The Oxidative Transformation of Substituted Mandelic acids by Ethylenediammonium Dichromate in AcOH-H2 O medium: (A Kinetic Study)

Abstract

The oxidation of Mandelic Acids to the corresponding oxoacids with ethylenediammonium dichromate (EDDC) in aqueous acetic acid has been studied. The reaction is first order with respect to [EDDC] and less than two order observed for Mandelic acids and [H+]. The oxidation of α-deuteriomandelic acid shows the presence of a primary kinetic isotope effect (kH/kD = 6.01 at 298K). The reaction has been found to be catalyzed by [H+] ions. The various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of the isokinetic relationship. With a negative reaction constant (ρ), the reaction displayed a strong correlation with the Hammett σ values. All of the chosen Mandelic acids are oxidised by the same process, according to the Exner plot.