水助甲酰胺-H2O2氧化乙烯制环氧乙烷反应机理的理论研究

采用MP2方法研究了甲酰胺-H2O2氧化乙烯制取环氧乙烷的反应机理.优化得到了反应物、过渡态、中间体及产物的几何构型并计算了反应势垒.研究结果表明:没有水参与时,反应需要通过四元环过渡态完成,反应势垒很高,在常温下难以进行;有水参与时,在水分子的协助下,反应可以通过六元环过渡态完成,反应势垒较低,常温下反应容易进行.

Theoretical Study on the Epoxidation Reaction Mechanism between Ethene, Formamide and H2O2 Assisted by Water Molecule

Theoretical study on the epoxidation reaction mechanism between ethene, formamide and H2O2 was carried out using MP2 methods. The optimal structures of reactants, transition states, intermediates and products were located at the MP2/6-31G(d,p) level of theory. The reaction barriers were then calculated at the MP2/6-311 ++G(d,p) level of theory. The calculation results show that the high reaction barriers exist for the pathways where no water molecule involves, whereas for the pathways in which a water molecule involves, the low reaction barriers were found because of the formation of the six-membered ring transition state structures, indicating that both the water molecule and the six-membered ring transition state structure play a very important role in the epoxidation reaction between ethene, formamide and H2O2.