Preparation of aromatic fluoro compounds

The present invention relates to a process for the preparation of 4,4'-difluorobenzophenone. 4,4-difluorobenzophenone may be prepared by diazotization of 4,4'-diamino-diphenylmethane in anhydrous or concentrated aqueous hydrogen fluoride, decomposition of the diazonium fluoride thus produced to yield 4,4'-difluoro-diphenylmethane and oxidation of 4,4'-difluoro-diphenylmethane to yield 4,4'-difluorobenzophonone.Thus, according to the present invention, there is provided a process for the preparation of 4,4'-difluorobenzophenone which comprises the following steps:(1) diazotization of 4,4'-diamino-diphenylmethane in anhydrous or concentrated aqueous hydrogen fluoride to yield a solution of a corresponding diazonium fluoride; and(2) (i) thermally decomposing the diazonium fluoride in the solution thus produced to yield 4,4'-difluoro-diphenylmethane and (ii) subsequently oxidizing the 4,4'-difluoro-diphenylmethane to yield 4,4'-difluorobenzophenone.

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Description
Patent History
Patent number: T993005
Type: Grant
Filed: Mar 19, 1979
Date of Patent: Apr 1, 1980
Assignee: Imperial Chemical Industries Limited (London)
Inventor: Philip A. Staniland (Tewin Wood)
Application Number: 6/22,597
Classifications
Current U.S. Class: 260/591
International Classification: C07C 4500;