3-溴-5-氯苯甲酸的合成

SYNTHESIS OF 3-BROMO-5-CHLOROBENZOICACID

以2-氨基-5-氯苯甲酸为原料,通过溴化、重氮化及重氮盐转化反应得到3-溴-5-氯苯甲酸,反应总收率为41.7%。分别考察了反应时间、投料比及反应温度对溴化反应及重氮化反应的影响。溴化反应适宜的条件为:反应温度45℃,n(2-氨基-5氯-苯甲酸)∶n(N-溴代丁二酰亚胺)=1∶1,反应时间60min;重氮化反应适宜条件为:反应温度5℃,n(2-氨基-3-溴-5-氯苯甲酸)∶n(NaNO_2)为1∶1.2,保温时间30min。

3-Bromo-5-chlorobenzoicacid was synthesized using 2-amino-5-chlorobenzoic acid as raw material by the reactions of bromination and diazotization diazonium salt conversion.The total yield of3-bromo-5-chlorobenzoicacid was 41.7%.The influence of amount of reaction temperature,the ratio of raw material,the time of reaction on the yields of the reactions of bromination and diazotization were investigated.The corresponding optimal reaction of bromination and diazotization as follows：reaction temperature of bromination was 45 ℃,（2-amino-5-chlorobenzoic acid）∶n（NBS）=1∶1,reaction time 60 min;reaction temperature of diazotization was 5 ℃,（2-amino-3-bromo-5-chlorobenzoic acid）∶n（NaNO_2）=1∶1.2,reaction time 30 min.