甲醇与O[3P]反应机理的从头算及动力学

采用UQCISD/ 6-311G (d,p )从头算方法,优化甲醇和O ³P ]的反应两个通道、反应物、过渡态和产物的几何构型。进一步运用G2方法进行单点能量校正,得出通道 (1)和通道 (2)的位垒分别是48.86kJ/mol和28.89kJ/mol。并指出通道 (1 )是吸热反应,而通道 (2 )是放热反应。在300～3200K温度范围内,采用传统过渡态理论计算两个反应通道各自的速率常数k₁ 和k₂ ,由此采用非线性最小二乘法,得出这两个反应通道各自的速率方程为k₁=2.43×10^-18×T^2.23×exp(- 32.97/T)cm³mol^-1 s^-1 (300K≤T≦3200K), k₂=6.12× 1 0 ^-18×T^2.19×exp(- 1396/T)cm³mol^-1s^-1(300K≤T≦3200K) 2/k₁对温度变化的依赖关系。计算得出CH₃OH和O³P]反应的总速率常数k₁₊₂ ,与实验结果取得很好的一致。

Kinetics and ab initio study of the reaction methanol with O[3p]

Ab initio UQCISD calculations, with 6-311G(d, p) basis sets were performed for the title reaction. The results show that the reaction has two product channels. Both reactions are classical hydrogen abstraction. Using G2 theory, the calculated energy barriers were 48.86kJ/mol and 28 89kJ/mol respectively. In the range of temperature 300～3200K, the rate constants k₁ and k₂ were obtained by the transition state theory. Using the nonlinear least square method, the simulated rate equations were obtained by the transition state theory.Using the nonlinear least square method,the stimulated rate equation were sequentially obtained for the both reactions.k₁=2.43×10^-18×T^2.23×exp(- 32.97/T)cm³mol^-1 s^-1 (300K≤T≦3200K), k₂=6.12× 1 0 ^-18×T^2.19×exp(- 1396/T)cm³mol^-1s^-1(300K≤T≦3200K) 2OH is the dominant channel.The overall rate constants of the title reaction are consistent with the experimental values.