Method of obtaining mixture of carboxylic acid/diol suitable for use during manufacture of polyester

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

 

The technical field

The present invention relates to a method by which a mixture of carboxylic acid/diol obtained from discolored solution of carboxylic acid without isolating the essentially dry solid carboxylic acid. More specifically, the present invention relates to a method by which a mixture of terephthalic acid/ethylene glycol, suitable as starting material for the production of complex polyester, obtained from discolored solution of terephthalic acid without isolating the essentially dry solid terephthalic acid.

The level of technology

Thermoplastic polyesters are growing speed polymers, which are useful when they are brought to a high molecular wt. The first stage in a General way produce complex polyester such as polyethylene terephthalate (PET), is a stage of the esterification or ester exchange, where dikelola (typically terephthalic acid) reacts with a suitable diola (usually ethylene glycol) to obtain the complex bis(hydroxyalkyl) ether and some linear oligomers. At this stage, water is allocated, and it is usually removed by fractional distillation.

According to the task of production of polyethylene terephthalate and other polyesters principal amount of patent literature devoted to the description of the ways of obtaining mixtures of terephthalic acid/ethylene glycol, acceptable as initial substances. In General, these inventions describe certain schemes mixing with solid purified terephthalic acid and liquid ethylene glycol as the starting materials. In addition, there is a large mass of literature devoted to production of purified terephthalic acid in powder form, which can be used in the manufacture of PET. The present invention is a method by which a mixture of terephthalic acid/ethylene glycol, suitable as starting material for the production of complex polyester, obtained from discolored solution of terephthalic acid without isolating the essentially dry solid terephthalic acid.

Developed a number of methods of producing solid purified terephthalic acid, and these methods are industrially available. Usually solid purified terephthalic acid is obtained multi-way receive crude terephthalic acid. Crude terephthalic acid does not have sufficient quality for direct use as source material for industrial PET. Therefore, the crude terephthalic acid is usually purified to solid purified terephthalic acid.

Liquid-phase oxidation of p-xylene gives the crude terephthalic acid. Raw therephtale the second acid is dissolved in water and hydronaut in order to convert 4-carboxybenzene in p-Truelove acid, which is derived, it is better soluble in water, and for the conversion of the characteristic yellow compounds into colourless derivatives. Any number of 4-carboxybenzene and p-Truelove acid in the final product purified terephthalic acid is particularly harmful for polymerization processes, as they act as agents breaking a chain, in the course of the condensation reaction between terephthalic acid and ethylene glycol in the production of PET. Ordinary purified terephthalic acid contains by weight less than 25 parts per million (h/m) 4-carboxybenzene and less than 150 hours/million p-Truelove acid.

Crude terephthalic acid typically contains by weight from 800 to 7000 ppm (h/m) 4-carboxybenzene and from 200 to 1500 h/m p-Truelove acid as the major impurities. Crude terephthalic acid also contains smaller amounts, in the range of 20-200 hours/million, yellow colored aromatic compounds containing the structure of benzil, fluorenone and/or anthraquinone, which are characterized by yellow compounds as impurities resulting from adverse reactions combinations occurring during the oxidation of p-xylene. You should clean the crude terephthalic acid, when it is used as the starting material in the production of complex polyester fiber, is AutoRAE as starting substances require application of purified terephthalic acid.

Such cleaning methods typically include adding water to the crude terephthalic acid to obtain a solution of crude terephthalic acid, which is heated to dissolve the crude terephthalic acid. A solution of crude terephthalic acid is then passed through the reactor zone in which the solution is injected into contact with hydrogen in the presence of a heterogeneous catalyst at temperatures of from 200 to 375°C. This is the stage of recovery makes different colored components present in the crude terephthalic acid, unpainted products. The main impurity, 4-carboxybenzene, is converted into p-Truelove acid.

Conventional crude terephthalic acid contains excessive amounts as 4-carboxybenzene and p-Truelove acid based on weight. Thus, to achieve less than 25 wt. hours/million 4-carboxybenzene and less than 150 wt. h/m p-Truelove acid in purified terephthalic acid necessary mechanisms purification of crude terephthalic acid and the removal of pollutants.

Subsequent separation and isolation of purified terephthalic acid can be carried out using a wide variety of separation methods, including crystallization, centrifugation, filtration, extraction, and combinations thereof, followed by drying. Such methods are described in U.S. patents 4500732, 517555 and 5583254; all of which are included as references. It is necessary to conduct phase separation according to the nature of the crude terephthalic acid which is a raw material for hydrogenation process.

Developed a number of ways to get solid purified terephthalic acid from the crude terephthalic acid. In General, common features of these methods are:

stage (1) is a discoloration of the crude terephthalic acid is usually by hydrogenation in the aquatic environment;

stage (2) is a cleaning/separating terephthalic acid from the products of partial oxidation is usually fractional crystallization, followed by liquid exchange with water, not containing pollutants; and

stage (3) is the production of a solid product purified terephthalic acid with the appropriate working properties of the substance, usually by crystallization of terephthalic acid, followed by drying the purified terephthalic acid from the water.

The resulting powder was purified terephthalic acid with ethylene glycol are starting materials in the production of polyesters, especially PET. Due to the complexity when working, mixing and dissolution of solid terephthalic acid solid purified terephthalic acid is usually mixed with ethylene glycol to form a paste to put in place the program system of the esterification reactor.

In the present invention has developed a new way, leading to a smaller number of stages than currently used methods. The main benefit of the invention is to reduce capital and operating costs associated with the separation of powder terephthalic acid. In conventional techniques relating to the production of terephthalic acid, aqueous solution after hydrogenation is passed through a series capacitive moulds with the aim of purifying terephthalic acid by crystallization and to obtain uniform distribution of particle sizes required for good fluidity powder of purified terephthalic acid. In addition, contaminated p-Truelove acid mother liquor of the crystallization process must be removed before the stage of drying to highlight powder of purified terephthalic acid.

In one of the embodiments of the present invention a solution of crude terephthalic acid with a low concentration p-Truelove acid and 4-carboxybenzene hydronaut obtaining discolored solution of terephthalic acid. The use of crude terephthalic acid with a low concentration p-Truelove acid and 4-carboxybenzene eliminates the need for separation of contaminated p-Truelove acid mother liquor from terephthalic acid. Sledovatel is but discolored solution of terephthalic acid can be directly combined with ethylene glycol in an esterification zone with a mixture of terephthalic acid/ethylene glycol. By eliminating the conventional methods of powder production of purified terephthalic acid need the equipment needed for cleaning and allocation of purified terephthalic acid, disappears.

Another amazing and apparently controversial aspect of the invention consists in the advantages of adding large quantities of water to the starting substances of the esterification reaction. This is directly contrary to the accepted methods of esterification. The reaction of esterification:

RCOOH + R OH → RCOOR' + H2O

usually does not reach the end. Water formed during the reaction, tends to react with a complex ether, gidrolizu it, i.e. regeneration of the original alcohol and acid. To shift the reaction in the direction of ester prior art recommends removing water from the system in various ways, such as distillation or dehydration of the hydrophilic compound. According to conventional methods of esterification adding large amounts of water to educt acid/alcohol is not intuitive action.

The essence of the invention

The present invention relates to a method in which the mixture is Urbanova acid/diol obtained from discolored solution of carboxylic acid without isolating the essentially dry solid carboxylic acid. More specifically, the present invention relates to a method of obtaining a mixture of terephthalic acid/ethylene glycol, which is suitable as raw material for the production of industrial PET. The final method involves fewer stages than currently used methods, and can be conducted at lower current costs and implemented at lower capital cost. Specifically, the present invention includes a step of direct substitution of water with ethylene glycol after hydrogenation of crude terephthalic acid. The introduction stage of replacement eliminates the need for separation of the solid purified terephthalic acid, except as a result, the need for crystallization, phase separation and equipment to work with solids, usually present in industrial methods of production of purified terephthalic acid.

The present invention is to develop production of a mixture of carboxylic acid/diol without releasing essentially dry solid carboxylic acid.

Another objective of the present invention is to develop a method of production of a mixture of terephthalic acid/diol without releasing essentially dry solid terephthalic acid.

Another objective of the present invention is to develop a method of production of a mixture of terephthalic acid/this is lepicol without releasing essentially dry solid terephthalic acid.

Another objective of the present invention is to develop a method of production of a mixture of terephthalic acid/ethylene glycol without releasing essentially dry solid terephthalic acid by evaporation of water from discolored solution of terephthalic acid due to the enthalpy of the water flow of the glycol in the esterification reactor.

Another objective of the present invention is to develop a method of production of a mixture of terephthalic acid/ethylene glycol without releasing essentially dry solid terephthalic acid by removal of water from discolored solution of terephthalic acid through the use of devices eviction solid/liquid, such as centrifuges, filters or cyclones.

In the first embodiment, the invention features a method of obtaining a mixture of carboxylic acid/diol, and this method includes adding a diol to discolored to a solution of carboxylic acid in the area of the esterification reactor to remove parts of water to obtain a mixture of carboxylic acid/diol; where the specified carboxylic acid and diol essentially react in the area of atrificial with the formation of the complex flow hydroxyalkyl ether. Typically, the carboxylic acid is chosen from the group comprising terephthalic acid, isophthalic acid, naphthaleneboronic acid, and their mixture is.

In another embodiment, the present invention proposes a method of obtaining a mixture of carboxylic acid/diol, and this method includes the following stages:

(a) mixing powder raw carboxylic acid with water in the mixing zone with the formation of a solution of the crude carboxylic acid; where the carboxylic acid is chosen from the group comprising terephthalic acid, isophthalic acid, naphthaleneboronic acid, and mixtures thereof;

(b) bleaching solution of the crude carboxylic acid in a reactor with getting discolored solution of carboxylic acids;

(C) optionally, instant evaporation discolored solution of carboxylic acid in the area of flash evaporation for removal of the contaminated water from discolored solution of carboxylic acid; and

(d) adding a diol to discolored to a solution of carboxylic acid in the reactor for the esterification evaporating part of the water with formation of a mixture of carboxylic acid/diol; where the carboxylic acid and diol essentially react in the esterification zone to form complex flow hydroxyalkyl ether.

In yet another embodiment, the present invention proposes a method of production of a mixture of terephthalic acid/diol; and this method involves evaporation discolored solution of terephthalic acid with diol in the area of the esterification reactor with removal the m parts of water with formation of a mixture of terephthalic acid/diol; where terephthalic acid and diol essentially react in the esterification zone to form complex flow hydroxyalkyl ether.

In another embodiment, the present invention proposes a method of obtaining a mixture of terephthalic acid/diol, and this method includes the following stages:

(a) mixing powder of crude terephthalic acid with water in the mixing zone with the formation of a solution of crude terephthalic acid;

(b) discoloration of the solution of crude terephthalic acid in the reactor zone with the formation of discolored solution of terephthalic acid;

(C) optionally, instant evaporation discolored solution of terephthalic acid in the flash evaporation zone to remove part of the water from the aqueous solution of terephthalic acid; and

(d) adding a diol to discolored solution of terephthalic acid in the area of the esterification reactor to remove part of the water with formation of a mixture of terephthalic acid/diol; where terephthalic acid and diol essentially react in the esterification zone to form complex flow hydroxyalkyl ether.

In another embodiment, the present invention proposes a method of production of a mixture of carboxylic acid/diol; and this method involves removal of the contaminated p-Truelove acid water from the aqueous slurry of terephthalic to the slots by adding a diol in the area of removal of fluid with obtaining the above-mentioned mixture of carboxylic acid/ethylene glycol.

In another embodiment, the present invention proposes a method of production of a mixture of carboxylic acid/diol, and this method includes the following stages:

(a) mixing powder raw carboxylic acid with water in the mixing zone with the formation of a solution of the crude carboxylic acid;

(b) bleaching solution of the crude carboxylic acid in the reactor zone with the formation of discolored solution of carboxylic acids;

(C) crystallization discolored solution of carboxylic acid in the crystallization zone with formation of an aqueous slurry of terephthalic acid; and

(d) removing a portion of contaminated water from a specified water suspension of terephthalic acid by adding a diol in the area of removal of fluid with obtaining the above-mentioned mixture of carboxylic acid/diol.

In another embodiment, the present invention proposes a method of obtaining a mixture of terephthalic acid/ethylene glycol; and this method involves removal of the contaminated p-Truelove acid water from the aqueous slurry of terephthalic acid by adding a diol in the area of removal of fluid with obtaining the above-mentioned mixture of terephthalic acid/diol.

In another embodiment, the present invention proposes a method of production of a mixture of terephthalic acid/ethylene glycol, and this method includes the following stages:

(a) mixing powder raw terephthalonitrile with water in the mixing zone with the formation of a solution of crude terephthalic acid;

(b) discoloration of the solution of crude terephthalic acid in a reactor with the formation of discolored solution of terephthalic acid;

(C) crystallization discolored solution of terephthalic acid in the crystallization zone with formation of an aqueous slurry of terephthalic acid; and

(d) removal of the contaminated p-Truelove acid water from a specified water suspension of terephthalic acid by adding a diol in the area of removal of fluid with obtaining the above-mentioned mixture of terephthalic acid/diol.

These tasks and other objects of the invention will become more clear to the experts in this field after reading the description.

Brief description of drawings

Figure 1 illustrates one of the embodiments of the present invention. A method is proposed that uses powder carboxylic acid to obtain a mixture of carboxylic acid/diol and carboxylic acid and diol essentially react with the formation of the complex flow hydroxyalkyl ether.

Figure 2 illustrates an alternative method of the present invention. A method is proposed that uses a powder of terephthalic acid to obtain a mixture of terephthalic acid/diol and terephthalic acid and diol essentially react with the formation of the complex flow hydroxyalkylated the Fira.

Figure 3 illustrates another alternative implementation of the present invention. We propose a method that uses powder carboxylic acid to obtain a mixture of carboxylic acid/diol.

Figure 4 illustrates another alternative implementation of the present invention. We propose a method where the powder of crude terephthalic acid is used to obtain a mixture of terephthalic acid/diol.

Detailed description of the invention

In the first embodiment, the present invention proposes a method of production of a mixture of carboxylic acid/diol, and this method includes adding a diol to discolored to a solution of carboxylic acid in the area of the esterification reactor to remove parts of water with the formation of a mixture of carboxylic acid/diol; where the carboxylic acid is chosen from the group comprising terephthalic acid, isophthalic acid, naphthaleneboronic acid and mixtures thereof; where mentioned carboxylic acid and diol essentially react in the esterification zone to form complex flow hydroxyalkyl ether.

The area of the esterification reactor, discolored solution of carboxylic acid and method for the production of bleached solution of carboxylic acid is described essentially in the second embodiment of the present invention.

In the second in which the approaches of the present invention proposes a method of production of a mixture of carboxylic acid/diol, which is represented in figure 1.

Stage (1) comprises a mixture of a powder of a crude carboxylic acid of the pipeline 105 with water from pipe 115 in the zone 110 of mixing with obtaining a solution of the crude carboxylic acid in the pipeline 120. Typically, the carboxylic acid is chosen from the group comprising terephthalic acid, isophthalic acid, naphthaleneboronic acid and mixtures thereof. Mixing powder raw carboxylic acid of the pipeline 105 with water from pipe 115 in the zone 110 of mixing can be accomplished by any means known in this field. Area 110 of mixing may be any vessel or equipment capable of mixing the powder of the crude carboxylic acid. Temperature and pressure zone 110 of mixing are temperature and pressure which are sufficient to properly suspended powder crude carboxylic acid of the pipeline 105 with water from the pipe 115. Typically, the powder of the crude carboxylic acid of the pipeline 105 is suspended with water from pipe 115 in the zone 110 of the mixture at a concentration of 15-35 wt.%.

Stage (2) is a bleaching solution of the crude carboxylic acid of the pipe 120 in the area 125 of the reactor with getting discolored solution 135 carboxylic acid.

The bleaching solution of the crude carboxylic acid from the pipeline 12 may be effected by any means, known in this field. Preferably the bleaching can be carried out by the interaction of a solution of the crude carboxylic acid of the pipe 120 with hydrogen from the pipeline 130 in the presence of a catalyst in the zone 125 reactor with getting discolored solution of carboxylic acid.

In the case of zone 125 of the reactor there are no special restrictions on its form and design, provided that the device that allows you to feed hydrogen from the pipeline 130, provides an effective contacting of the solution of the crude carboxylic acid of the pipe 120 with the catalyst in the zone 125 of the reactor. Usually the catalyst is a metal of group VIII, or a combination of metals of group VIII. Preferably the catalyst is chosen from the group comprising palladium, ruthenium, rhodium and their combination. Most preferably the catalyst is a palladium. Normally, the catalyst is deposited on a substrate, preferably a porous coal.

Area 125 of the reactor includes a hydrogenation reactor, which operates at a temperature and pressure sufficient to hydrogenation characteristic yellow compounds in a solution of the crude carboxylic acid of the pipeline 120. Due to hydrogenation characteristic yellow compound in a solution of the crude carboxylic acids are converted to colorless derivatives. Color index b* about svechina solution of carboxylic acid in the pipe 135 is in the range from 0.5 to 4. Preferably the color index b* discolored solution of carboxylic acid in the pipe 135 is in the range from 0.5 to 2.0. Most preferably the color index b* discolored solution of carboxylic acid in the pipe 135 is in the range from 0.5 to 1.5. Color index b* is one of the tri-color characteristics, measured by spectroscopic instrument for measuring the reflected luminous flux. Color can be measured using any device known in this field. Usually the measuring device is a Hunter Ultrascan XE. Positive readings indicate the degree of yellow color (or absorption coefficient blue), while negative readings indicate the degree of blue color (or absorption coefficient of yellow).

Hydrogen pipeline 130 serves at speeds sufficient to turn the typical yellow compounds in suspension of carboxylic acid from the pipeline 120 to colorless derivatives; where in the bleached solution of carboxylic acid in the pipeline 135 color index b* is from 0.5 to 4.0.

Stage (3), optional, includes instant evaporation discolored solution 135 carboxylic acid in the zone 145 flash evaporation for removal of the water from discolored solution of carboxylic acid in trubor the water 135. Instant evaporation of an aqueous solution 135 carboxylic acid can be carried out by means known in the field. Usually for instant evaporation using a single vessel or multiple vessels. In the area of 145 instantaneous evaporation of the water and the remaining hydrogen can be removed as a vapor through line 150. Vessel(s) flash evaporation operate at a temperature sufficient to remove part of the water. On the other hand, area 145 flash evaporation can be excluded, as shown, with the use of the pipeline 140.

Stage (4) includes adding a diol of the pipe 170 to the discolored to a solution of carboxylic acid from pipe 155. Part of the water through the pipe 165 is removed from the zone 160 of the esterification reactor with obtaining the above-mentioned mixture of carboxylic acid/diol in the zone 160 of the esterification reactor. Carboxylic acid and diol essentially react with the formation of flow 175 complex hydroxyalkyl ether. Thread 175 complex hydroxyalkyl ether contains complex hydroxyalkyloxy ether.

Diol of the pipe 170 is injected in such a way as to replace water as the main suspendida fluid. This can be done by introducing a diol through line 170 in the form of liquid at saturation line at a temperature which is sufficient to evaporate water. predpochtitelno diol of the pipe 170 is injected in the form of saturated or superheated steam. Diol of the pipe 170 is selected from the group including ethylene glycol, diethylene glycol, n-butyleneglycol, isobutylamino, n-propylene glycol, 1,4-butanediol, cyclohexanedimethanol and mixtures thereof. Preferably diol of the pipe 170 is a glycol. Alternatively, it may be used by an external heat source to supply sufficient heat to evaporate water, which enters through line 165. The flow of complex hydroxyalkyl ether goes through the pipeline flow 175.

Area 160 of the esterification reactor operates at a temperature, which is enough to get hydroxyethyl from a mixture of carboxylic acids. Area 160 of the esterification reactor includes a reactor for esterification. The esterification can be conducted by any means known in this field.

In the third embodiment of the present invention a method of production of a mixture of terephthalic acid/diol includes evaporation discolored solution of terephthalic acid with diol in the area of the esterification reactor to remove part of the water with formation of a mixture of terephthalic acid/diol; where terephthalic acid and diol essentially react in the esterification zone to form complex flow hydroxyalkyl ether.

The area of the esterification reactor, discolored solution of terephthalic acid and fashion PR the production discolored solution of terephthalic acid is described essentially in the fourth embodiment of the present invention.

In the fourth embodiment, the present invention proposes a method of production of a mixture of terephthalic acid/diol, which is represented in figure 2.

Stage (1) comprises a mixture of a powder of crude terephthalic acid from the pipeline 205 with water from the pipeline 215 in the zone 210 mixing with obtaining the solution of crude terephthalic acid in the pipeline 220. The mixture of powder of crude terephthalic acid from the pipeline 205 with water from the pipeline 215 may be implemented by any means known in this field. Raw material is a powder of crude terephthalic acid from the pipeline 205 with some specific physical characteristics that differ from the crude terephthalic acid, described in U.S. patent 5095146 and U.S. patent 5175355, which are included as references. Specifically, the total number of p-Truelove acid and 4-carboxybenzene powder crude terephthalic acid in the pipe 205 is less than 900 hours/million based on weight, preferably less than 500 h/m and more preferably less than 250 hours/million Other characteristics of the powder of crude terephthalic acid in the pipe 205 is the color that when measuring indicator b* value is less than 7. Preferably the color, measured as b*, has a value of from 4 to 6.

Area 210 of mixing may present with the fight any vessel or equipment, capable of mixing the powder of crude terephthalic acid from the pipeline 205 with water from the pipe 215. The powder of crude terephthalic acid in the pipe 205 is suspended in water in the pipe 215 in the zone 210 mixing with obtaining the solution of crude terephthalic acid in the pipeline 220. Crude terephthalic acid and the water is heated in the zone 210 of the mixture to a temperature of 230°With or above for the dissolution of the powder of crude terephthalic acid from the pipeline 205 in the zone 210 mixing with obtaining the solution of crude terephthalic acid in the pipeline 220. Preferably the slurry of crude terephthalic acid in the zone 210 mixture is heated to a temperature in the range from 240 to 300°C. the Pressure of the mixing zone ranges from 900 to 1400 psi for the dissolution of the powder of crude terephthalic acid from the pipeline 205 in the zone 210 of mixing. Usually the concentration of the crude terephthalic acid solution of crude terephthalic acid is from 15 to 30 wt.%, preferably from 20 to 30 wt.%.

Stage (2) is a discoloration of the solution of crude terephthalic acid from the pipeline 220 in the area of 225 reactor with getting discolored solution of terephthalic acid in the pipeline 235.

The discoloration of the solution of crude terephthalic acid from the pipeline 220 can be implemented by any means known in this field. Site is preferably the bleaching can be carried out by reacting the solution of crude terephthalic acid from the pipeline 220 with hydrogen from the pipeline 230 in the presence of a catalyst in the zone 225 reactor with getting discolored solution of terephthalic acid.

In the case of zone 225 of the reactor there are no special restrictions on its form and design, provided that the device that allows you to feed hydrogen from the pipeline 230, provides an effective contacting of the solution of crude terephthalic acid from the pipeline 220 with the catalyst in the reactor zone 225. Usually the catalyst is a metal of group VIII, or a combination of metals of group VIII. Preferably the catalyst is chosen from the group comprising palladium, ruthenium, rhodium and their combination. Most preferably the catalyst is a palladium. Normally, the catalyst is deposited on a substrate, preferably a porous coal.

Area 225 of the reactor includes a hydrogenation reactor, which operates at a temperature of 230°C or higher. Preferably the hydrogenation reactor operates in the temperature range from 240 to 300°C. the hydrogenation Reactor operates at a pressure of from 900 to 1400 psi and the partial pressure of hydrogen of at least 100 psi. Preferably the partial pressure of hydrogen is in the range from 100 to 300 psi. Due to hydrogenation characteristic yellow compound in the solution of crude terephthalic acids are converted to colorless derivatives. In addition, a reactor part 4-carboxybenzene turns into p-that is willbuy acid. The hydrogen from the pipeline 230 serves in the amount of at least a 1.5 molar relationship, necessary for the conversion of 4-carboxybenzene in the solution of crude terephthalic acid from the pipeline 220 p-Truelove acid. Preferably the hydrogen 230 serves in the amount of at least a 2.0 molar relationship, necessary for the conversion of 4-carboxybenzene in solution 220 crude terephthalic acid to p-Truelove acid. Color index b* discolored solution of terephthalic acid from pipe 235 is in the range from 0.5 to 4. Preferably the color index b* of a solution of terephthalic acid in the pipe 235 is in the range from 0.5 to 2. Most preferably the color index b* discolored solution of terephthalic acid in the pipe 235 is in the range from 0.5 to 1.5.

Stage (3), optional, includes instant evaporation discolored solution 235 terephthalic acid in the zone 245 flash evaporation to remove 250 parts of water of the aqueous solution of 235 terephthalic acid. Instant evaporation of an aqueous solution of 235 terephthalic acid can be carried out by means known in the field. Usually for instant evaporation using a single vessel or multiple vessels. In the area of 245 instantaneous evaporation of the water and the remaining hydrogen can is to be removed as a vapor through line 250. Vessel(s) flash evaporation throu(h)t at a temperature of 150°C or higher. Preferably the vessel(s) flash evaporation throu(h)t in the temperature range from 155 to 260°C. Vessel(s) flash evaporation throu(h)t under pressure from 75 to 1400 psi. Specific work intervals vary depending on the amount of water removed through line 250. Alternatively, the zone 245 flash evaporation may be omitted, as shown by pipeline 240.

Stage (4) includes adding a diol of the pipe 270 to the discolored to a solution of terephthalic acid from the pipeline 255 in the area 260 of the esterification reactor to remove part of the water through the pipeline 265 obtaining the above-mentioned mixture of terephthalic acid/diol in the area 260 of the esterification reactor. Carboxylic acid and diol essentially react with the formation of flow 275 difficult hydroxyalkyl ether. Stream 275 difficult hydroxyalkyl ether contains complex hydroxyalkyloxy ether.

Diol of the pipe 270 is injected in such a way as to replace water as the main suspendida fluid. This can be done by introducing a diol through line 270 in the form of saturated liquid at a temperature in the range from 150 to 300°C. Preferably diol of the pipe 270 is injected in the form of saturated or superheated, parapro temperature in the range from 150 to 300° With in shape with sufficient heat content to evaporate the water through the pipe 265. Diol in the pipe 270 is selected from the group including ethylene glycol, diethylene glycol, n-butyleneglycol, isobutylamino, n-propylene glycol, 1,4-butanediol, cyclohexanedimethanol and mixtures thereof. Preferably diol of the pipe 270 is a glycol. Alternatively, it may be used by the external heat source to supply sufficient heat to evaporate water, which enters through line 265. The flow of complex hydroxyalkyl ether goes through the pipeline flow 275.

Area 260 of the esterification reactor operates at a temperature of 240°C or higher. Preferably the area 260 of the esterification reactor operates at a temperature in the range of from 260 to 280°C. Area 260 of the esterification reactor is operated under pressure from 40 to 100 psi so as to cause the esterification mixture 275 terephthalic acid/diol with getting complicated hydroxyalkyl ester of terephthalic acid.

In the fifth embodiment of the present invention a method of production of a mixture of carboxylic acid/diol involves removal of the contaminated water in the aqueous suspension by adding a diol in the area of removal of fluid with obtaining the above-mentioned mixture of carboxylic acid/diol.

The area of removal of the liquid, aqueous suspension and the method produced the production of aqueous suspensions described essentially in the sixth embodiment of the present invention.

In the sixth embodiment, the invention features a method of obtaining a mixture of carboxylic acid/diol, which is represented in figure 3.

Stage (1) comprises a mixture of a powder of a crude carboxylic acid of pipeline 305 with water from the pipeline 315 in the area 310 mixing with formation of a solution of the crude carboxylic acid in the pipeline 320. Mixing powder raw carboxylic acid of pipeline 305 with water from the pipeline 315 in the area 310 of mixing can be accomplished by any means known in this field. Raw material is a powder of a crude carboxylic acid of pipeline 305. Typically, the carboxylic acid is chosen from the group comprising terephthalic acid, isophthalic acid, naphthaleneboronic acid and mixtures thereof. Area 310 of mixing may be any vessel or equipment capable of mixing the powder of crude carboxylic acid of pipeline 305 with water from the pipe 315.

Powder crude carboxylic acid of pipeline 305 and the water from the pipeline 315 in the zone 310, the mixture is heated to a temperature sufficient to dissolve the powder crude carboxylic acid of pipeline 305 in the area 310 mixing with obtaining a solution of the crude carboxylic acid in the pipeline 320. The pressure in zone 310 mixing is a pressure sufficient to dissolve on osca crude carboxylic acid of pipeline 305 in the area 310 of mixing. Usually the concentration of the crude carboxylic acid in a solution of the crude carboxylic acid is from 15 to 35 wt.%.

Stage (2) is a bleaching solution of the crude carboxylic acid of the pipe 320 in the area of 325 reactor with getting discolored solution of carboxylic acid in the pipeline 330.

The bleaching solution of the crude carboxylic acid of the pipe 320 may be implemented by any means known in this field. Preferably the bleaching can be carried out by the interaction of a solution of the crude carboxylic acid pipeline 320 with hydrogen from the pipeline 330 in the presence of a catalyst in the area of 325 reactor with getting discolored solution of carboxylic acid.

In the case of zone 325 reactor there are no special restrictions on its form or construction, provided that the device that allows you to feed hydrogen from the pipeline 330, provides effective communication suspension 320 crude carboxylic acid with a catalyst in a reactor. Usually the catalyst is a metal of group VIII, or a combination of metals of group VIII. Preferably the catalyst is chosen from the group comprising palladium, ruthenium, rhodium, and combinations thereof. Most preferably the catalyst is a palladium. Normally, the catalyst is deposited on odlokw, preferably the porous coal.

Area 325 of the reactor includes a hydrogenation reactor, which operates at a temperature sufficient to transform a characteristic yellow compounds in solution 320 crude carboxylic acid as colorless derivatives. Color index b* discolored solution of carboxylic acid in the pipe 335 is in the range from 0.5 to 4. Preferably the color index b* of a solution of carboxylic acid in the pipe 335 is in the range from 0.5 to 2. Most preferably the color index b* discolored solution of carboxylic acid in the pipe 335 is in the range from 0.5 to 1.5.

Hydrogen pipeline 330 serves at speeds sufficient to turn the typical yellow compounds in suspension of the crude carboxylic acid pipeline 320 colorless derivatives; where in the bleached solution of carboxylic acid from the pipeline 335 color index b* is in the range from 0.5 to 4.

Stage (3) comprises crystallization discolored solution of carboxylic acid from the pipeline 335 in the area of 345 crystallization to obtain aqueous slurry in the pipeline 355.

Area 345 crystallization includes a single vessel or multiple vessels, capable of removing water from discolored solution of carboxylic acid from the pipeline 335 obtaining water suspension in Trou is oprovide 355. Usually the vessels include at least one mold. Examples of such systems can be found in U.S. patent 5567842 and 3931305, which are included as references. Usually aqueous suspension of the pipeline 355 has a concentration of carboxylic acid from 10 to 60 wt.%. The temperature interval solution of carboxylic acid in the area of 345 crystallization is an interval, which is sufficient to remove part of the water.

Stage (4) involves removal of the contaminated water through a pipeline 365 of the aqueous suspension 355 by adding a diol of the pipeline 370 in an area of 360 removal of fluid with a mixture of carboxylic acid/diol in the pipeline 375.

Task area 360 liquid removal is to replace the contaminated water diola pipeline 370. Polluted water contains water and conventional pollutants. Diol pipeline 370 selected from the group comprising ethylene glycol, diethylene glycol, n-butyleneglycol, isobutylamino, n-propylene glycol, 1,4-butanediol, cyclohexanedimethanol and mixtures thereof. Preferably diol in the pipeline 370 is a glycol. Diol pipeline 370 injected into an area of 360 removal of liquid through the pipe 370. Remove contaminated water through line 365 from the zone 360 liquid removal can be accomplished using several techniques, including, but without limitation, cyclones, centrif the guy and filters. A key factor zone 360 liquid removal is the choice of the temperature interval in which the typical pollutants preferably remain in the aqueous mother liquor, instead of staying in a carboxylic acid. The mixture of carboxylic acid/diol output through line 375. The mixture of carboxylic acid/diol in the pipeline 375 is a suitable raw material for the esterification of carboxylic acids diola with the receipt of ester carboxylic acid.

In the seventh embodiment of the present invention a method of production of a mixture of terephthalic acid/diol involves removal of the contaminated p-Truelove acid water from the aqueous slurry of terephthalic acid by adding a diol in the zone of removal of fluid with obtaining the above-mentioned mixture of terephthalic acid/diol.

The area of removal of the liquid, aqueous suspension of terephthalic acid and method for producing aqueous suspension described essentially in the eighth embodiment of the present invention.

In the eighth embodiment, the present invention proposes a method of production of a mixture of terephthalic acid/diol, which is represented in figure 4.

Stage (1) comprises a mixture of a powder of crude terephthalic acid from the pipeline 405 water from the pipeline 415 in the zone 410 mixing with obtaining a solution si is Oh terephthalic acid in the pipeline 420. The mixture of powder of crude terephthalic acid from the pipeline 405 water from the pipeline 415 in the area 410 of mixing can be accomplished by any means known in this field. Raw material is a powder of crude terephthalic acid from pipe 405. The total number of p-Truelove acid and 4-carboxybenzene powder crude terephthalic acid in the pipe 405 is less than 6000 hours/million based on weight. Another characteristic of the powder 405 crude terephthalic acid is the color that when measuring index b* is less than 7. Preferably the color, measured by b*, has a value of from 4 to 6. This powder crude terephthalic acid from pipe 405 is introduced into the zone 410 mixing. Area 410 mixing may be any vessel or equipment capable of mixing the powder of crude terephthalic acid from the pipeline 405 with water from pipe 415.

The powder of crude terephthalic acid and the water is heated to a temperature of 230°With or above for the dissolution of the powder of crude terephthalic acid from the pipeline 405 in the zone 410 mixing with obtaining the solution of crude terephthalic acid in the pipeline 420. Preferably a solution of crude terephthalic acid in the zone 410 mixture is heated to a temperature in the range from 240 to 300°C. the Pressure zone 410 with the solutions ranges from 900 to 1400 psi for the dissolution of the powder of crude terephthalic acid from the pipeline 405 in the area 410 of mixing. Usually the concentration of the powder 405 crude terephthalic acid in a solution of 420 crude terephthalic acid is from 15 to 35 wt.%, preferably from 20 to 30 wt.%.

Stage (2) is a discoloration of the solution of crude terephthalic acid from the pipeline 420 in the area of 425 reactor with getting discolored solution of terephthalic acid in the pipe 435.

The bleaching solution of the crude carboxylic acid of the pipe 420 may be implemented by any means known in this field. Preferably the bleaching can be carried out by the interaction of a solution of the crude carboxylic acid pipeline 420 with hydrogen from the pipeline 430 in the presence of a catalyst in the zone 425 reactor with getting discolored solution of carboxylic acid.

In the case of zone 425 reactor there are no special restrictions on its form and design, provided that the device that allows you to feed hydrogen from the pipeline 430, provides contact suspension 420 crude terephthalic acid with a catalyst in a reactor. Usually the catalyst is a metal of group VIII, or a combination of metals of group VIII. Preferably the catalyst is chosen from the group comprising palladium, ruthenium, rhodium and their combination. Most preferably the catalyst is a palladium. the usual catalyst deposited on a substrate, preferably the porous coal.

Area 425 of the reactor includes a hydrogenation reactor, which operates at a temperature of 230°C or higher. Preferably the hydrogenation reactor operates in the temperature range from 240 to 300°C. the hydrogenation Reactor operates at a pressure of from 900 to 1400 psi and at a partial pressure of hydrogen of at least 100 psi. Preferably the partial pressure of hydrogen is in the range from 100 to 300 psi. Due to hydrogenation characteristic yellow compounds in solution 420 crude terephthalic acids are converted to colorless derivatives. In addition, a reactor part 4-carboxybenzene turns into p-Truelove acid.

The hydrogen from the pipeline 430 serves in the amount of at least a 1.5 molar relationship, necessary for the conversion of 4-carboxybenzene in suspension 420 crude terephthalic acid to p-Truelove acid. Preferably the hydrogen 430 serves in the amount of at least a 2.0 molar relationship, necessary for the conversion of 4-carboxybenzene in suspension 420 crude terephthalic acid to p-Truelove acid. Color index b* discolored solution of terephthalic acid from the pipeline 435 is in the range from 0.5 to 4. Preferably the color index b* of a solution of terephthalic acid in the pipeline 435 on titsa in the range from 0.5 to 2. Most preferably the color index b* discolored solution of terephthalic acid in the pipeline 435 is in the range from 0.5 to 1.5.

Stage (3) comprises crystallization discolored solution of terephthalic acid from the pipeline 435 in the area of 445 crystallization to obtain aqueous slurry of terephthalic acid in the pipeline 455.

Area 445 crystallization includes a single vessel or multiple vessels, capable of removing water through line 450 of discolored solution of carboxylic acid from the pipeline 435 obtaining aqueous slurry of terephthalic acid in the pipeline 455. Usually the vessels include at least one mold, as described previously. In General aqueous suspension of terephthalic acid from the pipeline 455 is the concentration of terephthalic acid from 10 to 60 wt.%, preferably from 20 to 40 wt.%. Examples of such systems can be found in U.S. patent 5567842 and 3931305, both of which are included as references. The temperature interval aqueous slurry of terephthalic acid in the pipeline 455 is from 120 to 270°C. the range of pressure during crystallization ranges from 75 to 1400 psi.

Stage (4) involves removal of the contaminated p-Truelove acid water through the pipeline 465 from aqueous suspensions 455 by adding a diol of the pipeline 470 in an area of 460 removal liquid is obtaining the above-mentioned mixture of terephthalic acid/diol in the pipeline 475.

Task area 460 liquid removal is to replace the contaminated p-Truelove acid water diola pipeline 470. Diol pipeline 470 selected from the group comprising ethylene glycol, diethylene glycol, n-butyleneglycol, isobutylamino, n-propylene glycol, 1,4-butanediol, cyclohexanedimethanol and mixtures thereof. Preferably diol pipeline 470 is a glycol. Diol pipeline 470 injected into an area of 460 removal of liquid through the pipe 470. Remove contaminated p-Truelove acid water through the pipeline 465 in the zone 460 liquid removal can be accomplished using several techniques, including, but without limitation, cyclones, centrifugation and filtration. A key factor zone 460 liquid removal is the choice of the temperature interval in which p-tolarova acid and 4-carboxybenzene preferably remain in the aqueous mother liquor, instead of staying in terephthalic acid. Area 460 liquid removal works in the temperature range from 120 to 270°C, preferably in the range from 120 to 150°C. Contaminated p-Truelove acid water out through the pipe 465. The mixture of terephthalic acid/diol output through line 475. The mixture of terephthalic acid/diol in the pipeline 475 is a suitable source of prophetic is the primary objective for the esterification of terephthalic acid diola obtaining a complex ester of terephthalic acid.

1. Method for the production of a mixture of carboxylic acid/diol, where the method includes adding a diol to discolored to a solution of carboxylic acids, including carboxylic acid and water, in the area of the esterification reactor, where the diol is at a temperature sufficient to evaporate part of the water to become the main suspendida fluid with the formation of the above-mentioned mixture of carboxylic acid/diol; where mentioned carboxylic acid and diol then react in a specified area of esterification with the formation of the complex flow hydroxyalkyl ether.

2. The method according to claim 1, where the specified carboxylic acid selected from the group comprising terephthalic acid, isophthalic acid, naphthaleneboronic acid and mixtures thereof.

3. Method for the production of a mixture of carboxylic acid/diol, where the method includes the following stages:

(a) mixing powder raw carboxylic acid with water in the mixing zone with the formation of a solution of the crude carboxylic acid; where the specified carboxylic acid selected from the group comprising terephthalic acid, isophthalic acid, naphthaleneboronic acid and mixtures thereof;

(b) discoloration of the specified solution of crude carboxylic acid in a reactor with getting discolored solution of carboxylic acids;

(c) optionally, instant evaporation indicated the data discolored solution of carboxylic acid in the flash evaporation zone to remove a portion of water from a specified discolored solution of carboxylic acid and

(d) adding a diol to the specified discolored to a solution of carboxylic acid in the area of the esterification reactor, where the specified diol is at a temperature sufficient to evaporate part of the water to become the main suspendida fluid with the formation of the above-mentioned mixture of carboxylic acid/diol; where mentioned carboxylic acid and diol then react in a specified area of esterification with the formation of the complex flow hydroxyalkyl ether.

4. Method for the production of a mixture of terephthalic acid/diol, where the method includes adding a diol to the specified discolored solution of terephthalic acid comprising terephthalic acid and water, in the area of the esterification reactor, where the diol is at a temperature sufficient to evaporate part of the water to become the main suspendida fluid with the formation of the above-mentioned mixture of terephthalic acid/diol; where mentioned terephthalic acid and diol then react in a specified area of esterification with the formation of the complex flow hydroxyalkyl ether.

5. Method for the production of a mixture of terephthalic acid/diol, where the method includes the following stages:

(a) mixing powder of crude terephthalic acid with water in the mixing zone with the formation of a solution of crude terephthalic acid;

(b) discoloration indicated the data of the solution of crude terephthalic acid in a reactor with the formation of discolored solution of terephthalic acid;

(c) optionally, instant evaporation of the specified discolored solution of terephthalic acid in the flash evaporation zone to remove a portion of water from a specified discolored solution of terephthalic acid and

(d) adding a diol to the specified discolored solution of terephthalic acid in a reactor in the esterification, where the specified diol is at a temperature sufficient to evaporate part of the water to become the main suspendida fluid with the formation of the above-mentioned mixture of terephthalic acid/diol; where mentioned terephthalic acid and diol then react in a specified area of esterification with the formation of the complex flow hydroxyalkyl ether.

6. The method according to claim 5, where the aforementioned bleaching carried out by reaction of the specified solution of crude terephthalic acid with hydrogen in the presence of a catalyst in this zone of the reactor with getting discolored solution of carboxylic acid.

7. The method according to claim 5, where the powder of crude terephthalic acid has a concentration of p-Truelove acid and 4-carboxybenzene less than 900 parts by weight of/million

8. The method according to claim 5, where the specified instant evaporation is carried out at a pressure of from 75 to 1400 psi and at temperatures above 150°C.

9. The method according to claim 5, where the addition is carried out at temperatures above 240°and if Yes is the population from 40 to 100 psi.

10. The method according to claim 5, where the specified diol is introduced into the specified area of the esterification reactor at a temperature of from 150 to 300°C.

11. Method for the production of a mixture of carboxylic acid/diol, where the method includes the following stages:

(a) mixing powder raw carboxylic acid with water in the mixing zone with the formation of a solution of the crude carboxylic acid;

(b) discoloration of the specified solution of crude carboxylic acid in the reactor with the formation of discolored solution of carboxylic acids;

(c) crystallization of the specified discolored solution of carboxylic acid in the crystallization zone with the formation of the aqueous suspension

(d) removing a portion of contaminated water at a specified water suspension and adding a diol in the area of removal of fluid with obtaining the above-mentioned mixture of carboxylic acid/diol, where the diol is at a temperature sufficient to evaporate part of the contaminated water from a specified water suspension to become the main suspendida liquid.

12. The method according to claim 3 or 11, where the aforementioned bleaching carried out by reaction of the specified solution of crude carboxylic acid with hydrogen in the presence of a catalyst in this zone of the reactor with getting discolored solution of carboxylic acid.

13. The method according to claim 11, where the concentration of the specified crude carboxylic acid in the decree is nom solution of the crude carboxylic acid is in the range from 15 to 35 wt.%.

14. The method according to item 12, where the above reaction is carried out at a speed of hydrogen, sufficient to obtain discolored solution of carboxylic acid with the color index b* of from 0.5 to 4.

15. Method for the production of a mixture of terephthalic acid/diol, where the method includes the following stages:

(a) mixing powder of crude terephthalic acid with water in the mixing zone with the formation of a solution of crude terephthalic acid;

(b) discoloration of the specified solution of crude terephthalic acid in a reactor with the formation of discolored solution of terephthalic acid;

(c) crystallization of the specified discolored solution of terephthalic acid in the crystallization zone to remove a portion of water from a specified discolored solution of terephthalic acid with formation of an aqueous slurry of terephthalic acid and

(d) removal of the contaminated p-Truelove acid water from a specified water suspension of terephthalic acid, and adding a diol in the area of removal of fluid with obtaining the above-mentioned mixture of terephthalic acid/diol, where the diol is at a temperature sufficient to evaporate part of the contaminated water from a specified water suspension to become the main suspendida liquid.

16. The method according to clause 15, where the aforementioned bleaching carried out by reaction of the specified solution ServiceReference acid with hydrogen in the presence of a catalyst in this zone of the reactor with getting discolored solution of carboxylic acid.

17. The method according to clause 15, where the powder of crude terephthalic acid has a total concentration of p-Truelove acid and 4-carboxybenzene less than 6000 parts by weight of/million

18. The method according to claims 1, 3 to 5, 11 or 15, where the specified diol selected from the group comprising ethylene glycol, diethylene glycol, n-butyleneglycol, isobutylamino, n-propylene glycol, 1,4-butanediol, cyclohexanedimethanol and mixtures thereof.

19. The method according to claim 5 or 15, where the powder of crude terephthalic acid has a color index b* of less than 7.

20. The method according to claim 5 or 15, where the specified mixing is carried out at a pressure of from 900 to 1400 psi.

21. The method according to claim 5 or 15, where the concentration of the specified crude terephthalic acid in a specified solution of crude terephthalic acid is in the range from 15 to 35 wt.%.

22. The method according to claim 6 or 16, where this interaction takes place at temperatures above 230°and at a pressure of from 900 to 1400 psi.

23. The method according to claim 6 or 16, where the specified amount of hydrogen introduced at the stage of bleaching, 1.5 molar ratio required for the conversion of 4-carboxybenzene in p-Truelove acid in the specified solution of crude terephthalic acid.

24. The method according to claim 9 or 16, where the catalyst in this zone of the reactor contains a metal of group VIII or a combination of both.

25. The method according to clause 15, where the specified crystallization PR the lead at temperatures above 150° C and at a pressure of from 75 to 1400 psi.

26. The method according to clause 15, where the addition of the specified diol is carried out at a temperature of from 120 to 270°C.

27. The method according to clause 15, where the specified diol is introduced into the zone of removal of liquid at a temperature of from 150 to 300°C.

28. The method according to claim 11 or 15, where the specified zone, removing liquid contains at least one device selected from the group comprising a cyclone filter and a centrifuge.

29. The method according to clause 15, where the specified aqueous solution of terephthalic acid has a concentration of terephthalic acid from 20 to 60 wt.%.



 

Same patents:

The invention relates to a process for the preparation of ester, which comprises carrying out the esterification reaction in the presence of a catalyst which is a reaction product of artefiera or condensed orthoevra titanium or zirconium and alcohol containing at least two hydroxyl group of 2-hydroxycarboxylic acids and bases

The invention relates to the field of organic chemistry, namely, the method of production of esters, which are used as plasticizers of various polymers
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Catalyst and method // 2316396

FIELD: organic synthesis and catalysts.

SUBSTANCE: invention relates to esterification method utilizing organotitanium or organozirconium catalyst and provides catalytic composition useful in preparation of esters, including polyesters, which contains (i) product of reaction between metal M alcoholate or condensed alcoholate selected from titanium, zirconium, and hafnium alcoholates, (ii) alcohols containing at least two hydroxy groups, (iii) 2-hydroxycarboxylic acid, and (iv) base, wherein molar ratio of base to hydroxycarboxylic acid is within the range between 0.01:1 and 0.79:1. Esterification reaction in presence of above catalyst is also described.

EFFECT: avoided yellowness in final product, raised temperature for the beginning of crystallization and crystallization temperature of polyester.

14 cl, 4 tbl, 20 ex

FIELD: organic chemistry, chemical technology.

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EFFECT: improved method of synthesis.

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of saturated aliphatic carboxylic acids with stable carbon isotopes (1-13C). Method involves the hydrocarboxylation reaction of α-olefins with carbon monoxide (13CO) and water at temperature 100-170°C and under pressure not exceeding 5 MPa in the presence of a solvent and catalytic system containing palladium compound as complex PdCl2(PPh3)2 and triphenylphosphine PPh3 taken in the ratio from 1:2 to 1:100, respectively. Synthesized carboxylic acids can be used as diagnostic test-preparations in medicine practice and in criminology, scientific investigations and in other fields. Invention provides synthesis of enanthic acid and caprylic acid labeled by stable carbon isotope 13C at position 1 for a single step, to increase yield of acids as measured for isotope raw, to decrease cost price of acids and to obtain derivatives of (1-13C)-caprylic acid - (1-13C0-caprylate sodium and (carboxy-13C)-trioctanoine.

EFFECT: improved methods of synthesis.

9 cl, 6 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for synthesis of carboxylic acid esters that are used as components of lacquered resins and components of paint-and varnish materials, especially, as plasticizer for plastics. Method involves interaction of di- or polycarboxylic acids or their anhydrides with alcohols wherein reaction water is removed by azeotropic distillation with alcohol, and liquid removed from reaction by azeotropic distillation is replaced with alcohol completely again. The improvement of periodic method used in synthesis of esters provides enhancing yield of the end product and reducing the reaction process time.

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5 cl, 4 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

The invention relates to an improved method for producing a plasticizer, which is used to obtain the compounds, based on the waste production of alcohols and phthalic anhydride in the presence of ORGANOMETALLIC or acid catalyst, which comprises the following stages: a) VAT residue of butyl alcohols production and CBM product of distillation of phthalic anhydride is heated, driving away in this light fraction alcohols; b) the esterification is carried out at a temperature of 100-200°C in the presence of a catalyst, taken in an amount of 0.1 to 3.0 % by weight of the reaction mixture; C) carry out the distillation of the volatile components

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The invention relates to an improved process for the preparation of esters of carboxylic acids of General formula (I) esterification of the corresponding acids or anhydrides with alcohols in a molar ratio acid:ethanol=1: 0.35 to 2.2 in the presence of hydrocarbons as solvent and aromatic sulfonic acids or acidic sulfate as a catalyst at the boiling temperature of the reaction mixture by distillation of the formed water, followed by washing of the reaction mixture and neutralizing it with an alkaline solution, taken from 5-20 wt

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 process for the preparation of terephthalic and isophthalic acids
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