Ruthenium(III) Mediated Cerium(IV) Oxidation of Thallium(I) in Aqueous Sulphuric Acid--A Kinetic and Mechanistic Study
Abstract:The cerium(IV) oxidation of thallium(I) has been studied in an aqueous sulphuric acid medium. A minute amount (10−6 mol dm−3) of ruthenium(III) is sufficient to catalyse the reaction. The reaction is first order in [cerium(IV)] in the presence of ruthenium(III) catalyst. The order in [thallium(I)] varies from zero to unity, whereas that in [ruthenium(III)] is unity. Increase in sulphuric acid concentration accelerates the reaction rate. The added products cerium(III) and thallium(III) do not significantly effect the reaction rate. The active catalyst, substrate and oxidant species are [Ru(H2O)6]3+, Tl(SO4)− and H3Ce(SO4)4−, respectively. Possible mechanisms are proposed and the reaction constants involved have been determined.
Document Type: Research Article
Publication date: January 1, 2002