Production of hydrogen peroxide from dioxygen and hydroxylamine or hydrazine catalysed by manganese complexes

Abstract

Manganese(II) catecholate complexes efficiently catalyse the production of H₂O₂ from dioxygen in the range pH 7.5–8.6 using hydroxylamine or hydrazine as substrates; concentrations of hydrogen peroxide >0.2 mol dm^–3 and turnover numbers [H₂O₂]/[Mn^II] > 10⁴ can be obtained. The rate of production and yields are very sensitive to the electronic effect of the substituents on the catecholate ring with the best results being achieved using 4,5-dihydroxybenzene-1,3-disulfonate. Deuteriation studies (using ND₂OD) indicated that the reduction of O₂ occurs via an electron transfer from the substrate and a mechanism is proposed whereby both O₂ and the substrate become bound to manganese and the electron transfer is mediated through the manganese catecholate complex.