Catalyzed Oxidation of Tetrahydrofurfuryl Alcohol by Cerium(Ⅳ) in Aqueous Sulphuric Acid Medium

Abstract

The kinetics of trace Ir(Ⅲ) catalyzed oxidation of tetrahydrofurfuryl alcohol(THFA) by Ce(Ⅳ) in aqueous sulphuric acid medium was studied by titrimetric technique of redox in the temperature range of 298~313 K. The order was found to be unity with respect to both Ce(Ⅳ) and Ir(Ⅲ), and for tetrahydrofurfuryl alcohol the apparent reaction order was a positive fraction. It was found that the pseudo first order ([THFA]»[Ce(Ⅳ)]) rate constant, k(subscript obs) increased with the increase of [H(superscript +)] but decreased with the increase of [HSO(superscript - subscript 4)]. Under the protection of nitrogen, however, the reaction system could induce polymerization of acrylonitrile, indicating the generation of free radicals. A reasonable mechanism involving a preequilibrium was proposed. From the relation between k and [HSO(superscript - subscript 4)], Ce(SO4)2 was found to be the kinetically active species. The equilibrium constants and rate constants of the rate-determining step along with the activation parameters were evaluated.