Kinetics and mechanisms of redox reactions in aqueous solution. Part 6. Oxidation of cyclohexanone by aquamanganese(III) ions in aqueous perchloric acid

Abstract

The rate of the title reaction has a first-order dependence both on Mn^III and cyclohexanone. The rate is retarded by increasing [H⁺] but unaffected by Mn^II. Unlike the oxidations by manganese(III) pyrophosphate and manganese(III) acetate, in which the enolic form was oxidised, the oxidation of cyclohexanone by aquamanganese(III) ions is found to be much faster than the rate of enolisation. An outer-sphere mechanism is suggested. The rate constants corresponding to the oxidation effected by Mn³⁺(aq) and [Mn(OH)]²⁺(aq) are separated and the associated thermodynamic parameters discussed.