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Oxidation of substituted ethanols by sodium N ‐bromobenzenesulphonamide: A kinetic study
Author(s) -
Mahadevappa D. S.
Publication year - 1989
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610020809
Subject(s) - chemistry , substituent , enthalpy , reaction rate constant , kinetic isotope effect , ionic strength , kinetics , sodium , solvent , kinetic energy , medicinal chemistry , organic chemistry , thermodynamics , aqueous solution , physics , deuterium , quantum mechanics
The kinetics of the oxidation of seven substituted ethanols by sodium N ‐bromobenzenesulphonamide or bromamine‐B (BAB) in the presence of HCl was studied at 45 °C. The rate shows a first‐order dependence on [BAB] 0 and is fractional in [alcohol] 0 , [H + ] and [Cl − ]. Ionic strength variations, addition of benzenesulphonamide reaction product and variation of dielectric constant of the medium have no effect on the rate. The solvent isotope effect k H 2 O ′ / k D 2 O ′≈ 0·97. The rates do not correlate satisfactorily with Taft's substituent constants. Activation parameters Δ H ≠ , Δ S ≠ , Δ G ≠ and log A were calculated by studying the reaction at different temperatures (308–323 K). It was found that Δ H ≠ and Δ S ≠ are linearly related and an isokinetic relationship is observed with isokinetic temperature β = 393 K, indicating enthalpy as a controlling factor.