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Kinetics of Butacaine Sulfate Oxidation by Sodium N- Chlorobenzenesulfonamide in Acidic Medium : A Mechanistic Approach

K. Vasantakumar Pai and K. M. Meenakshi

A kinetic study of oxidation of butacaine sulfate (one of the potent local anesthetics) by sodium N-chlorobenzenesulfonamide (Chloramine-B or CAB) in the presence of HClO4 at 303 K has been investigated. The reaction exhibits first order kinetics with respect to [CAB] and fractional order dependence with substrate, but it is independent of the [HClO4]. The stoichiometry of the reaction was found to be 1 : 3 and oxidation products were identified. The experimental rate laws obtained are -d[CAB]/dt =k[CAB]0[S]x[H+]y, where x is less than unity and y is zero. The reaction was subjected to changes in (a) concentration of benzene sulfonamide, (b) concentration of added neutral salts, (c) ionic strength, and (d) dielectric permittivity of the medium. The oxidation reactions were studied at different temperatures and overall activation parameters have been evaluated. The oxidation reaction fails to induce the polymerization of added acrylonitrile. Formation and decomposition constants have been determined. The proposed mechanism and derived rate law are consistent with the observed kinetic data. The observed results have been explained by plausible mechanisms and the relative rate laws have been deduced.