Process for production of a carboxylic acid/diol mixture suitable for use in polyester production

• US 7,226,986 B2
• Filed: 03/10/2005
• Issued: 06/05/2007
• Est. Priority Date: 03/06/2003
• Status: Expired due to Term

• Current Assignee: Alpek Polyester SA de CV
• Original Assignee: Eastman Chemical Company
• Inventors: Parker, Kenny Randolph, Lin, Robert, Hall, Duane Alan, Upshaw, Timothy Alan
• Primary Examiner(s): BOYKIN, TERRESSA M
• Application Number:
  US11/077,481
• Publication Number:
  US 20050228164A1
• Time in Patent Office: 817 Days
• Field of Search: 528/308, 560/80, 562/485
• US Class Current: 528/308
• CPC Class Codes: C07C 51/09 from carboxylic acid esters or lactones
• CPC Class Codes: C07C 51/47 by solid-liquid treatment; by chemisorption
• CPC Class Codes: C07C 63/26 1,4 - Benzenedicarboxylic acid
• CPC Class Codes: C08G 63/183 Terephthalic acids
• CPC Class Codes: C08G 63/78 Preparation processes

Abstract

The present invention relates to a process by which a carboxylic acid/diol mixture is obtained from a carboxylic acid/solvent slurry without isolation of a substantially dry carboxylic acid solid. More specifically, the present invention relates to a process by which a terephthalic acid/ethylene glycol mixture is obtained from a terephthalic acid/solvent slurry without isolation of a substantially dry terephthalic acid solid.

Claims

1. A process for producing a carboxylic acid/diol mixture suitable for the production of polyesters, said process comprising adding a diol to a water-wet carboxylic acid cake in a carboxylic acid/diol mixing zone to remove at least a portion of the water from said water-wet carboxylic acid cake to form said carboxylic acid/diol mixture;

wherein said carboxylic acid/diol mixture is produced without the isolation of a substantially dry carboxylic acid solid;

wherein said water is displaced from said water-wet carboxylic acid cake by the addition of said diol.

2. A process according to claim 1 wherein said carboxylic acid is selected from a group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, trimellitic acid, and mixtures thereof.

3. A process according to claim 1 or 2 wherein said diol is selected from the group consisting of ethylene glycol, diethylene glycol, n-butylene glycol, i-butylene glycol, n-propylene glycol, 1,4 butanediol, cyclohexanedimethanol, and mixtures thereof.

4. A process according to claim 1 wherein said carboxylic acid/diol mixing zone comprises at least one device selected from the group consisting of an agitated vessel, a static mixer, and a screw conveyor.

5. A process for producing a carboxylic acid/diol mixture suitable for the production of polyesters, said process comprising the following steps:

(a) removing in a first solid-liquid separation device impurities from a carboxylic acid/solvent slurry to form a carboxylic acid cake with acetic acid and a solvent mother liquor stream;

(b) removing a portion of a solvent in a second solid-liquid separation device from said carboxylic acid cake with acetic acid to form a water-wet carboxylic acid cake and a solvent/water byproduct liquor;

(c) adding a diol to said water-wet carboxylic acid cake in a carboxylic acid/diol mixing zone to remove at least a portion of the water from said water-wet carboxylic acid cake to form said carboxylic acid/diol mixture;

wherein said carboxylic acid/diol mixture is produced without the isolation of a substantially dry carboxylic acid solid;

wherein said water is displaced from said water-wet carboxylic acid cake by the addition of said diol.

6. A process according to claim 5 wherein said carboxylic acid is selected from a group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, trimellitic acid and mixtures thereof.

7. A process according to claim 5 or 6 wherein said diol is selected from the group consisting of ethylene glycol, diethylene glycol, n-butylene glycol, i-butylene glycol, n-propylene glycol, 1,4 butanediol, cyclohexanedimethanol, and mixtures thereof.

8. A process according to claim 5 wherein said diol/carboxylic acid mixing zone comprises at least one device selected from the group consisting of an agitated vessel, a static mixer, and a screw conveyor.

9. A process for producing a carboxylic acid/diol mixture suitable for the production of polyesters, said process comprising the following steps:

(a) removing a solvent from a carboxylic acid/solvent slurry in a solid-liquid separation zone;

wherein a portion of the solvent in said carboxylic acid/solvent slurry is replaced with water to form a water-wet carboxylic acid cake;

(b) adding a diol to said water-wet carboxylic acid cake in a carboxylic acid/diol mixing zone to remove at least a portion of the water from said water-wet carboxylic acid cake to form said carboxylic acid/diol mixture;

wherein said carboxylic acid/diol mixture is produced without the isolation of a substantially dry carboxylic acid solid;

wherein said water is displaced from said water-wet carboxylic acid cake by the addition of said diol.

10. A process according to claim 9 wherein said carboxylic acid is selected from a group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, trimellitic and mixtures thereof.

11. A process according to claim 9 or 10 wherein said diol is selected from the group consisting of ethylene glycol, diethylene glycol, n-butylene glycol, i-butylene glycol, n-propylene glycol, 1,4 butanediol, cyclohexanedimethanol, and mixtures thereof.

12. A process according to claim 9 wherein said carboxylic acid/diol mixing zone comprises at least one device selected from the group consisting of an agitated vessel, a static mixer, and a screw conveyor.

13. A process for producing a terephthalic acid/diol mixture, said process comprising adding a diol to a water-wet terephthalic acid cake in a terephthalic acid/diol mixing zone to remove a portion of the water to form said terephthalic acid/diol mixture.

14. A process according to claim 13 wherein said diol is selected from the group consisting of ethylene glycol, diethylene glycol, n-butylene glycol, i-butylene glycol, n-propylene glycol, 1,4 butanediol, cyclohexanedimethanol, and mixtures thereof.

15. A process according to claim 13 wherein said diol is ethylene glycol.

16. A process according to claim 13, 14 or 15 wherein said adding occurs at a temperature between about 40°

C. and about 290°

C.

17. A process according to claim 13 wherein said terephthalic acid/diol mixing zone comprises a device selected from the group consisting of an agitated vessel, a static mixer, a screw conveyor, and a PET esterification reactor.

18. A process for producing a terephthalic acid/diol mixture suitable for the production of polyesters, said process comprising the following steps:

(a) removing in a first solid-liquid separation device impurities from a terephthalic acid/solvent slurry to form a terephthalic acid cake with acetic acid;

(b) removing a portion of a solvent in a second solid-liquid separation device from said terephthalic acid cake with acetic acid to form a water-wet terephthalic acid cake; and

(c) adding a diol to said water-wet terephthalic acid cake in a terephthalic acid/diol mixing zone to remove at least a portion of the water from said water-wet carboxylic acid cake to form said terephthalic acid/diol mixture;

wherein said carboxylic acid/diol mixture is produced without the isolation of a substantially dry carboxylic acid solid;

wherein said water is displaced from said water-wet carboxylic acid cake by the addition of said diol.

19. A process according to claim 18 wherein said first solid-liquid separation device is operated at a temperature between about 40°

C. to about 155°

C.

20. A process according to claim 19 wherein said second solid-liquid separation device is operated at a temperature between about 40°

C. to about 155°

C.

21. A process according to claim 18 or 20 wherein said adding occurs at a temperature between about 40°

C. and about 290°

C.

22. A process according to claim 18 wherein said diol is selected from the group consisting of ethylene glycol, diethylene glycol, n-butylene glycol, i-butylene glycol, n-propylene glycol, 1,4 butanediol, cyclohexanedimethanol, and mixtures thereof.

23. A process according to claim 18 wherein said diol is ethylene glycol.

24. A process according to claim 18 wherein said terephthalic acid/diol mixing zone comprises a device selected from the group consisting of an agitated vessel, a static mixer, and a screw conveyor.

25. A process for producing a terephthalic acid/diol mixture suitable for the production of polyesters, said process comprising the following steps:

(a) removing a solvent from a terephthalic acid/solvent slurry in a solid-liquid separation zone;

wherein a portion of the solvent in said terephthalic acid/solvent slurry is replaced with water to form a water-wet terephthalic acid cake;

(b) adding a diol to said water-wet terephthalic acid cake in a terephthalic acid/diol mixing zone to remove at a portion the water from said water-wet carboxylic acid cake to form said terephthalic acid/diol mixture;

wherein said carboxylic acid/diol mixture is produced without the isolation of a substantially dry carboxylic acid solid;

wherein said water is displaced from said water-wet carboxylic acid cake by the addition of said diol.

26. A process according to claim 25 wherein said solid-liquid displacement zone is operated at a temperature between about 40°

C. to about 155°

C.

27. A process according to claim 25 wherein said adding occurs at a temperature between about 40°

C. and 290°

C.

28. A process according to claim 25 wherein said diol is selected from the group consisting of ethylene glycol, diethylene glycol, n-butylene glycol, i-butylene glycol, n-propylene glycol, 1,4 butanediol, cyclohexanedimethanol, and mixtures thereof.

29. A process according to claim 25 wherein said diol is ethylene glycol.

30. A process according to claim 25 wherein said diol/terephthalic acid mixing zone comprises a device selected from the group consisting of an agitated vessel, a static mixer, and a screw conveyor.