Kinetics and Mechanism of the Oxidation of Chloroquinephosphate with Chloramine-B in Acidic Buffer Medium

Abstract

The kinetics of oxidation of Chloroquine phosphate [CP] by Chloramine-B [Sodium N-chlorobenzene Sulfonamide, CAB] has been studied in acidic buffer solution of P^H 4 at 303 K. The reaction was first order with respect to [CAB], fractional order with respect to [H⁺] and [CP]. Activation parameters were evaluated from the kinetic data at different temperatures. Negative entropy of activation indicated the involvement of a rigid complex in the activated state. The dependence of the reaction rate on dielectric constant of the medium, ionic strength, reaction product and solvent isotope effect were studied. The reduction product benzene sulphonamide [BSA] has no effect on the reaction rate. The reaction product was identified by spectral (IR and NMR) data. Rate equation is derived to account for the observed kinetic data and a probable mechanism has been proposed.