Guo Jiapeng, Su Weike, Su An
Key Laboratory of Pharmaceutical Engineering of Zhejiang Province, Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Chemistry-Synthesis Technology of Zhejiang Province, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China.
Beilstein J Org Chem. 2024 Sep 24;20:2408-2420. doi: 10.3762/bjoc.20.205. eCollection 2024.
Nitration of -methylisouronium sulfate under mixed acid conditions gives -methyl--nitroisourea, a key intermediate of neonicotinoid insecticides with high application value. The reaction is a fast and highly exothermic process with a high mass transfer resistance, making its control difficult and risky. In this paper, a homogeneous continuous flow microreactor system was developed for the nitration of -methylisouronium sulfate under high concentrations of mixed acids, with a homemade static mixer eliminating the mass transfer resistance. In addition, the kinetic modeling of this reaction was performed based on the theory of NO attack, with the activation energy and pre-exponential factor determined. Finally, based on the response surface generated by the kinetic model, the reaction was optimized with a conversion of 87.4% under a sulfuric acid mass fraction of 94%, initial reactant concentration of 0.5 mol/L, reaction temperature of 40 °C, molar ratio of reactants at 4.4:1, and a residence time of 12.36 minutes.
在混酸条件下对硫酸 - 甲基异脲鎓进行硝化反应可得到 - 甲基 - - 硝基异脲，它是具有高应用价值的新烟碱类杀虫剂的关键中间体。该反应是一个快速且高度放热的过程，传质阻力大，导致其控制困难且存在风险。本文开发了一种用于在高浓度混酸条件下对硫酸 - 甲基异脲鎓进行硝化的均相连续流微反应器系统，利用自制的静态混合器消除了传质阻力。此外，基于NO 攻击理论对该反应进行了动力学建模，确定了活化能和指前因子。最后，基于动力学模型生成的响应面，在硫酸质量分数为94%、初始反应物浓度为0.5 mol/L、反应温度为40℃、反应物摩尔比为4.4:1以及停留时间为12.36分钟的条件下对反应进行了优化，转化率达到87.4%。
