Basf Aktiengesellschaft

Jost H Manegold

Hans Leitner

Wolfgang Hoelderich

Toni Dockner

Stefan Karbach

Manfred Sauerwald

Guenter Herrmann

Peter Magnussen

Gert Buerger

Gerhard Frank

Ruediger Schmitz

Hubert Lendle

Wolfgang Leitenberger

A process for working up mother liquors resulting from the preparation of adipic acid by oxidation of cyclohexanol or cyclohexanone or mixtures thereof with nitric acid entails removal of nitric acid by azeotropic distillation with water, heating the resulting melt at from 130.degree. to 180.degree. C. and then dissolving it in water, treating the aqueous solution with cation exchangers, subsequently again evaporating off the water and heating the resulting dicarboxylic acid melt at from 200.degree. to 240.degree. C. and then obtaining a mixture of dicarboxylic acids by distillation.

Workup of mother liquors resulting from the preparation of adipic acid

Aliphatic dinitriles are prepared by reacting aliphatic dicarboxylic acids with ammonia in excess at from 200.degree. to 500.degree. C. in the presence of zeolites as catalysts.

Preparation of aliphatic dinitriles

Adipodinitrile is prepared by reacting adipic acid with excess ammonia at from 250.degree. to 350.degree. C. in the liquid phase in the presence of a diluent by a process in which a liquid hydrocarbon which is inert under the reaction conditions is used as the diluent.

Preparation of adipodinitrile

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Lambsheim, Germany

Jost H Manegold