RUTHENIUM(VI) IN THE OXIDATION OF 2-PROPANOL AND 1-PROPANOL - A KINETIC-STUDY

Sodium ruthenate catalyses the oxidation of 2-propanol by hexacyanoferrate(III) ([Fe(CN)6]3-), diperiodatocuprate(III) (DPC), periodate (IO4-) and chloramine-T (CAT) in aqueous alkali. Except when CAT was used as an oxidant, the reactions were first order with respect to [Ru(VI)] and zero order in [oxidant]. The reaction rate increases with the increase in [substrate] and exhibits Michaelis-Menton type behaviour. The rate is independent of [alkali] and ionic strenght. The rate data suggests that oxidation proceeds via the formation of a 1:1 Ru(VI)-2-propanol precursor complex which disproportionates into acetone and Ru(IV) in a rate determining step. The rates of Ru(VI)-catalysed oxidation of 2-propanol by different oxidants were found to be similar to the rate of 2-propanol oxidation by Ru(VI) in the absence of the oxidant. A plausible mechanism, consistent with the experimental data, is proposed and discussed.