Kinetic and Mechanistic Studies in the Oxidative Regeneration of Carbonyl Compounds from Oximes by Imidazolium Fluorochromate

The oxidative deoximination of several aldo- and keto-oximes by imidazolium fluorochromate (IFC), in dimethylsulphoxide (DMSO), exhibited a first order dependence on IFC. A Michaelis-Menten type kinetics was observed with respect to oximes. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in nineteen different organic solvents. The solvent effect has been analysed by multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step is suggested.