Method for oxidising of aromatic hydrocarbons and catalytic system thereof

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

 

The prior art inventions

The present invention relates to liquid-phase oxidation of aromatic hydrocarbons to aromatic carboxylic acids in the presence of an oxidation catalyst based on at least one heavy metal and bromine, which is activated by anthracene or other polycyclic aromatic compound. The present invention includes a liquid-phase oxidation of pseudocumene (PSC) (1,2,4-trimethylbenzene) with the formation of trimellitic acid (TMLA) in the presence of a catalyst comprising a polyvalent catalyst, a source of bromine and polycyclic aromatic hydrocarbons. The present invention relates to liquid-phase oxidation of PSC with the formation of TMLA in the presence of a catalyst comprising a polyvalent catalyst, a source of bromine and polycyclic aromatic hydrocarbons, which are selected from anthracene, naphthalene, tetracene and combinations thereof. Trimellitic acid can be degidratiruth with the formation of anhydride trimellitic acid (TMA). TMA and TMLA are important industrial source substances in the production of polyesters. Esters trimellitic acid is used as plasticizers for polyvinyl chloride, especially for high-quality wire and cable insulation, because they have such important quality is in question, as thermal stability and low volatility. Trimellitic anhydride used in the production of resins for electrolytic deposition and powder coatings, and as a binder for fiberglass, sand, and other composites. Trimellitic anhydride are used for decoration of embossed vinyl flooring and as a curing reagent for epoxy resins. It is also used as an intermediate product in the synthesis of chemicals for surface coatings, adhesives, polymers, dyes, inks, pharmaceuticals and agricultural chemicals.

Aromatic carboxylic acids, such as benzylcarbamoyl acid and naphthalenesulphonate acid, is important for the industry because they are the starting materials for the production of polyesters used in the production of fibers, films, resins and many other petrochemical products. U.S. patent No. 2833816 discloses liquid-phase oxidation of xylene isomers into the corresponding dicarboxylic acid in the presence of bromine using a catalyst containing cobalt and manganese. As shown in U.S. patent No. 5103933, liquid-phase dimethylnaphthalene you can also oxidize in naphthalenesulphonate acid in the presence of bromine and catalyst containing cobalt and manganese. Usually aromatic carboxylic acids PTS who participate way described, for example, in U.S. patent No. 3584039, U.S. patent No. 4892972 and U.S. patent No. 5362908.

Liquid-phase oxidation of aromatic hydrocarbons to aromatic carboxylic acid is carried out in a reaction mixture containing aromatic hydrocarbons and a solvent. Typically the solvent is a C1-C8monocarboxylic acid such as acetic acid, benzoic acid or their mixtures with water. Used herein, the term "aromatic hydrocarbon" mainly means a molecule that contains mostly carbon atoms and hydrogen and containing one or more aromatic rings, in particular dimethylbenzene, trimethylbenzene and dimethylnaphthalene. Aromatic hydrocarbons, suitable for liquid-phase oxidation with the formation of aromatic carboxylic acids, are typically aromatic hydrocarbons containing at least one Deputy, which can be oxidized to carboxyl group. Used herein, the term "aromatic carboxylic acid" mainly means an aromatic hydrocarbon with at least one carboxyl group.

The promoter - bromine and catalyst added to the reaction mixture in which the reaction takes place in the presence of a gas-oxidizing agent. Typically, the catalyst contains at least one suitable heavy metal. Podhodjashjaja metals include heavy metals with an atomic weight in the range of from about 23 to about 178. Examples include cobalt, manganese, vanadium, molybdenum, Nickel, zirconium, titanium, cerium or the metal of the lanthanide group, such as hafnium. Suitable forms of these metals include, for example, acetates, hydroxides and carbonates. The use of bromine for the preparation of aromatic carboxylic acids by liquid-phase oxidation increases conversion of the reactants.

Patent USSR No. 239936 discloses a method of liquid-phase oxidation of alkylaromatic hydrocarbons by molecular oxygen in acetic acid solution in the presence of a catalyst is a salt of cobalt and dibromoanthracene - at a temperature of 90-110°C, in order to intensify the process in the reaction mixture were injected salt of manganese in the amount of 1-3% of the concentration of cobalt salts.

The quality of the aromatic carboxylic acid is often determined by the concentration of intermediates detected in the form of impurities in the obtained aromatic carboxylic acids. The nature and concentration of these impurities vary depending on the type and concentration of catalyst and promoter, is used to obtain the required aromatic carboxylic acid. The presence of such impurities may prevent the use of the obtained carboxylic acid, or make it undesirable for some purposes. For example, when using terephthalic acid in the condensation reaction with about what adowanie polyesters impurities in terephthalic acid may cause undesirable staining of polyester and cause chain termination.

It was found that the anthracene and other polycyclic aromatic hydrocarbons, even in small quantities activate the oxidation of alkylaromatic compounds to aromatic carboxylic acids. This activation appears to increase the absorption of oxygen, the temperature increases, the rate of formation of intermediates and reaction time reduction and leads to a higher yield of the main product.

Supplements anthracene, naphthalene and other polycyclic aromatic hydrocarbons in the reaction of oxidation of alkylaromatic compounds, such as xylene, trimethylbenzene and dimethylnaphthalene lead to unexpected and pronounced activation, which can improve the yield of aromatic acids such as terephthalic acid (TA), isophthalic acid (IPA), trimellitate acid (TMLA) and natalijagolosova acid (NDA). Increased activity in these oxidative reactions (catalyzed Co, mn and Br) can lead to reduced output intermediate and by-products, reduction of the catalyst and to reduce corrosion and emissions associated with VG. In order to cause such activation, need very small amounts of anthracene and other polycyclic aromatic hydrocarbons. Using the anthracene or other polycyclic aromatic hydrocarbons as activator, you can reduce the price the catalyst, because they provide a good conversion of the original aromatic hydrocarbon to the desired aromatic carboxylic acid with a lower metal content in the catalyst. For example, if you can use less of cobalt, the way will cost you much less.

Activation of the oxidation of aromatic hydrocarbons to aromatic carboxylic acids, polycyclic aromatic compounds such as anthracene, allows to significantly reduce the concentration of catalyst that will reduce the cost of the catalyst, especially if you can reduce the amount of cobalt, which is a pricing component. The ability to use less catalyst creates an unexpected advantage in terms of cheaper way and offer a more economical option. This advantage in cost reduction is especially important for such methods, in which the separation and recycling of expensive catalyst components, such as cobalt, is difficult or impossible.

In addition, the use of anthracene to activate the oxidation of aromatic hydrocarbons to aromatic carboxylic acids allows the oxidation process at lower temperatures, which means less energy. It can also help lower costs and, in addition, lower energy consumption, preferably with ekologicheskogo of view.

Another difficulty of liquid-phase oxidation of aromatic hydrocarbons to aromatic carboxylic acids consists in the loss of solvent and aromatic hydrocarbons. Liquid-phase oxidation generally results in a loss of at least 2% of the solvent and more than 2% of aromatic hydrocarbons. We found that the use of polycyclic aromatic hydrocarbon as a promoter increases the yield of aromatic carboxylic acids without the undesirable increase of the losses of solvent and hydrocarbons.

The invention

The present invention relates to a method for oxidation of aromatic hydrocarbon with a source of molecular oxygen with the formation of aromatic carboxylic acids in liquid-phase conditions in the presence of a catalytic system containing at least one suitable heavy metal, a source of bromine and at least one polycyclic aromatic hydrocarbon. The invention includes a method of liquid-phase oxidation of pseudocumene in trimellitic acid, namely the oxidation of pseudocumene in the presence of a catalyst comprising a at least one suitable heavy metal, a source of bromine and at least one polycyclic aromatic hydrocarbon.

The present invention also relates to a catalytic system for receiving the Oia aromatic carboxylic acids by liquid-phase oxidation of aromatic hydrocarbons, moreover, the catalytic system is:

(a) an oxidation catalyst based on at least one heavy metal;

(b) a source of bromine and

(c) polycyclic aromatic hydrocarbon.

The present invention also relates to a method of liquid-phase oxidation of pseudocumene in trimellitic acid, in which the catalyst contains at least one suitable heavy metal, a source of bromine and anthracene.

Further, the present invention relates to a method of liquid-phase oxidation of pseudocumene in trimellitic acid at a temperature from about 50°to about 250°C in the presence of a catalytic system containing at least one suitable heavy metal, a source of bromine and at least one polycyclic aromatic hydrocarbon, which is preferably selected from anthracene, naphthalene, tetracene and mixtures thereof.

In the catalytic system according to this invention polycyclic aromatic hydrocarbon can be an anthracene, naphthalene, tetrazene, and mixtures thereof. Another source of polycyclic aromatic hydrocarbon may be threads heavier by-products of oil refining, containing polycyclic aromatic hydrocarbons.

Heavy metal is cobalt and one or more of the additional metal is, which are selected from manganese, cerium, zirconium, titanium and hafnium, and is present in amount from about 100 ppm by weight to about 6000 ppm by weight. Typically, the atomic ratio of elemental bromine to heavy metal is from about 0.1:1 to about 4:1, for example from approximately 0.2:1 to about 2:1; for example from about 0.3 to about 1:1. Polycyclic aromatic hydrocarbon is an anthracene, naphthalene or tetrazene, alone or in combination.

The invention relates also to a method for oxidation of pseudocumene gas-oxidant education trimellitic acid in a solvent, which represents a C1-C8monocarboxylic acid, in liquid phase conditions at temperatures from about 120°to about 250°C, and the method consists in the oxidation of pseudocumene in the presence of a catalyst containing at least one suitable heavy metal, a source of bromine and one or more polycyclic aromatic hydrocarbons.

The source of bromine may be one or more compounds of bromine, which are selected from Br2, HBr, NaBr, KBr, NH4Br, benzylbromide, bromoxynil acid, dibromoquinone acid, tetrabromoethane, dibromoethylene and bromoacetamide.

The total number of added bromine may be in the form of a single source of bromine, for example, ionic compounds bromine (HBr, NaBr NH 4Br and the like) or in a combined form of bromine, for example organic bromides such as benzylbromide, tetrabromide and other

Polycyclic aromatic hydrocarbon preferably is an anthracene, naphthalene or tetrazene, or a mixture thereof, and more preferred is anthracene.

Disclosure of inventions

The present invention relates to the use of anthracene or other polycyclic aromatic hydrocarbons as activator of the catalyst in the ways catalyzed by cobalt oxidation of alkylaromatic compounds. Specifically, for the oxidation of para-xylene (PX) terephthalic acid (TA), which is then cleaned and get purified terephthalic acid (MOUTH), oxidation of meta-ksilola (MX) isophthalic acid (IPA), pseudocumene (1,2,4-trimethylbenzene) in trimellitic acid (TMLA) and 2,6-dimethylnaphthalene (2,6-DMN) in 2,6-naphthaleneboronic acid (NDA). Increased activity due to anthracene and related compounds can be considered as an advantage among different ways depending on the nature of the target product.

The present invention includes a method of oxidation of pseudocumene (PSC) by molecular oxygen in trimellitic acid (TMLA) in liquid-phase conditions in the presence of a catalytic system, representing an oxidation catalyst on osnovatelei metal, the source of bromine and activator - polycyclic aromatic hydrocarbon.

The addition of anthracene or other polycyclic aromatic hydrocarbons to the original catalyst or continuous additive (i.e. to the final catalyst) allows to obtain a high conversion pseudocumene in trimellitic acid with small quantities of by-products - methyldiazonium acids, using a reduced amount of cobalt in the catalyst system. The activating effect of anthracene more noticeable when it is added continuously to the catalyst by decreasing its activity.

In one embodiment of the catalytic system is a cobalt-manganese-cerium-bromo and anthracene.

In another embodiment of the catalytic system is a cerium titanium-cobalt-manganese-brainy catalyst and anthracene. In yet another embodiment of the catalytic system is a cerium zirconium-cobalt-manganese-brainy catalyst and anthracene.

The present invention also provides a method of oxidation of aromatic hydrocarbons by gas-oxidizing agent with the formation of aromatic dicarboxylic acids in a solvent, which represents a C1-C8monocarboxylic acid, in liquid phase conditions at temperatures from about 120°to about 250°C., for example from about 100 to about 25°C, for example, from about 100°to about 200°C., for example from about 120°to about 250°C., for example from about 120°to about 210°C. Using anthracene, or other polycyclic hydrocarbon can optionally carry out the oxidation at lower temperatures.

The method consists in the oxidation of aromatic hydrocarbons in the presence of a catalyst consisting of at least one suitable heavy metal, bromine and one or more polycyclic aromatic hydrocarbons. Heavy metal may be cobalt and one or more additional metals selected from manganese, cerium, zirconium, titanium and hafnium. Heavy metal preferably is present in amount from about 100 ppm by weight to about 6000 ppm by weight, for example from about 500 ppm by weight to about 3000 ppm by weight.

The oxidation is performed at a pressure from about 1 to about 40 kg/cm2(from about 15 psi to about 569 psi), for example from about 90 psi to about 450 psi, such as from about 90 psi to about 400 psi. Oxidation of DMN in NDA is performed at a pressure from about 300 to about 450 psig, preferably from about 350 to about 400 psi.

Aromatic hydrocarbons are preferably a pair to ilol, meta-xylene, pseudotumor and dimethylnaphthalene. Polycyclic aromatic hydrocarbons are preferably an anthracene, naphthalene, tetrazene, and mixtures thereof, and most preferred is anthracene. In some embodiments the use of anthracene as activator can reduce the need for the catalyst to about 75%, so that the catalyst may contain fewer heavy metal.

The invention provides a catalytic system for liquid-phase oxidation of aromatic hydrocarbons to aromatic carboxylic acid at a temperature from about 50°to about 250°C., for example from about 100°to about 250°C., for example from about 150°to about 200°C., for example from about 120°to about 220°C., for example from about 170°to about 210°C., for example from about 170°to about 200°C.

In one embodiment of the invention, in which pseudotumor oxidize in trimellitic acid, the temperature is about 170°C at the beginning of oxidation and increased to the reaction temperature of about 210-220°C.

Oxidation pseudocumene usually carried out at a pressure from about 90 psi to about 400 psi, for example from about 90 psi to about 300 psi, for example from about 100 psi to about 290 psi, such as from about 105 lb/quedando about 280 psi.

A number of polycyclic compounds used in the catalyst system can range from about 5 ppm to about 10000 ppm, for example from about 5 ppm to about 5000 ppm, for example from about 5 ppm to about 1000 ppm, for example from about 5 ppm to about 200 ppm

The catalytic system comprises at least one suitable heavy metal, a source of bromine and one or more polycyclic aromatic hydrocarbons. Preferably, the heavy metal and anthracene or other polycyclic aromatic hydrocarbons were in the solvent, representing1-C8monocarboxylic acid. Heavy metal is preferably cobalt and one or more additional metals, which are selected from manganese, cerium, zirconium, titanium and hafnium, and preferably is present in amount from about 100 ppm by weight to about 6000 ppm by weight. Preferably, when the atomic ratio of elemental bromine to heavy metal is from about 0.1:1 to about 4:1, more preferably from about 0.3 to about 1:1. Polycyclic aromatic hydrocarbon preferably is an anthracene, naphthalene or tetrazene, or a mixture thereof. Another source of polycyclic aromatic hydrocarbons can be flows of by-products of nefteperera ODI, containing polycyclic aromatic hydrocarbons.

The oxidation of aromatic hydrocarbons to aromatic carboxylic acids in the present invention is performed at a pressure from about 1 to about 40 kg/cm2for example , from about 5 to about 40 kg/cm2for example , from about 14 to about 32 kg/cm2for example , from about 22 to about 29 kg/cm2. Aromatic hydrocarbons include, but are not limited to, alkylaromatic hydrocarbons, preferably containing from one to four methyl groups, such as para-xylene, meta-xylene, pseudotumor and dimethylnaphthalene. Polycyclic aromatic hydrocarbons are selected from anthracene, naphthalene, tetracene and mixtures thereof. Another source of polycyclic aromatic hydrocarbons can be flows of by-products of oil refining, containing polycyclic aromatic hydrocarbons.

The present invention relates to a method for oxidation of aromatic hydrocarbons by molecular oxygen into the aromatic carboxylic acid in the liquid-phase conditions in the presence of a catalyst, activated by anthracene. In preferred embodiments the catalyst is a cobalt-manganese-brainy catalyst, activated anthracene, which may also contain other metals.

Us is Aasee invention also provides a catalytic system for liquid-phase oxidation of aromatic hydrocarbons to aromatic carboxylic acid at a temperature of from about 100°to about 250°C. The catalytic system comprises at least one suitable heavy metal, a source of bromine and one or more polycyclic aromatic hydrocarbons. The source of bromine is preferably one or more compounds of bromine, which are selected from Br2, HBr, NaBr, KBr, NH4Br, benzylbromide, bromoxynil acid, dibromoquinone acid, tetrabromoethane, dibromoethylene and bromoacetamide. Preferably, the heavy metal, a source of bromine and polycyclic aromatic hydrocarbons were in the solvent, which is a C1-C8monocarboxylic acid. Heavy metal is preferably cobalt and one or more second metals which are selected from manganese, cerium, zirconium, and hafnium, and preferably is present in amount from about 100 ppm by weight to about 6000 ppm by weight. Preferably, when the atomic ratio of elemental bromine to heavy metal is from about 0.1:1 to about 4:1, for example from about 0.2 to about 2:1, for example from about 0.3:1 to about 1:1. Polycyclic aromatic hydrocarbon is an anthracene, naphthalene, tetrazene, or a mixture thereof.

In one embodiment of the invention, in which pseudotumor oxidizes to trimellitic acid, the oxidation catalyst contains one or more heavy metals on the tea cerium, zirconium, cobalt and manganese, and in which the cerium content is from about 9 to about 30 wt.%, the zirconium content of from about 2 to about 5 wt.%, the manganese content of from about 25 to about 40 wt.% and the content of cobalt is from about 30 to about 70 wt.%, moreover, the amount of each metal are given in weight percents of the total content of all metals; in which the source of bromine is added in an amount such that the total molar ratio of added bromine to total metals ranged from about 30 to about 100%; and in which the polycyclic aromatic hydrocarbon is added in an amount of from about 5 ppm to about 10000 ppm, polycyclic aromatic hydrocarbon, for example from about 5 ppm to about 5000 ppm, polycyclic aromatic hydrocarbon, for example from about 5 ppm to about 1000 ppm, polycyclic aromatic hydrocarbon, for example from about 5 ppm to about 200 ppm of polycyclic aromatic the hydrocarbon.

Methods of liquid-phase oxidation of pseudocumene to TMLA using polyvalent catalyst and promoter - bromine described in U.S. patent No. 4755622 and 4992579.

U.S. patent No. 4755622 discloses liquid-phase oxidation of pseudocumene in the presence of polyvalent catalyst promoted with a source of bromine, in which oxidation of the wire is t in two stages, the amount of bromine added in the first stage is from about 10 to about 35% of the total number of added bromine, and the rest is injected in the second stage.

U.S. patent No. 4992579 discloses liquid-phase oxidation of pseudocumene (PSC), in which the initial stage of the reaction is carried out in semi-continuous or periodic mode and complete in periodic mode, with the greatest part of the promoter - bromine and trivalent cerium add the final stage in the periodic mode, thereby reducing the contact time of the fragments of the polycarboxylic acid with cobalt-manganese-bromidum or zirconium-cobalt-manganese-bromidum catalysts and increasing output trimellitic acid (TMLA) of the PSC.

One embodiment of the present invention relates to a method of turning pseudocumene in trimellitic acid, which includes the catalytic oxidation of raw materials containing pseudotumor, using a source of molecular oxygen in the liquid-phase conditions in the presence of a catalyst containing a source of cobalt, a source of manganese plus source of bromine and polycyclic aromatic hydrocarbon with a source of zirconium and at a temperature of from about 100°to about 250°C in two stages, the first stage carried out in batch or semi-continuous mode, and the second stage is carried out in periodic activities the ish mode and bromine is added in an amount of from about 10 to about 35 wt.% from the total amount of bromine in the first stage, and the rest is injected in the second stage, and the temperature in the second stage comes to a value of from about 175°to about 250°C, and the temperature in the first stage support from about 125°to about 165°C., and bromine is injected in two stages, as the source of molecular oxygen is supplied together with the raw materials.

Another embodiment of the present invention relates to a method for oxidation of pseudocumene molecular oxygen in trimellitic acid in liquid-phase conditions in the presence of a catalyst comprising an oxidation catalyst based on one or more heavy metals, including trivalent cerium, zirconium, cobalt and manganese in such quantities that g-mol of pseudocumene had from about 3 to about 10 mg-atom of metal, a source of bromine and polycyclic aromatic hydrocarbon at a temperature from about 100°C. to about 275°C, and the method is the stepwise addition of bromine in at least two stages, when 0 to about 35 wt.% the total bromine added in the first stage and the rest at the last stage and the temperature of the last stage set from about 175°C. to about 275°C, and the temperature of the previous stage from about 125°to about 165°C.

Liquid-phase oxidation of aromatic hydrocarbons to aromatic carboxylic acids can be carried out periodically and the definition method a continuous process or semi-continuous manner. The oxidation reaction can be performed in one or more reactors. The reaction mixture is prepared by mixing raw materials, aromatic hydrocarbon, solvent, oxidation catalyst on the basis of heavy metals, a source of bromine and activator - polycyclic aromatic hydrocarbon. In continuous or semi-continuous method, the components of the reaction mixture is preferably mixed in the vessel-mixer before entering them in the oxidation reactor, however, the reaction mixture can be cooked in the oxidation reactor.

Aromatic carboxylic acids, for which applies the present invention include mono - and polycarboxylic connection with one or more aromatic rings, which can be obtained by the reaction of gaseous and liquid reactants in the liquid phase system, and especially those in which the formation of solid reaction products and/or liquid components of the reaction mixture is transferred into the vapor phase above the liquid phase in the reactor. Examples of aromatic carboxylic acids, for which the invention is particularly applicable include timesyou acid, terephthalic acid, benzoic acid and naphthaleneboronic acid.

Suitable aromatic hydrocarbons include aromatic hydrocarbon with at least one group, SP is capable of oxidation to carboxyl group. Deputy or deputies, capable of oxidation, can be an alkyl group such as methyl, ethyl or isopropyl group. It can also be a group that already contains oxygen, for example hydroxyalkyl, formyl or keto-group. The substituents may be the same or different. Aromatic portion of the compounds included in the composition of the raw material may have a benzene nucleus, as well as bi - or polycyclic, for example naphthalene nucleus. The number capable of oxidation of substituents in the aromatic part of the feedstock may be equal to the number of centers in the aromatic part, but generally it is less than the total number of centres, preferably from 1 to 4 and more preferably from 1 to 3. Examples of compounds included in the composition of raw materials are toluene, ethylbenzene, o-xylene, p-xylene, m-xylene, 1-formyl-4-methylbenzol, 1-hydroxymethyl-4-methylbenzol, 1,2,4-trimethylbenzene, 1-formyl-2,4-xylene, 1,2,4,5-tetramethylbenzene, alkyl-, hydroxymethyl-, formyl and acyl-derivatives of naphthalene, such as 2,6 - and 2,7-dimethylnaphthalene, 2-acyl-6-methylnaphthalene, 2-formyl-6-methylnaphthalene, 2-methyl-6-ethylnaphthalene and 2,6-deethylation.

For the preparation of aromatic carboxylic acids by oxidation of the corresponding precursors are aromatic hydrocarbons, such as isophthalic acid from meta-disubstituted benzene derivatives, those who eftalou acid from para-disubstituted benzene derivatives, trimellitic acid from 1,2,4-trimethylbenzene, naphthalenesulphonic acids from disubstituted derivatives of naphthalene, it is preferable to use a relatively pure raw materials and more preferably raw materials, in which the content of its predecessor, the corresponding target acid is at least about 95 wt.% and more preferably at least 98 wt.% and even more. Preferred aromatic hydrocarbons in the production of terephthalic acid is para-xylene. The preferred raw material for producing isophthalic acid is meta-xylene. The preferred raw material for obtaining trimellitic acid is pseudocolor. The preferred raw material for producing 2,6-naphthaleneboronic acid is 2,6-dimethylnaphthalene. Toluene is the preferred raw material for production of benzoic acid.

In one embodiment of the invention the liquid-phase oxidation of pseudocumene to trimellitic acid can conduct periodic way, a continuous process or semi-continuous manner. The oxidation reaction can be performed in one or more reactors. The reaction mixture is prepared by mixing raw materials - pseudocumene, solvent, catalyst, promoter - bromine and promoter - polycyclic aromatic hydrocarbon. In continuous or semi-continuous method, the components of the reaction is ionic mixture is preferably mixed in the vessel-mixer before how to enter them into the oxidation reactor, however, the reaction mixture can be cooked in the oxidation reactor.

Preferred solvents, which is an aqueous solution of carboxylic acid and particularly lower alkyl (for example, C1-C8) monocarboxylic acids, such as acetic or benzoic acid, because they are a very small extent prone to oxidation under typical conditions of the oxidation reaction used in the production of aromatic acids, and can enhance the catalytic effect in the oxidation. Examples of such carboxylic acids include acetic acid, propionic acid, butyric acid, benzoic acid and mixtures thereof. Can also be used with good results ethanol and other solvents, which are oxidized in the monocarboxylic acid in the reaction conditions, oxidation to aromatic acids, by themselves or in combination with carboxylic acids. In order to increase the overall efficiency of the method and minimize separation preferably, when using a solvent composed of a mixture of monocarboxylic acid and an additional solvent, additional solvent was able to oxidize in monocarboxylic acid, with which it is used.

The catalysts used in the method of the present invention, pre whom are substances, which effectively catalyze the oxidation of the raw material aromatic hydrocarbons to aromatic carboxylic acids. Preferably, the catalyst was dissolved in the reaction liquid to create a close contact of the catalyst, oxygen, and liquid raw materials; however, it is possible to use heterogeneous catalysts or components of the catalysts. Typically, the catalyst contains at least one suitable heavy metal, for example metal with an atomic weight of from about 23 to about 178. Examples of heavy metals include cobalt, manganese, vanadium, molybdenum, chromium, iron, Nickel, zirconium, titanium, cerium or lanthanide type hafnium. Suitable metal compounds include, for example, acetates, hydroxides and carbonates. The catalyst of the present invention preferably contains only compounds of cobalt, or a combination of one or more compounds of manganese, cerium compounds, zirconium compounds, titanium compounds or compounds of hafnium.

The promoter - bromo use for promotion of oxidative activity of the catalytically active metal, preferably without the formation of undesirable types or concentrations of by-products and is preferably used in the form of a substance soluble in the liquid reaction mixture. Traditional promoters - bromine compounds include Br2 , NVG, NaBr, KBr, NH4Br and organic bromides.

The authors found that the anthracene and other polycyclic compounds such as naphthalene and tetrazene (2,3-benzanthracene), are effective activators of liquid-phase oxidation of hydrocarbons with the formation of aromatic carboxylic acids. Liquid-phase oxidation of aromatic hydrocarbons to aromatic carboxylic acids can be carried out in the presence of a promoter, which represents an anthracene, naphthalene or tetrazene, and a catalytically active metal, preferably cobalt or manganese, cerium, or the addition of other metals.

Supplements anthracene, naphthalene and other polycyclic aromatic hydrocarbons in the reaction of the homogeneous oxidation of alkylaromatic compounds such as xylenes and dimethylnaphthalene produce sudden and pronounced activation, which leads to increased formation of aromatic acids such as terephthalic acid (TA), isophthalic acid (IPA), trimellitate acid/anhydride (TMLA/TMA) and natalijagolosova acid (NDA). Increased activity in this oxidation (catalyzed Co, mn and Br) is accompanied by a decrease in the number of intermediate and by-products and the reduction catalyst. For the specified activation requires very small concentrations of polycyclic aroma is practical hydrocarbon.

Depending on the specific reaction of anthracene or other polycyclic aromatic hydrocarbon can be added first, in periodic mode, oxidation, continuously in a continuous mode of oxidation, it already worked the catalyst in the periodic oxidation or as periodic and eventually periodic modes. The magnitude of the activating effect may vary depending on the concentration of anthracene or other polycyclic aromatic hydrocarbon, is added as an activator, and method of its introduction. In some reactions the use of anthracene as the catalyst activator may allow the reaction at a lower temperature or decrease the amount of catalytically active metal, particularly cobalt. In some reactions, if the catalytic system is already chosen optimally, anthracene may not increase the activity of the catalyst, however, in such systems anthracene will show activating effect when carrying out the reaction in less than optimal conditions such as low temperature or a smaller amount of catalyst. This has the advantage to reduce the cost of the process.

The oxidation reaction is carried out in the oxidation reactor. The oxidation reactor may consist of one or more vessels. Gas-oxidizer injected into the reactor ocil the deposits. Gas-oxidizing agent in this invention is molecular oxygen. As the source of molecular oxygen is convenient to use the air. Also use air, enriched with oxygen, pure oxygen, and other gaseous mixtures containing at least about 5% of molecular oxygen. Advantage have enriched oxygen source containing at least about 10% of molecular oxygen. It should be emphasized that with the increasing concentration of molecular oxygen in the source reduced requirement for gas compression and content of inert gases in the exhaust gas from the reactor.

The ratio of the quantities of raw materials, catalyst, oxygen and solvent are not critical in this invention and vary not only depending on the choice of raw materials and the desired product, but also from equipment selection and operating parameters. The mass ratio of solvent to raw materials vary from about 1:1 to about 10:1. Gas-oxidizing agent is usually used in a quantity smaller than the stoichiometric calculation for raw materials and not in such great order of unreacted oxygen is released from the liquid phase in the exhaust gases form a flammable mixture with other components of the gas phase. The catalysts are usually used at concentrations of catalytically active metal in the region of the account on the weight of the raw material aromatic hydrocarbon and the solvent is more than about 100 ppm by weight, more preferably about 500 ppm by weight and less than about 10,000 ppm by weight, preferably less than about 6000 ppm by weight, more preferably less than about 3000 ppm by weight. The promoter is preferably bromine is present in an amount such that the atomic ratio of bromine to the catalytically active metal was more than approximately 0.2:1, more preferably about 0.3:1 and less than about 4:1, preferably less than about 3:1. In accordance with the present invention the promoter is one or more polycyclic aromatic hydrocarbons in combination with traditional promoter - bromine in an amount such that the atomic ratio of bromine to the catalytically active metal was preferably from about from 0.25:1 to about 2:1.

The pressure in the reaction vessel should be at least as high, to keep the vessel raw material and the solvent in the liquid phase. Generally suitable pressure from about 5 to about 40 kg/cm2moreover , the preferred pressure for the specific methods vary depending on the composition of the raw material, solvent, temperature, and other factors. The residence time of the solvent in the reaction vessel can be changed in accordance with the performance and services is of from about 20 to about 150 minutes, what is suitable for a number of ways. As it is obvious to experts in the field of production of aromatic acids, the preferred conditions and operating parameters change depending on the products and methods and can be in either of the above within and even outside of those limits.

Aromatic carboxylic acid selected from the liquid, can be used or stored in this form, or be subjected to cleaning or other processing. Cleaning is necessary to remove by-products and impurities that may be present along with selected aromatic carboxylic acid. For aromatic carboxylic acids, such as terephthalic and isophthalic acid, treatment preferably includes the hydrogenation products of oxidation, usually dissolved in water or other aqueous solvents, at elevated temperature and pressure in the presence of a catalyst comprising an active hydrogenation metal, such as ruthenium, rhodium, platinum or palladium, is usually printed on coal, titanium oxide or other suitable chemically resistant carriers or substrates for catalytically active metal. Cleaning methods are known, for example, from U.S. patent 3584039, 4782181, 4626598 and 4892972. If cleaning is performed using water as a solvent, instead of drying can be used rinsing water for separation R is storytale, remaining after oxidation, the solid aromatic carboxylic acid. Such washing can be performed using the appropriate devices for the exchange of solvent, such as filters, as disclosed in U.S. patent 5679846, 5175355 and 5200557.

Usually the mother liquor is separated from the aromatic carboxylic acid partitioning methods, known in the art, for example filtration, centrifugation, or a combination of known methods. It is preferable to return to the process at least a portion of the mother liquor, and in industry generally return a significant portion of the mother liquor.

It was found that when 2,6-naphthaleneboronic acid (NDA) is produced by oxidation of 2,6-dimethylnaphthalene (DMN) using metal complex catalysts, in some cases, additives anthracene increase the output NDA to about 2 wt.%. Increasing access to 2 wt.% is significant for industrial environments.

It is obvious that the addition of anthracene allow oxidation under mild conditions and in a result to get a higher output NDA. Milder conditions have the advantage that they are cheaper.

The ability to reduce the amount of cobalt in the catalyst is especially important for oxidation of DMN in the NDA. Since oxidation DMN in NDA runs harder than the oxidation of PX in THAT, to obtain NDA in the composition of the cat who lyst is required to use more expensive catalytically active metals. The use of anthracene or other polycyclic aromatic hydrocarbons as activator oxidation DMN in NDA may have the advantage of reducing costs by reducing the number of catalytically active metals, the ability to conduct the reaction under milder conditions and/or reduce losses DMN and acetic acid.

It was also found that when 2,6-naphthaleneboronic acid (NDA) was obtained by oxidation of 2,6-dimethylnaphthalene (DMN) using metal complex catalysts with optimal output of NDA supplements anthracene did not increase the output of the NDA. This can be explained by the fact that in the selected conditions, the oxidation reaction proceeds with optimal activity and selectivity and is not stimulated by the addition of anthracene.

In the case of oxidation DMN to NDA activating effect of anthracene was noticeable when the continuous introduction of anthracene, but was not seen when anthracene was added in the initial reaction mixture.

Upon receipt trimellitic acid from pseudocumene you can reduce the cost of the catalyst with the ability to use smaller amounts of cobalt in the catalyst. In the case of anthracene observed lower losses of the solvent is acetic acid and raw materials - pseudocumene that also saves.

The use of anthracene or other suitable polycyclic ar the automatic hydrocarbon as an activator enhances the rate of oxidation and allows the oxidation of pseudocumene at a lower temperature, that means less consumption of acetic acid, improved color and improved selectivity of the formation of products. At lower temperatures and reduced consumption of cobalt is possible to obtain a product of improved color.

Anthracene and other polycyclic compounds such as naphthalene and tetrazene (2,3-benzanthracene), are effective activators of liquid-phase oxidation of pseudocumene in trimellitic acid. Liquid-phase oxidation of pseudocumene education trimellitic acid can be carried out in the presence of the activator, which represents a polycyclic compound which is preferably selected from anthracene, naphthalene, tetracene or combinations thereof, and a catalytically active metal, preferably cobalt or manganese or cerium, or both of these metals together with a source of bromine. When using anthracene or other polycyclic compounds as the promoter, the amount of cobalt in the catalyst can be reduced to concentrations that are two to three times lower than that required in the absence of polycyclic activator of the catalytic system, which leads to the outputs and conversions comparable to those that obtain in the presence of conventional amounts of cobalt.

In one embodiment of the method of the present invention is the oxidation of pseudocumene forefront of the popular oxygen in trimellitic acid in liquid-phase conditions in the presence of a zirconium-cobalt-manganese-cerium-bromides or cobalt-manganese-cerium-bromides catalyst and anthracene as catalyst activator.

The oxidation of pseudocumene in acetic acid solution, each of the metals Zr, Mn and convenient to use in the form of acetates. Cubic Zirconia is available in industry in the form of a solution ZrO2in acetic acid, and in this form it is ideally suited for liquid-phase oxidation in acetic acid solution. When cerium is a component of the catalyst, it is preferable to add at the final stage of the reaction. Suitable trivalent compounds should be dissolved in the solution at the final stage, and that the carbonate and cerium acetate. The source of molecular oxygen for the oxidation in the framework of the present invention may vary according to the content of O2from air to oxygen gas. The air is preferably used as the source of molecular oxygen for oxidation at temperatures of 120°C and up to 275°C. For oxidation by molecular oxygen, the preferred temperature from 100°C to 200°C. the Minimum pressure for such oxidation is the pressure at which the liquid phase is 70-80% of the reaction medium or pseudocumene or pseudocumene with 70-80% acetic acid. Acetic acid as a solvent is from 1 to 10 parts by weight per 1 part of pseudocumene. Pseudotumor and/or acetic acid released from the liquid phase by evaporation under the action heats the reaction, mostly condensed and the condensate is returned to the oxidation reaction for heat dissipation and, thus, to control the exothermic oxidation reactions. Such evaporation of the reagent - pseudocumene and/or solvent - acetic acid is also accompanied by the evaporation of more low-boiling by-product is water. If you want to dispose of acetic acid and water released in the reaction liquid-phase oxidation, the condensate is not returned in the response.

The source of molecular oxygen for the oxidation in the framework of the present invention may vary according to the content of O2from air to oxygen gas. The air prefer to use as the source of molecular oxygen for oxidation at temperatures of 120°C and up to 275°C. For oxidation by molecular oxygen, the preferred temperature from 100°C to 200°C. the Minimum pressure for such oxidation is the pressure at which the liquid phase is 70-80% of the reaction medium or pseudocumene (PSC)or PSC with 70-80% acetic acid. Acetic acid as a solvent is 1-10 parts by weight per 1 part of the PSC. The PSC and/or acetic acid, evaporating from the liquid phase due to the heat of reaction, mostly condensed and the condensate is returned to the oxidation reaction, providing heat and regulation Ekster the practical oxidation reactions. Evaporation of the reagent (PSC) and/or solvent - acetic acid is also accompanied by the evaporation of more low-boiling by-product is water. If you want to use acetic acid and water released in the reaction liquid-phase oxidation, as will be shown below, the condensate is not returned in the response.

The ratio of the quantities of raw materials, catalyst, oxygen and solvent are not critical in this invention and vary not only depending on the choice of raw materials and the desired product, but also from equipment selection and operating parameters. The mass ratio of solvent to raw materials vary from about 1:1 to about 10:1. Gas-oxidizing agent is usually used at least in stoichiometric quantities in the calculation of raw materials, but not in such great order of unreacted oxygen is released from the liquid phase in the exhaust gases form a flammable mixture with other components of the gas phase. The catalysts are usually used at concentrations of catalytically active metal per mass of raw material aromatic hydrocarbon and the solvent is more than about 100 ppm by weight, more preferably about 500 ppm by weight and less than about 10,000 ppm by weight, preferably less than about 6000 ppm by weight, more preferably less than about 3000 ppm by weight. The use of the anthracene is as activator may reduce the need for cobalt at 75%, that will reduce the number of cobalt as the catalytically active metals and generally use less number.

The promoter is preferably bromine is present in an amount such that the atomic ratio of bromine to the catalytically active metal was more than about 0.1:1, more preferably about 0.3:1 and less than about 4:1, preferably less than about 1:1. In accordance with the present invention the source of bromine is present in an amount such that the atomic ratio of bromine to the catalytically active metal is preferably ranged from about 0.3:1 to about 1:1.

Acetic acid or an aqueous solution of acetic acid is the preferred solvent when the ratio of the solvent and the raw material is from about 1:1 to about 5:1, for example from about 1.8:1 to about 4:1, for example from about 1.5:1 to about 3:1. The catalyst preferably contains cobalt in combination with manganese, cerium, zirconium, titanium, hafnium, or any combination of them. As a promoter, preferably use a source of bromine. The catalyst is taken in amounts from about 600 ppm by weight to about 2500 ppm by weight of catalytically active metal per weight of aromatic hydrocarbon and solvent. The promoter - bromo - most preferably is present in an amount such that the atomic is compared bromine to the metal catalyst ranged from about 0.3:1 to about 1:1.

Received trimellitic acid, isolated from the liquid, can be used or stored in this form, or be subjected to cleaning or other processing. Cleaning is necessary to remove by-products and impurities that may be present together with selected aromatic carboxylic acid. Usually the mother liquor is separated from the aromatic carboxylic acid by methods of separation known in the art, for example filtration, centrifugation, or a combination of known methods.

The examples illustrate the invention in more detail. The following examples will illustrate certain specific embodiments of the disclosed invention here. These examples, however, do not limit the scope of the new invention, as it is clear to experts, many possible ways that do not contradict the spirit of the disclosed invention.

EXAMPLES 1-5

Oxidation of meta-xylene to isophthalic acid: experimental technique and results

Experiments were performed in a 300 ml titanium minireactor Parra. The first loading of the reactor contains a catalyst and 76 g of 95% acetic acid (SPLA). The reactor was filled with N2to a pressure of 400 pounds per square inch and heated to the desired temperature. Upon reaching this temperature, the nitrogen atmosphere was replaced with a continuous current of a mixture of N2with 8 vol.% About2. After the reactor was filled g the zoom, containing 8% O2(as evidenced by the concentration of O2in the exhaust gas), filed 25 to 30 ml MX for more than 60 minutes At the same time continuously introduced an additional 25 ml of the SPLA. Anthracene was added either to the initial loading of the reactor (periodic additive), or continuously in the form of a solution in the SPLA during the entire oxidation (60 min). After 60 min 8% O2was replaced with nitrogen, the reactor was cooled to room temperature, the contents of the reactor were unloaded and sent to the analysis of HPLC. During oxidation was continuously analyzed by the exhaust gas on the content of O2, CO2WITH. During the experience also two to three times the samples were taken off-gas and analyzed for their content of volatile organic compounds method for laboratory GC. In all the examples the catalyst in the initial loading consisted of: (OAU)24H2About=0,264 g; Mn(OAc)24H2O=0,278 g; 48% Nug=0,240, In examples 2 and 4 anthracene (AC) was added to a saturated solution of 0.12 to 0.14 wt.% AU) in a mixture of 95/5 wt.% SPLA/N2O. In example 5 was added to the AU (0,300 g) in the initial loading of the reactor.

The influence of anthracene was studied in the presence of normal Co-Mn-Br catalyst oxidation at two different temperatures of 180°C and 195°C and at two ways of introducing anthracene (continuous and periodic). The results are shown in table 1.

Table 1
ExampleNoteT, °CThe molar yield, %Mor/MX (loss)MeBr, ppm
IPA3-CBAm-toluyl. acid
1Control without anthracene180730,702,50,213
2Anthracene continuous.921,75,60,214
3Anthracene periodic activities.800,62,20,234
4Control without anthracene195910,30that 0 0,5819
5Anthracene continuous.890,250,80,6023

Discussion of experimental results:

The influence of anthracene (AC) output IPA.

Continuous introduction of anthracene in the oxidation reaction MX leads to an unexpected increase in the yield of IPA. Comparison of examples 1 and 2 shows that the continuous introduction of speaker leads to an increase in output IPA from 73 to 92 mol.%. The increase in the yield of IPA is not accompanied by an increase in ash, which creates another unexpected advantage.

The additive effect of anthracene on the IPA output may vary depending on temperature oxidation. This effect is weaker at higher temperatures (with the same other conditions of the experiment). While at 180°C is observed a very significant effect (examples 1 and 2), at 195°C increase is not noticeable (see examples 3 and 4). Perhaps at higher temperatures the oxidation reaction takes place under optimal conditions.

Anthracene allows oxidation at lower temperatures.

Comparison of control experiments at 180°C and 195°C. (examples 1 and 4) shows that the oxidation at 180°C results in a significantly smaller o what do IPA (73%), than 195°C (91%). Therefore, to achieve high output IPA in the industry, the oxidation is carried out at 190-200°C. However, the oxidation at higher temperatures leads to a significantly higher loss of reagents and high concentrations of methyl bromide (MeBr) connection, causing depletion of the ozone layer. As can be seen from examples 1 and 4, the oxidation with continuous addition of anthracene at 180°C leads to higher output IPA (92%)than the oxidation without the AC at 195°C (91%). At the same time loss at 180°With approximately 1/3 of the losses at 190°C. At 180°C To form up to 80% less MeBr compared to the experience at 195°C. Therefore, the additive anthracene allow oxidation at lower temperatures without reducing the output of the IPA to reduce losses by entrainment and reduce the formation of MeBr.

The influence of periodic addition of anthracene.

Example 3 shows that anthracene can be added periodically. The addition of 0.3 g of anthracene (or 0.4 wt.% from bootstrap) leads to increased output IPA from 73 to 80 mol.%.

Need a small amount of anthracene.

For promotion of the oxidation reaction requires only a small amount of anthracene. In examples 2 and 5 the total number of input anthracene for 60 minutes was 0,06 mol.% from the number of MX. In example 3, the amount of anthracene entered periodically, was equal to 0.6 mol.% from filing MX.

EXAMPLES 6, 7

The oxidation of para-xylene to terephthalic acid

Experiments were performed in a 300 ml titanium minireactor Parra. Initial loading of the reactor contains a catalyst and 100 g of 95% of the SPLA. The reactor was filled with N2to a pressure of 400 pounds per square inch and heated to 170°C. Upon reaching this temperature, the nitrogen atmosphere was replaced with a continuous current of the N2containing 8 vol.% About2. After the reactor was filled with gas containing 8% O2(as evidenced by the concentration of O2in the exhaust gas), applied materials (para-xylene) at a rate of 0.5 ml/min for 60 min After 60 min gas with 8% O2was replaced with nitrogen and the reactor was cooled to room temperature, selected the entire contents of the reactor (TRE) and sent to the analysis of HPLC. During the oxidation exhaust gas is continuously analyzed for the content Of2, CO2WITH. During the experience of the exhaust gas is also two to three times samples were taken and analyzed for volatile organic compounds method for laboratory gas chromatography (GC). In examples 6 and 7, the catalyst in the initial loading consisted of: Co(OAc)24H2O=0.400 g; MP(SLA)24H2About=0,115 g; 48% Nug=to 0.127, In example 7 ° C (0,300 g) was added to the initial loading into the reactor.

Table 2
ExampleNoteThe molar yield, %Mor/PX (loss)
THE4-CBAp-toluyl. acid
6Control without anthracene245220,08
7Anthracene periodic activities.447290,08

Discussion of examples 6 and 7

In examples 6 and 7 presents data on the oxidation of p-xylene in THAT at 170°C.

The control experiment (example 6, without anthracene) shows that THE output is equal to 24 mol.% when the losses of 0.08. Periodic Supplement to 0.3 wt.% anthracene in the initial loading of the reactor led to the increase of THE output to 44 mol.%, and the amount of losses remained of 0.08. Thus, examples 6 and 7 illustrate the fact that the anthracene promotiom oxidation of p-xylene in such and such promotion does not increase unwanted losses.

EXAMPLES 8-14

Oxidation of 2,6-dimethylnaphthalene (DMN) with the formation of 2,6-naphthaleneboronic acid (NDA) with continuous new the anthracene

The reactor was loaded right amount of cobalt acetate, manganese acetate and NVG. Water was added to the initial load before reaching the water concentration at the end of the reaction 8-10%. In the initial loading of the reactor was placed approximately 108 ml of glacial acetic acid. During the experience to the reactor was added 18 ml of acetic acid and 27 g DMN within 60 minutes Source of oxygen gas containing 8 mol.% O2. In the experiments used two of a solution of anthracene. The solution containing 1750 ppm by weight of anthracene was prepared by saturation of glacial acetic acid anthracene at 72°F (22,2°C). Another solution containing 530 ppm by weight, were prepared by saturation of the solution of 95/5 (wt./wt.) acetic acid/water at 72°F (22,2°C). These two sources of anthracene were used for throttling anthracene added to the oxidation reactor. Example 8 represents a control experience without the addition of anthracene in the reaction mixture. In examples 9 and 10 of the anthracene was added only in the initial loading of the reactor without additional additives anthracene during oxidation. In examples 11 and 12 glacial acetic acid saturated with anthracene at 72°F, used as a solvent in the initial loading of the reactor, and also as a solvent, is added continuously during the oxidation. In example 13 the initial loading of the reactor did not contain anthracene, but ice is xunwu acid, rich anthracene at 72°F, was added continuously during the oxidation. In example 14 the initial loading of the reactor did not contain anthracene, but mixed solvent 95/5 acetic acid/water, saturated with anthracene at 72°F, was added continuously during the oxidation.

The real amount of anthracene in different experiments are shown in table 3.

Table 3
PRPRPRProverbs 11PRPRPR
DescriptionBasics. case (control)VI. case antrac. in began. retrieve.The main case antrac started. retrieve but 20% less CoThe main case with the continuous. it is time to relax. antrac.The main case with the continuous. it is time to relax. antrac., but 30% less CoVI. the case of the continuous. it is time to relax. antrac.VI. the case of the continuous. it is time to relax. antrac.
CatalystFreshFresh + ant the AC. in began. retrieve.Fresh + antrac. in began. retrieve.Fresh + antrac. in the initial load. + continuous. add.Fresh 30% less cobalt + entre Deux. in the initial load. + continuous. add.Fresh + antrac. add. the continuous.Fresh + antrac. add. the continuous.
The anthracene in the initial load.noYesYesYesYesnono
End-I antrac. in will dissolve. in the reactor, ppm by mass0365036501622162223070
The ratio of solvent (g/g)the 4.7the 4.7the 4.7the 4.7the 4.7the 4.7the 4.7
Beg. retrieve. reactor
Acetate Co (g)1,37371,37421,09951,37430,96181,37391,3741
Acetate MP (g)0,45070,45020,36050,45060,45060,45060,4506
48% Nug (g)0,61960,61970,49620,61970,61980,62020,6198
Water (g)3,97533,97494,14523,97523,94803,97513,975
Acetic acid (g)108,70108,70108,87108,70108,70108,7108,7
Other (g)0,50020,5003
Reaction conditions
Just DMN to relax. (g)27,0027,0027,0027,0027,0027,0027,00
Just SPLA entered (g)18,0018,0018,0018,0018,0018,0018,00
Conc. O2in the feed gas (vol.%)of 7.968,008,008,008,00
Reaction time (min) 60606060606060
Mass suspense. (g)158,60156,50153,10152,50157,40155,5156,2

td align="left"> 0,07
The average temperature.(.F)407°F (of 208.3°C)407°F (of 208.3°C)407°F (of 208.3°C)407°F (of 208.3°C)407°F (of 208.3°C)407°F (of 208.3°C)407°F (of 208.3°C)
AVG. press. (lb/CVD)353350350350350351351
AVG. ADJ. gas inlet (cu.ft/h)of 7.96of 10.588,689,9510,7510,1710,17
AVG. ADJ. gas output (cu.ft/h)7,6010,178,30at 9.5310,289,819,80
The total yield (mol. %)
TMLA1,692,411,432,351,912,69to 2.57
FNA0,400,762,200,490,430,480,62
2-NA0,710,530,450,420,461,121,16
2-Me-6-NA0,040,451,640,100,140,25
2,6-NDA75,9876,5569,4874,4482,3584,4686,71

The results of examples 8 to 12 show that the addition of anthracene can reduce the number of cobalt and increase yields NDA with continuous addition of anthracene and when using reduced amounts of cobalt in the catalyst system.

In examples 8 and 9 anthracene in the initial loading has no effect.

In example 10, the combination of low concentrations of cobalt and anthracene in the initial loading fail.

In example 11 when the base concentration of cobalt continuous addition of anthracene is not effective.

In example 12, when the cobalt concentration is 30% smaller and continuous addition of anthracene yield of 2,6-NDA is increased from 76 to 82,3 mol.%, that means a significant increase in product yield.

The effect of the concentration of anthracene

In examples 8, 13 and 14 all conditions of oxidation were the same as in the main scenario, except number of anthracene, continuously added to the oxidation reactor. In all these examples, the anthracene was absent in the initial load R. the actor. The yield of 2,6-NDA was increased from 76 mol.% to 86.7 mol.% adding 70 ppm by weight of anthracene. However, adding more anthracene (230 ppm by weight) yield of 2,6-NDA dropped to 84,5 mol.%. It is obvious that the concentration of anthracene in solvent in the reactor affects the yield of 2,6-NDA. The optimal concentration of anthracene, apparently, depends on if it is present in the initial loading or continuously added during the experiment; in addition, it depends on the concentrations of cobalt, manganese and bromine in the reaction mixture and the reaction temperature.

In example 11, the concentration of anthracene was 1392 ppm in the initial loading of the reactor and another 230 ppm by weight of anthracene was added continuously during the experience. However, in example 13 anthracene in the initial loading of the reactor was not, but the anthracene was continuously added over the course of the experience in the amount of 230 ppm by weight. Due to the high initial concentration of anthracene yield of 2,6-NDA was only 74,4 mol.% in example 11 compared with 84,5 mol.% in example 13. This clearly shows that a high initial concentration of anthracene in the reactor before oxidation reduces the yield of 2,6-NDA in terms of the main event.

Examples of liquid-phase oxidation of pseudocumene (PSC)

Comparative example a

Download 0.87 g of cobalt acetate tetrahydrate, 1,74 g of manganese acetate tetrahydrate, 0.29 grams of a solution of HBR (48%) and 0,086 the solution zirconolite (17% Zr) 2 l titanium autoclave, containing 529 g of glacial acetic acid, 28 g of water and 293 g of pseudocumene.

This initial mixture was heated to 320°F (160°C) under a slow nitrogen purge and then gave compressed air enriched with oxygen up to 24.5%) at 54 STD. cubic feet/hour for 15 minutes for the first 15 minutes the temperature was maintained at a level of 330°F (165,6°C) at a pressure of about 105 psi. Three minutes after the air supply was added to the solution of the final catalyst with a speed of 0.8 g/min to the total number 40,0 graniczny solution of catalyst was prepared by mixing 325 g of acetic acid, 60 g of water, 1.31 g of manganese acetate tetrahydrate, of 0.91 g of a solution of zirconium, KZT 12.39 g of the solution NVG and 2.10 g of cerium acetate.

Starting with 15 minutes of oxidation, the pressure and the temperature was increased linearly from 345°F (173,9°C) and 105 pounds/square inch up to 410°F (210°C) and 280 lb/square inch, respectively. The final temperature and pressure were established after about 40 min of oxidation. The temperature and the pressure is then maintained at this level until such time as the oxygen content in the exhaust gas is not started quickly grow to 14%, which indicated the completion of the oxidation.

In addition to raising the temperature and pressure of the blower speed was gradually increased from 54 to 60 STD. cubic feet/hour with 15 to 20 minutes, the feed Rate of air was maintained at a level of 58 STD. cubic feet/hour to 45 min and then p is gradually reduced to 50 STD. cubic feet/hour for 7 minutes, the feed Rate of air was maintained at a level of 50 STD. cubic feet/hour to complete the oxidation. The air supply was cut in such a way as to maximize the absorption of oxygen and not a flammable mixture.

The oxidation product was collected, the sample was dried to a solid state and analyzed. Table 4 presents data on this experience and examples 15 and 16.

Example 15

The oxidation was carried out similarly to comparative example a except that the initial reaction mixture is added 0.5 g of anthracene.

Example 16

The oxidation was carried out similarly to comparative example a except that the final catalyst was saturated by anthracene (320 ppm), and to the original catalyst was not added anthracene.

Table 4
Component wt.% solidComparative example And without anthraceneExample 15
0.5 g of anthracene first
Example 16
320 ppm anthracene in the final catalyst
Trimellitate acid86,290,592,9
Metilcarbonievy sour is you 4,361,170,31
Reaction time (min)58,256,058,7

Table 4 shows the activating effect of anthracene as when adding it at the beginning of the reaction, and adding to the final catalyst (i.e. with continuous addition of low concentrations in the periodic oxidation). Output trimellitic acid (TMLA) increases as the content of the primary intermediate products - methyldiazonium acids (also known as methyldienolone acid or MDBs) is noticeably reduced due to the increased activity.

In the reaction used cobalt at concentrations 2-3 times lower than conventional industrial concentrations, which indicates the possibility of significant reduction of the catalyst by the addition of anthracene. The cobalt concentration in comparative example A, example 15 and example 16 is 0.07 wt.% per loaded pseudotumor. In a typical industrial reactions of the cobalt concentration is equal to 0.16 wt.%. Therefore, comparing the results of examples 15 and 16 with the results of comparative example a, it can be seen that the addition of anthracene to the source or destination of the catalyst allows you to get a good conversion of pseudomo the Ola in trimellitic acid with small amounts of by-products - methyldiazonium acids with a lower content of cobalt (i.e. 0.07 wt.%) in the catalytic system. Much lower amounts of cobalt, used in the above examples, is a decreasing cobalt content of 56% compared with conventional binder content of 0.16 wt.%. The possibility is so significantly reduce the amount of cobalt while maintaining acceptable activity can lead to signicant reduction catalyst.

1. The method of oxidation of aromatic hydrocarbon with a source of molecular oxygen with the formation of aromatic carboxylic acids in liquid phase conditions at a temperature of from 50 to 250°C in the presence of a catalyst comprising a:
a) oxidation catalyst based on at least one heavy metal is a cobalt and one or more additional metals selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, Nickel and hafnium;
b) a source of bromine; and
c) unsubstituted polycyclic aromatic hydrocarbons.

2. The method according to claim 1, in which unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and their combinations.

3. The method according to claim 2, in which unsubstituted polycyclic aromatic hydrocarbon is anthracene.

4. The way p is 1, the source of bromine is one or more of the compounds of bromine, which are selected from Br2, HBr, NaBr, KBr, NH4Br, benzylbromide, bromoxynil acid, dibromoquinone acid, tetrabromoethane, dibromoethylene and bromoacetamide.

5. The method according to claim 1, in which the heavy metal is present in an amount of from 100 ppm by weight to 6000 ppm by weight.

6. The method according to claim 1, wherein the oxidation is carried out at a temperature of from 120 to 250°C.

7. The method according to claim 1, wherein the oxidation is carried out at a pressure of from 6.5 to 32.5 kg/cm2.

8. The method according to claim 7, in which the oxidation is carried out at a pressure of from 7.2 to 29 kg/cm2.

9. The method according to claim 1, wherein the aromatic carboxylic acid selected from isophthalic acid, terephthalic acid, trimellitic acid and 2,6-naphthaleneboronic acid.

10. The method according to claim 1, in which unsubstituted polycyclic aromatic hydrocarbon is a stream of by-products of oil refining, containing polycyclic aromatic hydrocarbons.

11. The method according to claim 1, in which unsubstituted polycyclic aromatic hydrocarbon is a stream of by-products of oil refining, containing polycyclic aromatic hydrocarbons.

12. Catalyst system for producing aromatic carboxylic acids by liquid-phase oxidation aromaticheski the hydrocarbons, representing:
a) oxidation catalyst based on at least one heavy metal is a cobalt and one or more additional metals selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, Nickel and hafnium;
b) a source of bromine; and
c) unsubstituted polycyclic aromatic hydrocarbons.

13. The catalytic system according to item 12, which is unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and their combinations.

14. The catalytic system according to item 12, which is unsubstituted polycyclic aromatic hydrocarbon is anthracene.

15. The catalytic system according to item 12, in which the source of bromine is one or more of the compounds of bromine, which are selected from Br2, HBr, NaBr, KBr, NH4Br, benzylbromide, bromoxynil acid, dibromoquinone acid, tetrabromoethane, dibromoethylene and bromoacetamide.

16. The catalytic system according to item 12, in which the heavy metal is present in an amount of from 100 to 6000 ppm by weight.

17. The catalytic system according to clause 12, in the presence of which the oxidation is carried out at a temperature of from 100 to 250°C.

18. The catalytic system 17, in the presence of which the oxidation is carried out at a temperature of from 120 to 250°C.

19. The catalytic system according to clause 12, in the presence of the Torah oxidation is carried out at a pressure of from 6.5 to 32.5 kg/cm 2.

20. The catalytic system according to claim 19, in presence of which the oxidation is performed at a pressure from 21.6 to 29 kg/cm2.

21. The catalytic system according to item 12, in which the aromatic carboxylic acid selected from isophthalic acid, terephthalic acid, trimellitic acid and 2,6-naphthaleneboronic acid.

22. The catalytic system according to item 12, which is unsubstituted polycyclic aromatic hydrocarbon is a stream of by-products of oil refining, containing polycyclic aromatic hydrocarbons.

23. The method of oxidation of para-xylene using a source of molecular oxygen with the formation of terephthalic acid in the liquid-phase conditions in the presence of a catalyst comprising a:
a) oxidation catalyst based on at least one heavy metal is a cobalt and one or more additional metals selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, Nickel and hafnium;
b) a source of bromine; and
c) unsubstituted polycyclic aromatic hydrocarbons.

24. The method according to item 23, which is unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and their combinations.

25. The method according to paragraph 24, which is unsubstituted polycyclic aromatic hydrocarbons are the two which is the anthracene.

26. The method of oxidation of meta-xylene using a source of molecular oxygen with the formation of isophthalic acid in the liquid-phase conditions in the presence of a catalyst comprising a:
a) oxidation catalyst based on at least one heavy metal is a cobalt and one or more additional metals selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, Nickel and hafnium;
b) a source of bromine; and
c) unsubstituted polycyclic aromatic hydrocarbons.

27. The method according to p, which is unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and their combinations.

28. The method according to item 27, which is unsubstituted polycyclic aromatic hydrocarbon is anthracene.

29. The method of oxidation of 2,6-dimethylnaphthalene using a source of molecular oxygen with the formation of 2,6-naphthaleneboronic acid in liquid-phase conditions in the presence of a catalyst comprising a:
a) oxidation catalyst based on at least one heavy metal is a cobalt and one or more additional metals selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, Nickel and hafnium;
b) a source of bromine; and
c) unsubstituted polycyclic, aromati the definition hydrocarbons.

30. The method according to clause 29, which is unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and their combinations.

31. The method according to item 30, which is unsubstituted polycyclic aromatic hydrocarbon is anthracene.

32. The method of oxidation of pseudocumene in trimellitic acid, which is the catalytic oxidation of raw materials containing pseudotumor, using a source of molecular oxygen in liquid phase conditions at a temperature of from 50 to 250°C., in the presence of a catalyst comprising a:
a) oxidation catalyst based on at least one heavy metal is a cobalt and one or more additional metals selected from manganese, cerium, zirconium, titanium, vanadium, molybdenum, Nickel and hafnium;
b) a source of bromine; and
c) unsubstituted polycyclic aromatic hydrocarbons.

33. The method according to p, which is unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and their combinations.

34. The method according to p, which is unsubstituted polycyclic aromatic hydrocarbon is anthracene.

35. The method according to p, in which the heavy metal is present in an amount of from 100 to 6000 ppm by weight.

36. The method according to p, in which the oxidation is carried out at a temperature of from 100 to 25°C.

37. The method according to p, in which the oxidation is carried out at a pressure of from 6.5 to 21.6 kg/cm2.

38. A way of turning pseudocumene in trimellitic acid, which is the catalytic oxidation of raw materials containing pseudotumor, using a source of molecular oxygen in liquid phase conditions at a temperature of from 50 to 250°C., in the presence of a catalyst comprising a:
a) the catalyst is a cobalt-manganese-cerium;
b) a source of bromine; and
c) anthracene.

39. A way of turning pseudocumene in trimellitic acid, which is the catalytic oxidation of raw materials containing pseudotumor, using a source of molecular oxygen in liquid phase conditions at a temperature of from 50 to 250°C., in the presence of a catalyst comprising a:
a) the catalyst is a zirconium-cobalt-manganese-cerium;
b) a source of bromine; and
c) anthracene.

40. A way of turning pseudocumene in trimellitic acid, which is the catalytic oxidation of raw materials containing pseudotumor, using a source of molecular oxygen in the liquid-phase conditions in the presence of a catalyst comprising a:
a) oxidation catalyst based on at least one heavy metal is a cobalt and one or more additional metals selected from manganese, cerium, zirconium, is Ethan and hafnium, and in which the heavy metal is present in an amount of from 100 to 6000 ppm by weight;
b) a source of bromine; and
c) unsubstituted polycyclic aromatic hydrocarbons, which are selected from anthracene, naphthalene, tetracene and combinations thereof; at a temperature of from 130 to 220°C.; at a pressure of from 6.5 to 21.6 kg/cm2.

41. The method according to p, in which the oxidation is carried out at a temperature of from 170 to 220°C. and at a pressure of from 7.5 to 20 kg/cm2and in which the polycyclic aromatic hydrocarbon is anthracene.

42. A way of turning pseudocumene in trimellitic acid, which is the catalytic oxidation of raw materials containing pseudotumor, using a source of molecular oxygen in the liquid-phase conditions in the presence of a catalyst containing a source of cobalt, a source of manganese plus source of bromine and unsubstituted polycyclic aromatic hydrocarbon, in the presence of a source of zirconium or without it at a temperature of from 100 to 250°C in two stages, the first of which is conducted periodically or semi-continuous, and the second carried out periodically, and add bromine so that from 10 to 35 wt.% the total bromine added in the first stage and the rest is added in the second stage, and the temperature of the second stage is from 175 to 250°C., and the temperature of the first stage from 125 to 165°C., while at the two-stage call for the attachment of the bromine source of molecular oxygen is added to the raw materials.

43. The method according to § 42, which is unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and their combinations.

44. The method of oxidation of pseudocumene molecular oxygen in trimellitic acid in liquid-phase conditions in the presence of a catalyst containing an oxidation catalyst based on one or more heavy metals, including trivalent cerium, zirconium, cobalt and manganese in an amount of from 3 to 10 mg from all metals 1 g/mol of pseudocumene, a source of bromine and unsubstituted polycyclic aromatic hydrocarbon, at a temperature of from 100 to 275°C, and the method includes the step-wise introduction of bromine in at least two stages, when from 0 to 35 wt.% the total bromine added in the first stage and the rest is added in the second stage, and the cerium added at the last stage, and the temperature of the last stage ranges from 175 to 275°C and the temperature of the previous stage from 125 to 165°C.

45. The method according to item 44, which is unsubstituted polycyclic aromatic hydrocarbon is selected from anthracene, naphthalene, tetracene and combinations thereof.



 

Same patents:

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for preparing dimethyl-1,5-naphthalene dicarboxylate that is used in preparing polymers based on thereof and articles made of these polymers. The economic and effective method involves the following stages: (1) dehydrogenation of 1,5-dimethyltetraline to yield 1,5-dimethylnaphthalene; (2) oxidation of 1,5-dimethylnaphthalene prepared at dehydrogenation stage to yield 1,5-naphthalene dicarboxylic acid being without accompanying isomerization stage, and (3) esterification of 1,5-naphthalene dicarboxylic acid prepared at oxidation stage in the presence of methanol to yield the final dimethyl-1,5-naphthalene dicarboxylate.

EFFECT: improved preparing method.

9 cl, 3 dwg, 5 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for purifying naphthalene carboxylic acid. Method involves contacting crude naphthalene acid with solvent used for purifying in the presence of hydrogen and catalyst that comprises a precious metal of VIII group taken among palladium, platinum and ruthenium and metal of group IVB taken among silicon, germanium, tin and lead at temperature about from 520 to 575°F. Proposed method provides preparing reduced amount of organic pollution in purified acid as compared with other methods of purification.

EFFECT: improved purifying method.

19 cl, 1 dwg, 5 tbl, 5 ex

The invention relates to a method for producing an aromatic carboxylic acid, which comprises oxidizing in the liquid phase source of aromatic compounds containing at least one capable of oxidation of alkyl or acyl group, oxygen-containing gas in a solvent containing a low molecular weight carboxylic acid, in the presence of an oxidation catalyst containing heavy metals, when 121-232oC with formation of a reaction mixture of oxidation products containing the obtained aromatic carboxylic acid

The invention relates to organic chemistry and relates to a method of obtaining naphthalenol acid or its derivatives, which are used as intermediates to obtain phosphors used in fluorescent penetrant inspection, as fluorescent components when getting day fluorescent pigments and dyes in the production of organic scintillators, for the dyeing of polymeric materials and other purposes in the national economy

The invention relates to organic chemistry, in particular to a method for producing an aromatic dicarboxylic acid, 2,6-naphthaleneboronic acid, 4,4-diphenylcarbinol, 4,4-diphenylcarbinol acid, 4,4-diphenylmethanediisocyanate acid, which is used in the production of liquid-crystalline thermoplastics

The invention relates to a method for producing naphthalene-2,6-dicarboxylic acid (2,6-NIR), which is widely used as a monomer in polymer chemistry: introduction naphthalene cycle gives polymeric materials of high heat - resistance, fire resistance, radiation resistance

FIELD: organic chemistry of polymers, chemical technology.

SUBSTANCE: invention relates to the improved method for preparing trimellitic acid anhydride. Method for preparing intramolecular trimellitic acid anhydride is carried out by liquid phase oxidation of pseudocumene with air oxygen for a single stage at increased temperature and pressure under conditions of countercurrent of oxygen-containing gas and reaction products in the presence of a catalyst comprising heave metal salts and halide compounds followed by distilling off a solvent and thermal dehydration of mellitic acid up to its intramolecular anhydride. Oxidation of pseudocumene is carried out in reaction volume separated for three zones wherein hydrogen bromide acid is added to each reaction zone by distributed feeding to provide the discrete increase of the HBr concentration up to [HBr] ≥ 0.052% in the first (upper) zone, [HBr] ≤ 0.09% in the middle (second) zone, and [HBr] ≤ 0.111% in the bottom third) zone. The composition of catalyst is maintained as constant in all zones in the ratio of its components in the limit Co : Mn : Ni = (0.28-0.66):1:0.04, respectively, and the process is carried out in the temperature range 160-205°C by its step-by-step increase in zones in the range: 160-180°C in the upper (first) zone, 180-190°C in the middle (second) zone, and 195-205°C in the bottom (third) zone. Invention provides improving the technological process of oxidation of pseudocumene, to improved quality of the end product and to enhance specific output of the reaction volume. Trimellitic acid anhydride is used broadly in preparing high-quality plasticizers, insulating varnishes, high-temperature polyimidoamide coatings and other polymeric materials.

EFFECT: improved preparing method.

2 tbl, 3 dwg, 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: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for isolating crystalline terephthalic acid comprising less 150 mas. p. p. per million (ppm) of p-toluic acid with respect to weight of terephthalic acid. Method involves the following steps: (1) preparing a solution containing from 10 to 35 wt.-% of dissolved terephthalic acid wherein from 150 to 1100 ppm of p-toluic acid is dissolved with respect to mass of terephthalic acid at temperature from 260°C to 320°C and under pressure providing maintaining the solution in liquid phase; (2) charge of solution from step (1) to crystallization zone comprising multitude amount of associated crystallizers wherein the solution is subjected for cooling at evaporation at the controlled rate by the moderate pressure and temperature reducing resulting to crystallization of terephthalic acid and wherein the solution pressure at the end of crystallization zone is equal to atmosphere pressure or lower; (3) condensation of solvent evaporated from crystallizers and recovering the condensed solution to the crystallization zone to place of descending flow from crystallizer wherein solvent is removed by evaporation, and (4) isolation of solid crystalline terephthalic acid comprising less 150 ppm of p-toluic acid with respect to the terephthalic acid mass by separation of the phase liquid-solid substance under atmosphere pressure. The advantage of method is preparing the end product in improved crystalline form and carrying out the process under atmosphere pressure or pressure near to atmosphere pressure.

EFFECT: improved method of crystallization.

3 cl, 1 dwg, 1 tbl, 2 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for chemical reutilization of depleted polyethylene terephthalate, especially to non-classified crumbs of utilized polyethylene terephthalate articles resulting to preparing terephthalic acid and ethylene glycol. Method involves hydrolysis of utility waste polyethylene terephthalate with aim for its depolymerization and involves the following steps: (a) separation of polyethylene terephthalate component in the parent raw by its transfer to fragile form by using crystallization, grinding and the following screening processes; (b) continuous two-step hydrolysis of polyethylene terephthalate carried out at the first step by injection of steam into polymer melt followed by carrying out the hydrolysis reaction of products from the first step with ammonium hydroxide and by the following (c) precipitation of terephthalic acid from aqueous solution of hydrolysis products from the second step with inorganic acid and separation of terephthalic acid by filtration method and by the following (d) extraction of ethylene glycol by rectifying from solution of the second step hydrolysis products after separation of terephthalic acid. This technologically simple and effective method provides possibility for treatment of very contaminated the parent raw and providing high purity of end products.

EFFECT: improved treatment method.

5 cl, 1 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a continuous method for preparing highly pure terephthalic acid. Method involves oxidation of p-xylene with oxygen-containing gas in acetic acid medium in the presence of catalyst comprising heavy metal salts, such as cobalt and manganese and halide compounds under increased pressure and temperature up to the definite degree of conversion of para-xylene to terephthalic acid at the first step and the following two-step additional oxidation of prepared reaction mixture and isolation of the end product. Mixing time of reagents is <25 s, oxidation at the first step is carried out at temperature 180-200°C up to conversion degree of p-xylene 95%, not above, oxidation at the second step is carried out at temperature 175-185°C and before feeding to the third step of oxidation the reaction mass is heated to 200-260°C, kept for 8-12 min and oxidized at temperature 180-200°C in the presence of catalyst comprising Ni and/or Zr salts additionally. As halide compounds method involves using XBr or XBr + XCl wherein X is H, Na, Li followed by isolation of solid products of oxidation after the third step and successive treatment with pure acetic acid and water in the mass ratio terephthalic acid : solvent = 1:3. Invention provides intensification of process and to enhance quality of terephthalic acid.

EFFECT: improved method for preparing.

1 tbl, 1 dwg, 14 ex

The invention relates to an improved method of reducing the content of 4-carboxybenzene in the production of terephthalic or 3-carboxymethylthio in the production of isophthalic acid, comprising: (a) dissolving crude terephthalic acid or crude isophthalic acid in a solvent at a temperature of from 50 to 250With obtaining a solution; (b) crystallization of the purified acid from this solution by reducing the temperature and/or pressure; (C) the Department specified crystallized terephthalic acid or isophthalic acid from the solution; (d) adding an oxidant to the reactor oxidation carboxyanhydride for oxidation specified filtered solution of stage (C), leading to the transformation of 4-carboxybenzene or 3-carboxymethylthio in terephthalic acid or isophthalic acid; (e) evaporating the solvent from this solution from step (d); (f) cooling the concentrated solution from step (e) for crystallization additional quantities of purified terephthalic acid or isophthalic acid and filtering the specified slurry and recycling the most part, the mother liquor from step (f) in the devices is

The invention relates to an improved method of reducing the content of 4-carboxybenzene in the production of terephthalic or 3-carboxymethylthio in the production of isophthalic acid, comprising: (a) dissolving crude terephthalic acid or crude isophthalic acid in a solvent at a temperature of from 50 to 250With obtaining a solution; (b) crystallization of the purified acid from this solution by reducing the temperature and/or pressure; (C) the Department specified crystallized terephthalic acid or isophthalic acid from the solution; (d) adding an oxidant to the reactor oxidation carboxyanhydride for oxidation specified filtered solution of stage (C), leading to the transformation of 4-carboxybenzene or 3-carboxymethylthio in terephthalic acid or isophthalic acid; (e) evaporating the solvent from this solution from step (d); (f) cooling the concentrated solution from step (e) for crystallization additional quantities of purified terephthalic acid or isophthalic acid and filtering the specified slurry and recycling the most part, the mother liquor from step (f) in the devices is

The invention relates to an improved process for the preparation of terephthalic and isophthalic acids

The invention relates to an improved method for producing isophthalic acid used in copolymerization ways of producing fibers, films, plastic bottles and structures made of polyester resin, which consists in the oxidation of metaxalone in the reaction solvent to obtain a liquid dispersion

The invention relates to an improved method for producing isophthalic acid, which is an important monomer and intermediate in polymer chemistry for the production of chemical fibers, polyester films, varnishes, dyes, plastics
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