Insight into D-galactose Oxidation: Kinetic and Mechanistic Analysis with Imidazolium Fluorochromate

Abstract

In a 50% (v/v) aqueous acetic acid medium, a study on the oxidation kinetics of D-galactose by imidazolium fluorochromate (IFC) was conducted. The study revealed unit-order dependence on [D-galactose], [IFC], and [perchloric Acid]. The reaction was catalyzed by perchloric acid, and followed a 1:1 stoichiometric ratio. Adding sodium hyperchlorate (VII) salt did not affect the reaction. Polymerization of acrylonitrile was not observed in the oxidation process. The oxidation rates were retarded on adding Mn2+ ions in the mixture, and rates increased as the reaction medium’s dielectric constant (D) decreased. The observed results follow the Amis and Kirkwood plots {log k1 vs. (1/D) and ((D-1/2D+1))}. Several thermodynamic variables were determined by analyzing the kinetic data across a temperature range. Arabinose and formic acid were formed as the products of the reaction. A mechanistic path involving the formation of an ester followed by hydride ion transfer was proposed.