噻虫嗪绿色合成工艺

Green Synthesis Process of Thiamethoxam

以2-氯-5-氯甲基噻唑与3-甲基-4-硝基亚胺基四氢-1,3,5-噁二嗪为原料,通过双分子亲核取代反应得到噻虫嗪,产品采用HPLC、IR、^(1)H-NMR等手段进行了分析与表征。通过改进生产工艺,优选工艺条件为:DMF作溶剂,K_(2)CO_(3)作缚酸剂,n(3-甲基-4-硝基亚胺四氢-1,3,5-噁二嗪)∶n(2-氯-5氯甲基噻唑)∶n(K_(2)CO_(3))为1.1∶1.0∶1.2,反应温度35℃,甲醇作重结晶溶剂,噻虫嗪产品的外标含量高于98%,收率达80%。该工艺路线有效地降低了废水排放量,产品收率高,适用于工业化生产。

Using 2-chloro-5-chloromethylthiazole and 3-methyl-4-nitroimino-dihydro-1,3,5-oxadiazine as materials,thiamethoxam is synthesized by bimolecular nucleophilic substitution reaction.The product is analyzed and characterized by HPLC,IR and^(1)H-NMR.By improving the production process,the optimized process conditions are as follows,DMF as solvent,K_(2)CO_(3)as acid binding agent,the molar ratio of raw materials 3-methyl-4-nitroimine tetrahydro-1,3,5-oxadiazine,2-chloro-5-chloromethylthiazole and K_(2)CO_(3)is 1.1∶1.0∶1.2,the reaction temperature is 35℃,methanol as recrystallization solvent.The external standard content of thiamethoxam product is more than 98%and the yield is 80%.The process route can effectively reduce the discharge of wastewater,and the product yield is high,which is suitable for industrial production.