A MECHANISTIC STUDY OF THE SULFITE-INDUCED AUTOXIDATION OF MN(II) IN AQUEOUS AZIDE MEDIUM

The sulfite-induced autoxidation of Mn(II) was studied in aqueous azide medium as a function of the Mn(II), Mn(III), S(IV) and O2 concentrations. The reaction exhibits autocatalytic behaviour and requires the presence of Mn(III) in order to be effective. The O2, Mn(II) and S(IV) concentrations determine whether only oxidation of Mn(II) to Mn(III), or reduction of Mn(III) to Mn(II), or both processes in one or two redox cycles, is observed.