物理化学学报 >> 2011, Vol. 27 >> Issue (02): 337-342.doi: 10.3866/PKU.WHXB20110201

理论与计算化学 上一篇    下一篇

CH3OCF2CF2OCH3+Cl的反应机理及动力学性质

崔凤超, 于洪波, 王钦, 叶宛丽, 刘靖尧   

  1. 吉林大学理论化学研究所, 理论化学计算国家重点实验室, 长春 130023
  • 收稿日期:2010-09-27 修回日期:2010-11-12 发布日期:2011-01-25
  • 通讯作者: 刘靖尧 E-mail:ljy121@jlu.edu.cn
  • 基金资助:

    国家自然科学基金(20333050, 20303007, 20973077)和教育部新世纪优秀人才支持计划(NCET)资助项目

Mechanism and Kinetics of the CH3OCF2CF2OCH3+Cl Reaction

CUI Feng-Chao, YU Hong-Bo, WANG Qin, YE Wan-Li, LIU Jing-Yao   

  1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, P. R. China
  • Received:2010-09-27 Revised:2010-11-12 Published:2011-01-25
  • Contact: LIU Jing-Yao E-mail:ljy121@jlu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20333050, 20303007, 20973077) and Program for New Century Excellent Talents in University, China (NCET).

摘要:

利用密度泛函理论直接动力学方法研究了反应CH3OCF2CF2OCH3+Cl的微观机理和动力学性质. 在BB1K/6-31+G(d,p)水平上获得了反应的势能面信息, 计算中考虑了反应物CH3OCF2CF2OCH3两个稳定构象(SC1和SC2)的氢提取通道和取代反应通道. 利用改进的正则变分过渡态理论结合小曲率隧道效应(ICVT/SCT)计算了各氢提取通道的速率常数, 进而根据Boltzmann配分函数得到总包反应速率常数(kT)以及每个构象对总反应的贡献. 结果表明296 K温度下计算的kT(ICVT/SCT)值与已有实验值符合得很好. 由于缺乏其他温度速率常数的实验数据, 我们预测了该反应在200-2000 K温度区间内反应速率常数的三参数表达式: kT=0.40×10-14T1.05exp(-206.16/T).

关键词: 密度泛函理论, 直接动力学, 速率常数, 改进的正则变分过渡态理论, CH3OCF2CF2OCH3

Abstract:

A direct density functional theory dynamics method was used to determine the mechanism and kinetics of the CH3OCF2CF2OCH3+Cl reaction. Potential energy surface information was obtained at the BB1K/6-31+G(d,p) level. The hydrogen abstraction channels and displacement processes of the two stable conformers (SC1 and SC2) of CH3OCF2CF2OCH3 were taken into consideration. Theoretical rate constants of the individual H-abstraction channels (one from SC1 and two from SC2) were calculated by improved canonical variational transition state theory (ICVT) with a small-curvature tunneling (SCT) correction. The overall rate constant (kT) was obtained by considering the weight factor of each conformer from the Boltzmann distribution function and the contribution of the two conformers to the whole reaction was discussed. The calculated kT(ICVT/SCT) at 296 K agrees well with the experimental value. Since experimental data were lacking for other temperatures, a three-parameter rate constant temperature expression for the total reaction within 200-2000 K was fitted to: kT=0.40×10-14T1.05exp(-206.16/T).

Key words: Density functional theory, Direct dynamics, Rate constant, Improved canonical variational transition state theory, CH3OCF2CF2OCH3

MSC2000: 

  • O641