have established lower bounds for the formation of carbon oxides, below which, apparently, significant formation of harmful aromatic impurities, as indicated below, and the General low level of conversion inevitably become too unfavorable so that you can consider carrying out the process economically feasible. The authors of the present invention has also established upper bounds for the formation of carbon oxides, above which the formation of carbon oxides continues to increase, and further improvements related to the reduction of harmful aromatic impurities, no longer on udaetsya.

The authors of the present invention have found that the reduction in the liquid phase reaction medium concentrations is able to oxidize the original aromatic compounds and intermediates of aromatic compounds decreases the speed of formation of harmful impurities in the partial oxidation process is able to oxidize aromatic compounds. These impurities include condensed aromatic cycles and/or aromatic molecules containing more than necessary carboxyl groups (in particular, in the oxidation of para-xylene impurities include 2,6-dicarboxaldehyde, 2,6-dicarboxylate, trimellitic acid, 2,5,4'-tricarboxymethyl and 2,5,4'-benzophenone). Intermediate aromatic substances include aromatic compounds that come along with capable to oxidize the original aromatic compound and still maintain the non-aromatic hydrocarbon group (in particular, in the oxidation of para-xylene in the intermediate aromatic substances include para-tolualdehyde, terephthalaldehyde, para-Truelove acid, 4-CBA, 4-hydroxymethylbenzene acid and alpha-bromo-para-Truelove acid). Able to oxidize the original aromatic compound and intermediate aromatic substances, preserving non-aromatic hydrocarbon groups, if they are present in W is dcoi phase reaction medium, apparently, lead to harmful impurities in the same way as mentioned in this description for dissolved aromatic substances, not containing non-aromatic hydrocarbon group (in particular, for isophthalic acid).

Solving the problem of increasing the activity of the reaction in order to suppress the formation of toxic aromatic impurities in the partial oxidation process is able to oxidize aromatic compounds, the authors of the present invention have found that undesirable concomitant result is an increase in the formation of carbon oxides. It is important to understand that these oxides of carbon are lost not only oxidant, but also able to oxidize compounds and oxidant. Obviously, significant and sometimes basic fraction of carbon oxides formed from able to oxidize compounds, its derivatives, and not solvent; and the cost is able to oxidize compounds in terms of a carbon unit, often considerably more than the cost of the solvent. In addition, it is important to understand that the carboxylic acid, which is the target product (in particular, TRA), is also subject to excessive oxidation to oxides of carbon when it is present in the liquid phase reaction medium.

It is also important to understand that the present invention relates to reactions, proteous the m in the liquid phase reaction medium and the concentration of reagents in it. It differs in this way from some famous inventions that relate directly to the reaction precipitated solid form aromatic compounds, preserving the non-aromatic hydrocarbon group. In particular, in the case of partial oxidation of para-xylene with the formation of TRA, some famous inventions related to the number of 4-CBA, deposited in the solid phase of the HUNDRED. However, the authors of the present invention found that there is a discrepancy of more than two to one for the ratio of 4-CBA in the solid phase to the amount of 4-CBA in the liquid phase under other equal parameters for temperature, pressure, catalysis, solvent composition and spatio-temporal velocity para-xylene, depending on whether partial oxidation in a well-mixed autoclave or in a reaction medium, in which the oxygen and para-xylene are distributed in accordance with the present invention. In addition, the authors of the present invention have found that the ratio of the number of 4-CBA in the solid phase to the amount of 4-CBA in the liquid phase may also vary more than two to one as in the well-mixed reaction medium and the reaction medium, where a certain distribution of reagents, depending on the speed of the spatial and temporal reaction of para-xylene, ceteris paribus pair is the parameters for temperature, pressure, catalysis and composition of the solvent. In addition, 4-CBA in the solid phase of a HUNDRED, apparently, does not lead to the formation of harmful impurities, and 4-CBA can be distinguished from the solid and easily with a large output docility in ENGLAND (in particular, by oxidative deliriouse suspension HUNDRED, as indicated in this description); while removing harmful impurities is significantly more difficult and expensive procedure than removing the solid phase 4-CBA, and the formation of oxides of carbon leads to a permanent loss in product yield. Thus, it is necessary to distinguish that this aspect of the present invention concerns compositions of the liquid phase reaction medium.

The authors of the present invention have found that no matter what is the source of a solvent or able to oxidize connection when performing transformations on an industrial scale, the formation of carbon oxides is directly determined by the level of General activity of the reaction, regardless of variation in a wide range of specific combinations of temperature, metals, Halogens, temperature, acidity of the reaction medium, determined by the pH value, the concentration of water used to achieve a level of overall activity of the reaction. The authors of the present invention found that, by partial oxidation of xylene should assess the level is ü total activity reaction using concentration Truelove acids in the liquid phase at half the height of the reaction medium, in the lower part of the reaction medium and in the upper part of the reaction medium.

Thus, it is important to simultaneously maintain a balance between minimizing the formation of impurities due to the increased activity of the reaction and at the same time minimizing the formation of carbon oxides by lowering the activity of the reaction. Thus, if the total formation of carbon oxides is suppressed to a low value, then generates significant levels of impurities, and Vice versa.

In addition, the authors of the present invention have found that the solubility and the relative activity of the desired carboxylic acid (in particular, TRA) and the presence of other dissolved aromatic substances that are non-aromatic hydrocarbon group, is an important means of maintaining equilibrium between the number of carbon oxides and contaminants. Carboxylic acid, which is the target product, usually soluble in the liquid phase reaction medium, even when it is present in solid form. For example, at temperatures falling within the preferred ranges, TRA soluble in the reaction medium containing acetic acid and water, at a level of from about 1000 ppm wt. to more than 1 wt.%, in this case, the solubility increases with increasing temperature. The independent is IMO, the speed of reaction of formation of different impurities for various is able to oxidize the original aromatic compounds (in particular, para-xylene), for intermediate aromatic compounds (in particular, para-Truelove acid), for the desired product, which is an aromatic carboxylic acid (in particular, TRA), and aromatic substances, not containing non-aromatic hydrocarbon group (in particular, isophthalic acid), the presence and reactivity of the latter two groups defines the scope of reduction of output depending on the further suppression of the previous two groups, are able to oxidize the original aromatic compounds and intermediates of aromatic compounds. For example, partial oxidation of para-toluene with the formation of TRA in the case when, under specified conditions dissolved TRA in the liquid phase of the reaction medium reaches 7000 ppm wt., dissolved benzoic acid reaches 8000 ppm wt., dissolved isophthalic acid reaches 6000 ppm wt., and dissolved phthalic acid reaches 2000 ppm wt., the ability of the process to further reduce the total amount of harmful impurities begins to decrease as the activity of the reaction increases and decreases the concentration of para-that is willoway acid and 4-CBA in the liquid phase to the values smaller than the specified levels. Thus, the presence and concentration in the liquid phase reaction medium aromatic substances, not containing non-aromatic hydrocarbon group, varies slightly with the increase in the reaction, and their presence allows you to extend the upper boundary of the losses from the decrease in the concentration of intermediates in suppressing the formation of harmful impurities.

So, in one of the embodiments of the present invention are specified preferred ranges for carbon oxides, which are at the lower limit determined by the low activity of the reaction and excess formation of harmful impurities, and the upper limit is determined by the excess loss of carbon, but these levels are less than those previously discovered and disclosed as commercially acceptable. Thus, the formation of carbon oxides is preferably controlled in the following way. The ratio of moles formed the total of the oxides of carbon to moles received in response able to oxidize aromatic compounds, preferably, is greater than approximately 0,02:1, more preferably is greater than approximately 0,04:1, even more preferably is greater than about 0.05:1 and, most preferably, is greater than to 0.06:1. At the same the time, the ratio of moles formed the total of the oxides of carbon to moles received in response able to oxidize aromatic compounds, preferably, less than about 0.24 to:1, more preferably, is less than approximately 0,22:1, even more preferably less than about 0,19:1 and, most preferably, is less than about 0.15:1. The ratio of moles of formed carbon dioxide to moles received in response able to oxidize aromatic compounds, preferably is greater than about 0.01:1, more preferably is greater than about 0.03:1, even more preferably is greater than approximately 0,04:1 and, most preferably, is greater than 0.05:1. At the same time, the ratio of moles of formed carbon dioxide to moles submitted in response able to oxidize aromatic compounds, preferably less than about 0,21:1, more preferably, is less than approximately 0,19:1, even more preferably less than about 0,16:1 and, most preferably, is less than 0,11:1. The ratio of moles of formed carbon monoxide to the received moles in the reaction is able to oxidize aromatic compounds, preferably, is greater than approximately from 0.005:1, more preferably is greater than approximately 0,010:1, even more preferred the equipment, is greater than approximately 0,015:1 and, most preferably, is greater than 0,020:1. At the same time, the ratio of moles of formed carbon monoxide to the received moles in the reaction is able to oxidize aromatic compounds, preferably less than about 0,09:1, more preferably less than about 0.07 to:1, even more preferably less than about 0.05:1 and, most preferably, is less than 0,04:1.

The content of carbon dioxide in dry gas, which is withdrawn from the reactor for oxidation, preferably, is greater than approximately 0,10 mol%, more preferably, is greater than approximately 0.20% of the mol., even more preferably, is greater than approximately 0.25 mol%. and, most preferably, is greater than 0,30%

mol. At the same time, the content of carbon dioxide in dry gas, which is withdrawn from the reactor for oxidation, preferably less than about 1.5 mol%, more preferably, is less than approximately 1.2 mol%, even more preferably, is less than approximately 0.9% of mol. and, most preferably, is less than 0.8 mol%. The content of carbon monoxide in shangase, which is derived from the reactor for oxidation, preferably, is greater than about 0.05 mol%, more preferably, is greater than approximately 0,10 mol%, even more preferably, is greater than about 0.15 mol%. and, most preferably, is greater than 0,18 mol%. At the same time, the content of carbon monoxide in dry gas, which is withdrawn from the reactor for oxidation, preferably, is less than approximately 0,60% mol., more preferably is less than about 0.50 mol%, even more preferably, is less than approximately 0.35% of the mol. and, most preferably, is less than 0,28 mol%.

The inventors have found that, according to the description of the present invention, an important factor in reducing the formation of oxides of carbon to these preferred ranges is to increase the purity of the recycled filtrate and is able to oxidize the parent compound, to reduce the concentration of aromatic compounds that do not contain non-aromatic hydrocarbon groups, at the same time decreases the formation of carbon oxides and contaminants. Another factor, according to the description of the present invention is to improve the distribution of pair-KS is Lola and oxidant within the reactor. Another factor that helps to maintain the above preferred levels of carbon oxides is the formation in the reaction medium described in the present description gradients of pressure, temperature, concentration is able to oxidize compounds in the liquid phase and the concentration of oxidizer in the gas phase. Another factor that helps to maintain the above preferred levels of oxides of carbon, is the use referred to in the present description of the preferred values of the spatial-temporal velocity, pressure, temperature, solvent composition, catalyst composition and mechanical configuration of the reactor.

An important advantage of the preferred boundaries of the oxide of carbon is that it is possible to reduce the consumption of molecular oxygen, although not to the stoichiometric value. No matter how good, in accordance with the present invention, distributed oxidant and can oxidize the connection, as shown by the calculation performed for only one able to oxidize the original compounds, should remain an excess of oxygen over the stoichiometric value, so that could be some losses in the form of carbon oxides, and in order to provide due to excess oxygen control over education in the region impurities. Specifically in the case when it is able to oxidize the reference compound is xylene, the ratio in the original substances mass of molecular oxygen by weight of xylene, preferably, is greater than approximately 0,91:1,00, more preferably is greater than about 0.95:1.00 and, most preferably, is greater than 0,99:1,00. At the same time, the ratio in the original substances mass of molecular oxygen by weight of xylene, preferably less than approximately 1,20:to 1.00, more preferably less than approximately 1,12:1.00 and, most preferably, is less than 1,06:1,00. Specifically in the case when the reference compound is xylene, averaged over time, the content of molecular oxygen in the dry gas, which is extracted from the reactor for oxidation, preferably, is greater than about 0.1 mol%, more preferably is more than about 1 mol%. and, most preferably, is greater than 1.5 mol%. At the same time, averaged over time, the content of molecular oxygen in the dry gas, which is extracted from the reactor for oxidation, preferably less than about 6 mol%, more preferably, less than about 4 mol%. and, most preferably, is less than 3 mol%.

Another important advantage of the preferred boundaries of the formation of carbon oxides is that fewer aromatic compounds are converted into oxides of carbon and other low forms. This benefit is measured by the amount of moles of the aromatic compounds, which leaves the reaction medium, divided by the sum of the moles of aromatic compounds coming into the reaction medium during the continuous period of time, preferably within one hour, more preferably within one day and, most preferably, within 30 consecutive days. This ratio is hereinafter referred to as the index of molar selection for aromatic compounds in the reaction medium and is expressed as a numerical percentage. If all incoming reacting aromatic compounds leave the reaction medium in the form of aromatic compounds, although they are mainly in the oxidized forms received by the reaction of aromatic compounds, in this case, the index of molar selection has a maximum value of 100%. If strictly 1 out of every 100 input aromatic molecules passing through the reaction medium, is converted into carbon oxides and/or other non-aromatic molecules (in particular, acetic to the slot), the index of molar extraction is 99%. Specifically for the case when xylene is a basic able to oxidize the original aromatic compound index molar selection of aromatic compounds in the reaction medium, preferably, is greater than about 98%, more preferably is greater than about 98.5% and, most preferably, is less than 99,0%. At the same time, with the aim of preserving sufficient total activity of the reaction, the index molar selection of aromatic compounds in the reaction medium, preferably, is less than approximately 99.9%of, more preferably, is less than an estimated 99.8% and, most preferably, is less than 99.7 per cent in the case, when xylene is a basic able to oxidize the original aromatic compound.

Another aspect of the present invention includes the formation of methyl acetate in the reaction medium containing acetic acid and one or more are able to oxidize aromatic compounds. The specified acetate is a relatively volatile compound, in comparison with water and acetic acid, and thus tends to be swept exhaust gas unless it is cooling or not used unit operations, with the purpose of extraction of methyl acetate and/or the its destruction before than the exhaust gas will be released into the environment. Thus, the formation of acetate leads to production losses and capital costs. Methyl acetate, apparently, is formed in the first stage, due to the connection of a methyl radical that might arise from the decomposition of acetic acid with oxygen with the formation of methylhydroperoxide with its subsequent decomposition with the formation of methanol and, finally, due to the interaction of the formed methanol with the rest of acetic acid, with the formation of acetate. Regardless of how the reaction proceeds, the authors of the present invention found that if the rate of formation of acetate is too small, oxides of carbon also is too low, and harmful aromatic impurities is too much. If the rate of formation is too high, then the carbon oxides are also formed excessively, which leads to loss of solvent, able to oxidize compounds and oxidant. When used in the present description of the preferred embodiments of the invention the molar ratio of the formed acetate to able to oxidize the original aromatic compound, preferably, is greater than approximately from 0.005:1, more preferably is greater than approximately 0,010:1 and,most preferably, is more than 0,020:1. At the same time, the molar ratio of the formed acetate to the source is able to oxidize aromatic compound, preferably is less than about 0,09:1, more preferably less than about 0.07 to:1, even more preferably less than about 0.05:1 and, most preferably, is less than 0,04:1.

The authors of the present invention note that for all the above numerical value range upper and lower limits of the ranges can be independent from each other. For example, the numerical values range from 10 to 100 mean more than 10 and/or less than 100. Thus, the range of 10 to 100 is the basis for the claimed limitations more than 10 (no upper bound), stated restrictions less than 100 (no lower bound), and for the full range of 10 to 100 (lower and upper boundaries).

Some embodiments of the present invention can be further illustrated by the following example, however, it should be understood that this example is provided only to illustrate the present invention and, unless otherwise specified, does not restrict the scope of the present invention.

EXAMPLE

In this example, evaluate the properties of new particles HUNDRED (represented by the and figa and 32V) and HUNDRED samples for comparison (presented at Figo and 33B). In particular, for particles HUNDRED and determine the particle size, surface area, BET and dissolution rate. Test particles is carried out in accordance with the methods described in the section "Detailed description of the invention".

Particles HUNDRED new get in the way partial oxidation of commercially pure para-xylene using recycled filtrate in a bubble column reactor type, in accordance with many design options implementation of the present invention, including solvent, which contains acetic acid and water, using the components of the catalyst containing cobalt, manganese and bromine, using temperature, component approximately 160°C at half the height of the reaction medium using the preferred gradient of the composition of the gas phase, liquid phase composition and temperature within the reaction medium, and using the preferred General STR values and preferred values for STR for oxygen. Particles HUNDRED for comparison get in a well-mixed reactor mixing also by the method of partial oxidation of commercially pure para-xylene using recycled filtrate solvent, which contains acetic acid and water, and using the components of the catalyst containing cobalt, manganese is bromine, however, the process provides a more uniform spatial distribution of reaction rates, speeds evaporation of the solvent, the composition of the liquid phase and gas-phase composition and, in addition, the process is conducted at a higher pressure and at a temperature of approximately 200°Spolecenstvi the obtained results are summarized in table 5, and the full dataset for the test for dissolution for a certain period of time presented on Fig.

Table 5
Properties HUNDRED
New HUNDREDOne HUNDRED to compare
MicrographFiga and 32VFiga and 33B
D(4, 3) (µm)62205
D(v, 0,1) (μm)3527
D(v, 0.5) is (µm)58181
D(v, 0,9) (μm)9236
The relative distribution of particle sizes0,921,67
The surface area BET (m2/g)1,180,57
Dissolution within a specified time interval
After 1 min (ppm in THF)621458
After 2 min (ppm in THF)765579
After 4 min (ppm in THF)886695
The model constants of dissolution for a certain period of time
A (ppm in THF)198243
In (ppm in THF)748695
(Min-1)0,770,29

Comparing the two types of one HUNDRED, one can note a similar amount of the smaller particles, as indicated by the values for D(v, 0,1); however, the new one HUNDRED has a much smaller average particle size (D(4, 3)) and the median particle size (D(v, 0,5)). New HUNDRED has also significantly shorter relative distribution of particle size and contains fewer very large particles (D(v, 0,9)), which, as a rule, the most difficult to dissolve and/or enter into interaction when conducting subsequent operations of the process. In addition, despite the similarity in the number of very small particles having a very large surface area, the new one HUNDRED has a much larger total surface area, which is confirmed by BET and what would be expected on the basis of visual inspection of the micrographs. The combination of all physical factors led to considerably more beneficial rates of dissolution for the new HUNDRED, despite the fact that the final values of solubility at equilibrium are the same. It was unexpectedly discovered that the new HUNDRED is suitable for use in many subsequent refining processes, including dissolution and/or chemical reaction, as specified in this described and, despite the fact that the new one HUNDRED at the same time presents a number of difficulties and less favorable for processes such as filtering and rinsing liquid to remove residues of cobalt, manganese and bromine.

The present invention is described with reference to preferred variants of its implementation, but you should understand what can be offered in various variations and modifications are consistent with the essence of the invention and are included in the scope of the present invention.

1. Crude terephthalic acid, consisting of a set of solid particles crude terephthalic acid extracted from the reactor for oxidation, in which these particles are formed, and the particle crude terephthalic acid contains less than about 100 h/million mass 2,6-dicarboxylate has a transmittance at 340 nm (%T340) more than about 25%, wherein the particle crude terephthalic acid further comprises less than approximately 12 h/million mass 4,4-decarboxylase and/or contains less than approximately 400 h/million mass of isophthalic acid.

2. Acid according to claim 1, characterized in that the particle crude terephthalic acid contains less than about 6 h/million mass 4,4-decarboxilase.

3. Acid according to claim 1, characterized in that Castineiras terephthalic acid contains less than about 200 h/million mass of isophthalic acid.

4. Acid according to claim 1, characterized in that the particle crude terephthalic acid contains less than about 30 h/million mass 2,7-dicarboxylate.

5. Acid according to claim 1, characterized in that the particle crude terephthalic acid is dissolved in tetrahydrofuran within one minute to a concentration of at least approximately 500 h/million

6. Acid according to claim 1, characterized in that the particle crude terephthalic acid has a time constant regression "With" more than approximately 0.5 min-1determined by dissolution for a certain period of time.

7. Acid according to claim 1, characterized in that the particle crude terephthalic acid is dissolved in tetrahydrofuran within two minutes to a concentration of at least approximately 700 h/million and has a time constant regression "With" more than approximately 0.6 min-1.

8. Acid according to claim 1, characterized in that the particle crude terephthalic acid has an average surface area according to BET more than approximately 0.6 m2/year

9. Acid according to claim 1, characterized in that the particle crude terephthalic acid has an average particle size in the range from about 20 to about 150 microns.

10. Acid according to claim 1, characterized in that 90% of the total volume of the particles of the crude terephthalic acid have a size of arr is siteline 30 to about 150 microns.

11. Crude terephthalic acid, consisting of a set of solid particles crude terephthalic acid extracted from the reactor for oxidation, in which these particles are formed, and the particle crude terephthalic acid is characterized by an average size in the range from about 20 to about 150 microns, wherein the particle crude terephthalic acid is dissolved in tetrahydrofuran within one minute to a concentration of at least approximately 500 h/million and/or characterized by an average surface area according to BET more than approximately 0.6 m2/year

12. Acid according to claim 11, characterized in that the particle crude terephthalic acid has a time constant regression "With" more than approximately 0.5 min-1determined by dissolution for a certain period of time.

13. Acid according to claim 11, characterized in that the particle crude terephthalic acid is dissolved in tetrahydrofuran within two minutes to a concentration of at least approximately 700 h/million and has a time constant regression "With" more than approximately 0.6 min-1.

14. Acid according to claim 11, characterized in that the particle crude terephthalic acid has one or more of these properties:
(i) contains less than about 12 h/million mass 4,4-decarboxilase,
(i) contains less than about 400 h/million mass of isophthalic acid,
(iii) contains less than about 100 h/million mass
2,6-dicarboxylate,
(iv) has a transmittance at 340 nm (%T340) more than about 25%.

15. Acid according to claim 11, characterized in that the particle crude terephthalic acid contains less than about 30 h/million mass 2,7-dicarboxylate.

16. Acid according to claim 11, characterized in that 90% of the total volume of the particles of the crude terephthalic acid have a size from about 30 to about 150 microns.

17. A method of obtaining a crude terephthalic acid, comprising the oxidation of paraxylene in the liquid phase of the multiphase reaction medium in the reaction zone, at least one primary reactor for the oxidation process and removing from the reaction zone a suspension containing mother liquor and solid particles of crude terephthalic acid, and the particle crude terephthalic acid contains less than 100 hours/million mass 2,6-dicarboxylate and has a transmittance at 340 nm (%T340) more than about 25%, wherein the particle crude terephthalic acid further comprises less than approximately 12 h/million mass 4,4-decarboxylase and/or less than about 400 h/million mass of isophthalic acid.

18. The method according to 17, wherein h is stica crude terephthalic acid has one or more of these properties:
(v) contains less than about 9000 h/million mass of isophthalic acid,
(vi) contains less than about 3000 h/million mass phthalic acid,
(vii) contains less than about 3000 h/million mass trimellitic acid,
(viii) contains less than about 15000 h/million mass of benzoic acid.

19. The method according to 17, characterized in that the particle crude terephthalic acid is dissolved in tetrahydrofuran within one minute to a concentration of at least approximately 500 h/million

20. The method according to 17, characterized in that the particle crude terephthalic acid has a time constant regression "With" more than approximately 0.5 min-1determined by dissolution for a certain period of time.

21. The method according to 17, characterized in that the particle crude terephthalic acid is dissolved in tetrahydrofuran within two minutes to a concentration of at least approximately 700 h/million and has a time constant regression "With" more than approximately 0.6 min-1.

22. The method according to 17, characterized in that the particle crude terephthalic acid contains less than about 30 h/million mass 2,7-dicarboxylate.

23. The method according to 17, characterized in that the particle crude terephthalic acid contains less than 6 h/million mass 4,4-decarboxilase.

24. Spasibo 17, characterized in that the particle crude terephthalic acid contains less than 200 h/million mass of isophthalic acid.

25. The method according to 17, characterized in that the particle crude terephthalic acid contains less than about 50 h/million mass 2,6-dicarboxylate.

26. The method according to 17, characterized in that the particle crude terephthalic acid has a transmittance at 340 nm (%T340) more than about 50%.

27. The method according to 17, characterized in that the particle crude terephthalic acid has an average surface area according to BET more than approximately 0.6 m2/year

28. The method according to 17, characterized in that the particle crude terephthalic acid has an average particle size in the range from about 20 to about 150 microns.

29. The method according to 17, characterized in that 90% of the total volume of the particles of the crude terephthalic acid have a size from about 30 to about 150 microns.

30. The method according to 17, characterized in that as the primary reactor for oxidation using a bubble column reactor type.

31. The method according to 17, wherein the paraxylene is fed to the reaction zone so that theoretical separation of the reaction zone by a pair of intersecting vertical planes into 4 vertical quadrants of equal volume, not more than in listello 80 wt.% paraxylene is fed into the reaction zone only in one of the vertical quadrants.

32. The method according to 17, characterized in that at least part of the reaction zone is limited to one or more vertical side walls of the reactor, at least 25 wt.% paraxylene is fed into the reaction zone in one or more locations inside of the vertical side walls at a distance of at least 0,05D at the maximum diameter of the reaction zone D.

33. The method according to 17, characterized in that the oxidation is carried out in the presence of a catalyst system containing cobalt.

34. The method according to p, characterized in that the catalytic system further comprises bromine and manganese.

35. The method according to 17, characterized in that at least part of the particles of the crude terephthalic acid oxidizes in a secondary oxidation reactor.

36. The method according to p, characterized in that the oxidation in a secondary oxidation reactor is carried out at an average temperature at least 10°C higher than the temperature of oxidation in the primary oxidation reactor.

37. The method according to p, characterized in that the oxidation in a secondary oxidation reactor is carried out at an average temperature of about 20-80°C higher than the average temperature in the primary reactor oxidation, and the oxidation in the primary oxidation reactor is carried out at an average temperature of from about 140 to about 180°C and oxidation in a secondary oxidation reactor is carried out at an average temperature of from about 180 to about 220°C.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method involves, for example: (a) evaporation of said oxidised discharge stream, containing terephthalic acid, metallic catalyst, impurities, water and solvent, in the first zone of an evaporator to obtain a vapour stream and a concentrated suspension of the discharge stream; and (b) evaporation of the said concentrated suspension of the discharge stream in the second zone of the evaporator to obtain a stream rich in solvent and a high-concentration suspension of the discharge stream, where the said second zone of the evaporator has an evaporator operating at temperature ranging from 20°C to 70°C, where from 75 to 99 wt % of the said solvent and water is removed by evaporation from the said oxidised discharge stream at step (a) and (b); (c) the said high-concentration suspension of the discharge stream is filtered in a zone for separating solid products and liquid to form a filtered product and a mother liquid; (d) washing the said filtered product using washing substances fed into the said zone for separating solid products and liquid to form a washed filtered product and washing filtrate; and dehydration of the said filtered product in the said zone for separating solid products and liquid to form a dehydrated filtered product; where the said zone for separating solid products and liquid has at least one pressure filtration device, where the said pressure filtration device works at pressure ranging from 1 atmosphere to 50 atmospheres; (e) mixing water and optionally extractive solvent with the said mother liquid and with all of the said washing filtrate or its portion in the mixing zone to form an aqueous mixture; (f) bringing the extractive solvent into contact with the said aqueous mixture in the extraction zone to form a stream of extract and a purified stream, where the said metallic catalyst is extracted from the said purified stream.

EFFECT: improved method of extracting metallic catalyst from an oxidised discharge stream obtained during production of terephthalic acid.

36 cl, 3 dwg, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing a dry residue of aromatic dicarboxylic acid containing 8-14 carbon atoms, suitable for use as starting material for synthesis of polyester, where the said method involves the following sequence of stages, for example: (a) oxidation of aromatic material in the oxidation zone to obtain a suspension of carboxylic acid; (b) removal of impurities from the suspension of aromatic dicarboxylic acid in the liquid-phase mass-transfer zone where at least 5% liquid is removed, with formation of a residue or suspension of aromatic dicarboxylic acid, and a stream of mother solution, where the liquid-phase mass-transfer zone includes a device for separating solid substance and liquid; (c) removal of residual impurities from the suspension or residue of aromatic dicarboxylic acid obtained at stage (b) in the zone for countercurrent washing with a solvent to obtain a residue of aromatic dicarboxylic acid with the solvent and a stream of mother solution together with the solvent, where the number of steps for countercurrent washing ranges from 1 to 8, and the countercurrent washing zone includes at least one device for separating solid substance and liquid, and the said solvent contains acetic acid, (d) removal of part of the solvent from the residue of aromatic dicarboxylic acid together with the solvent obtained at stage (c) in the zone for countercurrent washing with water to obtain a residue of aromatic dicarboxylic acid wetted with water and a stream of liquid by-products together with the solvent/water, where the number of countercurrent washing ranges from 1 to 8, and the countercurrent washing zone includes at least one device for separating solid substance and liquid, where stages (b), (c) and (d) are combined into a single liquid-phase mass-transfer zone, and directing the residue of aromatic dicarboxylic acid wetted with water directly to the next stage (e), (e) drying the said residue of aromatic dicarboxylic acid wetted with water in the drying zone to obtain the said dry residue of aromatic dicarboxylic acid suitable for synthesis of polyester, where the said residue wetted with water retains the form of residue between stages (d) and (e).

EFFECT: design of an improved version of the method of preparing dry residue of aromatic dicarboxylic acid.

21 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a continuous stepped counterflow method of catalytic oxidation in a solvent of at least one benzene compound, containing two substituting groups, which are selected from alkyl, hydroxyalkyl, aldehyde, carboxyl groups and their mixtures, which can be oxidised to the corresponding acid derivative, involving the following steps: (a) introducing a mixture of material into the first oxidation step, containing at least part of the total amount of each of: (i) solvent, which is an organic acid, (ii) at least one catalytically active metal, selected from manganese, cobalt, nickel, zirconium, hafnium, cerium and their mixtures, and (iii) bromine in molar ratio, in terms of all catalytically active metals, in the interval from 1:20 to 5:1 and from 7 to 60 wt % of the total amount of at least one disubstituted benzene, introduced at steps (a) and (d); (b) partial oxidation of at least one disubstituted benzene at the first oxidation step in the presence of a gas, containing molecular oxygen initially in amount of 3 to 20 vol. %, at temperature ranging from 121°C to 205°C and relative quantities of disubstituted benzene, catalytic metal, solvent and bromine, introduced at step (a), so that from 25 to 99.95 wt % disubstituted benzene, added at the first oxidation step, is oxidised with formation of a gaseous mixture, containing unreacted molecular oxygen, evaporated solvent and a first mixture of products, containing acid derivative, partially oxidised disubstituted benzene, unreacted disubstituted benzene and solvent, and at pressure from 8.96·105 to 14.8·105 Pa, sufficient for keeping disubstituted benzene, partially oxidised disubstituted benzene, acid derivative and solvent in liquid state or in form of a suspension of solid substance in a liquid, so that concentration of residual molecular oxygen in the remaining gaseous mixture ranges from 0.3 to 2 vol. %; (c) extraction of the obtained first product mixture after the first oxidation step and supplying at least part of the extracted first product mixture to the second oxidation step; (d) supplying gas to the second oxidation step, containing molecular oxygen and residue form total amount of disubstituted benzene, catalytic metal, solvent and bromine; (e) oxidation at the second oxidation step of partially oxidised disubstituted benzene and unreacted disubstituted benzene, supplied to the second oxidation step, with a gas containing molecular oxygen in amount of 15 to 50 vol. %, at temperature ranging from 175°C to 216°C and relative quantities of disubstituted benzene, partially oxidised disubstituted benzene, catalytic metal, solvent and bromine, introduced at step (a), so that from 96 to 100 wt % disubstituted benzene and partially oxidised disubstituted benzene is oxidised with formation of a gaseous mixture, which contains unreacted molecular oxygen, evaporated solvent and a second product mixture, containing acid derivative and solvent, and at pressure from 11.7·105 to 16.2·105 Pa so as to keep the acid derivative, partially oxidised disubstituted benzene and unreacted disubstituted benzene mainly in liquid state or in form of a suspension of solid substance in a liquid, so that concentration of residual molecular oxygen in the remaining gaseous mixture ranges from 3 to 15 vol. %; (f) extraction after the second oxidation step of the second product mixture, containing acid derivative; and (g) tapping gas which contains residual molecular oxygen after the second oxidation step and returning it to the first oxidation step.

EFFECT: method allows for maximum use of oxygen without reducing quality of the desired carboxylic acid using a stepped counterflow oxidation system.

25 cl, 11 tbl, 29 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention refers to the improved method for oxidising of aromatic hydrocarbon such as para-xylol, meta-xylol, 2,6-dimethylnaphthalene or pseudocumene with forming of corresponding organic acid. The oxidation is implemented by the source of molecular oxygen in liquid phase at temperature range from 50°C to 250°C in the presence of catalyst being a) oxidation catalyst based on at least one heavy metal representing cobalt and one or more additive metals being selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, nickel and hafnium; b) bromine source; and c) unsubstituted polycyclic aromatic hydrocarbon. The invention refers also to the catalytic system for obtaining of organic acid by the liquid-phase oxidation of aromatic hydrocarbons representing: a) oxidation catalyst based on at least one heavy metal representing cobalt and one or more additive metals being selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, nickel and hafnium; b) bromine source; and c) unsubstituted polycyclic aromatic hydrocarbon.

EFFECT: activation of the aromatic hydrocarbons oxidation increasing the yield of target products and allowing to decrease the catalyst concentration and the temperature of the process.

45 cl, 4 tbl, 16 ex

FIELD: chemistry.

SUBSTANCE: method of obtaining product - purified carboxylic acid, includes: (a) oxidation of aromatic initial materials in primary oxidation zone with formation of raw carboxylic acid suspension; where raw carboxylic acid suspension contains terephthalic acid; where said oxidation is carried out at temperature within the range from 120°C to 200°C; (b) withdrawal of admixtures from raw suspension of carboxylic acid, removed at temperature from 140°C to 170°C from stage of oxidation of paraxylol in primary oxidation zone and containing terephthalic acid, catalyst, acetic acid and admixtures, realised in zone of solid products and liquid separation with formation of mother liquid flow and product in form of suspension; where part of said catalyst in said suspension of raw carboxylic acid is removed in said mother liquid flow; and where into said zone of solid products and liquid separation optionally additional solvent is added; (c) oxidation of said product in form of suspension in zone of further oxidation with formation of product of further oxidation; where said oxidation is carried out at temperature within the range from 190°C to 280°C; and where said oxidation takes place in said zone of further oxidation at temperature higher than in said primary oxidation zone; (d) crystallisation of said product of further oxidation in crystallisation zone with formation of crystallised product in form of suspension; (e) cooling of said crystallised product in form of suspension in cooling zone with formation of cooled suspension of purified carboxylic acid; and (i) filtration and optionally drying of said cooled suspension of purified carboxylic acid in filtration and drying zone in order to remove part of solvent from said cooled suspension of carboxylic acid with obtaining of said product - purified carboxylic acid.

EFFECT: purified carboxylic acid with nice colour and low level of admixtures, without using stages of purification like hydration.

8 cl, 1 tbl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention pertains to improved method of lowering content of 4-carboxybenzoldehyde and p-toluic acid in benzenedicarboxylic acid, which is terephtalic acid. Method involves: (1) supplying (i) p-xylene (ii) water acetic acid reaction medium, containing oxidation catalyst, containing source of cobalt, manganese and bromine source, dissolved in it, and (iii) acid containing gas in the first oxidation zone at high pressure, in which there is liquid phase, exothermal oxidation of p-xylene. In the first reactor, oxidation at high temperature and pressure is maintained at 150-165°C and 3.5-13 bars respectively; (2) removal from the upper part of the first reactor of vapour, containing water vapour, acetic acid reaction medium and oxygen depleted gas, and directing the vapour into the column for removing water; (3) removal from the lower part of the column for removing water of liquid, containing partially dehydrated acetic acid solution; (4) removal from the lower part of the first reactor of the oxidation product, containing (i) solid and dissolved terephtalic acid, 4-carboxybenzaldehyde and p-toluic acid, (ii) water acetic acid reaction medium, containing oxidation catalyst dissolved in it; (5) supplying (i) product of oxidation from stage (4), (ii) oxygen containing gas and (iii) solvent in vapour form, containing acetic acid, obtained from a portion of partially dehydrated acetic acid solvent from stage (3) into the second oxidation zone high pressure, in which there is liquid phase exothermal oxidation of 4-carboxybenzaldehyde and p-toluic acid, where temperature and pressure in the second reactor of oxidation at high pressure is maintained at 185-230°C and 4.5-18.3 bars respectively; (6) removal from the upper part of the second reactor of vapour, containing water vapour, acetic acid reaction medium, and oxygen depleted gas; (7) removal from the lower part of the second reactor of the product of second oxidation, containing (i) solid and dissolved terephtalic acid and (ii) water acetic acid reaction medium; and (8) separation of terephtalic acid from (ii) water acetic acid reaction medium from stage (7) with obtaining of terephtalic acid. The invention also relates to methods of obtaining terephtalic acid (versions). The obtained product is terephtalic acid, with an overall concentration of 4-carboxybenzaldehyde and p-toluic acid of 150 ppm or less.

EFFECT: improved method of lowering content of 4-carboxybenzoldehyde and p-toluic acid in benzenedicarboxylic acid and obtaining terephtalic acid.

13 cl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method, by which the carboxylic acid/diol mixture, that is suitable as the initial substance for the manufacture of polyester, obtained from the decolourised solution of carboxylic acid without actually isolating the solid dry carboxylic acid. More specifically, the invention relates to the method of manufacturing a mixture of carboxylic acid/diol, where the said method includes the addition of diol to the decolourised solution of carboxylic acid, which includes carboxylic acid and water, in the zone of the reactor etherification, where diol is located at a temperature sufficient for evaporating part of the water in order to become the basic suspending liquid with the formation of the specified carboxylic acid/diol mixture; where the said carboxylic acid and diol enter into a reaction in the zone of etherification with the formation of a flow of a complex hydroxyalkyl ether. The invention also relates to the following variants of the method: the method of manufacture of the carboxylic acid/diol mixture, where the said method includes the following stages: (a) mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of damp carboxylic acid; where the said carboxylic acid is selected from the group, which includes terephthalic acid, isophthatic acid, naphthalenedicarboxylic acid and their mixtures; (b) discolourisation of aforesaid solution of damp carboxylic acid in the zone for reaction obtaining the decolourised solution of carboxylic acid; (c) not necessarily, instantaneous evaporation of the said decolourised solution of carboxylic acid in the zone of instantaneous evaporation for the removal of part of the water from the decolourised solution of carboxylic acid; and (d) addition of diol to the decolourised solution of carboxylic acid in the zone of the reactor of the etherification, where the said diol is located at a temperature, sufficient for the evaporation of part of the water in order to become the basic suspending liquid with the formation of the carboxylic acid/diol mixture; where the aforesaid carboxylic acid and diol then enter the zone of etherification with the formation of the flow of complex hydroxyalkyl ether; and relates to the method of manufacture of carboxylic acid/diol, where the said method includes the following stages: (a) the mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of carboxylic acid; (b) discolourisation of the said solution of damp carboxylic acid in the reactor core with the formation of the decolourised solution of carboxylic acid; (c) crystallisation of the said decolourised solution of carboxylic acid in the zone of crystallisation with the formation of an aqueous suspension; and (d) removal of part of the contaminated water in the aforesaid aqueous solution and addition of diol into the zone of the removal of liquid with the obtaining of the said carboxylic acid/diol mixture, where diol is located at a temperature sufficient for evaporating part of the contaminated water from the said aqueous suspension in order to become the basic suspending liquid.

EFFECT: obtaining mixture of carboxylic acid/diol.

29 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: invention pertains to the perfection of the method of regulating quantities of dissolved iron in liquid streams during the process of obtaining aromatic carboxylic acids or in the process of cleaning technical aromatic carboxylic acids, characterised by that, to at least, part of the liquid stream for regulating the quantity of dissolved iron in it, at least one peroxide with formula R1-O-O-R2 is added. Here R1 and R2 can be the same or different. They represent hydrogen or a hydrocarbon group, in quantities sufficient for precipitation of the dissolved iron from the liquid. The invention also relates to the perfection of the method of obtaining an aromatic carboxylic acid, through the following stages: A) contacting the crude aromatic material which can be oxidised, with molecular oxygen in the presence of an oxidising catalyst, containing at least, one metal with atomic number from 21 to 82, and a solvent in the form of C2-C5 aliphatic carboxylic acid in a liquid phase reaction mixture in a reactor under conditions of oxidation with formation of a solid product. The product contains technical aromatic carboxylic acid, liquid, containing a solvent and water, and an off-gas, containing water vapour and vapour of the solvent; B) separation of the solid product, containing technical aromatic carboxylic acid from the liquid; C) distillation of at least part of the off gas in a distillation column, equipped with reflux, for separating vapour of the solvent from water vapour. A liquid then forms, containing the solvent, and in the upper distillation cut, containing water vapour; D) returning of at least, part of the liquid from stage B into the reactor; E) dissolution of at least, part of the separated solid product, containing technical aromatic carboxylic acid, in a solvent from the cleaning stage with obtaining of a liquid solution of the cleaning stage; F) contacting the solution from the cleaning stage with hydrogen in the presence of a hydrogenation catalyst and under hydrogenation conditions, sufficient for formation of a solution, containing cleaned aromatic carboxylic acid, and liquid, containing a cleaning solvent; G) separation of the cleaned aromatic carboxylic acid from the solution, containing the cleaning solvent, which is obtained from stage E, with obtaining of solid cleaned aromatic carboxylic acid and a stock solution from the cleaning stage; H) retuning of at least, part of the stock solution from the cleaning stage, to at least, one of the stages B and E; I) addition of at least, one peroxide with formula R1-O-O-R2, where R1 and R2 can be the same or different, and represent hydrogen or a hydrocarbon group, in a liquid from at least one of the other stages, or obtained as a result from at least one of these stages, to which the peroxide is added, in a quantity sufficient for precipitation of iron from the liquid.

EFFECT: controlled reduction of the formation of suspension of iron oxide during production of technical aromatic acid.

19 cl, 1 dwg, 6 ex, 4 tbl

FIELD: carbon materials and hydrogenation-dehydrogenation catalysts.

SUBSTANCE: invention relates to improved crude terephthalic acid purification process via catalyzed hydrogenating additional treatment effected on catalyst material, which contains at least one hydrogenation metal deposited on carbonaceous support, namely plane-shaped carbonaceous fibers in the form of woven, knitted, tricot, and/or felt mixture or in the form of parallel fibers or ribbons, plane-shaped material having at least two opposite edges, by means of which catalyst material is secured in reactor so ensuring stability of its shape. Catalyst can also be monolithic and contain at least one catalyst material, from which at least one is hydrogenation metal deposited on carbonaceous fibers and at least one non-catalyst material and, bound to it, supporting or backbone member. Invention also relates to monolithic catalyst serving to purify crude terephthalic acid, comprising at least one catalyst material, which contains at least one hydrogenation metal deposited on carbonaceous fibers and at least one, bound to it, supporting or backbone member, which mechanically supports catalyst material and holds it in monolithic state.

EFFECT: increased mechanical strength and abrasion resistance.

8 cl, 4 ex

FIELD: chemical industry; methods of production of the purified crystalline terephthalic acid.

SUBSTANCE: the invention is pertaining to the improved method of production and separation of the crystalline terephthalic acid containing less than 150 mass ppm of the p-toluene acid in terms of the mass of the terephthalic acid. The method provides for the following stages: (1) loading of (i) para- xylene, (ii) the water reactionary acetic-acidic medium containing the resolved in it components of the oxidation catalyst, and (iii) the gas containing oxygen fed under pressure in the first zone of oxidation, in which the liquid-phase exothermal oxidization of the para-xylene takes place, in which the temperature and the pressure inside the first being under pressure reactor of the oxidization are maintained at from 150°С up to 180°С and from 3.5 up to 13 absolute bars; (2) removal from the reactor upper part of the steam containing the evaporated reactionary acetic-acidic medium and the gas depleted by the oxygen including carbon dioxide, the inertial components and less than 9 volumetric percents of oxygen in terms of the non-condensable components of the steam; (3) removal from the lower part of the first reactor of the oxidized product including (i) the solid and dissolved terephthalic acid and (ii) the products of the non-complete oxidation and (ii) the water reactionary acetic-acidic medium containing the dissolved oxidation catalyst; (4) loading of (i) the oxidized product from the stage (3) and (ii) the gas containing oxygen, into the second being under pressure zone of the oxidation in which the liquid-phase exothermal oxidization of the products of the non-complete oxidization takes place; at that the temperature and the pressure in the second being under pressure reactor of the oxidization are maintained from 185°С up to 230°С and from 4.5 up to 18.3 absolute bar; (5) removal from the upper part of the second steam reactor containing the evaporated water reactionary acetic-acidic medium and gas depleted by the oxygen, including carbon dioxide, the inertial components and less, than 5 volumetric percents of oxygen in terms of the non-condensable components of the steam; (6) removal from the lower part of the second reactor of the second oxidized product including (i) the solid and dissolved terephthalic acid and the products of the non-complete oxidation and (ii) the water reactionary acetic-acidic medium containing the dissolved oxidation catalyst; (7) separation of the terephthalic acid from (ii) the water reactionary acetic-acidic medium of the stage (6) for production the terephthalic acid containing less than 900 mass ppm of 4- carboxybenzaldehyde and the p-toluene acid; (8) dissolution of the terephthalic acid gained at the stage (7) in the water for formation of the solution containing from 10 up to 35 mass % of the dissolved terephthalic acid containing less than 900 mass ppm of the 4- carboxybenzaldehyde and the p-toluene acid in respect to the mass of the present terephthalic acid at the temperature from 260°С up to 320°С and the pressure sufficient for maintaining the solution in the liquid phase and introduction of the solution in contact with hydrogen at presence of the catalytic agent of hydrogenation with production of the solution of the hydrogenated product; (9) loading of the solution of the stage (8) into the crystallization zone including the set of the connected in series crystallizers, in which the solution is subjected to the evaporating cooling with the controlled velocity using the significant drop of the temperature and the pressure for initiation of the crystallization process of the terephthalic acid, at the pressure of the solution in the end of the zone of the crystallization is atmospheric or below; (10) conduct condensation of the dissolvent evaporated from the crystallizers and guide the condensed dissolvent back into the zone of the crystallization by feeding the part of the condensed dissolvent in the line of removal of the product of the crystallizer, from which the dissolvent is removed in the form of the vapor; and (11) conduct separation of the solid crystalline terephthalic acid containing less than 150 mass ppm of the p-toluene acid in terms of the mass of the terephthalic acid by separation of the solid material from the liquid under the atmospheric pressure. The method allows to obtain the target product in the improved crystalline form.

EFFECT: the invention ensures production of the target product in the improved crystalline form.

8 cl, 3 tbl, 2 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: group of inventions relates to liquid-phase catalytic oxidation of an aromatic compound and a reactor-type bubble column. A stream of starting material containing an oxidisable compound and an stream of oxidising agent containing molecular oxygen are fed into the reaction zone of a reactor-type bubble column with maximum height H and maximum width W. At least a portion of the said oxidisable compound is oxidised in liquid-phase by a multiple-phase reaction medium in the reaction zone when at least part of the reaction medium comes into contact with at least one deflector placed in the reaction zone. At least approximately 10 wt % of the oxidisable compound is converted to solid substance in the reaction medium. The ratio H:W of the column is at least approximately equal to 6:1. At least approximately 30 wt % of the oxidisable compound is fed into the reaction zone at a distance of approximately 1.5 H from the lowest mark for inlet of molecular oxygen into the reaction zone. When the oxidisable compound is paraxylene and the oxidation reaction product is crude terephthalic acid, the said product can be purified and extracted using methods which are cheaper than methods which would be used if the product were to be obtained via high-temperature oxidation.

EFFECT: more efficient and cheaper oxidation of the oxidisable compound at relatively low temperature.

38 cl, 58 dwg, 4 tbl, 10 ex

FIELD: chemistry.

SUBSTANCE: group of inventions relates to oxidation of para-xylene to obtain crude terephthalic acid and a reactor type bubble column. Mainly a gas-phase stream of oxidising agent containing molecular oxygen, and mainly a liquid-phase stream of initial materials containing para-xylene are fed into a reaction zone with maximum diametre D of the reactor type bubble column, and part of the para-xylene is oxidised in liquid phase of the multi-phase reaction medium contained in the reaction zone to obtain crude terephthalic acid. The initial materials are fed into the reaction zone through several inlet openings, at least two of which are spaced out from each other vertically by at least approximately 0.5D. At least part of the reaction zone is defined by one or more vertically lying side walls of the bubble column. At least approximately 25 wt % of para-xylene is fed into the said reaction zone in one or more places lying inside from the vertical side walls at a distance of at least 0.5D. Oxidation is carried out in the volume of the reaction medium with maximum height H, maximum width W and ratio H:W equal to at least approximately 3:1.

EFFECT: more efficient and economical liquid-phase oxidation of an oxidised compound at relatively low temperatures.

31 cl, 35 dwg, 7 tbl, 13 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing gold catalysts on a porous metal oxide support and aurichlorohydric acid as a precursor, a catalyst and its use for oxidising alcohols, aldehydes, polyhydroxy compounds and carbohydrates. Described is a method of making a supported gold catalyst, involving the following steps: a) preparation of the support in dry form, b) bringing the support into contact with a solution of precursor-aurichlorohydric acid, wherein the maximum volume of the solution is as great as the pore volume of the support, so that an impregnated catalyst precursor is obtained, and c) drying the impregnated catalyst precursor, where in aqueous solution of the precursor aurichlorohydric acid is a HAuCl4 solution and aqueous hydrochloric acid with acid concentration ranging from 0.1 mol/l to 12 mol/l. Described is a catalyst prepared using said method, its use to oxidise organic compounds, including for producing aldonic acids.

EFFECT: increased activity and selectivity of the catalyst.

16 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a continuous stepped counterflow method of catalytic oxidation in a solvent of at least one benzene compound, containing two substituting groups, which are selected from alkyl, hydroxyalkyl, aldehyde, carboxyl groups and their mixtures, which can be oxidised to the corresponding acid derivative, involving the following steps: (a) introducing a mixture of material into the first oxidation step, containing at least part of the total amount of each of: (i) solvent, which is an organic acid, (ii) at least one catalytically active metal, selected from manganese, cobalt, nickel, zirconium, hafnium, cerium and their mixtures, and (iii) bromine in molar ratio, in terms of all catalytically active metals, in the interval from 1:20 to 5:1 and from 7 to 60 wt % of the total amount of at least one disubstituted benzene, introduced at steps (a) and (d); (b) partial oxidation of at least one disubstituted benzene at the first oxidation step in the presence of a gas, containing molecular oxygen initially in amount of 3 to 20 vol. %, at temperature ranging from 121°C to 205°C and relative quantities of disubstituted benzene, catalytic metal, solvent and bromine, introduced at step (a), so that from 25 to 99.95 wt % disubstituted benzene, added at the first oxidation step, is oxidised with formation of a gaseous mixture, containing unreacted molecular oxygen, evaporated solvent and a first mixture of products, containing acid derivative, partially oxidised disubstituted benzene, unreacted disubstituted benzene and solvent, and at pressure from 8.96·105 to 14.8·105 Pa, sufficient for keeping disubstituted benzene, partially oxidised disubstituted benzene, acid derivative and solvent in liquid state or in form of a suspension of solid substance in a liquid, so that concentration of residual molecular oxygen in the remaining gaseous mixture ranges from 0.3 to 2 vol. %; (c) extraction of the obtained first product mixture after the first oxidation step and supplying at least part of the extracted first product mixture to the second oxidation step; (d) supplying gas to the second oxidation step, containing molecular oxygen and residue form total amount of disubstituted benzene, catalytic metal, solvent and bromine; (e) oxidation at the second oxidation step of partially oxidised disubstituted benzene and unreacted disubstituted benzene, supplied to the second oxidation step, with a gas containing molecular oxygen in amount of 15 to 50 vol. %, at temperature ranging from 175°C to 216°C and relative quantities of disubstituted benzene, partially oxidised disubstituted benzene, catalytic metal, solvent and bromine, introduced at step (a), so that from 96 to 100 wt % disubstituted benzene and partially oxidised disubstituted benzene is oxidised with formation of a gaseous mixture, which contains unreacted molecular oxygen, evaporated solvent and a second product mixture, containing acid derivative and solvent, and at pressure from 11.7·105 to 16.2·105 Pa so as to keep the acid derivative, partially oxidised disubstituted benzene and unreacted disubstituted benzene mainly in liquid state or in form of a suspension of solid substance in a liquid, so that concentration of residual molecular oxygen in the remaining gaseous mixture ranges from 3 to 15 vol. %; (f) extraction after the second oxidation step of the second product mixture, containing acid derivative; and (g) tapping gas which contains residual molecular oxygen after the second oxidation step and returning it to the first oxidation step.

EFFECT: method allows for maximum use of oxygen without reducing quality of the desired carboxylic acid using a stepped counterflow oxidation system.

25 cl, 11 tbl, 29 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method for prolonged heterogeneously catalysed partial oxidation of propene to acrylic acid in gaseous phase, in which the initial gaseous reaction mixture 1, containing propene, molecular oxygen and at least one inert gas, where molecular oxygen and propene are in molar ratio O2:C3H6≥1, is first passed through a fixed catalyst bed 1 at high temperature at the first stage of the reaction, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and/or tungsten, as well as at least one element from a group consisting of bismuth, tellurium, antimony, tin and copper, so that, conversion of propene in a single passage is ≥93 mol % and associated selectivity of formation of acrolein, as well as formation of acrylic acid by-product together is ≥90 mol %, temperature of the product gaseous mixture 1 leaving the first reaction stage is reduced if necessary through direct and/or indirect cooling, and if necessary, molecular oxygen and/or inert gas is added to the product gaseous mixture 1, and after that, the product gaseous mixture 1, acting as initial reaction mixture 2, which contains acrolein, molecular oxygen and at least one inert gas, where molecular oxygen and acrolein are in molar ratio O2:C3H4O≥0.5, is passed through a second fixed catalyst bed 2 at high temperature at the second reaction stage, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and vanadium so that, conversion of acrolein in a single passage is ≥90 mol % and selectivity of the resultant formation of acrylic acid at both stages is ≥80 mol % in terms of converted propene, and temperature of each fixed catalyst bed is increased independently of each other. Partial oxidation in gaseous phase is interrupted at least once and at temperature of fixed catalyst bed 1 ranging from 250 to 550°C and temperature of fixed catalyst bed 2 ranging from 200 to 450°C, gaseous mixture G, which consists of molecular oxygen, inert gas and water vapour if necessary, is first passed through fixed catalyst bed 1, and then, if necessary, through an intermediate cooler and then finally through fixed catalyst bed 2, in which at least a single interruption takes place before temperature of the fixed catalyst bed 2 increases by 8°C or 10°C, wherein prolonged increase of temperature by 8°C or 10°C, is possible when virtual passage of temperature of the fixed catalyst bed in the period of time on the leveling curve running through the measuring point using the Legendre-Gauss method of the least sum of squares of errors, temperature increase of 7°C or 10°C is achieved.

EFFECT: method increases service life of catalyst.

24 cl, 1 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improvement of the method of producing (meth)acrylic acid or (meth)acrolein through gas-phase catalytic oxidation of at least one oxidisable substance, chosen from propylene, propane, isobutylene and (meth)acrolein, molecular oxygen or a gas, which contains molecular oxygen, using a multitubular reactor, with such a structure that, there are several reaction tubes, with one (or several) catalytic layer (catalytic layers) in the direction of the axis of the tube, and a coolant can flow outside the said reaction tubes so as to regulate temperature of reaction, in which temperature of the said reaction of gas-phase catalytic oxidation is increased by varying temperature of the coolant at the inlet for regulating temperature of the reaction, while (1) temperature of coolant at the inlet for regulating temperature of the reaction is varied by not more than 2°C for each variation as such, and (2) when variation is done continuously, the time interval from the variation operation, directly preceding the present, is not more than 10 minutes, and, in addition, the difference between the maximum value of peak temperature of reaction of the catalyst layer of the reaction tube and temperature of the coolant at the inlet for regulating temperature of reaction is not less than 20°C.

EFFECT: method in which sharp increase of temperature is suppressed even after changing reaction conditions with aim of increasing temperature for improving efficiency, thus preventing catalyst deactivation, and achieving stable output.

3 cl, 5 dwg, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of carrying out heterogenous catalytic partial oxidation in gas phase of acrolein into acrylic acid, during which reaction gas mixture, containing acrolein, molecular oxygen and at least one inert gas-thinner, is passed through having higher temperature catalytic still layer, whose catalysts are made in such way that their active mass contains at least one oxide of multimetal, containing elements Mo and V, and in which during time, temperature of catalytic still layer is increased, partial oxidation in gas phase being interrupted at least once and at temperature of catalytic still layer from 200 to 450°C acrolein-free, containing molecular oxygen, inert gas and, if necessary, water vapour, as well as, if necessary, CO, gas mixture of G oxidative action is passed through it, at least one interruption being performed before increase of catalytic still layer temperature constitutes 2°C or 4°C or 8°C or 10°C during a long period of time, temperature increase constituting 2°C or 4°C or 8°C or 10°C over a long period of time occurring when in plotting factual course of temperature of catalytic still layer during time on laid through measurement points equation curve according to elaborated by Legendre and Gauss method of the least sum of error squares 2°C or 4°C or 8°C or 10°C temperature increase is achieved.

EFFECT: ensuring spread of hot point with time which is less than in previous methods.

21 cl, 3 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing (met)acrolein and/or (met)acrylic acid through heterogeneous catalytic partial oxidation in gaseous phase, in which a fresh fixed-bed catalyst at 100-600°C in a reactor is loaded with a mixture of loading gas, which along with at least, one C3/C4 organic precursor compound subject to partial oxidation and oxidation with molecular oxygen, contains at least one gas-diluent. The process is carried out after establishing content of the mixture of loading gas at constant conversion of organic precursor compound and at constant content of the mixture of loading gas initially in the input period for 3-10 days with load of 40-80% of higher final load, and then at higher filling load of the catalyst with a mixture of loading gas. In the input period, maximum deviation of conversion of organic precursor compound from arithmetic time-averaged and maximum deviation of the volume ratio of one component of the mixture loading gas, oxidising agent, organic precursor compound and gas-diluent, from the arithmetic time-averaged volume ratio of the corresponding component of the mixture of loading gas should not exceed ±10% of the corresponding arithmetic mean value.

EFFECT: method allows for eliminating shortcomings of previous technical level.

3 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to an improved method of monitoring and/or controlling the process of producing (meth)acrolein and/or (meth)acrylic acid through partial oxidation in a gas of C3- and/or C4- precursor compounds in the presence of heterogeneous catalyst in form of particles, in a reactor with two or more vertical thermo-plates, placed parallel each other, forming gaps between them. A heterogeneous catalyst in form of particles is put in the gaps. The gaseous reaction mixture is passed through the gaps. The controlled and/monitored value chosen is one or several temperature values, which are measured in one or several gaps, in one or several points of measurement, which are distributed along the height of each gap.

EFFECT: provision for homogeneity of measured temperature zones with the aim of controlling the process.

25 cl, 7 dwg

FIELD: chemistry.

SUBSTANCE: present invention relates to an improved method of producing at least one product of partial oxidation and/or ammoxidation of a hydrocarbon, chosen from a group containing acrolein, acrylic acid, methacrolen, methacrylic acid, acrylonitrile and methacrylonitrile. At least one saturated hydrocarbon is subjected to heterogeneous catalysed dehydrogenation in a gas phase, obtaining a gas mixture, containing at least one partially dehydrogenated hydrocarbon. Components of the gas mixture except saturated hydrocarbon and partially dehydrogenated hydrocarbon are left in the mixture. Alternatively, the extra gas mixture obtained is partially or completely separated, and the gas mixture and/or extra gas mixture are used for obtaining another gas mixture, containing molecular oxygen and/or molecular oxygen and ammonia. This gas mixture is subjected to at least single heterogeneous catalysed partial oxidation and/or ammoxidation of at least one partially dehydrogenated hydrocarbon contained in the gas mixture and/or extra gas mixture. The gas mixture, extra gas mixture and/or the other gas mixture, before at least one partial heterogeneous catalysed oxidation and/or ammoxidation, are subjected to at least a single mechanical separation, aimed at separating particles of solid substance contained in the above mentioned gas mixtures.

EFFECT: reliable and continuous realisation of the process for relatively long periods of time.

6 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: group of inventions relates to liquid-phase catalytic oxidation of an aromatic compound and a reactor-type bubble column. A stream of starting material containing an oxidisable compound and an stream of oxidising agent containing molecular oxygen are fed into the reaction zone of a reactor-type bubble column with maximum height H and maximum width W. At least a portion of the said oxidisable compound is oxidised in liquid-phase by a multiple-phase reaction medium in the reaction zone when at least part of the reaction medium comes into contact with at least one deflector placed in the reaction zone. At least approximately 10 wt % of the oxidisable compound is converted to solid substance in the reaction medium. The ratio H:W of the column is at least approximately equal to 6:1. At least approximately 30 wt % of the oxidisable compound is fed into the reaction zone at a distance of approximately 1.5 H from the lowest mark for inlet of molecular oxygen into the reaction zone. When the oxidisable compound is paraxylene and the oxidation reaction product is crude terephthalic acid, the said product can be purified and extracted using methods which are cheaper than methods which would be used if the product were to be obtained via high-temperature oxidation.

EFFECT: more efficient and cheaper oxidation of the oxidisable compound at relatively low temperature.

38 cl, 58 dwg, 4 tbl, 10 ex

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