2-氯-5-氯甲基吡啶生产工艺的改进

2-氯-5-氯甲基吡啶是吡虫啉等农药的关键中间体。工业生产中采用直接环合法生产存在甲苯用量大、不易回收、精馏过程产品损失等问题。通过优化环合反应,用结晶法提纯产品,使环合反应收率达到77.91%,结晶提纯率大于83%,产品纯度达到90%以上,能够满足工业生产要求,且减少了甲苯的使用和精馏废渣的排放。

Innovation of technics for producing 2-chloro-5-chloromethylpyridine

2-Chloro-5-chloromethylpyridine is the crucial intermediate of pesticides such as Imidacloprid, which is produced through the direct cyclization of 2-chloro-2-chloromethyl-4-cyanobutyraldehyde and phosphorus oxychloride.This route is widely used in industries,but toluene used as solvent lead the difficulty of recycling, and the product decomposed in distillation.So the conditions of cyclization were optimized and the crystallization was used to purify the product.Under the improved conditions,the yield of c...