Oxidation of substituted phenethyl alcohols by sodiumN-chlorobenzenesulphonamide: A kinetic study

Abstract

The kinetics of the oxidation of six substituted phenethyl alcohols by sodium N-chlorobenzenesulphonamide or chloramine-B (CAB) in the presence of HCl was studied at 35°C. The rate shows a first order dependence on [CAB]0 and [H+] and is of fractional order in [PEA]0 and [Cl−]. Ionic strength variations, addition of the reaction product of benzenesulphonamide and variation of the dielectric constant of the medium have no effect on the rate. The solvent isotope effect k1/k1 ≅ 0·78. Proton inventory studies were made in H2O-D2O mixtures. The rates correlate satisfactorily with Hammett's LFER. The reaction constant ρ was −3·5 for electron-releasing substituents and −0·30 for electron withdrawing groups at 35°C. Activation parameters ΔH‡, ΔS‡, ΔG‡ and log A were computed for the reaction. An isokinetic relationship is observed with β = 338 K, indicating enthalpy as a controlling factor.