以3-（二甲基胺）丙烯腈和二氯乙酰氯为起始原料，经加成消除反应和环合反应两步管道连续化反应合成了二氟吡唑甲酰胺类杀菌剂的重要中间体3-（二氯甲基）-1-甲基-4-氰基-1H-吡唑，并对反应工艺进行了优化。最佳合成工艺为：加成消除反应温度0℃，反应停留时间30 s；环合反应温度0℃，反应停留时间90 s。在最佳工艺条件下，两步反应总收率93.5%，产品气相色谱含量97.2%，异构体小于0.1%，反应收率高于釜式反应5%。

3-Dichloromethyl-1-methyl-4-cyanide-1H-pyrazol is the key intermediate for synthesizing difluoro-pyrazole carboxamide series bactericides.It is prepared via two-step pipeline continuous reaction including addition-elimination reaction and cyclization reaction,with 3-(dimethylamino)acrylnitrile and dichloroacetyl chloride as raw materials.The reaction process is optimized to obtain the optimum reaction conditions as follows:addition-elimination reaction for 30 s at 0℃ and cyclization reaction for 90 s at 0℃.Under these optimal process conditions,the total yield after two-step reactions reaches 93.5%,the gas chromatograph content of the product is 97.2%,the content of isomers is less than 0.1% isomer and the reaction yield is 5% higher than that of the kettle type reaction.