KINETICS AND MECHANISM OF CERIUM(IV) OXIDATION OF PRIMARY AND SECONDARY ALCOHOLS CATALYZED BY CHROMIUM(III)

The cerium(IV) oxidation of isobutanol, isoamyl alcohol isopropyl alco hol, and secondary butanol catalysed by chromium(III) was studied in s ulphuric and perchloric acid mixture at 30 degrees C. The reaction was found to proceed with the formation of a chromium(IV) intermediate fo llowed by its complexation with alcohol. The complex thus formed decom posed into an aldehyde or ketone by a two-electron hydride ion transfe r. The formation constants for complexes were determined from Michaeli s-Menten plots. The accelerating effect of [H+] on the reaction is att ributed to the formation of active species, HCe(SO4)(3-) and HAlcohol( +), of the oxidant and alcohol, respectively. The activation parameter s were also determined and an isokinetic plot was found to be linear. (C) 1998 John Wiley gr Sons, Ltd.