Oxidation of aliphatic alcohols by pyridinium fluorochromate: a kinetic study

Abstract

The oxidation of aliphatic primary alcohols by pyridinium fluorochromate (PFC), to the corresponding aldehydes, is first order with respect to PFC but the order with respect to the alcohol is less than one. The initial formation of a complex between the alcohol and PFC is thus indicated. The oxidation of [1,1-²H₂]ethanol indicated the presence of a substantial primary kinetic isotope effect. The formation constants of the alcohol–PFC complex and the rate of its disproportionation have been determined. The rate of decomposition of the complex is susceptible to both polar and steric effects of the substituent. The reaction involves a hydride-ion transfer in the rate-determining step.