Process for tetrafluorobenzoic acid
AssigneeWarner-Lambert Company
InventorsJames N. Wemple, Timothy P. Puls, James Vande Vusse
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Abstract
An improved process for the preparation of 2,3,4,5-tetrafluorobenzoic acid is described which involves decarboxylation of tetrafluorophthalic acid in the presence of a base catalyst. Also described is an improved method for preparing tetrafluorophthalic acid and, in turn, a one-pot process for tetrafluorobenzoic acid using the combination of the two improvements.
Claims10
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.
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.
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.
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.
Dependencies are inferred from the claim text.