Synthesis of 6-Acetamino-4-hydroxy-2-naphthlenesulfonic Acid

Dye intermediate 6-acetamino-4-hydroxy-2-naphthalenesulfonic acid was synthesized from 6-amino-4-hydroxy-2-naphthalenesulfonic acid(γ-acid) and acetic anhydride.The product was characterized by FT-IR and its chemical structure was confirmed.Three factors including the amount of water,the amount of acetic anhydride and the reaction temperature which influence on the reaction were investigated by orthogonal experiments.The results showed that the optimal conditions of synthesis reaction were as follows: the water 20 g,γ-acid∶ acetic anhydride=1∶ 1.5,the reaction temperature 70 ℃;the highest acylation yield was 97.17% in this condition.