化学学报 ›› 2001, Vol. 59 ›› Issue (9): 1413-1417. 上一篇    下一篇

研究论文

CH2O+H→CHO+H2反应途径和变分速率常数计算研究

李会英;冯文林;冀永强;徐振峰   

  1. 北京化工大学理学院
  • 发布日期:2001-09-15

Theoretical study on the reaction path and variational rate constant of the hydrogen abstraction reaction CH2O+H→CHO+H2

Li Huiying;Feng Wenlin;Ji Yongqiang;Xu Zhenfeng   

  • Published:2001-09-15

采用QCISD/6-311G^** 从头算方法,优化了吸氢反应CH2O+H→CHO+H2的反应物、过渡态、产物几何结构,得出该反应的正、逆反应活化位垒分别是35.4kJ/mol和98.8kJ/mol。沿IRC分析指出该反应是一个C—H键断裂和H—H键生成协同进行的反应,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—0.4~0.55(amu)^1/2之间。在300~3200K温度范围内,运用变分过渡态理论(CVT),计算了该反应的速率常数。

关键词: 甲醛, 从头计算法, 过渡态理论, 反应速度常数

The hydrogen abstraction reaction CH2O+H→CHO+H2 was studied using ab initio calculation theory. The geometries of the reactants, transition state and products were optimized at QCISD/6-311G^** level. The forward and reverse reaction potential bariers were found to be 35.4 kJ/mol and 98.8 kJ/mol respetively. By analyzing the changes of the generalized normal -mode vibrational frequencies along the IRC, it was found that the C—H bond breaking and the H—H bond forming took place simultaneously. There is a reactive vibrational normal- mode which leads to the reaction process form the reactants to the products. At temperature ranging from 300 to 3 000K, the calculated forward and reverse reaction rate constants are consistent with the experimental values.

Key words: FORMALDEHYDE, AB INITIO CALCULATION, TRANSITION STATE THEORY, REACTION RATE CONSTANT

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