CH_3CF_2O_2与HO_2自由基反应机理的理论研究

Theoretical Study on the Mechanism of the Reaction of CH_3CF_2O_2 with HO_2 Radical

用密度泛函理论(DFT)的B3LYP方法,在6-311G、6-311+G(d)、6-311++G(d,p)基组水平上研究了CH3CF2O2与HO2自由基反应机理.结果表明,CH3CF2O2与HO2自由基反应存在两条可行的通道.通道CH3CF2O2+HO2邛IM1邛TS1邛CH3CF2OOH+O2的活化能为77.21kJ·mol-1,活化能较低,为主要反应通道,其产物是O2和CH3CF2OOH.这与实验结果是一致的;而通道CH3CF2O2+HO2邛IM2邛TS2邛IM3邛TS3邛IM4+IM5邛IM4+TS4邛IM4+OH+O2邛TS5+OH+O2邛CH3+CF2O+OH+O2邛CH3OH+CF2O+O2的控制步骤活化能为93.42kJ·mol-1,其产物是CH3OH、CF2O和O2.结果表明这条通道也能发生,这与前人的实验结果一致.

Density functional theory (DFT) B3LYP method was employed to study the mechanism of the reaction of CH3CF2O2 radical and HO2 radical at the 6-311G,6-311+G(d),6-311++G(d, p) levels. The results indicate that there are two reaction pathways in this reaction. The main reaction pathway is CH3CF2O2 +HO2 -> IM1 -> TS1 -> CH3CF2OOH +O-2, the corresponding activation energy is 77.21 kJ center dot mol(-1), and the main products are O-2 and CH3CF2OOH. They are in good agreement with the experimental results. The other reaction pathway is CH3CF2O2+HO2 -> IM2 -> TS2 -> IM3 -> TS3 -> IM4+ IM5 -> IM4+ TS4 -> IM4+OH+O-2 -> TS5+OH+O-2 -> CH3+ CF2O+OH+O-2 -> CH3OH+CF2O+O-2, and the corresponding activation energy is 93.42 kJ center dot mol(-1). The results show that this reaction pathway can also occur, and it is in agreement with the results in literatures.