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...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.展开更多
The paper analyses the principal and the methods of the optimal design of refrigerating plants.It compares the method of the static characteristics with that of the thermo dynamics,and puts the stress on the discussio...The paper analyses the principal and the methods of the optimal design of refrigerating plants.It compares the method of the static characteristics with that of the thermo dynamics,and puts the stress on the discussion of the latter which is general researched and applied in the refrigeration field.展开更多
文摘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.
文摘The paper analyses the principal and the methods of the optimal design of refrigerating plants.It compares the method of the static characteristics with that of the thermo dynamics,and puts the stress on the discussion of the latter which is general researched and applied in the refrigeration field.
