Kinetics of vanadium (V) catalyzed oxidation of gallic acid by potassium bromate in acid medium

Abstract

The kinetics of oxidation of gallic acid with potassium bromate in the presence of vanadiurn(V) catalyst in aqueous acid medium has been studied under varying conditions. The active species of catalyst and oxidant in the reaction were understood to be HBrO, and VO,+The autocatalysis exhibited by one of the products, i e., Br-, was attributed to complex formation between bromide and vanadiurn(V) A composite scheme and rate law were possible, some reaction constants involved in the mechanism have been evaluated. 0 1996 john Wiley & Sons Inc

Dissociation and rate of proton transfer of HXO3 (X = Cl, Br) in aqueous solution determined by Raman spectroscopy

“…In Pourbaix's Atlas 9 there is a pK a value of 0.7 (K a D 0.2), but there is no indication of how it was determined. Kinetic experiments 10,11 allowed the determination of apparent dissociation constants values of 0.0135 and 1.96 mol L 1 but these are dependent on the proposed mechanism for the reactions studied. For chloric acid we did not find in the literature any experimental value of the dissociation constant.…”

Sorption characteristics and mechanisms of oxyanions and oxyhalides having different molecular properties on Mg/Al layered double hydroxide nanoparticles

“…The sorption of bromate was about 19% at pH 4.5 and reduced gradually to 14% as the pH increased to 11. The insensitivity of bromate sorption to pH change was probably due to the presence of single negatively charged bromate species at pH ranging from 4.5 to 11 (HBrO 3 ↔ BrO 3 − + H + ; pK a = 1.87) [26]. The lower sorption of chromate or vanadate at high pH values was owing to an increased Donnan exclusion between the more negatively charged chromate or vanadate species and negatively charged surface sites of FCHT-LDH.…”