Photochemical Sources and Reactions of Free Radicals in the Aqueous Phase

The spectra and molar absorbancies of SO₃−., SO₄−. and SO₅−. have been determined by the technique of pulse radiolysis. The rate constants of fifteen reactions that are important in the free-radical and transition-metal-catalysed oxidation of S(IV) have been determined, including the mutual reaction of SO₅−. radicals and the propagation steps of the chain oxidation. Some reactions relevant to the free-radical induced oxidation of hydroxymethane sulfonate (HMS) have been studied and absorption spectra of CH(OH)SO₃− and the peroxy-radical derived from it have been recorded. The reactivities of SO₃−., SO₄−. and SO₅−. with Fe(II) have been studied and also the reaction of SO₅−. with Mn(II).