生物催化概念下苯佐卡因合成实验的改进

Improvement of the Synthetic Experiment of Benzocaine Based on Biocatalysis

对氨基苯甲酸乙酯(苯佐卡因)的制备是大学有机化学实验教学中的重要内容之一。传统的实验方案是将对硝基苯甲酸在浓硫酸的作用下与乙醇发生酯化反应,然后以铁粉和盐酸为还原条件,将中间产物对硝基苯甲酸乙酯转化成苯佐卡因。本文设计在酯化和硝基还原的步骤中,分别引入超声辅助和生物酶催化的合成手段,使反应可以在温和、环境友好的条件下进行。该方案通过在本科教学实验中引入生物催化的概念,成功避免了强腐蚀性硫酸或盐酸的使用,有效减少了污染性废弃物的产生,在实验安全和绿色合成方面,具有明显的优势。

The preparation of benzocaine is an important organic experiment in teaching laboratory for college students.Currently,the general experimental plan is esterifying para-nitrobenzoic acid with ethanol in the presence of concentrated sulfuric acid,following by the reduction of ethyl nitrobenzoate with iron powder and hydrochloric acid,to afford the benzocaine product.In this paper,the technologies of ultrasonic assisted synthesis and biocatalysis were introduced into the steps of esterification and the reduction of nitro group,respectively,which allowed the reactions could be conducted under mild and environmentally friendly conditions.This new experimental program successfully avoided the use of highly corrosive sulfuric acid or hydrochloric acid,as well as the generation environmental unfriendly by-products,by applying the concept of biocatalysis into the fundamentally experimental training,leading to a teaching experiment with distinguished advantages on operational safety and green synthesis.