Process for production of a carboxylic acid/diol mixture suitable for use in polyester production
View Patent ↗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.
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.