氟虫腈所含主要微量杂质的相关研究

目的]分析氟虫腈产品所含的主要微量杂质。方法]利用MS、NMR、IR等光谱分析技术对用拜尔公司工艺生产的氟虫腈产品所含的主要微量杂质进行初步分析和结构鉴定。结果]氟虫腈成品中所含的主要杂质是(±)-5-氨基-1-(2,6-二氯-α,α,α-三氟-p-甲苯基-)-4-三氟甲基磺酰基-3-氰基吡唑。追溯杂质的来源,发现该杂质和氟虫腈最后一步生产工艺的氧化反应有关。不加催化剂,仅用双氧水则氧化反应不完全,导致成品中未完全反应的(±)-5-氨基-1-(2,6-二氯-α,α,α-三氟-p-甲苯基-)-4-三氟甲硫基-3-氰基吡唑含量增加。采用间氯过氧化苯甲酸这种氧化剂成本太高。采用双氧水/三氟乙酸这种混合氧化剂同时加入硼酸作抗腐蚀剂,效果较好。结论]该研究为氟虫腈实际生产工艺的改良提供了指导意见。

Relative Study on the Main Trace Impurity in Fipronil

Objective] The aim was to analyze main trace impurity contained in fipronil.Method] The main trace impurity contained in fipronil produced by Bayer production technology were preliminary analyzed by spectrum analysis techniques such as mass spectrometry(MS),nuclear magnetic resonance(NMR) and infrared spectrum(IR) and its structure was identified.Result] The main trace impurity contained in fipronil was(±)-5-amino-1-(2,6-α,α,α-fluoro-p-methylphenyl-)-4-trifluoromethylsulfonyloxy-3-cynaopyrazole.Tracing back to the origin of the impurity,it found that the impurity was related with oxidation in the last step of fipronil production.Without adding catalyst,oxidation was not complete only using hydrogen peroxide,which increased the content of incompletely reacted(±)-5-amino-1-(2,6-α,α,α-fluoro-p-methylphenyl-)-4-trifluoromethylsulfonyloxy-3-cynaopyrazole in finished product.The cost of using oxidant m-chloroperoxybenzoic acid was too high.The effect of using hydrogen peroxide/trifluoroacetic as mixed oxidant and boracic acid as anticausticon was better.Conclusion] The research provided guiding opinions for improvement of actual production of fipronil.