己烷催化异构化反应中氢溢流机理的理论研究

Theoretical Studies on Hydrogen overfall Mechanism for Catalyzed Hydroisomerization of n-Hexane

采用密度泛函理论(DFT)在B3LYP/6-311++G**//B3LYP/6-311G*水平下,对正己烷(C6H14)催化异构化反应中的氢溢流机理进行了理论探讨.通过对振动模式分析和内禀反应坐标(IRC)计算确认了各可能反应的过渡态.同时在MP2/6-311++G**水平上对各驻点做了单点能计算和零点能校正,计算出各反应通道的活化能,进而确定了该反应的主反应通道,其活化能为42.52kJ/mol.

The mechanism and the related reaction paths in the hydroisomerization of n-hexane were studied with DFTcalculations at the B3LYP/6-311 ＋ ＋ G＊ ＊ level. Five possible transition states were theoretically predicted and verified by the vibration frequency analysis as well as the calculations of intrinsic reaction coordinates （IRC）. Further more, the related reaction barriers were evaluated on the basis of single point energy with zero point vibration correction, and the distribution of natural charge was analyzed at MP2/6-311 ＋ ＋ G＊＊ level. Consequently, six pathways were found and the barrier energy of the main isomerization pathway is 42.52 kJ/mol.