Kinetics of oxidation of methanol,ethanol and isopropanol by hexachloroiridate(IV)

Kinetics of the oxidation of methanol, ethanol and isopropanol by hexachloroiridate(IV) have been studied spectrophotometrically in sodium acetate-acetic acid buffer. Each reaction is first order with respect to iridium(IV) but the order with respect to alcohol is less than unity. Hydrogen ion inhibits the rate of the reactions. Initial complex formation between the alcohols and iridium(IV) is suggested. The complex then decomposes to give free radical and iridium(III). The free radical further reacts with another iridium(IV) and by a fast step gives the products of the reaction. The activation parameters have been evaluated and a tentative reaction mechanism suggested.