Bayer Aktiengesellschaft

Norbert Majer

Hans-Samuel Bien

Gunther Boehmke

Reinold Schmitz

Helmut Judat

Bernd Thelen

Armin Lieberam

In a process for the preparation of monoaroylated 1,4-diaminoanthraquinone by contacting 1,4-diaminoanthraquinone with an aroyl halide in the presence of an organic solvent and an acid-binding agent and in the presence of a small amount of water at an elevated temperature, the improvement which comprises carrying out the process in the presence of a tertiary aliphatic aminoalcohol and/or quaternary ammonium compound and commencing the reaction at a temperature of 20.degree. to 50.degree. C. and, after addition of the aroyl halide, completing the reaction at a temperature of 80.degree. to 130.degree. C.

Process for the preparation of monoaroylated 1,4-diaminoanthraquinones

A process for concentrating at least one of (a) individual halogenoanthraquinones (b) binary mixtures of di-halogenoanthraquinones and (c) binary mixtures of trihalogenoanthraquinones, from a mixture containing at least two halogenoanthraquinones, comprising subjecting said mixture containing at least two halogenoanthraquinones to fractional vacuum distillation in a heated rectification column having an efficiency corresponding to about 20 to 50 theoretical stages with an absolute pressure at the top of about 0.5 to 50 mm Hg and a reflux to take-off ratio of about 5/1 to 50/1. Advantageously, distillation is carried out continuously in a cascade of columns, the products withdrawn from the top of the first column being 2-chloroanthraquinone in the first stage, 1-chloroanthraquinone in the second stage, 1,6- and 1,7-dichloroanthraquinone in the third stage and 1,5- and 1,8-dichloroanthraquinone in the fourth stage, 1,4,5- and 1,4,6-trichloroanthraquinone being obtained in the sump of the 4th stage and being separated therefrom by film evaporation. The mixture of halogenoanthraquinones is advantageously a mixture of chloroanthraquinones such as is obtained by the action of chlorine, chloric acid or a chlorate on various industrial mixtures of nitro- or sulfo-anthraquinones.

Process for concentrating halogenoanthraquinones

A process for the preparation of a chloroanthraquinone or a bromoanthraquinone comprising treating a molten mixture of at least one nitroanthraquinone and diluent with halogen at a temperature of about 180 to 300.degree. C, the diluent being present in at least about 10% by weight of the mixture and comprising at least one chloroanthraquinone or bromoanthraquinone. The diluent may correspond to the halogenoanthraquinone obtained from the nitroanthraquinone by replacement of the nitro group. A portion of the product can be recycled as diluent for further reaction.

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Schildgen, Germany

Norbert Majer