Basf Aktiengesellschaft

Eberhard Michaelis

Helmut Hoch

Karl Schmeidl

Peter Miederer

Wilhelm Brunkhorst

Blue anthraquinonoid disperse dyes are prepared by reacting a 1-amino-4-nitroanthraquinonecarboxamide (II) with a cyanide in an aqueous medium in the presence of hydroxyl ion acceptors at above 20.degree. C. by a process in which the reaction is carried out in water at a pH of from 7.5 to 10.5 and in the presence of one or more quaternary ammonium salts at from 60.degree. to 100.degree. C. The process gives disperse dyes which are similar to C.I. Disperse Blue 87 and have similar color properties in high yields by an environmentally compatible process, the said disperse dyes having excellent properties.

Preparation of a blue anthraquinonoid disperse dye of

1,4-Diaminoanthraquinone-2-sulfonic acid or salts thereof are reacted with cyanide ions at pH 8-11 in the presence of oxidizing agents in a mixture of water and 1-methoxy-2-propanol, 2-methoxy-1-propanol, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, dimethyl sulfoxide, dioxane, N-methylpyrrolidone or mixtures thereof, the ratio water: organic liquid being .gtoreq.3:1, the reaction proceeding at higher concentrations than in a purely aqueous medium and producing appreciably purer products in a high space-time yield.

Preparation of 1,4-diamino-2,3-dicyanoanthraquinone

Solutions of nitrosylsulfuric acid in sulfuric acid are manufactured by reacting nitric acid with sulfur in sulfuric acid or oleum. Less than 0.33 gram atom of sulfur is employed per mole of nitric acid, and after completion of the reaction the free nitric acid still present in the nitrosylsulfuric acid solution is reduced with lactones.

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Eberhard Michaelis