The bromination mechanism of l-aminoanthraquinone-2,4-disulfonic acid in sulfuric acid

摘要

l-Amino-4-bromoanthraquinone-2-sulfonic acid (bromoamine acid) is an important intermediate for dyes.1-Aminoanthraquinone-2,4-disulfonic acid is the major impurity when 1-aminoanthraquinone is sulfonated in oleum to synthesize bromoamine acid.The mechanism of bromination of l-aminoanthraquinone-2,4-disulfonic acid in sulfuric acid has been studied.It is proved that l-aminoanthraquinone-2,4-disulfonic acid undergoes de-sulfonation first to form l-aminoanthraquinone-2-sulfonic acid,and then bromination to form bromoamine acid.Based on this mechanism,a new optimal process for the synthesis of bromoamine acid is developed.In this way,bromoamine acid is afforded in high yield and good quality.