The Decomposition of Hydrogen Peroxide with Metal Complexes. I. The Catalytic Decomposition of Hydrogen Peroxide by the Ammine-Copper(II) Complex Ions in an Aqueous Solution

Abstract

Abstract The catalytic decomposition of hydrogen peroxide by the ammine-copper(II) complex ions has been studied using kinetic measurements, UV and visible spectroscopy, electron-spin resonance spectroscopy, and polarography. It was found that there were two reaction paths in the catalytic decomposition of hydrogen peroxide. In the first case, a linear part was observed in the plot of the amount of oxygen evolved vs. time. In this case, a brown intermediate was formed which was later found to be a diamagnetic peroxo-copper complex and to contain some of the stable oxygen anion radical just after the mixing of the reactants. The activation energy of the reaction was found to be 23±1 kcal mol−1. In the second case, no linear part was observed in the kinetic curve. In this case, the reaction had a reaction order in hydrogen peroxide varying from the first- to the second-order depending on the initial concentrations of the reactants. The nature of the brown compound and the active species of the reaction is discussed.