麦草畏合成新方法研究

目的]建立麦草畏合成的新方法。方法]以2,5-二氯苯酚为起始原料,经酰化、重排、甲基化、卤仿反应4步合成麦草畏(3,6-二氯-2-甲氧基苯甲酸),并采用正交试验设计对中间体3,6-二氯-2-羟基苯乙酮的合成工艺进行优化,考察了反应温度、催化剂与反应物摩尔比及反应时间3个因素对其收率的影响。结果]新工艺3,6-二氯-2-甲氧基苯甲酸总收率为35.0%。中间体合成时,催化剂与反应物摩尔比对反应收率的影响最显著,其次是反应时间和温度;最佳反应条件为:催化剂与反应物摩尔比1.6,反应温度150℃,反应时间1.5 h。结论]为麦草畏的合成研究提供了参考。

A Novel Synthesis of Dicamba

Objective] The aim was to establish a novel synthesis method of Dicamba.Method]From 2,5-dichlorophenol,3,6-dichloro-2methoxy benzoic acid was prepared by the reaction of acylation,rearrangement,methylation and haloform reaction.The synthesis parameters of 3,6-dichloro-2-hydroxyl acetophenone were optimized by orthogonal design experiment,and the influence of temperature,the rate of catalvst / substrate（mol / mol） and reaction time on the yield were investigated.Result] The new method afforded 3,6-dichloro-2-methoxy benzoic acid in 35.0% yield.In the synthesis of 3,6-dichloro-2-hydroxyl acetophenone,the rate of catalvst / substrate was more important than reaction time and temperature,and the reaction proceeded optimally at the rate of 1.6（catalyst / substrate） and at 150 ℃ for 1.5 h.Conclusion] The research result provides reference for study on the synthesis of Dicamba.