OXIDATION OF SUBSTITUTED PHENETHYL ALCOHOLS BY SODIUM N-CHLOROBENZENESULPHONAMIDE: A KINETIC STUDY

摘要

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℃. The rate shows a first-order dependence on [CAB]_0 and [H~+] and is fractional order in [PEA]_0 and [Cl~-]. Ionic strength variations, addition of reaction product of benzenesulphonamide and variation of the dielectric constant of the medium have no effect on the rate. The solvent isotope effect k~1H_2O/k~1D_2O≈0.78. Proton inventory studies were made in H_2O-D_2O mixtures. The rates correlate satisfactorily with the Hammett linear free energy relationship. The reaction constant ρ was -3.5 for electron-releasing and -0.30 for electron-withdrawing groups at 35℃. Activation parameters ΔH, ΔS, ΔG and log A were calculated for the reaction. An isokinetic relationship is observed with β=338 K, indicating enthalpy as a controlling factor.