Catalytic Activity of Octamethoxy-Substituted Cobalt(II) Tetraphenylporphyrinate in Tetraterpene Oxidation by Hydrogen Peroxide

Abstract

The catalytic activity of cobalt(II) porphyrinate in the oxidative degradation of β-carotene and lycopene by hydrogen peroxide is studied using spectroscopic methods. The kinetic parameters of the redox process are obtained, and its tentative mechanism is proposed. The catalytic activity is shown to depend on the composition of the coordination site and the presence of additional redox activators. Before oxidative degradation of tetraterpenes takes place, hydrogen peroxide gets coordinated to metal cation of the complex and is subsequently activated. The activation gives rise to a highly reactive intermediate that contains a radical on the methoxy moiety and can initiate free-radical oxidation.