The catalytic effect of transition metal-ion ammine complexes on the decomposition of hydrogen peroxide in the presence of Dower-50W resin in aqueous medium

Abstract

The kinetics of the catalytic decomposition of hydrogen peroxide was studied in the presence of Dowex-50W resin in the form of some transition metal-ion ammine complexes in an aqueous medium. The transition metal-ions, Co2+, Ag+, Cd2+ and Zn2+ were chosen in this study and the rate constants (per gram of dry resin) were evaluated at various resin weights in the 25–40°C range. A coloured compound (peroxo-metal complex), which formed at the beginning of the reaction in each case, was found to contain the catalytic active species. Probable mechanisms for the reactions are proposed. The activation energy and the change in the entropy of activation increased in the following sequence: [Ag(NH3]2]+< [Cd(NH3)6]2+<[Co(NH3)6]2+<[Zn(NH3)6]2+, which is also the probability sequence for the formation of the activated complex.