| abstract |
A process for the preparation of 4,4'-diamino-1,1'-dianthrimides, characterized in that a mixture of an optionally substituted 1,4-diaminoanthraquinone and an optionally substituted 1-aminoanthraquinone in 30-60% H 2 S0 4 , preferably 40-60% H 2 SO 4 , oxidized with peroxomonosulfuric acid or peroxodisulfuric acid, which are preferably used in the form of the alkali or ammonium salts, and the batch is then reduced. |