Kinetics of oxidation of procaine hydrochloride by sodium N-chlorobenzenesulfonamide in acid and alkaline media: A mechanistic approach

Abstract

A kinetic study of oxidation of procaine hydrochloride (one of the potent local anaesthetics) by sodium N-chlorobenzenesulfonamide (chloramine-B or CAB) has been carried out in HClO₄ (30°C) and NaOH (20°C) media. In acid medium, the rate shows first -order dependence on [CAB]_o, and fractional - order dependence on [substrate]_o. But, it is

independent of the [acid]. In alkaline medium, the rate exhibits first-order dependence each on [CAB]_o and [substrate]_o, and inverse fractional-order on [OH^-]. Activation parameters have been evaluated. The reaction is found to be faster in alkaline  medium in comparison with acid medium. The conjugate free acid C₆H₅SO₂NHCl of CAB is postulated as the reactive oxidizing species in both the media. The observed results have been explained by plausible mechanisms and the related rate laws have been deduced.