Kinetics and mechanism of oxidation of D-galactose by quinolinium chlorochromate (QCC) in aqueous acetic acid medium

The oxidation kinetics of D-galactose with quinolinium chlorochromate, C9H7NHCrO3Cl, has been studied in aqueous acetic acid medium 50% (v/v) in the presence of perchloric acid at constant ionic strength. The reaction under pseudo-first order condition, is first order with respect to both the [oxidant] and the [substrate]. The reaction is markedly catalysed by [H+] and the effect of [NaClO4] is negligible. Increasing the dielectric constant of medium decreases the reaction rate. A 1 : 1 stoichiometry is observed and the reaction did not induce the polymerisation of acrylonitrile. The reaction has been carried out at different temperatures and the various activation parameters have been computed. A probable mechanism of the reaction is suggested.