Mechanistic aspects of uncatalyzed and ruthenium(III) catalyzed oxidation of 1,4-dioxane by a copper(III) periodate complex in aqueous alkaline medium

Oxidation of 1,4-dioxane (Dio) by a copper(III) periodate complex (DPC) has been investigated spectrophotometrically both in the absence and presence of a ruthenium(III) catalyst in aqueous alkaline medium at 298 K. Stoichiometry of (1 : 8) was observed in both the reactions and the order of the reaction with respect to [DPC] was unity while the order with respect to [Dio] was <1 over the concentration range studied. Order with respect to [OH-] and [IO4-] had negative order in both cases. Order with respect to [Ru(III)] was unity. The activation parameters (Delta H-# = 38 +/- 2 kJ mol(-1), Delta S-# = -164 +/- 15 J K-1 mol(-1) and Delta G(#) = 87 +/- 4 for uncatalyzed and Delta H-# = 34 +/- 3 kJ mol(-1), Delta S-# = -43 +/- 2 J K-1 mol(-1) and Delta G(#) = 47 +/- 3 for catalyzed reaction) with respect to the slow step of the proposed mechanism were computed and thermodynamic quantities were also calculated. Kinetic studies suggest that [Cu(OH)(2)(H3IO6)](-) is the reactive copper(III) species and [Ru(H2O)(5)(OH)](2+) is the reactive Ru(III) species.