微反应器中合成1-甲基-4,5-二硝基咪唑的连续流工艺

Continuous process for preparation of 1-methyl-4,5-dinitroimidazole in microreactor

在以内交叉多层式微反应器为核心的微反应体系中进行1-甲基-4,5-二硝基咪唑(4,5-MDNI)的合成研究。以甲基咪唑和硝硫混酸为原料,通过对层流流体中分子质量分布的掌控,加强该反应的传质传热过程,使4,5-MDNI的产率提升至87%。考察了硝化剂与原料的摩尔比、反应温度和体积流速对反应转化率的影响,实现了发烟硝酸及发烟硫酸高危性试剂的安全使用,且较常规反应条件下用量显著减少;在100℃精确的温度控制下,单个微反应器以18 mL/h的总体积流速可连续操作高效合成4,5-MDNI,单位时间及单位体积的生产能力显著提高,具有广阔的工业应用前景。

1-Methyl-4,5-dinitroimidazole（ 4,5-MDNI） is synthesized in the microreaction system with internal intersection multi-layer microreactor as a core.The yield of 4,5-MDNI is increased to 87% through controlling molecular weight distribution in the laminar flow fluid to enhance the mass and heat transfer processes in the reaction when raw materials 1-methylimidazole and nitric-sulfuric mixed acid are mixed in the microreactor. The effects of the molar ratio between nitration agent and raw material,reaction temperature and volume flow on the reaction conversion ratio are evaluated.The safe usages of fuming nitric acid and fuming sulfuric acid are achieved,and the consumptions are significantly reduced compared with the conventional reaction conditions. The continuous and efficient synthesis of 4,5-MDNI can be achieved when the temperature is controlled accurately at 100℃ and the total volume flow is 18 mL·h-1 in a single microreactor.The production capacity of unit time and unit volume is significantly improved,and the prospect of industrial application will be broad.