WO2004060847A1 - 高純度テレフタル酸の製造方法 - Google Patents
高純度テレフタル酸の製造方法 Download PDFInfo
- Publication number
- WO2004060847A1 WO2004060847A1 PCT/JP2003/016464 JP0316464W WO2004060847A1 WO 2004060847 A1 WO2004060847 A1 WO 2004060847A1 JP 0316464 W JP0316464 W JP 0316464W WO 2004060847 A1 WO2004060847 A1 WO 2004060847A1
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- WO
- WIPO (PCT)
- Prior art keywords
- amount
- terephthalic acid
- hydrogenation reactor
- reduction
- ratio
- Prior art date
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Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
Definitions
- the present invention relates to a method for producing a high-purity acid.
- Crude terephthalic acid obtained by the oxidation of para-xylene usually contains relatively large amounts of various impurities such as 4-carboxybenzaldehyde (hereinafter abbreviated as “4 CBA book”). It has been refined and used as a raw material for polyester.
- 4 CBA book 4-carboxybenzaldehyde
- a dissolving step of dissolving the crude terephthalic acid in water is performed, and then the above 4 CBA in the solution obtained in this dissolving step is reduced with hydrogen.
- this reduction step a decarboxylation reaction in which 4CBA becomes benzoic acid occurs as a side reaction.
- carbon monoxide is generated as a by-product.
- the carbon monoxide acts as a catalyst poison for the reduction catalyst used in the reduction step, and as a result, the degradation of the reduction catalyst progresses and the activity decreases.
- an object of the present invention is to suppress the deterioration of a reduction catalyst used in a reduction step of reducing 4CBA with hydrogen to form paratoluic acid and maintain the activity.
- paraxylene is oxidized to produce crude terephthalic acid containing 4 CBA as an impurity, and then a dissolving step of dissolving the same in an aqueous medium is performed.
- a hydrogenation reactor filled with a reduction catalyst the dissolving solution and the hydrogen obtained in the dissolving step are continuously supplied to perform a reducing step of reducing 4 CBA in the dissolving solution, and
- the reduction treatment liquid obtained in this reduction step is sent to a group of crystallization tanks in which at least two crystallization tanks are connected in series, and the crystallization of terephthalic acid is carried out by gradually reducing the pressure in each crystallization tank.
- the amount of Z reduction catalyst (t) 400 With 5000 (1 / h), is obtained by solving the above Symbol challenges.
- the ratio of the amount of 4 CBA supplied to the hydrogenation reactor to the amount of carbon monoxide generated in the hydrogenation reactor is preferably adjusted.
- Can be represented by the following formula: carbon monoxide Z4CBA 0.01 to 0.12 (molar ratio).
- the life of the reduction catalyst used in the reduction step can be extended.
- FIG. 1 is a flowchart showing an example of a process for producing high-purity terephthalic acid according to the present invention.
- FIG. 2 is a flow chart showing another example of the production process of the high-purity terephthalic acid according to the present invention.
- 11 is a mixing tank
- 12 is a first heat exchanger
- 13 is a hydrogenation reactor
- 14 and 14a are crystallization tanks
- 15 is a solid-liquid separator
- 16 is a second heat exchanger.
- 21 is a measuring tower
- 22 is a preheater
- 23 is a dissolving tower
- 24 is a hydrogenation reactor
- 25 is a receiver
- 26 is a first crystallization tank
- 27 is a second crystallization tank
- 28 is a pressure separator.
- A is crude terephthalic acid
- B is aqueous medium
- C is crude terephthalic acid slurry
- D is solution
- D is aqueous solution
- E is reduction treatment
- E is a reduction solution
- F is terephthalic acid slurry
- G is high-purity terephthalic acid
- G ' is high-purity terephthalic acid crystal
- H is separated mother liquor
- H' is separated mother liquor
- I is slurry
- S SI represents steam gas
- T and T1 represent exhaust gas
- U represents condensate.
- the high-purity terephthalic acid according to the present invention is produced through the steps shown in FIG. First, crude terephthalic acid A, which is produced by oxidizing para-xylene in an oxidation step and contains 4CBA as an impurity, is used as a raw material. This crude terephthalic acid A contains 100 to 50,000 ppm of 4CBA.
- This crude terephthalic acid A is suspended in an aqueous medium B in a mixing tank 11 to form a crude terephthalic acid slurry C.
- the crude terephthalic acid slurry C is pressurized to a predetermined pressure in the mixing tank 11 and heated in the first heat exchanger 12 to completely dissolve the crude terephthalic acid A in the aqueous medium B.
- a solution D is obtained by pressurized to a predetermined pressure in the mixing tank 11 and heated in the first heat exchanger 12 to completely dissolve the crude terephthalic acid A in the aqueous medium B.
- the dissolving solution D and hydrogen are continuously supplied to a hydrogenation reactor 13 filled with a reducing catalyst, and a reduction step of reducing paraffinic acid by reducing 4CBA in the dissolving solution is performed.
- the reduction treatment liquid E obtained in this reduction step is sent to a crystallization tank group in which at least two crystallization tanks 14 are connected in series, and a crystallization step for crystallizing terephthalic acid is performed.
- terephthalic acid is precipitated with most of the paratoluic acid dissolved, A terephthalic acid slurry can be obtained.
- the obtained terephthalic acid slurry F is introduced into a solid-liquid separator 15 and subjected to a solid-liquid separation step to be separated into a solid content of high-purity terephthalic acid G and a separated mother liquor H.
- the high-purity terephthalic acid G is dried and shipped as a product.
- the reduction catalyst is not particularly limited as long as it does not have the ability to reduce carboxyl groups and has the ability to reduce aldehyde groups.
- the catalyst is supported on a carrier such as activated carbon.
- the amount of the metal component supported may vary depending on conditions such as pressure, temperature, and flow rate, but is preferably 0.2 to 10% by weight. 3 to: 1_% by weight is preferred. If it is less than 0.2% by weight / 0, it tends to be difficult to perform a + reduction reaction. On the other hand, if it exceeds 10% by weight, the rate of occurrence of side reactions described later tends to increase.
- the aqueous medium refers to a medium used when producing high-purity terephthalic acid using the above crude terephthalic acid, and specifically refers to water.
- the reduction treatment liquid E was introduced into the crystallization tank 14 set at a pressure lower than the pressure of the reduction treatment liquid E or the pressure of the preceding crystallization tank 14,
- the pressure is released and cooling is performed in accordance with the pressure (hereinafter, the operation of the pressure release and cooling is abbreviated as “pressure release cooling”).
- pressure release cooling the operation of the pressure release and cooling is abbreviated as “pressure release cooling”.
- terephthalic acid is crystallized.
- the crystallization tank group is composed of at least two or more crystallization tanks 14, and the particle size distribution of terephthalic acid precipitated by stepwise decompression cooling in each crystallization tank 14 And the eutectic of paratoluic acid can be suppressed.
- the reduction treatment liquid E introduced into the first crystallization tank 14a of the crystallization tank group is 5.5 to 9.8 MPa, 270 to 300 ° C, It is introduced into the crystallization tank 14a and depressurized and cooled to 230 to 260 ° C.
- the operating pressure at this time is the saturated vapor pressure at this temperature, specifically, 2.8 to 4.7 MPa.
- the main reaction of the reduction reaction step is the production of paratoluic acid by the reduction of 4 CBA.
- benzoic acid and carbon monoxide are produced by decarboxylation of 4 CBA. Reaction occurs as a side reaction. This side reaction produces The formed carbon monoxide becomes a catalyst poison for the reduction catalyst in the hydrogenation reactor 13 and reduces the catalyst life.
- the molar ratio is preferably from 01 to 0.12 (molar ratio), and more preferably from 0.03 to 0.1 (molar ratio).
- the amount of carbon monoxide generated in the hydrogenation reactor can be obtained from (the flow rate of the gas generated from the first crystallization tank) X (the concentration of carbon monoxide in the gas). Further, in the crystallization tank 14a where the above-mentioned reduction treatment liquid E is sent at the beginning of the crystallization step, carbon monoxide and hydrogen in the vapor gas S1 mainly composed of an aqueous medium generated by depressurized cooling are removed.
- the content ratio of carbon monoxide is preferably 0.0003 to 0.03 (molar ratio), and is preferably 0.0005 to 0.01. This value may be simply used as the content ratio of carbon monoxide and hydrogen in the remaining exhaust gas T1 obtained by condensing moisture in the steam gas S1 in the heat exchanger 16. This is because the water is considerably removed from the exhaust gas T1, and the analysis is easier.
- the content ratio is less than 0.00003, the amount of hydrogen gas supplied to the hydrogenation reactor 13 becomes excessive, and a side reaction that causes hydrogenation of the benzene ring of the terephthalic acid tends to occur.
- the catalyst poison of carbon monoxide deteriorates the reduction catalyst in the hydrogenation reactor 13 and the catalyst life is apt to be shortened.
- Examples of a method for adjusting the ratio to the above range include a method of adjusting the amount of hydrogen gas supplied to the hydrogenation reactor 13 and a method of adjusting the throughput of the crude terephthalic acid A to be treated in the reduction step. Is raised.
- hydrogen supplied to the hydrogenation reactor 13 A combination of a method of adjusting the amount of gas and a method of adjusting the ratio of the amount of crude terephthalic acid A treated in the reduction step to the amount of catalyst is supplied to the hydrogenation reactor 13. 4 It is necessary to adjust the ratio of CBA to carbon monoxide generated in the hydrogenation reactor and the content ratio of carbon monoxide and hydrogen in the steam gas S 1 (or exhaust gas T 1) within the above ranges. preferable.
- the method of adjusting the throughput of the crude terephthalic acid A treated in the reduction step includes: treating the throughput (treatment speed) of the crude terephthalic acid A treated in the reduction step; Adjusting the amount of the reduction catalyst, that is, the ratio to the amount of the metal component in the reduction catalyst.
- the amount of the crude terephthalic acid A treated (t / h) 400 to 5000 (1 / h) is preferable, and 1000 to 3000 (l / h) is preferable. If the ratio is less than 400 (1 / h), the processing efficiency of crude terephthalic acid A decreases. On the other hand, if it is larger than 5000 (1 / h), sufficient reduction treatment may not be performed.
- Examples were performed using the process shown in FIG. Specifically, the mixing tank 1 1 with the 4 CBA put 3000 p pm crude terephthalic acid containing 1 8 ton / h, and water, to produce a crude terephthalic acid slurry C of 30 weight 0/0, the pressure this 8. 9MPa The pressure was increased, and the temperature was raised to 285 ° C. by the multitubular heat exchanger 12 to dissolve terephthalic acid. The terephthalic acid aqueous solution D was supplied to the hydrogenation reactor 13. The hydrogenation reactor 13 had a tower diameter of 1260 mm and a height of 10 m.
- the reduction catalyst palladium supported on activated carbon at 0.5% by weight was used, and the amount of the catalyst charged was 6 ton.
- hydrogen was simultaneously supplied to reduce the terephthalic acid aqueous solution D, and the resulting reduced solution E was crystallized to a final temperature of 155 ° C. in the next crystallization step. Prayed.
- the pressure was gradually reduced and cooled using a five-stage crystallization tank 14.
- the slurry obtained by the crystallization was separated into crystals and a separated mother liquor H by a solid-liquid separator 15, and the crystals were dried and recovered as high-purity terephthalic acid G.
- the water vapor gas S1 was depressurized and cooled to 250 ° C, and the obtained water vapor gas S1 was condensed in the second heat exchanger 16, after which most of the condensed components were condensed.
- Gas T1 was exhausted.
- the reduction catalyst used was able to stably produce high-purity terephthalic acid without a decrease in activity.
- the hydrogenation reaction was performed using the process shown in FIG. Specifically, 20 kg of crude terephthalic acid slurry C was prepared by adding 1.2 kg / hr of crude terephthalic acid A containing 3000 CPM of 4 CBA and water B to the measuring tank 21, and producing the slurry at a pressure of 7. The pressure was raised to 9 MPa, the temperature was raised to 280 ° C by the preheater 22, and the After dissolving the tallic acid, the terephthalic acid aqueous solution D was supplied to the hydrogenation reactor 24.
- the hydrogenation reactor 24 had a tower diameter of 15 mm and a height of 145 Omm.
- the reduction catalyst palladium supported on activated carbon at 0.5% by weight was used, and the amount of the catalyst charged was set to 120 g.
- hydrogen was supplied at the same time to reduce the terephthalic acid aqueous solution, and the obtained reduced solution E 'was once held in a receiver 25 for treatment amount control.
- the solution was cooled to 225 ° C in the crystallization tank 26 and cooled to 150 ° C in the second crystallization tank 27 for crystallization.
- the slurry obtained by crystallization was subjected to solid-liquid separation in a pressure separator 28 to separate into crystal G 'and separated mother liquor H'. After drying crystal G, it was recovered as high-purity terephthalic acid.
- the amount of carbon monoxide generated in the hydrogenation reactor is calculated by the ratio of the amount of 4 CBA supplied to the hydrogenation reactor in the solution to carbon monoxide Z4 CBA-0 .07 (molar ratio).
- the amount of carbon monoxide generated in the hydrogenation reactor 24 is calculated by the ratio of the amount of carbon monoxide 4 CB to the amount of 4 CBA supplied to the hydrogenation reactor in the solution.
- A 0.08 (molar ratio).
- 0.5g% dZC hydrogenation catalyst 0.5g, pure water 60g, crude tele 15 g of phthalic acid (4 CBA concentration 3000 ppm) was charged, and a predetermined composition gas (3 types of carbon monoxide 0 vol./., 2.5 vol.% And 50 vol.%) was applied at a pressure of 0.6 MPa. The reaction was started at a reaction temperature of 275 ° C. The 4 CBA concentration of the purified terephthalic acid after the 15-minute reaction was measured, and the 4 CBA disappearance rate was calculated.
- the elimination rate of 4CBA when using a composition gas containing 0% by volume of carbon monoxide was 0.150 (1 / min), that is, 2.5 volumes of carbon monoxide. /.
- the disappearance rate of 4CBA when using a composition gas of 0.086 (1 / min), and the disappearance rate of 4CBA when using a 50% by volume composition gas of carbon monoxide was 0.027. (l / min).
- the ratio in the hydrogenation reactor It is estimated that the concentration of carbon oxides increases above a certain level, and as a result, the activity of the catalyst decreases rapidly, and the catalyst needs to be replaced in less than one year.
- the amount of carbon monoxide in the gas from the first crystallization tank is within the predetermined range, deterioration of the reduction catalyst used in the reduction reaction can be suppressed and the activity can be maintained. Further, if the amount of carbon monoxide in the gas from the first crystallization tank is within a predetermined range, side reactions occurring in the reduction step will be suppressed, so that purified terephthalic acid with higher purity can be obtained in higher yield. Can be manufactured.
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- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2003289482A AU2003289482A1 (en) | 2003-01-07 | 2003-12-22 | Process for producing high-purity terephthalic acid |
BR0317930-3A BR0317930A (pt) | 2003-01-07 | 2003-12-22 | Processo para a produção de ácido tereftálico de alta pureza |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2003001060 | 2003-01-07 | ||
JP2003-1060 | 2003-01-07 |
Publications (1)
Publication Number | Publication Date |
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WO2004060847A1 true WO2004060847A1 (ja) | 2004-07-22 |
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ID=32708796
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2003/016464 WO2004060847A1 (ja) | 2003-01-07 | 2003-12-22 | 高純度テレフタル酸の製造方法 |
Country Status (4)
Country | Link |
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CN (2) | CN1323999C (ja) |
AU (1) | AU2003289482A1 (ja) |
BR (1) | BR0317930A (ja) |
WO (1) | WO2004060847A1 (ja) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN101531588B (zh) * | 2008-03-13 | 2016-02-24 | 周向进 | 一种新的精对苯二甲酸的制造方法 |
CN101704742B (zh) * | 2009-11-20 | 2013-06-26 | 华东理工大学 | 一种生产芳香族羧酸的反应器 |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0498591A2 (en) * | 1991-02-05 | 1992-08-12 | Imperial Chemical Industries Plc | Process for the production of terephthalic acid |
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2003
- 2003-12-22 AU AU2003289482A patent/AU2003289482A1/en not_active Abandoned
- 2003-12-22 WO PCT/JP2003/016464 patent/WO2004060847A1/ja active Application Filing
- 2003-12-22 CN CNB2003801003948A patent/CN1323999C/zh not_active Expired - Lifetime
- 2003-12-22 CN CNA2006101699771A patent/CN1982283A/zh active Pending
- 2003-12-22 BR BR0317930-3A patent/BR0317930A/pt not_active Application Discontinuation
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0498591A2 (en) * | 1991-02-05 | 1992-08-12 | Imperial Chemical Industries Plc | Process for the production of terephthalic acid |
Non-Patent Citations (1)
Title |
---|
"Kagaku Process - Kiso kara Gijutsu Kaihatsu made", THE SOCIETY OF CHEMICAL ENGINEERS JAPAN, 25 March 1998 (1998-03-25), TOKYO KAGAKU DOJIN, pages 149 - 153, XP002994487 * |
Also Published As
Publication number | Publication date |
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AU2003289482A1 (en) | 2004-07-29 |
CN1982283A (zh) | 2007-06-20 |
CN1692093A (zh) | 2005-11-02 |
BR0317930A (pt) | 2005-11-29 |
CN1323999C (zh) | 2007-07-04 |
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