Determination of Relative Rate Constants for Reactions of 2,2’-Azobis-(2-Amidinopropane) Dihydrochloride Peroxyl Radicals with Dihydroxybenzenes and Their Derivatives

Resumo

An iodometric method for determining the antiradical activity (ARA) of dihydroxybenzenes in the reaction with 2,2′-azobis-(2-amidinopropane) (AAP) peroxyl radicals (rOO^• ) in conditions close to those obtaining in biological systems was developed. A means of calculating relative rate constants of reactions of phenols with rOO^• from the kinetics of consumption of an inhibitor added at low concentration was proposed. The greatest levels of ARA were seen with resorcinol, orcinol, and hydroquinone, which are able to dissociate to form highly reactive mono-and bianionic forms of phenolate ions. A method of calculating relative rate constants of these reactions was proposed, based on the AAP - AAP peroxyl radical - phenol kinetic model.