Free-radical-induced oxidation of hydroxymethanesulfonate in aqueous solution Part 2A pulse and steady-state radiolysis study of oxygenated solutions
Abstract
At pH 4.0, the radical ˙CH(OH)SO3− formed by reaction of ˙OH with hydroxymethanesulfonate (HMS) reacts rapidly with oxygen to form the peroxyl radical, ˙OOCH(OH)SO3−, with k4 = (2.6 ± 0.3) × 109 d mol−1 s−1. This radical decays by a first-order process with k = 2.4 × 104 s−1 and Ea = (29 ± 1.2) kJ mol−1. The decay is by a split pathway, reactions (6) and (7), with k6 = 1.7 × 104 s−1 and k7 = 7.0×103 s−1. Reaction (6) involves direct elimination of HO2˙. Reaction (7) initially forms the formylperoxyl radical, but this is hydrolysed, reaction (8), to formic acid and HO2˙ with k8 = 2.46 × 103 s−1.