Kinetics and mechanism of ruthenium(III) chloride catalyzed oxidation of phosphorous acid by thallium(III) in acid perchlorate medium - role of tautomeric forms of the phosphorous acid

The stoichiometry of ruthenium(III) chloride catalyzed oxidation of phospho rous acid by thallium(III) in acid perchlorate medium corresponds to the re action represented by Eq. (i) Tl(III) + H3PO3 + H2O -->Ru-III Tl(I) + H3PO4 + 2H(+) A mechanism suggesting complexation between the catalyst and substrate this mechanism is represented by the Eq. (ii) -d[Tl(III)]/dt = kKK(h) [Tl(III)[Ru(III)][H3PO3]/([H+] + K-h) (1 + K[H3PO3] ) where K and K-h are the formation and hydrolytic constants respectively. Th e HP(O) (OH)(2) tautomeric form is assigned to be the reactive form of the phosphorous acid.