Oxidation of iminodiethanol by Ce (IV) in microheterogeneous system: a comprehensive kinetic analysis

Abstract

A comprehensive kinetic analysis of catalyzed oxidative degradation of iminodiethanol by Ce(IV) in pure aqueous and microheterogeneous or surfactant media has been reported. The oxidation reactions were first order with respect to [Ce (IV)], the dependence of rate on iminodiethanol concentration is first order, the rate constant values increased with increasing dielectric constant of the medium and the entropy of activation was negative. Kinetic information suggested that the oxidation reactions proceed through intermediate complex formation. The profile of pseudo-first order rate constant, kψ against [SDS] (sodium dodecyl sulfate) shows a maximum at about the concentration near which the randomized surfactant monomers started aggregating for the formation of micelle. To demonstrate the kinetic pattern and to evaluate the micelle-reactant binding constant values, Berezin’s model has been advanced. The transfer free energy per mole of the solute from water to the micellar phase has also been computed. Activation parameters for the oxidation reaction are obtained from the temperature dependence studies. Basing on all analytical results plausible mechanisms are proposed for the catalyzed oxidation of iminodiethanol by Ce (IV) both in aqueous and surfactant medium.