Mechanisms of peroxide decomposition. An EPR investigation of the reactions between some transition metal ions (TiIII, FeII, CuI) and monoperoxyphthalic acid and its anion

Abstract

Continuous-flow and spin-trapping experiments have been employed in conjunction with EPR spectroscopy to investigate the metal-ion induced decomposition of magnesium monoperoxy-phthalate (MMPP) in aqueous solution (at pH ca. 2 and 6). As with the corresponding reactions of peroxymonosulphate (HOOSO₃^–) it is shown that the behaviour of Cu^I(which leads to the formation of ˙OH and ArCO₂^–, Ar = 2-C₆H₄CO₂H) is in complete contrast with that of Ti^III and Fe^II, both of which bring about electron transfer to give ArCO₂˙ and OH^–. Some subsequent reactions of ArCO₂˙ and Ar˙, formed by rapid decarboxylation, have been studied.