Basf Aktiengesellschaft

Wolfgang Eisfeld

Walter Disteldorf

Albert Hettche

Rolf-Dieter Kohler

4,4'-diaminobenzophenones of the formula I ##STR1## where the rings A and B can be further substituted, are prepared by a process in which a compound of the formula II ##STR2## where the rings A, B and E can be substituted, is oxidized with aqueous nitric acid in the presence of nitrobenzene or of an alkanoic acid and under superatmospheric pressure, and the reaction product is cleaved. The process according to the invention gives the compounds of the formula I in high yield and purity.

Preparation of 4,4'-diaminobenzophenones

Pure halonaphthalic acid anhydrides are prepared from haloacenaphthenes by oxidation with nitric acid in a mixture of aliphatic carboxylic acid, water and nitric acid in the presence of vanadate, with or without further metal salts, at an elevated temperature and the reaction product is isolated and subjected to an oxidative after-treatment with hypochlorite in aqueous solution at a pH of from 9 to 12 at an elevated temperature. The products are intermediates for the manufacture of optical brighteners.

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Ludwigshafen, Germany

Wolfgang Eisfeld