电场增强催化作用探讨

The effect of equi weight electrostatic field on transesterification of MeCOOBu with EtOH in the presence of base catalyst in liquid phase was investigated. The conversion of forward reaction and backward reaction was slightly enhanced in the equi weight field ( E =1×10 5 V/m). SCC DV X α calculations showed that the HOMO energy level of CH 2O was decreased by about 9 6 eV in H + field, while increased by about 23 7 eV in O 2- field. It is concluded that the activation energy of the reaction in equi weight electrostatic field is almost the same as in free field, owing to the same potential energy change of the reactants, transition states and products. In the unequi weight electrostatic field, the negative charge center seems to be the active site for reactants or products, while the positive one seems to be the active site for transition states, resulting in great decrease in the activation energy.