Chemical Behavior of SO3- and SO5- Radicals in Aqueous Solutions

Article abstract of DOI:10.1021/j150667a042

The chemistry of the radicals SO3^- and SO5^- has been investigated by using pulse radiolysis with kinetic spectrophotometry.Rate constants for the oxidation by SO3^- of a variety of organic compounds were measured and equilibrium constants determined for the reactions of SO3^- with chlorpromazine and phenol.SO3^- was found to be a mild oxidant with a redox potential of E(SO3^-/SO3^2-) = 0.63 V (vs.NHE) at pH>7 and E(SO3^-/HSO3^-) = 0.84 V at pH 3.6.The reaction of SO3^- with O2 was shown to produce SO5^-.The oxidation of several compounds by SO5^- was found to occur more rapidly than their oxidation by SO3^-.E(SO5^-/HSO3^-) was estimated to be approximately 1.1 V at pH 7.