Odaryuk I. Activation of molecular oxygen by phenols in aqueous medium

The dissertation deals with direct experimental confirmation of the radical formation during the autoxidation of polyphenols in aqueous medium in the reaction between monoion of phenol and molecular oxygen. The rate constants of the radical formation in this reaction for hydroquinone, chlorohydroquinone, 2,5-dichlorohydroquinone, pyrocatechol, 4-methylpyrocatechol, pyrogallol, gallic acid have been estimated by the inhibitors method, ascorbic acid being used as an inhibitor. The autoxidation of polyphenols which generate redox pair phenol-quinone has been found to be the most effective and accompanied by chemiluminescence. Its emitters are the molecules of corresponding quinones in electron-exited state. The primary products of autoxidation, corresponding quinone and H2O2, have been shown to be involved into further oxidative conversions. The reactivity of dihydroxybenzenes in the autoxidation reaction in aqueous medium reduces in the series: para- >, orto- >, meta-isomers. The experiments on influence of the additions of superoxide dismutase, Cu(2+)-ions, 1,1-diphenyl-2-picrylhydrazyl, phenols, which are not oxidized in this conditions, hydrochloric acid, strong alkaline etc. upon kinetic of autoxidation polyphenols have proven the ion-radical mechanism of the process. Some inorganic ions of used buffer solutions have been found to be not inert in respect to reaction centres which generated during polyphenols autoxidation in aqueous medium.