农药中间体2-氯-5-三氟甲基吡啶的合成

Synthesis of pesticide intermediate 2-chloro-5-trifluoromethylpyridine

[目的]以2,3-二氯-5-三氟甲基吡啶生产过程中过度氯代产生的副产物2,3,6-三氯-5-三氟甲基吡啶为原料制备2-氯-5-三氟甲基吡啶。[方法]以2,3,6-三氯-5-三氟甲基吡啶为原料,经过水解、加氢脱氯、氯代反应制备2-氯-5-三氟甲基吡啶,并进行工艺优化。[结果]最优反应条件下,工艺总收率57.7%,产品纯度为99.3%。[结论]该工艺开发出一条新的制备2-氯-5-三氟甲基吡啶的路线,变废为宝,原料成本低,适合工业化生产。

[Aims]To synthesize 2-chloro-5-trifluoromethylpyridine with hyperchlorination byproduct 2,3,6-trichloro-5-trifluoromethylpyridine in the synthesis of 2,3-dichloro-5-trifluoromethyl pyridine as starting material.[Methods]2,3,6-Trichloro-5-trifluoromethylpyridine was used as starting material to synthesize 2-chloro-5-trifluoromethylpyridine via hydrolysis,hydrodechlorination,and chlorination reactions.[Results]Under the best reaction conditions,the total process yield was 57.7%,and the product purity was 99.3%.[Conclusions]A new technique for producing 2-chloro-5-trifluoromethylpyridine was developed,and the process is inexpensive and suitable for industrial manufacturing.Most significantly,it turns trash into treasure.