Bayer Aktiengesellschaft

Herbert Muller

Helmut Fiege

Reinhold Gehring

Ferdinand Hagedorn

Otto Neuner

Wolfgang Eymann

Heinrich Pelster

Georg Hardenbicker

Karl Goliasch

Werner Bussmann

Process for preparing nucleus-halogenated benzoyl chlorides

4-Fluorothiophenol is obtained in outstanding purifies and yields if 4-fluorobenzenesulphonyl chloride is reacted with sodium hydrogen sulphite solution to give a solution of sodium 4-fluorobenzenesulphinate, this solution is reduced with sulphur dioxide to give 4,4'-difluorodiphenyl disulphide and finally this is reacted with sodium borohydride in a water-miscible inert organic solvent to give 4-fluorothiophenol (sodium salt). Free 4-fluorothiophenol can be isolated from the sodium salt solution by acidification.

Process for the preparation of 4-fluorothiophenol

A process for preparing benzoic anhydride which comprises contacting benzotrichloride with benzoic acid in a molar ratio of 1:2-3 at a temperature in the range of 100.degree.-200.degree. C.

Process for the preparation of benzoic anhydride

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Kreuzau, Germany

Herbert Muller