物理化学学报 >> 1999, Vol. 15 >> Issue (10): 872-876.doi: 10.3866/PKU.WHXB19991003

研究论文 上一篇    下一篇

2-溴乙酸气相热消除反应的机理探讨

刘丹, 陈光巨, 刘若庄, 傅孝愿   

  1. 北京师范大学化学系,北京 100875
  • 收稿日期:1998-12-11 修回日期:1999-01-27 发布日期:1999-10-15
  • 通讯作者: 刘若庄

Exploration of the Mechanism of 2-bromoacetic Acid Gas-phase Elimination Process

Liu Dan, Chen Guang-Ju, Liu Ruo-Zhuang, Fu Xiao-Yuan   

  1. Department of Chemistry,Beijing Normal University,Beijing 100875
  • Received:1998-12-11 Revised:1999-01-27 Published:1999-10-15
  • Contact: Liu Ruo-Zhuang

摘要:

分别利用密度泛函、从头算分子轨道方法及半经验分子轨道AM 1法对 2-溴乙酸气相热消除反应的机理进行了理论研究 .结果表明 ,虽然用三种不同的方法得到的结果有一定差异 (如反应势能面上各驻点的几何构型、反应的活化能 ) ,但研究得到的反应机理是一致的 ,即反应分两步进行 .其中 ,具有五元环过渡态的第一步反应为速控步骤 ,与实验工作者所建议的机理相符 .

关键词: 2-溴乙酸, 气相热消除反应, 从头算分子轨道法, 密度泛函法, 反应机理

Abstract:

The gas phase elimination processes of 2-bromoacetic acid is theoretically studied by using ab initio MO method with basis set 3 21G,density functional method (B3LYP) with basis set lanl2dz, and the memi-empirical molecular orbital AM1 method. Although there are differences among the results calculated by using the three methods, such as the geometries of the transition states or intermediates, heights of energy barriers, the mechanism of the elimination reaction is yet found to be the same. The reaction studied is found to be a stepwise reaction, in which the first step, with a 5-membered ring transition state is the rate-determining one, which is in agreement with the mechanism, suggested by experimentalist.

Key words: 2-bromoacetic acid, Gas-phsae elimination reaction, Ab initio molecular orbital method, Density functional theory method(B3LYP/lan12dz)