Kinetics of Oxidation of Cobalt(III) Complexes ofaAcids by Hydrogen Peroxide in the Presence of Surfactants

Abstract

Hydrogen peroxide oxidation of pentaamminecobalt(III) complexes ofα-hydroxy acids at 35°C in micellar medium has been attempted. In this reaction the rate of oxidation shows first order kinetics each in [cobalt(III)] and [H2O2]. Hydrogen peroxide induced electron transfer in [(NH3)5CoIII-L]2+complexes ofα-hydroxy acids readily yields 100% of cobalt(II) with nearly 100% of C-C bond cleavage products suggesting that it behaves mainly as one equivalent oxidant in micellar medium. With unbound ligand also it behaves only as C-C cleavage agent rather than C-H cleavage agent. With increasing micellar concentration an increase in the rate is observed.

Kinetics and Stoichiometry of the Reduction of Hydrogen Peroxide by an Aminocarboxylactocobaltate(II) Complex in Aqueous Medium

“…The kinetics and mechanisms of its decomposition by transition metal complexes, which demonstrates the importance and role of specific free radical species [8], have received considerable attention [3] [9]- [11]. The reactions have been studied under acidic [9] [10] and basic [11] media and the mechanisms for the decomposition reaction established in addition to other kinetic parameters which are calculated. Furthermore, Schmitz and Furrow [12] used iodate reduction by hydrogen peroxide to demonstrate Bray-Liebhafsky and Briggs-Rauscher oscillatory reactions and Yong, et al [13] studied the reduction of the latter at Au (100) electrode.…”