Process for the preparation of anthraquinone imides

In a process for the preparation of an anthraquinone imide by condensing a vattable anthraquinone compound which contains at least one primary amino group with a halogenated anthraquinone, benzanthrone, anthanthrone, pyranthrone, dibenzanthrone, phthaloylacridone, flavanthrone, dibenzpyrenequinone or isoviolanthrone, which aromatic halogen compounds are unsubstituted or further substituted by halogen, alkyl, alkoxy, acylamino or fused benzene rings, in an non-aqueous inert organic solvent and in the presence of a base and a copper catalyst, the improvement of which comprises heating a portion of the inert organic solvent to the reaction temperature which is in the range of 140.degree. to 250.degree. C. and, at this temperature, adding the reactants in the form of a suspension or solution in such a manner that the reaction temperature can be maintained, the reactants thereby being heated to the reaction temperature within less than 10 minutes, and holding at the reaction temperature until the condensation reaction is complete.