Basf Aktiengesellschaft

Basf Se Corporation

Volker Weyrauch

Georg Henning

Arno Boehm

Willi Helfer

Bernhard Dung

Felix Mueller

Arno Böhm

Felix Müller

A process for preparing perylene-3,4:9,10-tetracarboxylic dianhydride, comprising: dimerizing a naphthalene-1,8-dicarboximide of the formula IIa; reoxidizing the resulting alkali metal salt of the leuco form of the perylene-3,4:9,10-tetracarboxylic diimide of the formula Ia; hydrolyzing the diimide to the tetraalkali metal salt of perylene-3,4:9,10-tetracarboxylic acid in the presence of an inert organic solvent, of an alkali metal base and of water; and subjecting the tetraalkali metal salt of perylene-3,4:9,10-tetracarboxylic acid to the action of an aqueous inorganic acid to convert it into perylene-3,4:9,10-tetracarboxylic dianhydride; wherein Ris cyclohexyl or phenyl which may each be substituted by up to three C-C-alkyl radicals, and the dimerizing is in a substantially homogeneous reaction medium consisting essentially of an apolar aprotic organic solvent and an alkali metal base.

Preparation of perylen-3,4:9,10-tetracarboxylic dianhydride and also of naphtalene-1,8-dicarboximides

A process for preparing perylene-3,4:9,10-tetracarboxylic diimides of the general formula I comprising in a reaction medium consisting essentially of an apolar aprotic organic solvent and an alkali metal base and subsequently reoxidizing the resulting alkali metal salt of the leuco form of the perylene-3,4:9,10-tetracarboxylic diimide in the presence of a polar solvent.

Method for the production of perylen-3,4:9,10-tetracarboxylic acid diimides and perylen-3,4:9,10-tetracarboxylic acid dianhydride and naphtalene-1,8-dicarboxylimides

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Deidesheim, Germany

Volker Weyrauch