Micelle Catalyzed Oxidative Degradation of Paracetamol by Water Soluble Colloidal MnO2 in Acidic Medium

Abstract

AbstractThe catalytic effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the MnO2-paracetamol (PCM) redox reaction has been examined spectrophotometrically in acidic medium at 298 K. The reaction demonstrates that the stoichiometric ratio of MnO2 and PCM is 1 : 1. The reaction exhibited first order kinetics with respect to [MnO2] and [PCM] but a negative fractional order was observed with respect to [H2SO4]. Various effects such as ionic strength, dielectric constant, [Mn(II)], [salts] and temperature have been studied. The catalytic effect of CTAB has been treated quantitatively by the well known Menger Portnoy and Piszkiewicz model. The values of binding constant (Ks), rate constant in the micellar phase (km), cooperativity index (n) and dissociation constant (KD) have also been calculated. From the several observations, a reaction mechanism has been proposed and the rate law has been derived. Applying the Arrhenius equation, various thermodynamic activation parameters have also been evaluated.