Photolysis of Aqueous Solutions of 9,10-Anthraquinone-2-sulfonate. Part I. Dependence of Product Yields on Reaction Conditions

Abstract

The products of the photolysis of neutral aqueous solutions of 9,lO-anthraquinone-2-sulfonate or of the action of Fenton's reagent on this quinone have been identified as 1-and 2-hydroxy-and dihydroxy-9,lOanthraquinone sulfonates. High quinone and low oxygen concentrations favor production of monohydroxyanthraquinone sulfonates, while low quinone and high oxygen concentrations result in preferential formation of dihydroxylated derivatives of the quinone. Photolysis in aqueous NaOH solution gives essentially only 2-hydroxy-9,lO-anthraquinone sulfonates.Les produits de la photolyse de solutions aqueuses neutres de sulfonate-2 anthraquinone-9,10 ou de I'action du reactif de Fenton sur ce quinone ont ete identifits comme ttant des sulfonates d'hydroxy-1 et -2 et de dihydroxy-anthraquinone-9,lO. De fortes concentrations en quinone et faibles en oxygene favorisent la production de sulfonates d'anthraquinone rnonohydroxylte tandis que de faibles concentrations en quinone et fortes en oxygene conduisent preferentiellement a la formation de dtrivts dihydroxylds de la quinone.La photolyse en solution aqueuse de soude ne donne essentiellernent que des sulfonates d'hydroxy-2 anthraquinone-9.10.

Photolysis of Aqueous Solutions Of 9,10-Anthraquinone-2-Sulfonate. Part II. Dependence of Rates of Hydroxylation on Reaction Conditions

“…Previous studies (1) showed that photolysis of A in H,O produces AOH and A(OH),, the latter exhibiting strong absorption at 610 nm in alkaline solution and being the major products at low [A] and high [O,]. This absorbance at 610 nm was found to be directly proportional to the irradiation time ( (Fig.…”

“…Spectra were recorded on freshly prepared alkaline solutions. The ratio of 1-HOAQS0,Na to 2-HOAQS0,Na photolysis products and their respective E values were determined by chromatographic separation of these products (1) and quantitative analysis of the resulting products by potentiometric titration. For personal use only.…”

“…fonates (A(OH)2) result, the actual product A* represents the appropriate electronically yields depending upon the photolysis conditions excited state of A, A'-, and A'+ radical ions (1). There is evidence (2-6) that this ~hotochemi-resulting from partial reduction and oxidation of cal reaction causes reduction of A and oxidation A, respectively, and AOH' the adduct from A of H 2 0 or HO-to HO', which, in the absence of and HO'.…”

Kinetic studies of hydroxyquinone formation from water soluble benzoquinones

“…that is (9) To support this assumed mechanism further, activation parameters for the rate determining step (8) of the 2-methyl-1,4-benzoquinone -hydrogen peroxide reaction were determined both experimentally and by DFT calculations.…”

“…7 The direct formation of hydroxyquinone in the photochemical process is unlikely because the triplet excited states of benzoquinones are strong oxidizing agents. 8,9 Thus, it is more likely that this triplet quinone oxidizes another quinone molecule to hydroxyquinone.…”