麦草畏合成工艺的研究

The Study on the Preparation of Dicamba

研究了以 2 ,5 -二氯苯酚为主要原料 ,经成盐脱水、羧化反应和O -烷基化反应合成麦草畏的工艺。羧化反应的适宜工艺条件为反应温度 (140～ 145 )℃ ,反应压力 5 .5～ 6 .0MPa ;开发成功了羧化反应催化剂JSY - 1,可使羧化收率由 40 %左右上升到 6 6 .4% ;O -烷基化反应的适宜(CH3 ) 2 SO4配比为 1.0∶2 .1～ 2 .2。本工艺总收率为 5

Dicamba was prepared from 2,5-dichlorophenol in a three-stage process. The optimum condition for carbonization was found to be temp.(140～145)℃,pressure 5.5～6.0MPa. In the presence of catalyst JSY-1, the yield of 3,6-dichlorosalicylic acid was increased evidently from 40% up to 66.4%. In process of methylation,the optimum C 7H 4O 3Cl 2∶(CH 3) 2SO 4 1.0∶2.1～2.2. The yield of dicamba was about 54%.