物理化学学报 >> 2002, Vol. 18 >> Issue (08): 721-726.doi: 10.3866/PKU.WHXB20020810

研究论文 上一篇    下一篇

CH3NO2和CH3自由基吸氢反应途径和变分速率常数计算

冀永强;冯文林;郝茂荣;李会英   

  1. 北京化工大学理学院,北京　100029
  • 收稿日期:2001-12-04 修回日期:2002-03-19 发布日期:2002-08-15
  • 通讯作者: 冯文林 E-mail:wlfeng@buct.edu.cn

The Reaction Path and Varitional Rate Constant of the Reaction CH3＋CH3NO2→CH4＋CH2NO2

Ji Yong-Qiang;Feng Wen-Lin;Hao Mao-Rong;Li Hui-Ying   

  1. Faculty of Science, Beijing University of Chemical Technology, Beijing　100029
  • Received:2001-12-04 Revised:2002-03-19 Published:2002-08-15
  • Contact: Feng Wen-Lin E-mail:wlfeng@buct.edu.cn

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摘要： 采用MP2(full)/6-311G(d, p)从头算方法,优化了硝基甲烷和甲基自由基吸氢反应的过渡态结构,经QCISD(T)方法进行能量校正,得出该反应的正逆向反应的活化位垒分别是58.21 kJ•mol－1和67.17 kJ•mol－1.沿IRC分析指出该反应是氢转移协同反应,而且在反应途径上存在一个引导反应进行的振动模式,这一反应模式引导反应进行的区间在反应坐标S的-0.9～1.0(amu)1/2bohr之间;在温度为800～2600 K范围内,运用改进的变分过渡态理论(ICVT),计算了该反应的速率常数,并与实验类比所得的速率常数随温度的变化趋势进行了比较.

关键词: 硝基甲烷, 速率常数, 从头算, 变分过渡态理论

Abstract: The geometries of the reactants, transition state, and products of hydrogen transfer reaction CH3＋CH3NO2→CH4＋CH2NO2 have been optimized at the UMP2(full)/6-311G(d, p) level. The forward and reverse reaction potential barriers are 58.21 kJ•mol－1 and 67.17 kJ•mol－1 respectively. Along the IRC, the reaction is a coordinative process and there is a reactivity normal-mode, which lead reaction from reactants to product. The variation of forward reaction rate constant versus temperature, obtained by using the variation transition-state theory (CVT) and ICVT, have identical tendency with experimental values.

Key words: Nitromethane, Rate constant, Ab initio, Variation transition-state theory