Process for the preparation of anthraquinone imides
AssigneeCiba-Geigy Corporation
InventorBernd Dill
Life of this patent
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Abstract
The invention relates to a process for the preparation of anthraquinone imides by condensing vattable anthraquinone compounds which contain at least one primary amino group with aromatic halogen compounds, in an organic solvent and at elevated temperature in the presence of a base and a copper catalyst. The process comprises first carrying out the condensation until a reaction of 60-95% has taken place, and then subjecting the reaction mixture, without isolating the reaction product, to an aftertreatment at a temperature which is 5.degree. to 60.degree. C. above the initial temperature of the condensation. This process permits the anthraquinone imides to be obtained in increased yield and additionally provides products with improved qualities. The intermediates so obtained can be further processed to vat dyes.
Claims8
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, anthranthrone, pyranthrone, dibenzanthrone, phthaloylacridone, flavanthrone dibenzpyrenequinone or isoviolanthrone, which halogen compounds are unsubstituted or further substituted by halogen, alkyl, alkoxy, acylamino or fused benzene rings, at a temperature of 180.degree. to 210.degree. C. in an inert organic solvent in the presence of a base and a copper catalyst, the improvement which comprises first carrying out the condensation until a reaction of 60 to 95% has taken place, and then subjecting the reaction mixture, without isolating the reaction product, to an aftertreatment at a temperature of 215.degree. to 250.degree. C., the aftertreatment being carried out under overpressure.
Dependencies are inferred from the claim text.