Kinetics of Oxidation of Propranolol by Sodium – N – Chloro – pToluene Sulphonamide in NaOH medium. A Mechanistic Study

Abstract

Propranolol is used for treating high blood pressure, heart pain, abnormal rhythms of the heart and some neurologic conditions. Kinetics and oxidation of Propranolol (PPL) ((RS)-1-(1-methylethylamino)-3-(1-naphthyloxy)propan-2-ol) by sodium-N-chlorop-toluenesulphonamide (Chloramine-T or CAT) in NaOH medium at 298K have been studied. The rate was first order in [CAT] o, fractional order in [PPL] and zero order in [OH-]. Addition of p-toluenesulphonamide, NaCl and NaBr did not affect the rate of the reaction. Variation in ionic strength did not affect the rate of the reaction indicating that nonionic species are involved in the rate limiting step. Dielectric effect of the medium showed positive effect. Rate increased with increase in temperature from 288K to 318K. From the linear Arrhenius plot, activation parameters were computed. Addition of reaction mixture to aqueous acrylonitrile solution did not initiate polymerization, showing the absence of free radicals species. Oxidation products were identified. TsNClNa, the reactive species oxidizes the substrate. Based on kinetic results, reaction stoichiometry and oxidation products, a suitable mechanism have been proposed.