环氧丙烷在盐酸中开环反应机理的量子化学研究

采用密度泛函(DFT)的B3LYP方法,在6-311G(d,p)基组下,研究了环氧丙烷与盐酸的反应机理.优化得到反应途径上的反应物、中间体、过渡态和产物的几何构型,并通过振动频率计算以确证其几何构型的正确性.对计算得到的可能反应途径的过渡态经内禀反应坐标(IRC)进行了分析和证实.结果表明:环氧丙烷在盐酸中开环反应存在着a和b2种主要通道,分别生成2-氯-1-丙醇和1-氯-2-丙醇2种产物,其中由于通道b的活化能相对较低且生成的产物1-氯-2-丙醇更稳定,因此是主产物,这一结论与实验结果一致,并从理论上解释了环氧丙烷在盐酸中开环反应的反应机理.

A quantum chemistry study on the ring-opening reaction mechanism of methyloxirane in HCl solutions

The reaction mechanism of methyloxirane(PO) in hydrochloric acid(HCl) has been studied using density functional theory(DFT) at the B3LYP method and 6-311G(d,p) basis set.The geometries of reactants,transition states,intermediates and products have been optimized and verified by frequency analysis,and their energies were calculated.The transition states are affirmed by Intrinsic Reaction Coordinate(IRC) calculation as well.The calculation results show that there are two main channels in the reaction of PO with HCl and their primary products are 2-chloro-1-propanol and 1-chloro-2-propanol,the 1-chloro-2-propanol is the main product due to its relatively lower energy and activation barriers in channel b.The conclusion is in good agreement with the corresponding experimental result.In addition,it is thus theoretically proved the reaction mechanism of methyloxirane in hydrochloric acid.