Azo dye oxidation with hydrogen peroxide catalysed by manganese 1,4,7-triazacyclononane complexes in aqueous solution.

A kinetic and mechanistic study is reported of the oxidation of a number of azonaphthol dyes with hydrogen peroxide in aqueous solution, catalysed by some mono and dinuclear manganese(IV) complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3TACN). The results of UV-Vis investigations, augmented by EPR and ESI-MS studies, are described for a series of experiments in which concentrations, pH and ionic strength have been varied. The reactions are characterised by an induction period followed by a relatively rapid oxidation.