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

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.