CALCULATION OF KINETIC-PARAMETERS OF THE REACTION DISSOCIATIVE ELECTROCHEMICAL REDUCTION OF HALOMETHANES IN POLAR-SOLVENT

The kinetics of dissociative reduction reactions of methyl halides in polar solvents, e(-) + CH(3)X --> CH3. + X(-), is considered in the fr amework of previously developed theory. The potential energies of the reactants and products are described by the Morse and exponential curv es as functions of the C-X distance. The parameters of the Morse poten tial are taken from experiment, and those for the exponential function are obtained from quantum-chemical calculations of radical anions CH( 3)X(.-) by the PM3 method. The solvent reorganization energy is calcul ated with the use of the real charge distribution on CH(3)X and CH(3)X (.-) in terms of the ellipsoidal model. Theoretical values of the rate constant are compared with experimental data at Delta F = 0. The agre ement is good for X = Cl and Br but is poor for X = I. The latter is a ttributed to bad values of quantum-chemical parameters of the PM3 meth od for I.