Bayer Aktiengesellschaft

Helmuth Kritzler

Walter Bohm

Wolfgang Kiel

Udo Birkenstock

Ulrich Kappler

Lutz Neumann

Hans D Winkelmann

Halogenated aromatic amines are rendered colorstable by distillation and/or storing in equipment made of a rustproof material such as a Cr/Ni/Mo steel, tin, zinc, enamel, glass and/or ceramic material.

Halogenated aromatic amines which are stable in color, and a process for

An improvement in a process for the preparation of chlorinated aromatic amines by hydrogenation of the corresponding chlorinated nitro-aromatic compounds in the presence of a noble metal catalyst on a carbon support and in the presence of a sulfur compound, the improvement residing in that the sulfur compound is a thio-ether. Preferably the reaction is carried out in a weakly basic medium.

Chlorinated aromatic amines

Aromatic diamines having the formula ##STR1## wherein R is alkyl or alkoxy having up to 6 carbon atoms are prepared by treating dinitro compounds having the formula ##STR2## wherein R is as previously defined, with hydrogen in the presence of one or more noble metals from the platinum or palladium groups as catalysts, optionally on catalyst supports, and in the presence of optionally substituted aniline as the solvent. The catalyst is generally used in amounts of 0.0005 to 0.1% by weight based on the amount of dinitro compound employed.

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Odenthal, Germany

Helmuth Kritzler