Kinetics and mechanism of the oxidation of substituted benzyl alcohols by pyridinium chlorochromate

Abstract

The oxidation of benzyl alcohol by pyridinium chlorochromate is first order with respect to both the oxidant and the alcohol. The reaction is catalysed by acid, the catalysed reaction being nearly first order in acidity. The kinetic isotope effect, k_H/k_D, is 5.07 at 30 °C. The reaction does not induce polymerisation of acrylonitrile. The reaction constant ρ for the uncatalysed and acid-catalysed oxidation of benzyl alcohol and eight monosubstituted benzyl alcohols have the values –1.70 ± 0.08 and –1.45 ± 0.06, respectively at 25 °C. Probable mechanisms are discussed.