2-甲基-5-硝基咪唑合成工艺改进

在 2甲基咪唑用硝酸和硫酸进行消化的过程中 ,通过加入 5%尿素和 50 %硫酸铵作为助剂 ,即消除了原工艺反应过程中有大量氧化氮毒气冒出的现象 ,又提高了收率。在硝化过程中 ,将通常的硫酸和硝酸作为混酸一起加入的方法改为先将硝酸和原料混合 ,然后滴加浓硫酸。改善了反应的再现性和易操作性。在综合优化的条件下 ,收率提高到 90 .7% ,含量为 99.5%。

THE PROCESS IMPROVEMENT FOR SYNTHESIZING 2METHYL5NITROIMIDAZOLE

The process for synthesizing 2methyl5nitroimidazole was improved by adding 5% urea and 50% ammonium sulphate to the reaction mixture. Nitrogen oxide was decomposed and yield was raised. In common process, nitric acid and sulfuric acid were added as mixed acid in the nitration process. In the improved process, nitric acid and 2methylimidazole were mixed first and concentrated sulfuric acid was then added, which was more easy for operation and for controlling reaction temperature. Under optimum conditions, the yield of 2methyl5nitroimidazole from 2methylimidazole reached 90.7% and purity was over 99.5%.