Process for separating off 1-amino-4-bromoanthraquinone-2-sulphonic acid

摘要

A process for separating off 1-amino-4-bromoanthraquinone-2-sulphonic acid from the reaction mixture formed by the bromination of 1-aminoanthraquinone-2-sulphonic acid in sulphuric acid, which process comprises adjusting the sulphuric acid concentration of the reaction mixture under the prevailing conditions of temperature and pressure to effect precipitation of 1-amino-4-bromoanthraquinone-2-sulphonic acid as the sulphate and thereafter separating the resultant sulphate precipitate from the reaction mixture.