羰基氧化物环化反应动力学的计算研究

A Density Functional Method(DFT) Study on the Cyclic Reaction Kinetics of Carbonyl Oxides

用密度泛函(DFT)方法计算了羰基氧化物(H2COO、HFCOO、F2COO和Me2COO)环化反应的动力学信息,优化了反应物和产物的几何构型,优化搜索了各反应的过渡态结构,并用频率分析和内禀坐标法(IRC)验证了各鞍点构型和反应路径.计算了不同温度下经零点能校正的活化热力学量、反应过程热力学改变量,反应速率常数及频率因子.计算表明,电负性较大的取代基对环化反应有促进作用.

The cyclic reaction kinetics of carbonyl oxides (H2COO, HFCOO, F2COO and Me2COO) has been studied using the density functional method (DFT) at B3LYP(full)/6-311G* level. The energies and structures of reactants and products were optimized in full geometries. The transition states were found by the QST2 (or QST3) method and were proved by IRC calculations. The activation thermodynamic data were calculated, based on the transition states theory, and the rate constants and frequency factors were obtained from 148. 15 K to 398. 15 K. The dynamic calculation results show that the carbonyl oxides easily isomering to form dioxiranes at room temperature, and the electronegative substituent can enhance cyclization of the carbonyl oxides.