F与自由基CH_2OH反应理论研究

Theoretical Studies on Reaction of F with CH_2OH Radical

用量子化学从头计算法对氟原子与羟亚甲基CH_2OH在势能面上的反应进行了研究.采用G2(MP2,SVP)理论计算出了势能面上各驻点物种的构型参数、振动频率和能量.结果表明:F与CH_2OH反应首先通过H转移形成甲基,然后甲基旋转,再通过甲基中一个H与F结合,最后产生HF和CH_2O.计算出反应热为455.9kJ·mol^(-1),与实验值439kJ·mol^(-1)符合较好.另外对前人红外吸收光谱研究中没有观测到CHOH提出了可能解释.

The potential energy surface of the reaction of F atom with·CH2OH is studied by ab initio MO method. The structure parameters, vibration frequencies and energy of each stationary point on its potential energy surface are given. G2(MP2, SVP) method is applied in the calculations. Results show that: firstly, the proton on the oxygen migrates to the carbon forming a methyl group and the methyl group rotates, then one of its protons binds to the fluorine, thereby leading to the formation of HF and CH2O. The calculated exothermic energy (455.9 kJ·mol-1) agrees with the experiment result (439 kJ·mol-1)- In addition, a possible explanation for the absence of CHOH in the products, which was previously observed using IR spectroscopy, is given.