Hoechst Aktiengesellschaft

Friedhelm Kluge

Thomas Martini

Sigmar-Peter Von Halasz

Perfluorocarboxylic acid salts of a monovalent metal are reacted with perfluorocarboxylic acid fluorides in aprotic polar solvents. Perfluoroketones are obtained. The salt of the perfluorocarboxylic acid can be replaced by alkali metal salts of formic acid, oxalic acid or of oxygen-containing mineral acids, the central atom of which is an element of the groups IIIA to VIIA of the periodic table and which mineral acid is weaker than trifluoroacetic acid. The same result is obtained if the anhydride of the perfluorocarboxylic acid is contacted with an alkali metal fluoride. The synthesized perfluoroketones are liquids of high chemical and thermal stability.

Process for the preparation of fluorine-containing ketones

Perfluorinated ethers containing carboxylic acid fluoride groups and optionally units derived from hexafluoropropene epoxide or tetrafluoroethylene epoxide are reacted with fluorine at temperatures of from 50.degree. to 350.degree.C in the presence of metallic catalysts. During the reaction carbonyl difluoride is splitt off and an ether is obtained in high yield which is free of carboxylic acid fluoride groups. Metallic silver is well suited as catalyst.

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Frankfurt-am-Main, Germany

Friedhelm Kluge