Method of preparing dry residue of carboxylic acid suitable for synthesis of polyesters

FIELD: chemistry.

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

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

21 cl, 4 dwg

 

The scope of the invention

The present invention relates to a method for dry sediment carboxylic acid in the slurry or sludge carboxylic acids by using at least one counterflow rinsing. More specifically, the present invention relates to a method for dry precipitate terephthalic acid is the source of the substance to obtain polyesters or polyester copolymers from suspension or precipitate terephthalic acid using at least one countercurrent washing.

The prior art inventions

With regard to the production of polyethylene terephthalate (PET) and other polyesters or polyester copolymers significant part of the patent literature is devoted to the description of the method of obtaining dry sediment carboxylic acid as the starting material. In General, these inventions describe a particular schema mixing purified terephthalic acid with liquid glycol. In addition, there is a large literature material on obtaining purified terephthalic acid in powder form, suitable for the production of polyethylene terephthalate (PET) and other polyesters or polyester copolymers.

The objective of this invention is to provide a method of producing a dry Deposit of carboxylic acids, are suitable as starting substances are obtained for the I polyesters or polyester copolymers, the slurry or sludge carboxylic acid using zone countercurrent washing with solvent. More specifically, the present invention is to provide a method for obtaining dry precipitate terephthalic acid, are suitable as starting substances for obtaining polyesters or polyester copolymers, suspension or precipitate terephthalic acid using zone countercurrent washing with a solvent to reduce the amount of fresh solvent used in the method.

Usually purified solid terephthalic acid is obtained by a multi-stage method, in which receive the crude terephthalic acid. Liquid-phase oxidationp-xylene get crude terephthalic acid. The quality of the crude terephthalic acid is not sufficient for direct use as the starting material in the industrial production of PET. Instead, the crude terephthalic acid is usually clean and get cleaned solid terephthalic acid.

Typically, in the methods of purification of terephthalic acid crude terephthalic acid is dissolved in water and hydronaut to transform 4-carboxybenzene inp-Truelove acid, which dissolves better in water, and to this end the connection characteristic yellow color turned into colorless derivatives. A significant share of the VA 4-carboxybenzene or p-Truelove acid in the final purified terephthalic acid is particularly harmful for polymerization processes, as each of them causes chain termination during the condensation reaction of terephthalic acid with ethylene glycol in the production of PET. Ordinary purified terephthalic acid contains less than 25 moschata per million 4-carboxybenzene and less than 150 parts/millionp-Truelove acid.

Was developed a number of other ways in which received terephthalic acid, are suitable as the starting material for the industrial production of PET, without the use of hydrogenation. Usually ways to obtain terephthalic acid include catalytic oxidationp-xylene in the solvent is acetic acid followed by filtration and drying of terephthalic acid.

Typically terephthalic acid (TPA), obtained by catalytic oxidation ofp-xylene in the solvent is acetic acid, is a suspension or a residue of terephthalic acid, which contains residual catalyst (for example, compounds of cobalt, manganese and bromine). In the conventional method of obtaining a substantially dry TRA of suspension or precipitate terephthalic acid suspension or precipitate terephthalic acid was filtered to separate the main quantity of liquid acetic acid from the solid TPA. Residual catalyst on the commonly separated from the suspension or precipitate terephthalic acid washing (rinsing) of wet sediment acetic acid, not containing catalyst, water or other solvent. Solid TRA allocate drying.

In the present invention developed a new method using less solvent than in existing methods. In the traditional approach to obtaining terephthalic acid by catalytic oxidationp-xylene in acetic acid obtained suspension or precipitate terephthalic acid is filtered, washed, then dried to produce a powder of terephthalic acid, are suitable as the starting material in the industrial production of PET.

In one embodiment of the present invention, the suspension or sludge obtained terephthalic acid is filtered off, receiving a residue of terephthalic acid with the solvent and the flow of the mother liquor solvent with TPA. The precipitate terephthalic acid, solvent, then washed (rinsed) with water to separate the residual catalyst and get soaked in water to precipitate terephthalic acid and the flow of liquid by-products together with TPA and water. Moistened with water to precipitate terephthalic acid then dried, yielding a dry residue of terephthalic acid, are suitable as the starting material for the industrial production of PET. In this embodiment of the invention is applied, at least one counterflow rinsing. Thanks used the Yu zone countercurrent washing solvent can significantly reduce the amount of solvent compared with the method without counter-current washing. In addition, the use of at least one countercurrent washing can reduce the size of the equipment and energy costs compared with the method of obtaining TRA without counterflow rinsing.

The invention

The present invention relates to a method for dry sediment carboxylic acid in the slurry or sludge carboxylic acid. More specifically, the present invention relates to a method for dry precipitate of terephthalic acid, which can be used as raw material for industrial production of PET. As a result, the method uses less solvent than the methods used at the present time and not use the zone countercurrent washing with a solvent.

The present invention is to develop a method of obtaining dry sediment carboxylic acid in the slurry or sludge carboxylic acids by using at least one countercurrent washing.

Another objective of the present invention is to provide a method of producing a dry precipitate terephthalic acid from the suspension or precipitate terephthalic acid.

Another object of the present invention is to provide a method of producing a dry precipitate terephthalic acid from the slurry of terephthalic acid in a solvent or sludge use zone countercurrent rinsing solution is Telem.

In the first embodiment of the present invention proposes a method of obtaining dry sediment carboxylic acid, which includes:

(a) deletion in the area of liquid-phase mass transfer of impurities from a suspension of carboxylic acid with the formation of water-soaked sediment carboxylic acid, the flow of the mother liquor, the flow of the mother liquor together with the solvent and the flow of liquid by-products together with the solvent/water, and the solvent or water is injected countercurrent to the flow of a suspension of carboxylic acids;

(b) drying moistened with water to precipitate the carboxylic acid in the drying zone with the formation of dry sediment carboxylic acid.

In another embodiment of the present invention proposes a method of obtaining dry sediment carboxylic acid, which includes:

(a) deletion in the area of liquid-phase mass transfer with the solvent impurities from a suspension of carboxylic acid with the formation of carboxylic acid, wetted with solvent flow the mother liquor and the flow of the mother liquor together with the solvent;

(b) adding water to the precipitate carboxylic acid, wetted with solvent, in the zone of countercurrent washing of water with the formation of water-soaked sediment carboxylic acid and flow with by-products together with the solvent/water;

(C) drying the water-wet sludge to benovoy acid in the drying zone with the formation of dry sediment carboxylic acid.

In another embodiment of the present invention proposes a method of obtaining dry sediment carboxylic acid, which includes:

(a) deletion in the zone of separation of solid and liquid impurities from a suspension of carboxylic acid with the formation of the product in the form of a suspension or sediment and flow of mother liquor;

(b) removing in a zone of countercurrent liquid-phase mass transfer of solvent-water residual impurities from the resulting suspension or sludge with the formation of water-soaked sediment carboxylic acid, the flow of the mother liquor together with the solvent and the flow of liquid by-products and solvent/water; and

(C) drying moistened with water to precipitate the carboxylic acid in the drying zone with the formation of dry sediment carboxylic acid.

In another embodiment of the present invention proposes a method of obtaining dry sediment carboxylic acid, which includes:

(a) removing the solvent from the resulting suspension or sludge in the zone of countercurrent liquid-phase mass transfer of solvent-water; and a significant part of the solvent in the obtained slurry or sludge is replaced by water with the formation of water-soaked sediment carboxylic acids;

(b) drying moistened with water to precipitate the carboxylic acid in the drying zone with the formation of dry sediment carboxylic acid.

In another embodiment the AI of the present invention proposes a method of obtaining dry precipitate of terephthalic acid, which includes:

(a) removing in a zone of countercurrent washing solvent residual impurities from the resulting suspension or precipitate terephthalic acid with formation of a precipitate of terephthalic acid with acetic acid;

(b) removing a substantial portion of the solvent in the zone of countercurrent wash water from the precipitate of terephthalic acid with acetic acid with the formation of water-soaked precipitate terephthalic acid; and

(C) drying moistened with water to precipitate the carboxylic acid in the drying zone with the formation of dry sediment carboxylic acid.

In another embodiment of the present invention proposes a method of obtaining dry precipitate of terephthalic acid, which includes:

(a) removing the solvent from the resulting suspension or precipitate terephthalic acid in a zone of countercurrent liquid-phase mass transfer of solvent-water; and a significant part of the solvent in the resulting suspension or precipitate terephthalic acid is replaced by water with the formation of water-soaked precipitate terephthalic acid;

(b) drying moistened with water to precipitate the terephthalic acid in the drying zone with the formation of the dry precipitate terephthalic acid.

In another embodiment of the present invention proposes a method of obtaining dry precipitate of terephthalic acid, which includes:

(a) deletion in the area, however, is offered by the washing solvent residual impurities from the suspension or precipitate terephthalic acid, obtained from the precipitate of terephthalic acid with acetic acid; and zone countercurrent washing includes at least one device for separating solids and liquids, which operates at a temperature of from about 40°to about 155°C;

(b) removing a substantial portion of the solvent in the zone of countercurrent wash water from the precipitate of terephthalic acid with acetic acid with the formation of water-soaked precipitate terephthalic acid; and a zone of countercurrent wash water includes at least one device for separating solids and liquids, which operates at a temperature of from about 40°to about 155°C;

(C) drying moistened with water to precipitate the terephthalic acid in the drying zone with the formation of the dry precipitate terephthalic acid.

In another embodiment of the present invention proposes a method of obtaining dry sediment carboxylic acid, which includes:

(a) deletion in the zone of separation of solid and liquid impurities from a suspension of carboxylic acid with the formation of the product slurry or sludge and flow of mother liquor;

(b) adding solvent to the resulting suspension or subsidence in the area of counter-current washing solvent with the formation of carboxylic acid with the solvent and the flow of the mother liquor to dissolve what ielem;

(C) the optional addition of water to the zone countercurrent washing with water to precipitate the carboxylic acid with the solvent to form moistened with water to precipitate the carboxylic acid and the flow of liquid by-products and solvent/water;

(d) drying moistened with water to precipitate the carboxylic acid in the drying zone with the formation of dry sediment carboxylic acid.

In another embodiment of the present invention proposes a method of obtaining dry precipitate of terephthalic acid, which includes:

(a) deletion in the zone of separation of solid and liquid impurities from a suspension of terephthalic acid with the formation of the suspension and the precipitate of terephthalic acid and flow of mother liquor;

(b) adding solvent to the resulting suspension or precipitate terephthalic acid in a zone of countercurrent washing with a solvent to form a precipitate of terephthalic acid with the solvent and the flow of the mother liquor together with the solvent;

(C) the optional addition of water to the precipitate of terephthalic acid with a solvent in the zone of countercurrent washing of water with the formation of water-soaked precipitate terephthalic acid and flow with by-products from the solvent/water;

(d) drying moistened with water to precipitate the carboxylic acid in the drying zone with the formation of dry sediment carboxylic sour the s.

These and other objectives will become more apparent to the ordinary experts after reading the following description.

Brief description of drawings

Figure 1 illustrates one embodiment of the present invention is a method of obtaining dry sediment carboxylic acid.

Figure 2 illustrates another embodiment of the present invention is a method of obtaining dry sediment carboxylic acid using the zone of liquid-phase mass transfer.

Figure 3 illustrates another embodiment of the present invention is a method of obtaining dry sediment carboxylic acid using zone countercurrent liquid-phase mass transfer of the solvent is water.

Figure 4 illustrates another embodiment of the present invention is a method of obtaining dry sediment carboxylic acid using the zone of liquid-phase mass transfer with the solvent.

Description of the invention

In the embodiment of the present invention, is shown in figure 1, the method for obtaining dry sediment carboxylic acid170. This method is as follows:

Stage (a) includes the optional removal of impurities from a suspension of carboxylic acid30in the area of the substitution solids liquid40with the formation of the resulting suspension or sludge carboxylic acid70and flow of mother liquor60.

Suspension ka is oil acid contains, at least one carboxylic acid, a catalyst, at least one solvent and impurities, and it is served by lines that are not shown. Impurities typically include one or more of the following compounds: 4-carboxybenzene (4-CBA), trimellitic acid (TMA) and 2,6-dicarboxylate (2,6-DCF). Suitable solvents include, but are not limited to, aliphatic monocarboxylic acids, preferably containing from 2 to 6 carbon atoms, or benzoic acid and its mixtures and mixtures of these compounds with water. It is preferable that the solvent was a mixture of acetic acid with water in a ratio of about 5:1 to about 99:1, preferably from about 8:1 to about 49:1. According to the specifications of acetic acid will be called a solvent. However, it should be emphasized that it is possible to use other suitable solvents, such as have been previously disclosed. The solvent generally contains acetic acid, but it can be any solvent as specified above.

A suspension of carboxylic acid can be obtained by oxidation in the oxidation zone of the aromatic raw material. In one embodiment of the aromatic feedstock is apair-xylene. The oxidation zone comprises at least one oxidation reactor, and a suspension of carboxylic acid contains at least one carboxylic KIS the GTC. The oxidation reactor can operate at a temperature of from about 120°to about 250°C., preferably from about 140°to about 170°C. Typically aromatic feedstock is apair-xylene, and the carboxylic acid is terephthalic acid. In one embodiment of the invention the oxidation zone includes a bubble column.

So, for example, using terephthalic acid suspension carboxylic acid30will be called a suspension of terephthalic acid, and a dry residue of carboxylic acid170we will call the dry precipitate terephthalic acid.

Carboxylic acids include any carboxylic acid obtained controlled oxidation of organic precursors. For example, carboxylic acids include aromatic dicarboxylic acids, preferably containing from 8 to 14 carbon atoms, aliphatic dicarboxylic acids, preferably containing from 4 to 12 carbon atoms, or cycloaliphatic dicarboxylic acids, preferably containing from 8 to 12 carbon atoms. Other examples of suitable carboxylic acids include, but are not limited to, terephthalic acid, benzoic acid,p-Truelove, isophthalic acid, trimellitic acid, naphthaleneboronic acid, cyclohexanecarbonyl acid, cyclohexadecane acid, diphenyl-4,4'-decarb the new acid, diphenyl-3,4'-dicarboxylic acid, 2,2-dimethyl-1,3-propertyeditormanager acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sabotinova acid and mixtures thereof.

A suspension of terephthalic acid are traditionally synthesized by liquid-phase oxidationpair-xylene in the presence of a suitable oxidation catalyst. Suitable catalysts include, but are not limited to, compounds of cobalt, manganese and bromine, soluble in the selected solvent. In one embodiment of the invention, the catalyst contains cobalt, bromine and manganese. The concentration of total cobalt and manganese can be from about 100 ppm to about 2700 ppm by weight in the mother solution. Bromine can be present in solution in concentrations of from about 1000 ppm to about 2500 ppm by weight.

The resulting suspension carboxylic acid served in the replacement zone solids liquid40in which you can remove part of the liquid contained in the suspension carboxylic acid30,with the formation of the suspension or sludge carboxylic acid in the pipeline70. Part of the liquid with the formation of the suspension or sludge carboxylic acid in the pipeline70you can delete any means known in the art. Part means, at least 5 wt.% the fluid. Usually replacement zone solids liquids is using 40includes a device for separating solids and liquids, which are selected from the group consisting of decantorului centrifuge, centrifuge with a rotating disk, belt filter, rotary vacuum filter, etc. a Suspension of carboxylic acid in the pipeline30served in the replacement zone solids liquid40that includes one device for separating solids from liquids. Device(s) for separation of solids and liquids can operate at temperatures from about 50°to about 200°C., preferably from 140°to about 170°C. a Device for separating solids and liquids can operate at pressures from about 0 psi to about 200 psi. Device for separating solids and liquids in the area of the substitution solids liquid40can operate in continuous or batch mode, although from the point of view of industrial production is preferred continuous method.

Impurities are displaced from the zone of substitution solids liquid40in the flow of the mother liquor and are selected through the line60. In one embodiment of the invention in the area of the substitution solids liquid40submit any additional solution through line50to replenish the suspension of carboxylic acid30and education is Uspenskii and sediment carboxylic acid 70. When used in the area of the substitution solids liquid40suspension of terephthalic acid are suspension or precipitate terephthalic acid. Suspension or precipitate terephthalic acid usually contains terephthalic acid and acetic acid. The mother liquor60away from the zone of substitution solids liquid40across the line60and it contains a solvent, usually acetic acid, the catalyst and bromine compounds. The mother liquor in line60you can either send in a stage of separation of the impurities from the solvent oxidation on lines that are not shown, or to return in the catalytic system according to the lines that are not shown. One way to remove impurities from the mother liquor60commonly used in the chemical industry, is the selection or "blow-off" part of the stream recycling. Usually when allocating valuable components of the stream Stripping simply remove or, if economically justified, is subjected to various treatments to remove unwanted impurities. Examples of methods for removing impurities contained in U.S. patents 4939297 and 4356319 included with references.

Stage (b) comprises a deletion in the zone of countercurrent washing solvent80residual impurities in the slurry or sludge carboxylic acid70with the formation of carboxylic acid pax is with solvent 110and flow of the mother liquor together with the solvent100.

Pipeline70contains a slurry or sludge carboxylic acid70,represents a carboxylic acid, residual impurities and the solvent. Residual impurities contain residual catalyst (usually, the composition includes, but is not limited to, cobalt, manganese or bromine). Suitable solvents include, but are not limited to, aliphatic monocarboxylic acids, preferably containing from 2 to 6 carbon atoms, or benzoic acid and its mixtures and mixtures of these compounds with water. Preferably, the solvent contains mainly acetic acid and/or a certain amount of water. The ratio of acetic acid to water can vary from 50:50 to 99:1 by weight, more preferably from 85:15 to 98:2 and most preferably from 90:10 to 97:3. Suitable carboxylic acids include, but are not limited to, terephthalic acid, naphthaleneboronic acid, trimellitic acid and mixtures thereof.

Suspension or sludge carboxylic acid70contains 10-90 wt.% carboxylic acid. Preferably, the suspension or sludge carboxylic acid70contained 25-40 wt.% carboxylic acid in suspension and 70-90 wt.% in the sediment. Most preferably, the slurry or sludge carboxylic acid70contained 30-40 wt.% carbon is howling acid. Suspension or precipitate the carboxylic acid in the pipeline70then injected into a zone of countercurrent washing solvent80in which a substantial portion of the solvent are separated into a stream of mother liquor together with the solvent in the pipeline100. The mother liquor together with the solvent102contains a significant portion of the solvent. Incremental solution can be introduced through the tubing90in the countercurrent to the flow of slurry or sludge carboxylic acid70in the zone of countercurrent washing80. The number of stages of counter-current washing can be anything that you want to obtain sediment carboxylic acid of the desired purity together with the solvent. Usually the number of stages of counter-current washing can be from about 1 to 8, preferably from about 2 to about 6, most preferably from about 2 to about 4. Countercurrent washing is preferred when the number of stages of washing more than one.

Zone countercurrent washing solvent80includes at least one device for separating solids and liquids, which allows you to effectively separate solids and liquids. Device for separating solids and liquids is usually, but not be limited to, the following type: centrifuges, cyclones, rotary drum f is ltry, belt filters, press filters, etc. Zone countercurrent washing solvent80includes at least one device for separating solids and liquids110that can work in the temperature range from about 40°C. to 155°C. Preferably, the device for separating solids and liquids110could work in the temperature range from about 80°to about 150°C. Most preferably, the device for separating solids and liquids110worked in the temperature range from about 90°to about 150°C. Receive the residue of carboxylic acid with a solvent110in which the moisture content can be in the range of 0.5-30 wt.%, preferably in the range of 1-20% water, most preferably in the range of 1-10% moisture. Optional residual solvent can be removed at the stage of displacement gas to minimize contamination of the solvent. When the carboxylic acid is a terephthalic acid, and the solvent is acetic acid, receive the residue of terephthalic acid with acetic acid.

Stage (C) includes, optionally, removing a substantial part of the solvent in the zone of countercurrent wash water120from the precipitate carboxylic acid with a solvent110with the formation of water-soaked the charge carboxylic acid 100and the flow of liquid by-products together with the solvent/water140.

The precipitated carboxylic acid with a solvent110then wash or rinse water or mostly water with residual amounts of solvent in the zone of countercurrent wash water120moreover , a substantial portion of the solvent is replaced by water with the formation of water-soaked sediment carboxylic acid150. The water-wet carboxylic acid residue150contains from about 0.5% to about 30% moisture, more preferably from about 1 to about 20% moisture, and most preferably from about 1% to about 10% moisture. Residual moisture is soaked in water to precipitate the carboxylic acid150should be less than about 2 wt.% the solvent. In addition, the water-wet carboxylic acid residue150must contain less than 1%, preferably less than 100 ppm by weight, most preferably less than 10 ppm by weight of metals commonly used as catalysts for oxidationp-xylene contained in the slurry or sludge carboxylic acid in the pipeline70and must be soaked in water to precipitate the carboxylic acid150. Examples of metals include, but are not limited to, cobalt and manganese.

Water for washing is introduced into a zone of countercurrent wash water120across the pipeline 130. The ratio of the mass rate of continuous supply of wash water to the solid content of the draft carboxylic acid with a solvent110should be from about 0.1:1 to about 1.5:1, preferably from about 0.1:1 to about 0.6:1, most preferably in the range from approximately 0.2:1 to about 0.4:1. Restrictions on temperature and pressure wash water, including the use of water vapor, water vapor or a mixture of water and steam for washing, otsutstvuet one embodiment of the invention the wash water is injected countercurrent to the precipitate carboxylic acid with a solvent.

Incremental water for washing can be fed through line130countercurrent to the flow of sediment carboxylic acid with a solvent110in the zone of countercurrent wash water120. The number of required stages of countercurrent washing can be anything to get soaked with water sludge carboxylic acid of the desired purity. Usually the number of stages of counter-current washing can be from about 1 to 8, preferably from about 2 to about 6, most preferably from about 2 to about 4.

Zone countercurrent rinsing water contains at least one device for separating solids and liquids120which usually may represent, but is not limited the tsya this, the following types of such devices: centrifuges, cyclones, rotary drum filters, belt filters, press filters, etc. Device for separating solids and liquids can operate in the temperature range from about 40°C. to 155°C. Preferably, a second device for separating solids and liquids can operate in the temperature range from about 80°to about 150°C. Most preferably, the device for separating solids and liquids can operate in the temperature range from about 90°to about 150°C.

Optional liquid by-products from the zone of countercurrent wash water120separated from the flow of the mother liquor together with the solvent obtained in the zone of countercurrent washing solvent80.

Stage (d) consists of drying the water-wet sediment carboxylic acid150in the area of drying160with the formation of dry sediment carboxylic acid170.

The water-wet carboxylic acid residue150discharged from the zone of countercurrent wash water120or zone countercurrent washing solvent80and served in the area of drying160. Part of the solvent or water and the remaining catalyst and impurities are separated, and the dry residue of carboxylic acid selected through the line170.

Zone drying160is the nd filter, suitable for separation of the solid carboxylic acid, and a dehumidifier. Filtering can be performed by any method known in the art. For example, to filter and receive filter cake you can use a rotary vacuum filter. The filter cake passes through the stage of initial removal of the solvent, then rinse acid rinse to remove residual catalyst and again remove the solvent before it enters the drier. Drying the filtered precipitate can be performed by any means known in the art, by which it is possible to vaporize at least 10% of volatile substances remaining in the filtered precipitate, with the formation of carboxylic acids. For example, you can use a dehumidifier Single Shaft Porcupine® Processor.

In other embodiments of the present invention stage (a), phase (b) and stage (C) can be combined into a single area known as the zone of liquid-phase mass transfer250as shown in figure 2. Area of liquid-phase mass transfer250includes at least one device for separating solids and liquids capable of performing the combined function of the zone of separation of solids from liquids40zone countercurrent washing solvent80and zone countercurrent rinsing water120as explained above. Stage (b) and stage (C) can also tasked denite in one area, known as the zone of liquid-phase mass transfer of solvent-water countercurrent260as shown in figure 3. Finally, stage (a) and (b) can be combined into a single area known as the zone of liquid-phase mass transfer with the solvent270shown in figure 4. Each of these embodiments includes at least one device for separating solids and liquids, which can perform the functions of the joint zones, as described above. Examples of devices that can be used in the area of liquid-phase mass transfer250or in the zone of the liquid-phase mass transfer of solvent-water260,or in the zone of the liquid-phase mass transfer with the solvent270include , but are not limited to, the following types of devices: centrifuges, cyclones, filters, and combinations thereof.

1. The method of obtaining dry sediment aromatic dicarboxylic acid containing 8 to 14 carbon atoms, are suitable as starting material for the manufacture of polyester, this method includes the following sequence of stages:
(a) oxidizing an aromatic feedstock in the zone of oxidation with obtaining a suspension of carboxylic acid;
(b) removing in the area of liquid-phase mass transfer, which remove at least 5% of the liquid impurities from the suspension aromatic dicarboxylic acid with formation of a precipitate or suspension aromatic dicarbon the howling acid, and flow of the mother liquor, where the area of the liquid mass transfer includes a device for separating solids and liquids;
(c) removal in the zone of countercurrent washing solvent residual impurities from the suspension or sludge aromatic dicarboxylic acid obtained in stage (b), with the formation of an aromatic dicarboxylic acid with the solvent and the flow of the mother liquor together with the solvent, where the number of stages of counter-current washing is from 1 to 8, zone countercurrent washing includes at least one device for separating solids and liquids, and the solvent includes acetic acid,
(d) removing part of the solvent in the zone of countercurrent wash water from sludge aromatic dicarboxylic acid with a solvent obtained in stage (C), with the formation of water-soaked sediment aromatic dicarboxylic acid and the flow of liquid by-products together with the solvent/water, where the number of stages of counter-current washing is from 1 to 8, and a zone of countercurrent washing includes at least one device for separating solids and liquids, and phase (b), (C) and (d) are combined into one zone of liquid-phase mass transfer, and the direction moistened with water sediment aromatic dicarboxylic acid neposredno is but the next stage (e),
(e) drying the specified moistened with water to precipitate the aromatic dicarboxylic acid in the drying zone with the formation of the specified dry sediment aromatic dicarboxylic acids, suitable for polyester, and specified moistened with water the precipitate retains the form of sediment between stages (d) and (e).

2. The method according to claim 1, in which the specified area of liquid-phase mass transfer includes from about 2 to about 4 stages of countercurrent washing with water or solvent.

3. The method according to claim 1, in which the specified aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, naphthaleneboronic acid, trimellitic acid and mixtures thereof.

4. The method according to claim 3, in which the specified carboxylic acid is terephthalic acid.

5. The method according to claim 1 or 2, wherein in said drying zone pariveda at least 10% volatile compounds from the specified moistened with water to precipitate the aromatic dicarboxylic acid.

6. The method according to claim 1, in which the specified suspension of the crude aromatic dicarboxylic acid containing terephthalic acid, catalyst, acetic acid and impurities, is withdrawn from the oxidation zone at a temperature of from about 110 to about 200°C, and the specified catalyst containing compounds of cobalt, manganese and bromine.

7. The method of obtaining dry sediment is romantic dicarboxylic acid, containing 8-14 carbon atoms, are suitable as starting material for the manufacture of polyester, this method includes the following sequence of stages:
(a) oxidizing an aromatic feedstock in the zone of oxidation of obtaining suspension of an aromatic dicarboxylic acid;
(b) removing in the area of liquid-phase mass transfer, which remove at least 5% of the liquid impurities from the suspension aromatic dicarboxylic acid with formation of a precipitate or suspension of an aromatic dicarboxylic acid and flow of mother liquor, where the area of the liquid mass transfer includes a device for separating solids and liquids;
(c) removal in the zone of countercurrent washing solvent residual impurities from the suspension or sludge aromatic dicarboxylic acid obtained in stage (b), with the formation of an aromatic dicarboxylic acid with the solvent and the flow of the mother liquor together with the solvent, where the number of stages of counter-current washing is from 1 to 8, and a zone of countercurrent washing includes at least one device for separating solids and liquids, and the solvent includes acetic acid,
(d) removing part of the solvent in the zone of countercurrent wash water from sludge aromatic dicarboxylic acid with a solvent, extracting the aqueous stage (C), with the formation of water-soaked sediment aromatic dicarboxylic acid and the flow of liquid by-products together with the solvent/water, where the number of stages of counter-current washing is from 1 to 8, and a zone of countercurrent washing includes at least one device for separating solids and liquids, and phase (b) and (C) combined into one zone of liquid-phase mass transfer, and the direction moistened with water sludge aromatic dicarboxylic acid directly to the next stage (e),
(e) drying the specified moistened with water to precipitate the aromatic dicarboxylic acid in the drying zone with the formation of the specified dry sediment aromatic dicarboxylic acids, suitable for polyester, and specified moistened with water the precipitate retains the form of sediment between stages (d) and (e).

8. The method according to claim 7, in which the specified aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, naphthaleneboronic acid, trimellitic acid and mixtures thereof.

9. The method according to claim 7, in which the specified aromatic dicarboxylic acid is terephthalic acid.

10. The method according to claim 7 or 8, in which this zone drying pariveda at least 10% volatile compounds from the specified moistened with water to precipitate the aromatic dicarbo the OIC acid.

11. The method according to claim 7, in which the specified suspension of the crude aromatic dicarboxylic acid containing terephthalic acid, catalyst, acetic acid and impurities are selected from a specified oxidation zone at a temperature of from about 110 to about 200°C, and the specified catalyst containing compounds of cobalt, manganese and bromine.

12. The method of obtaining dry sediment aromatic dicarboxylic acid containing 8 to 14 carbon atoms, are suitable as starting material for the manufacture of polyester, this method includes the following sequence of stages:
(a) oxidizing an aromatic feedstock in the zone of oxidation of obtaining suspension of an aromatic dicarboxylic acid;
(b) removing in the area of liquid-phase mass transfer, which remove at least 5% of the liquid impurities from the suspension aromatic dicarboxylic acid with formation of a precipitate or suspension of an aromatic dicarboxylic acid and flow of mother liquor, where the area of the liquid mass transfer includes a device for separating solids and liquids;
(c) removal in the zone of countercurrent washing solvent residual impurities from the suspension or sludge aromatic dicarboxylic acid obtained in stage (b), with the formation of an aromatic dicarboxylic acid with the solvent and the flow of the mother liquor instead of the e with the solvent, where the number of stages of counter-current washing is from 1 to 8, zone countercurrent washing includes at least one device for separating solids and liquids, and the solvent includes acetic acid,
(d) removing part of the solvent in the zone of countercurrent wash water from sludge aromatic dicarboxylic acid with a solvent obtained in stage (C), with the formation of water-soaked sediment aromatic dicarboxylic acid and the flow of liquid by-products together with the solvent/water, where the number of stages of counter-current washing is from 1 to 8, and a zone of countercurrent washing includes at least one device for separating solids and liquids, and phase (C) and (d) are combined into one zone of liquid-phase mass transfer, and the direction moistened with water sludge aromatic dicarboxylic acid directly to the next stage (e),
(e) drying the specified moistened with water to precipitate the aromatic dicarboxylic acid in the drying zone with the formation of the specified dry sediment aromatic dicarboxylic acids, suitable for polyester, and specified moistened with water the precipitate retains the form of sediment between stages (d) and (e).

13. The method according to item 12, in which the specified aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, naphthaleneboronic acid, trimellitic acid and mixtures thereof.

14. The method according to item 12, in which the specified aromatic dicarboxylic acid is terephthalic acid.

15. The method according to item 12, which indicated a suspension of the crude aromatic dicarboxylic acid containing terephthalic acid, catalyst, acetic acid and impurities, is withdrawn from the oxidation zone at a temperature of from about 110 to about 200°C, and the specified catalyst containing compounds of cobalt, manganese and bromine.

16. The method according to item 12 or 13, in which this zone drying pariveda at least 10% volatile compounds from the specified moistened with water to precipitate the aromatic dicarboxylic acid.

17. The method of obtaining dry sediment aromatic dicarboxylic acid containing 8 to 14 carbon atoms, are suitable as starting material for the manufacture of polyester, this method includes the following sequence of stages:
(a) deletion in the area of liquid-phase mass transfer, which remove at least 5% of the liquid impurities from the suspension aromatic dicarboxylic acid with formation of a precipitate or suspension of an aromatic dicarboxylic acid and flow of mother liquor, where the area of the liquid mass transfer includes a device for separating solids and liquids,
(b) udalenie zone countercurrent washing solvent residual impurities from the suspension or sludge aromatic dicarboxylic acid, obtained in stage (a), with the formation of an aromatic dicarboxylic acid with the solvent and the flow of the mother liquor together with the solvent, where the number of stages of counter-current washing is from 1 to 8, and a zone of countercurrent washing includes at least one device for separating solids and liquids, and the solvent includes acetic acid,
(c) removing part of the solvent in the zone of countercurrent wash water from sludge aromatic dicarboxylic acid with a solvent obtained in stage (b), with the formation of water-soaked sediment aromatic dicarboxylic acid and the flow of liquid by-products together with the solvent/water, where the number of stages of counter-current washing is from 1 to 8, and a zone of countercurrent washing includes at least one device for separating solids and liquids, and stage (a), (b) and (C) combined into one zone of liquid-phase mass transfer, and the direction moistened with water sediment aromatic dicarboxylic acid directly to the next stage (d),
(d) drying the specified moistened with water to precipitate the aromatic dicarboxylic acid in the drying zone with the formation of the specified dry sediment aromatic dicarboxylic acids, suitable for polyester, and specified mocenni the water residue maintains the shape of the sediment between stages (C) and (d).

18. The method according to 17, in which the specified aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, naphthaleneboronic acid, trimellitic acid and mixtures thereof.

19. The method according to p in which the specified aromatic dicarboxylic acid is terephthalic acid.

20. The method according to p, which indicated a suspension of the crude aromatic dicarboxylic acid containing terephthalic acid, catalyst, acetic acid and impurities are selected from a specified oxidation zone at a temperature of from about 110 to about 200°C, and the specified catalyst containing compounds of cobalt, manganese and bromine.

21. The method according to 17 or 18, in which this zone drying pariveda at least 10% volatile compounds from the specified moistened with water to precipitate the aromatic dicarboxylic acid.



 

Same patents:

FIELD: chemistry.

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

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

45 cl, 4 tbl, 16 ex

FIELD: 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: chemistry.

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

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

45 cl, 4 tbl, 16 ex

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

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

25 cl, 11 tbl, 29 ex, 3 dwg

FIELD: chemistry.

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

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

45 cl, 4 tbl, 16 ex

FIELD: chemistry.

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

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

8 cl, 1 tbl, 1 dwg, 1 ex

FIELD: chemistry.

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

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

13 cl, 1 dwg, 1 ex

FIELD: chemistry.

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

EFFECT: obtaining mixture of carboxylic acid/diol.

29 cl, 4 dwg

FIELD: chemistry.

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

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

19 cl, 1 dwg, 6 ex, 4 tbl

FIELD: carbon materials and hydrogenation-dehydrogenation catalysts.

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

EFFECT: increased mechanical strength and abrasion resistance.

8 cl, 4 ex

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

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

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

8 cl, 3 tbl, 2 dwg, 3 ex

FIELD: 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: 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 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
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