Claims
- 1. A process for the preparation of 2,3,4,5-tetrafluorobenzoic acid which comprises heating tetrafluorophthalic acid at 105.degree.-125.degree. C. with an organic amine catalyst in a polar, aprotic solvent.
- 2. A process according to claim 1, wherein the organic amine is triethylamine or diazabicyclo[2.2.2]octane.
- 3. A process for the preparation of 2,3,4,5-tetrafluorobenzoic acid which comprises heating tetrafluorophthalic acid at 105.degree.-125.degree. C. with triethylamine in dimethylsulfoxide.
- 4. A process according to claim 3, wherein 0.2 to 0.5 mole of triethylamine per mole of tetrafluorophthalic acid is used.
- 5. A process for the preparation of 2,3,4,5-tetrafluorobenzoic acid which comprises:
- (a) heating perchlorophthalide and potassium fluoride in a polar, aprotic solvent at about 100.degree.-170.degree. C.;
- (b) extracting tetrafluorophthaloyl fluoride from the reaction mixture and hydrolyzing it with aqueous base; and
- (c) heating the resulting hydrolysis product with a base catalyst in a polar, aprotic solvent at 90.degree.-140.degree. C.
- 6. A process according to claim 5, wherein the polar, aprotic solvent in steps (a) and (c) is tetramethylenesulfone.
- 7. A process according to claim 5, wherein the base catalyst in step (c) is triethylamine.
- 8. A process for the preparation of 3,4,5,6-tetrafluorophthalic acid which comprises heating perchlorophthalide and potassium fluoride at 100.degree.-170.degree. C. in a polar, aprotic solvent, and hydrolyzing with aqueous acid or aqueous base the resulting tetrafluorophthaloyl fluoride.
- 9. A process according to claim 8, wherein heating is carried out between 155.degree. and 160.degree. C.
- 10. A process according to claim 8, wherein tetramethylenesulfone is the polar, aprotic solvent.
Parent Case Info
This is a continuation-in-part of U.S. application Ser. No. 773,490 filed Sept. 9, 1985, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
2439237 |
Cass |
Apr 1948 |
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Foreign Referenced Citations (3)
Number |
Date |
Country |
0194671 |
Sep 1986 |
EPX |
3318145 |
Nov 1984 |
DEX |
61-85349 |
Apr 1986 |
JPX |
Non-Patent Literature Citations (2)
Entry |
Chem. Abstracts, vol. 76, Abstract No. 45887e, (1972), Chen et al. |
Zhurnal Obshchei Khimii; G. C. Yakobson, et al.; 36 (1), pp. 139-142, (1966). |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
773490 |
Sep 1985 |
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