H+CH_3NO_2→H_2+CH_2NO_2反应途径和变分速率常数计算研究  

Theoretical Study on the Reaction Path and Varitional Rate Constant of Reaction H+CH_3NO_2→H_2+ CH_2NO_2

作　　者：冀永强[1] 冯文林[1] 徐振峰[1] 

机构地区：[1]北京化工大学理学院,北京100029

出　　处：《高等学校化学学报》2002年第5期884-887,共4页Chemical Journal of Chinese Universities

基　　金：国家教育部博士学科点基金(批准号:1999002715); 宁夏教育厅高等学校科研基金资助.

摘　　要：采用MP2（FULL）／6－311G**从头算方法，优化了H＋CH3NO2——H2＋CH2NO2反应的过渡态结构，得出该反应的正逆反应的活化位垒分别是82．73和57．14 kJ·mol－1 ．沿IRC分析指出该反应是一个H—H键生成和C—H键断裂的协同反应，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- 0．7～0．2（amu）1/2·a0之间；在 1000～1400 K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，计算结果与实验相一致．Abstract Using ab initio theory, the geometries of the reactants, transition state, and products of the reaction H+CH3NO2 H2+CH2NO2 have been optimized at the UMP2(full)/6-31lG** level. The forward and reverse reaction potential barriers are 82. 73 and 57.14 kJ/mol respectively. The reaction, that is the formation of H桯 bond and breaking of C桯 bond, has been shown by a coordination process. Furthermore vibration normal-mode are discussed along the IRC, it is clear that there is a reactivity normal-mode which leads the reaction from reactants to product. The forward reaction theoretical rate constant, obtained by using the variational transition-state theory (CVT), are consistent with experimental value at the reaction temperature 1 000? 400 K.

关 键 词：反应途径 变分速率常数 硝基甲烷 从头算 变分过渡态理论 

分 类 号：O623.711[理学—有机化学] O643.11[理学—化学]