硝化法制备对氨基间硝基苯磺酸的研究

Study on synthesis of p-amino-m-nitro-benzenesulfonic acid by nitration method

以对氨基苯磺酸为起始原料 ,经过乙酰化、硝化、水解三步来制备标题物。通过正交试验找出了酰化的最佳反应条件为 :对氨基苯磺酸与乙酐的摩尔比为 1∶1.0 5 ,反应总时间为 1.5h ,反应温度为 2 5℃ ,酰化介质为酰化反应前用碳酸钠及水将对氨基苯磺酸完全溶解 ,使混合液 pH值为 5～ 6 ,反应过程中不再补加碳酸钠 ,其酰化转化率可达 99.6 % ,酰化产物的固体收率可达 96 .0 % ;硝化反应的最佳条件为 :硝化剂用 90 .2 %的硝酸 ,对乙酰氨基苯磺酸与硝化剂的摩尔比为 1∶1.0 5 ,反应温度为 10℃ ,浓硫酸与对乙酰氨基苯磺酸的摩尔比为 8.3∶1,其硝化转化率可达 96 .0 % ,硝化反应的选择性好 ,对氨基邻硝基苯磺酸的量不到 1.0 %。

The reaction was studied about synthesis of the title compound from p amino benzenesulfonic acid as raw material through acetylation, nitration and hydrolyzation. The optimum reaction conditions of acetylation were obtained by orthogonal experiment as follows: molar ratio of p amino benzenesulfonic acid to acetic anhydride was 1∶1.05, reaction time 1.5 h, reaction temperature 25 ℃,acetylation medium was that p amino benzenesulfonic acid was dissolved with sodium carbonate and water ,and pH value of this solution was kept 5～6 before acetylation,sodium carbonate wasn't added again, the conversion ratio of acetylation reaction was 99.6%, and yield of solid acetylated product was 96.0%.The best reaction conditions of nitration were as follows: nitrating agent was 90.2% nitric acid, molar ratio of p acetamino benzenesulfonic acid to nitrating agent was 1∶1.05, reaction temperature was 10 ℃, molar ratio of concentrated sulfuric acid to p acetamino benzenesulfonic acid was 8.3∶1, and the conversion ratio of nitration reaction reached 96.0%,the selectivity of nitration was good,the amount of p amino o nitro benzenesulfonic acid was less than 1.0%.