反应详情

The suspension thus obtained [1.20 moles of 2-amino- naphthalene-6(8)-sulfonic acid, pH 0.8] is brought at 70° C. with 245 parts of 33% strength sodium hydroxide solution to pH 7.0 and has added to it 155 parts of acetic anhydride (1.5 moles) in the course of 15 minutes, during which the pH decreases to 3.0 and the Bronner acid goes into solution. The acetylation is quantitative. Salting out gives 289 parts of 2-acetaminonaphthalene-6-sulfonic acid calculated at 100% (1.09 moles which corresponds to 73% of theory based on 2hydroxynaphthalene) having a purity of about 70% (diazotization value after hydrolysis, molecular weight 265.3).