酯化、水解两步法合成苯甲醇的工艺优化

以氯化苄和甲酸钠为原料,采用十六烷基三甲基溴化铵作为相转移催化剂,通过酯化和水解两步法合成苯甲醇。分别考察原料摩尔比、酯化反应温度、催化剂用量、初始水量等因素对酯化反应的影响以及水解反应温度、加碱方式、初始水量等因素对水解反应的影响。结果表明:适宜的氯化苄与甲酸钠摩尔比为1∶1,酯化反应温度为110～115℃,催化剂用量为2%(以氯化苄为基准),初始水量与氯化苄的体积比为1∶1;适宜的水解反应温度为100℃,加碱速率为5 mL/h,酯化液与水的体积比为1∶1。在最优工艺条件下,苯甲醇的收率可达98%。

Optimization of two-step synthesis of benzyl alcohol by esterification and hydrolysis

Benzyl alcohol was synthesized by the esterification and hydrolysis of benzyl chloride and sodium formate with phase-transfer catalyst.The effects of the initial molar-ratio of benzyl chloride to sodium formate,the esterification temperature,the amount of the catalyst,and the volume-ratio of benzyl chloride to water on the esterification process;and the effects of hydrolysis temperature,the pattern of adding the alkali,and the initial amount of water on the hydrolysis process were investigated.Results showed that the suitable process parameters were as follows: molar ratio of benzyl chloride to sodium formate of 1∶1,esterification temperature of 110~115 ℃,amount of catalyst of 2% of benzyl chloride,volume ratio of benzyl chloride to water of 1∶1,hydrolysis temperature of 100 ℃,feeding rate of alkali of 5 mL/h,and volume ratio of esterification liquid to water of 1∶1.Under the conditions,the yield of benzyl alcohol could reach 98%.