Kinetics of oxidation of chloroprocaine hydrochloride by N-halo-p-toluene sulfonamides in acid medium: A Mechanistic approach

A kinetic study of oxidation of a potent local anaesthetic chloroprocaine hydrochloride by sodium N- halo-p-toluenesulfonamides (chloramine-T and bromamine-T) has been carried in HClO4 medium at 303 K. The rate shows a first-order dependence on both (oxidant)o, and (substrate)o, and a fractional-order dependence on acid concentration. Increase in the rate of reaction has been observed with decrease of dielectric constant of the medium by adding methanol. Variation of ionic strength and addition of p-toluenesulfonamide or NaCl have no significant effect on the rate. The reaction was studied at different temperatures and the activation parameters have been evaluated. The stoichiometry of the reaction was found to be 1:3 and the oxidation products were identified by spectral analysis. The experimental results have been explained by probable mechanism and the associated rate law has been deduced. Keywords: Oxidation-kinetics, local anaesthetics, chloroprocaine hydrochloride, chloramine-T, bromamine-T, acid medium