Kinetics of autoxidation of polyphenols in an aqueous solution

Abstract

The kinetics of the oxygen uptake during the oxidation of polyphenols by molecular oxygen in an aqueous solution was studied. The partial reaction orders for phenol, oxygen, and hydroxide anion and effective rate constants of the process were determined. An increase in the autoxidation rate with increasing pH of the medium suggests that phenols and phenoxyl radicals react mainly in the ionized form. Hydroquinones and pyrogallol derivatives are more active in autooxidation than the catechol derivatives.