Siberian Federal University

We report in the present paper the kinetic and mechanistic study of the oxidation of L-arabinose by pyridinium chlorochromate C 5 H 5 NHCrO 3 Cl, The reaction has been carried out in aqueous acetic acid 50 % (v/v) medium in presence of perchloric acid at constant ionic strength. The reaction has been found to be first order with respect to each of the oxidant and substrate under pseudo-first order conditions. The reaction is catalyzed by acid and follows a first order dependence on H ion concentration. The ionic strength variation has no effect on the reaction rate. The decreases in dielectric constant of the medium increase the rate of reaction. A 1:1 stoichiometry is observed in the oxidation and the reaction rate is not retarded by the addition of radical trapping agent acrylonitrile. Effect of temperature on the rate of oxidation has been studied to show the validity of Arhenius equation and various activation parameters have been computed. The products are identified to be L-erythrose and formic acid. On the observed facts a hydride ion transfer mechanism is proposed.