Kinetics and Mechanism of Oxidation of Diclofenac Sodium by Keggin Type 12-Tungstocobalt(III) in Aqueous Medium

摘要

The kinetics of electron transfer reaction of diclofenac sodium with 12-tungstocobaltate (III) complex has been studied spectrophotometrically over the range 2.0 × 10~(-3) ≤ [diclofenac sodium] ≤ 6.0 × 10~3 mol/L, 6.03 ≤ pH ≤ 8.0 and at 293 ≤ T ≤ 308 K in aqueous medium at constant ionic strength I (0.5 mol/L sodium perchlorate). The electron transfer reaction showed pseudo-first order dependence in [diclofenac sodium] and [12-tungstocobaltate(III)] and less than unit order in [OH~-]T. The activation parameters calculated for the electron transfer reaction favoured the formation of a precursor complex between the reactants. The product is characterized by FTIR and NMR spectra and is found to be [2-(2,6-dichloro phenylamino)phenyl]methanol.