The kinetics of oxidation of aliphatic alcohols by pyridinium dichromate (PDC) in non-aqueous medium at 303 K leads to the formation of corresponding aldehydes. In this oxidation reaction Cr(VI) acts as two electron oxidizing agent. The reaction is first order with respect to each [oxidant], [TsOH] and [Alcohol] The reaction mixture failed to induce the polymerization of added acrylonitrile. The reaction is catalysed by hydrogen ions. The decrease in dielectric constant of the medium increases the rate of the reaction or low dielectric constant of the medium favours the reactivity. The reaction has been conducted at five different temperature and the activation parameters were calculated. The observed experimental data have been rationalized as follows: the intramolecular proton transfer occurs after the prior formation of a dichromate ester in the rate determining step. Negative ΔS# values indicate a structured transition state.
Kinetics and Mechanism, Oxidation, Pyridinium dichromate, p-Toluene sulphonic acid, Dimethyl sulphoxide