Claims
- 1. In a process for producing aromatic dicarboxylic acids which incorporates disproportionation of a salt of an aromatic carboxylic acid to produce unreacted salt of an aromatic carboxylic acid and the salt of the desired aromatic dicarboxylic acid, a method for separating the salt of the desired product from the unreacted salt which comprises passing both said unreacted salt and said salt of the desired product in an aqueous solution over a bed of adsorbent comprising activated carbon.
- 2. The process of claim 1 wherein the unreacted salt is potassium naphthoate, and the salt of the desired product is the dipotassium salt of naphthalene dicarboxylic acid 2,6-K2NDA.
- 3. The process of claim 1 wherein the aqueous solution of unreacted potassium naphthoate and dipotassium salt of 2,6-naphthalene dicarboxylic acid contains about 1-50% of the combined salts in water.
- 4. The process of claim 3 wherein the aqueous solution contains about 10-40% combined salts in water.
- 5. The process of claim 4 wherein the aqueous solution contains about 20-30% combined salts in water.
- 6. The process of claim 1 wherein said adsorbent is activated carbon.
- 7. The process of claim 6 wherein said activated carbon adsorbent further comprises a high purity carbon that has been washed to remove leachable metals.
- 8. The process of claim 7 wherein said high purity activated carbon is washed with an aqueous potassium hydroxide solution before first use.
- 9. The process of claim 1 wherein said adsorbent bed further comprises multiple adsorbent beds in a series.
- 10. The process of claim 9 wherein said aqueous solution is treated over an adsorbent bed until said bed is expended and then said aqueous solution is directed to the next adsorbent bed in the series.
- 11. The process of claim 10 which further comprises regenerating the expended bed by countercurrently backwashing the bed with water and then countercurrently passing displacing agent over the bed.
- 12. The process of claim 11 wherein the bed is countercurrently backwashed with about 1-3 bed volumes of water.
- 13. The process of claim 11 further comprising passing said displacing agent countercurrently over the bed at a rate of about 0.1-10 bed weights per hour.
- 14. The process of claim 11 wherein said displacing agent selected from the group consisting of at least partially water soluble alcohols, ethers or esters characterized by having from one to six carbons.
- 15. The process of claim 14 wherein the water soluble displacing agent is selected from the group consisting of methanol, acetone, isopropyl alcohol, ethyl acetate, and tetrahydrofuran.
- 16. The process of claim 15 wherein the water soluble displacing agent is tetrahydrofuran.
- 17. The process of claim 11 wherein said displacing agent is in a solution of water in an amount of 5-80%.
- 18. The process of claim 17 wherein said displacing agent is in a solution of water in an amount of 15-50%.
- 19. The process of claim 18 wherein said displacing agent is in a solution of water in an amount of about 20% or the solubility limit of the solvent in the aqueous solution, whichever is higher.
- 20. In a process for producing 2,6-naphthalene dicarboxylic acid by disproportionation of potassium naphthoate to produce the dipotassium salt of 2,6-naphthalene dicarboxylic acid and unreacted 1- and 2-potassium napthoate, a method for separating said potassium naphthoate from the dipotassium salt of napthalene dicarboxylic acid which comprises:passing both said potassium naphthoate and said dipotassium salt in an aqueous solution over the first of a series of two to six beds containing adsorbent comprising activated carbon until said activated carbon is expended; directing said aqueous solution to the second bed, or subsequent bed in the series, of activated carbon; backwashing the expended bed with water; and regenerating the expended bed by countercurrently passing a saturated solution of tetrahydrofuran in water over the expended bed.
CROSS REFERENCE
This application claims the benefit of U.S. Provisional Application No. 60/151,589, filed Aug. 30, 1999, the entire disclosure of which is hereby incorporated by reference.
This application is related to U.S. application Ser. Nos. 60/151,577, 60/151,607, 60/151,498, 60/151,602, 60/151,603, 60/151,529, 60/151,489, 60/151,604, 60/151,606, 60/151,497, 60/151,590, and 60/151,578, filed of even date.
US Referenced Citations (13)
Foreign Referenced Citations (1)
Number |
Date |
Country |
864587 |
Sep 1998 |
CA |
Provisional Applications (13)
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Number |
Date |
Country |
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60/151589 |
Aug 1999 |
US |
|
60/151577 |
Aug 1999 |
US |
|
60/151607 |
Aug 1999 |
US |
|
60/151498 |
Aug 1999 |
US |
|
60/151602 |
Aug 1999 |
US |
|
60/151603 |
Aug 1999 |
US |
|
60/151529 |
Aug 1999 |
US |
|
60/151489 |
Aug 1999 |
US |
|
60/151604 |
Aug 1999 |
US |
|
60/151606 |
Aug 1999 |
US |
|
60/151497 |
Aug 1999 |
US |
|
60/151590 |
Aug 1999 |
US |
|
60/151578 |
Aug 1999 |
US |