摘要
CH_2CH_2OH是C_2H_4和CH_3CH_2OH氧化反应重要中间体,HO_2是低温条件下浓度较大的自由基~[1]。本文通过精确地量子化学计算补充该反应通道并进一步完善低温氧化反应核心机理。采用高精度量子化学组合方法CBS-QB3结合传统过渡态理论(TST)、变分过渡态理论(VTST)和RRKM/ME理论计算CH_2CH_2OH+HO_2反应体系速率常数。在B3LYP/CBSB7水平下对反应物、产物和过渡态做几何优化和频率计算,采用CBS-QB3方法进行能量计算。结果表明CH_3CH_2OH+O_2和HO_2CH_2CH_2OH的产物形成反应是主要的竞争通道,并且在低温条件下反应HO_2CH_2CH_2OH=OCH_2CH_2OH+OH以及OCH_2CH_2OH=CH_2OH+CH_2O具有较强的敏感性。
Reaction of CH_2CH_2OH radical with HO_2 is of key importance in C_2H_4 and CH_3CH_2OH combustion at low temperature. In this work, all rates were determined computationally using the CBS-QB3 composite method combined with TST, VTST and RRKM/ME theory. The geometries optimization and the vibrational frequency analysis of reactants, transition states and products were performed at the B3LYP/CBSB7 level, single point energies and the thermodynamic parameters were calculated by using the composite CBS-QB3 method. It indicated that CH_2CH_2OH+HO_2=CH_3CH_2OH+O_2 and CH_2CH_2OH+HO_2=HO_2CH_2CH_2OH are important channels, while HO_2CH_2CH_2OH=OCH_2CH_2OH+OH, OCH_2CH_2OH=CH_2OH+CH_2O are much more sensitivity in low temperature.
引文
[1]Lopez J.G.;Rasmussen C.L.;Alzueta M.U.;Gao Y.;Marshall P.;Glarborg P.,P.Combust.Inst.2009,32(1):367