Particularities of catalysis mechanism of malonic acid with cerium(4) oxidation by ruthenium compounds

The kinetics of malonic acid oxidation by cerium (4) with ruthenium (3,4) compounds as catalysts was studied at different temperatures and concentrations of reagents. With the use of a stable free radical as a trap it was shown that no radicals appear at the stage responsible for the rate of the catalytic reaction. The mechanism of catalysis of the reaction by Ru(3,4) compounds involves presumably formation of the intermediate cerium(4) - malonic acid - ruthenium(4) complex, which is destroyed in a non-radical manner. The kinetic equation obtained by the topological graphs method is described satisfactorily the kinetic dependences. The rate constants for certain stages of the reaction were calculated, as well as the activation parameters. The mechanism suggested accounts for the increase in activation enthropy of the catalytic reaction with respect to the non-catalytic one