甲基橙制备方法的改进

Improvement of Methyl Orange Preparation

实验室中甲基橙的经典制备方法是低温三步法,这种方法特点是反应条件难以控制、需要很长时间、收率较低等。常温一步法制备甲基橙,通过实验,结果表明:室温下在烧杯中一次性加入无水对氨基苯磺酸、N,N-二甲基苯胺和水,搅拌溶解,在冷水中滴加亚硝酸钠,搅拌反应25 min。此方法收率可达到约87%,高于经典低温三步法。

The classical method of preparation methyl orange in the lab was three- step method at low temperature,which was difficult to control experimental condition,long reaction time and low yield. At room temperature,methyl orange can be prepared by one- step method. It was found that anhydrous p- aminobenzenesulfonic acid,N,N-dimethylaniline and water were added into the beaker at room temperature,while stirring and dissolving,sodium nitrite was slowly dropping at cold water,and the reaction should continue 25 min with stirring after dropping was finished,and the yield could reach about 87%. The yield was higher than that of the classical three- step method under low temperature