Claims
- 1. A process for preparing purified 2,6-naphthalenedicarboxylic acid comprising:
- a) hydrolyzing a dialkyl-2,6-naphthalenedicarboxylate with water at a reaction temperature of at least about 450.degree. F. under liquid phase conditions and for a time sufficient to convert a major portion of the dialkyl-2,6-naphthalenedicarboxylate to 2,6-naphthalenedicarboxylic acid thereby forming a reaction product mixture, the amount of water present being sufficient to solubilize, at the reaction temperature, at least about 10 weight percent of the 2,6-naphthalenedicarboxylic acid formed; and
- b) recovering 2,6-naphthalenedicarboxylic acid from the reaction product mixture.
- 2. The process of claim 1 wherein the amount of water present is an amount sufficient to solubilize at least about 50 weight percent of the 2,6-naphthalenedicarboxylic acid present in the reaction product mixture.
- 3. The process of claim 1 wherein the amount of water present is an amount sufficient to solubilize substantially all of the 2,6-naphthalenedicarboxylic acid present in the reaction product mixture.
- 4. The process of claim 1 wherein at least about 95 weight percent of the dialkyl-2,6-naphthalenedicarboxylate is converted to 2,6-naphthalenedicarboxylic acid.
- 5. The process of claim 1 wherein the reaction temperature is at least about 540.degree. F.
- 6. The process of claim 1 wherein the reaction temperature is at least about 570.degree. F.
- 7. The process of claim 1 wherein the alkyl portion of the dialkyl-2,6-naphthalenedicarboxylate contains 1 to about 4 carbon atoms.
- 8. The process of claim 1 wherein the dialkyl-2,6-naphthalenedicarboxylate is dimethyl-2,6-naphthalenedicarboxylate.
- 9. The process of claim 8 wherein the dimethyl-2,6-naphthalenedicarboxylate is at least about 98% pure.
- 10. The process of claim 1 wherein the 2,6-naphthalenedicarboxylic acid formed has an average particle size of at least about 100 microns.
- 11. The process of claim 3 wherein the reaction temperature is at least about 570.degree. F. and wherein at least about 95 weight percent of the alkyl-2,6-naphthalenedicarboxylate is converted to 2,6-naphthalenedicarboxylic acid.
- 12. The process of claim 11 wherein the 2,6-naphthalenedicarboxylic acid product is in the form of crystals, the crystals having an average size of at least about 100 microns.
- 13. The process of claim 1 wherein the reaction temperature is at least about 540.degree. F., the dialkyl-2,6-naphthalenedicarboxylate is dimethyl-2,6-naphthalenedicarboxylate and wherein the weight ratio of water to dimethyl-2,6-naphthalenedicarboxylate is at least about 4:1, respectively.
- 14. The process of claim 13 wherein the reaction temperature is at least about 570.degree. F.
- 15. The process of claim 14 wherein a column reactor is used as a reaction zone.
- 16. The process of claim 15 wherein the column reactor contains a plurality of trays to provide for liquid hold up.
RELATED APPLICATION
This is a continuation of application Ser. No. 08/206,517 filed Mar. 4, 1994 (U.S. Pat. No. 5,563,294); which is a Continuation of Ser. No. 08/065,486, filed May 19, 1993 abandoned; which is a Continuation of Ser. No. 07/900,637, filed Jun. 18, 1992 abandoned; which is a Continuation-in-Part of Ser. No. 07/810,481, filed Dec. 19, 1991 abandoned.
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Continuations (3)
|
Number |
Date |
Country |
Parent |
206517 |
Mar 1994 |
|
Parent |
65486 |
May 1993 |
|
Parent |
900637 |
Jun 1992 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
810481 |
Dec 1991 |
|