醇酸热消除反应的理论研究

• 作 者: 宋维平 何绍仁 傅孝愿
• 机 构: 北京师范大学化学系!北京,100875,北京师范大学化学系!北京,100875,北京师范大学化学系!北京,100875
• 出 处: 北京师范大学学报(自然科学版)
• 发表日期: 1997年02期
• 关键词: 消除反应 取代基效应 过渡态 反应机理 醇酸 分子轨道 热消除 五元环 理论研究 几何构型

采用AMI半经验分子轨道方法，辅以Berny梯度优化方法，对醇酸（即α一羟基酸）在气相中的热消除反应进行了研究．计算与实验结果对比得到如下结论：（1）反应是2步过程，通过2个过渡态和1个中间体得到产物．第1步通过1个五元环过渡态，第2步通过1个三元环过渡态．（2）该反应的取代基效应表明，烷基的斥电子效应有利于醇酸的热消除过程，取代基的加入有利于反应的进行．

The AMI semi-empirical molecular orbital method and the Berny gradient optimization method were used to study the thermal elimination reaction of alkyd (ie alpha-hydroxy acid) in the gas phase. Comparing the calculation results with the experimental results, the following conclusions are obtained: (1) The reaction is a two-step process, and the product is obtained through two transition states and one intermediate. Step 1 through a five-membered ring transition state, the second step through a three-ring transition state. (2) The substituent effect of this reaction shows that the electron-withdrawing effect of alkyl is favorable to the heat elimination of alkyd, and the substitution of substituents is in favor of the reaction.