烷烃中碳氢键离解能的估算及其应用

将烷烃中的C－H键看成氢原子H与烷基Ri相连接而成的Ri－H键，以烷基的 HOMO能级和氢原子的轨道能来关联Ri－H键的离解能BDE。研究表明，烷烃分子中 Ri－H键的离能BDE与烷基Ri的极化效应指数PEI（Ri）有良好的线性关系：BDE＝ c+dPEI(Ri)。所得方程具有良好的估算精度。烷基Ri极化效应指数PEI（Ri）在羟 基自由基与烷烃反应速度常数的定量相关中，也得到良好的应用。

Evaluation of bond dissociation energy for carbon-hydrogen bond in alkane and its application

The R i -H bond can be treated as the combination of alkyl radical R i with hydrogen atom H. The bond dissociation energy (BDE) of R i -H was related to the HOMO energy level of alkyl radical and the atom orbital energy of hydrogen atom. The results showed that a good linear correlation was found between the BDE of R i -H and the polarizability effect index (PEI) of alkyl radical R i : BDE= c+d PEI(R i ). The expression has good precision for evaluating the BDEs of C-H bonds. Moreover, the PEI of alkyl radical R i can be corelated quantitatively with the reaction rates of alkane with hydroxyl radicals.