Reductivity of methanol and ethanol towards permanganate in absence and presence of Tween-20 in perchloric acid medium. Mechanism of the oxidation processes

Abstract The reducing behaviour of methanol and ethanol towards permanganate in perchloric acid medium have been investigated in the absence and presence of the surfactant Tween-20. In the absence of surfactant the reaction is of first order with respect to both oxidant and H+ but of complex order in substrate. The alcohol molecule reacts with HMnO4 to form an intermediate complex which decomposes in the rate-determining step to give the product and Mnv. Effects of urea and acetonitrile on the reaction rate have also been studied. In the presence of Tween-20, the reaction appears to follow Berezin’s model where both the oxidant and the substrate are partitioned between the aqueous and the micellar phase and then react. Different thermodynamic and kinetic parameters have been evaluated. The reaction in the presence of the surfactant is entropy-controlled rather than enthalpy-controlled.