Ruthenium(III)-catalyzed oxidation of thallium(I)by 12-tungstocobaltate(III)in hydrochloric acid medium

摘要

The reaction between thallium(I)and [Co~(III)W_(12)O_(40)]~(5-)in the presence of ruthenium(III)as catalyst proceeds via initial outer-sphere oxidation of the catalyst to ruthenium(VI).The ruthenium(IV)thus generated will oxidize thallium(I)to an unstable thallium(II)which by reacting with oxidant gives the final product,thallium(III).The formation of ruthenium(II)by direct to-electronreduction of the catalyst by the [H~+],whereas it is catalyzed by chloride ion.The formation of reactive chlorocomplex,TlCl,in a prior equilibrium is the reason for the chloride ion catalysis.Incresing the relative permittivity of the medium increase the rate of the reaction,which is attributed to the formation of an outer-sphere complex between the catalyst and oxidant.