乙酰苯胺制备实验的改进及拓展  

Improvement and Expansion of the Acetanilide Preparation Experiment

作　　者：陈诚 党佳兴 王心怡 刘妍岑 高向静 Cheng Chen;Jiaxing Dang;Xinyi Wang;Yancen Liu;Xiangjing Gao(China Fire and Rescue Institute,Beijing 102202,China)

机构地区：[1]中国消防救援学院,北京102202

出　　处：《大学化学》2023年第4期44-52,共9页University Chemistry

基　　金：中国消防救援学院基础部教学改革项目;中国消防救援学院基础部科研项目。

摘　　要：对现行本科实验教学中常见的乙酰苯胺制备实验进行改进。改进后的实验仍以乙酸和苯胺为原料,选用氯化亚锡代替原实验中的锌粉(现已列为易制爆管制品)作为还原剂防止苯胺氧化。同时加入对甲苯磺酸作为催化剂。使用固定床脱水回流装置代替经典分馏装置,以填充式精馏柱作为固定床,固定床从下至上依次填充玻璃弹簧填料、4A分子筛和变色硅胶。反应时,蒸出的水和乙酸经玻璃弹簧填料分馏,乙酸回流至反应烧瓶,水被4A分子筛和变色硅胶吸收。变色硅胶吸水后颜色由橙色变为绿色,可直观判断反应进程。改进后的实验无需使用管制试剂、反应时间缩短、现象丰富,更适合本科教学。此外,本文还设计了两个拓展实验,可根据教学需要选用,一是利用产物乙酰苯胺制备4-乙酰氨基乙酸苯酯;二是用恒pH滴定法测定废液中未反应的苯胺含量。拓展实验涉及萃取、柱层析、滴定、数据处理和分析等内容,能够有效提升学生的综合实验能力。In this study,the preparation method of acetanilide,which is commonly taught in current undergraduate experimental courses,is improved.While acetic acid and aniline were used as starting materials in the improved method,zinc powder was replaced with stannous chloride(which is listed as an easy-to-make tube explosion product)as a reducing agent to prevent aniline from being oxidized.At the same time,p-toluene sulfonic acid was added as a catalyst.A fixed bed dehydration reflux device was used instead of the classical fractionation device,and a packed rectification column was used as the fixed bed.The column was filled with glass spring packing,a 4A molecular sieve and color-changing silica gel from bottom to top in turn.During the reaction,distilled water and acetic acid were fractionated by the glass spring packing,acetic acid was refluxed to the reaction flask,and water was absorbed by the 4A molecular sieve and color-changing silica gel.After absorbing water,the color of the silica gel changed from orange to green,which is a clear indication of the reaction process.The improved experiment does not require control reagents,the reaction time is shortened,and the phenomenon is rich,making it more suitable for undergraduate teaching.In addition,two extended experiments were designed in this study,which can be selected according to the needs of teaching.One is to prepare phenyl 4-acetylaminoacetate from acetanilide;the second is to determine the unreacted aniline content in the waste liquid by constant pH titration.This modified experimental procedure employs extraction,column chromatography,titration,and data processing and analysis,which can effectively improve the comprehensive experimental ability of the students.

关 键 词：乙酰苯胺 可视化 固定床脱水回流装置 乙酰氧基化反应 恒pH滴定 

分 类 号：G64[文化科学—高等教育学] O6[文化科学—教育学]