THE FORMATION OF DITHIONATE DURING THE IRON(III)-CATALYZED AUTOXIDATION OF SULFUR(IV)-OXIDES

The iron(III)-catalyzed autoxidation of sulfur(IV)-oxides results in t he formation of two different oxidation products of sulfur(IV): dithio nate, S2O62-, and sulfate, SO42-. The yield of these reaction products depends on the experimental conditions. Under the studied conditions ([Fe(III)]:[SIV)] = 1:10, pH = 2-4) dithionate is the minor reaction p roduct. The formation of dithionate is influenced by the initial pH bu t not by the initial O-2 concentration. The presence of Co2+, Mn2+, an d Ni2+ have no influence on the yield of dithionate, whereas in the pr esence of Cr3+ less and, in the presence of Cu2+, no dithionate is for med. (C) 1997 Elsevier Science Ltd.