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

Abstract

Hydrogen peroxide oxidation of pentaamminecobalt(III) complexes of α-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)₅ CoIII-L]²⁺ complexes of α-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.