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

✍ Scribed by H. Ramachandra; K. S. Rangappa; D. S. Mahadevappa

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 493 KB
• Volume: 9
• Category: Article
• ISSN: 0894-3230
• DOI: 10.1002/(sici)1099-1395(199607)9:7<439::aid-poc777>3.0.co;2-v

✦ Synopsis

The kinetics of the oxidation of six substituted phenethyl alcohols by sodium N-chlorobenzenesulphonamide or chloramine-B (CAB) in the presence of HCI was studied at 35 "C. The rate shows a first-order dependence on [CAB],, and [H+] and is fractional order in [PEA], and [Cl-1. 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'H20/k'D,0 = 0.78. Proton inventory studies were made in H,O-D,O mixtures. The rates correlate satisfactorily with the Hammett linear free energy relationship. The reaction constant p was -3-5 for electron-releasing and -0.30 for electron-withdrawing groups at 35 "C. Activation parameters AH*, AS*, AG* and log A were calculated for the reaction. An isokinetic relationship is observed with fi= 338 K, indicating enthalpy as a controlling factor.

EXPERIMENTAL Chloramine-B (CAB) was prepared as reported

An aqueous solution of the compound was prepared, standardized iodimetrically and stored in brown bottles to prevent its photochemical deterioration. Phenethyl alcohols (Aldrich) were of accepted grades of purity and were used without further purification. Solutions of the compounds were prepared in water. All other reagents were of analytical grade. Doubly distilled water was employed in the preparation of aqueous