Kinetics of the oxidation of quinol by aquocerium(IV) ions in aqueous perchlorate media

Abstract

The rapid reaction of aquocerium(IV) ions with quinol has been investigated in aqueous perchlorate media by the stopped-flow technique. The oscilloscope traces show a very rapid initial rise in optical density followed by a rapid decay. The rate of decay is of the first order in [Ce^IV]_Total and of zero order in [quinol]. The rate constant is independent of acidity in the range 0·2–2·0M-HClO₄. The rapid initial rise in optical density suggests the formation of an intermediate complex, and the interpretation of the kinetics of the decay also requires such a complex with a high formation equilibrium constant. The kinetics of the decay are compared with the kinetics of the oxidation of quinol by Fe^III, Mn^III, and Co^III.