Method of producing terephthalic acid

Patent metadata

Field	Value
Publication number	US-10315978-B2
Application number	US-201615775874-A
Country	US
Kind code	B2
Filing date	Nov 14, 2016
Priority date	Nov 16, 2015
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

A method of reducing the formation of an impurity in a terephthalic acid (TPA) production process includes: combining in a reactor, a catalyst, a mixture comprising the impurity and the TPA, and a compound comprising an active carbon atom; reacting the impurity with the compound in the presence of the catalyst by a condensation-dehydration reaction process comprising a nucleophilic addition of the active carbon atom of the compound to a carbonyl group of the impurity to form an intermediate followed by a dehydration reaction of the intermediate to form a product mixture comprising a water, the TPA, and an alkene; and recovering the product mixture from the reactor.

First claim

We claim:

1. A method of reducing the formation of an impurity in a terephthalic acid (TPA) production process comprising:
combining in a reactor, a catalyst, a mixture comprising the impurity and the TPA, and a compound comprising an active carbon atom;
wherein the impurity comprises formula (I);
R 1 -Bn-COH  (I)

wherein R 1 comprises a hydrogen atom, an alkyl, carboxyl, carbonyl, aldehyde, ether, ester, alkynyl, alkenyl, halo, hydroxyl, haloformyl, carbonate ester, carboxylate, peroxy, acetal, a nitrogen containing functional group, a sulfur containing functional group, a phosphorous containing functional group, or a combination comprising at least one of the foregoing;
wherein Bn is a benzene ring; and
wherein COH is an aldehyde group;
wherein the compound comprises formula (II), (III), or (IV);
Z 1 —CH 2 —Z 2   (II)

Z 1 —CHR 2 —Z 2   (III)

Z 1 —CHR 2 R 3   (IV)

wherein Z 1 and Z 2 each comprise an electron withdrawing functional group, and
wherein R 2 and R 3 each comprise an atom of carbon, hydrogen, oxygen, nitrogen, sulfur, or a combination comprising at least one of the foregoing;
reacting the impurity with the compound in the presence of the catalyst by a condensation-dehydration reaction process comprising a nucleophilic addition of the active carbon atom of the compound to a carbonyl group of the impurity to form an intermediate followed by a dehydration reaction of the intermediate to form a product mixture comprising a water, the TPA, and an alkene comprising formula (V), (VI), or (VII);
R 4 -Bn-C 2 Z 1 Z 2   (V)

R 4 -Bn-C 2 Z 1 R 2 Z 2   (VI)

R 4 -Bn-C 2 Z 1 R 2 R 3   (VII)

wherein R 4 comprises R 1 or COH; and
recovering the product mixture from the reactor.

2. The method of claim 1 , further comprising separating the product mixture to form a by-product comprising greater than or equal to 0.01 wt % of the alkene and greater than or equal to 0.01 wt % of the water, and a product comprising greater than or equal to 99.9 wt % of the TPA, wherein the weight percentages are based upon a total weight of the product mixture.

3. The method of claim 1 , further comprising separating the product mixture to form a by-product comprising greater than or equal to 0.01 wt % of the water, and a product comprising greater than or equal to 0.01 wt % of the TPA and greater than or equal to 99.9 wt % of the alkene, wherein the weight percentages are based upon a total weight of the product mixture.

4. The method of claim 1 , wherein a concentration of the impurity in the product is less than or equal to 25 ppmw.

5. The method of claim 4 , wherein the impurity is 4-CBA.

6. The method of claim 1 , further comprising recycling the product mixture to a second reactor.

7. The method of claim 1 , wherein the alkene comprises a fluorescent functional group.

8. The method of claim 1 , wherein the TPA production process is free of a hydrogenation process and the impurity is not hydrogenated.

9. The method of claim 1 , wherein the active carbon atom is of formula (II) or (III), and wherein Z 1 and Z 2 comprise the same molecular formula.

10. The method of claim 1 , wherein the active carbon atom is of formula (IV), and wherein R 2 and R 3 comprise the same molecular formula.

11. The method of claim 1 , wherein the catalyst comprises an acid, a base, a solvent, a metal, a halogen, or a combination comprising at least one of the forgoing.

12. The method of claim 1 , wherein the catalyst comprises an acid, a cobalt, a manganese, a bromide, a solvent, or a combination comprising at least one of the forgoing.

13. The method of claim 1 , further comprising washing the product mixture with heated water.

14. The method of claim 1 , wherein a concentration of the impurity in the product mixture is less than or equal to 25 ppmw.

15. The method of claim 14 , wherein the impurity is 4-CBA.

16. The method of claim 1 , wherein the electron withdrawing functional group comprises carbonyl, cyanate, ester, halogen, nitrate, nitrile, nitrite, nitro, or a combination comprising at least one of the foregoing.

17. The method of claim 1 , wherein the impurity comprises 4-carboxybenzaldehyde, 3-carboxybenzaldehyde, 2-carboxybenzaldehyde, 4-methylbenzoic acid (p-toluic acid), 3-methylbenzoic acid (m-toluic acid), 2-methylbenzoic acid (o-toluic acid), colored impurities, or a combination comprising at least one of the foregoing.

18. The method of claim 1 , wherein the impurity comprises 4-carboxybenzaldehyde, 4-methylbenzoic acid (p-toluic acid), or a combination comprising at least one of the foregoing.

19. The method of claim 1 , further comprising polymerizing the TPA to form a polymer.

Assignees

• Sabic Global Technologies Bv

Inventors

• Sankaran Nedumbamana
• Hashmi Syed Azhar
• Vasudevan Vinodkumar

Classifications

• C07C1/12 Primary

  from carbon dioxide with hydrogen · CPC title

• C07C51/487 Primary

  by treatment giving rise to chemical modification (by chemisorption C07C51/47) · CPC title

• C07C11/02

  Alkenes · CPC title