Oxidation of alcohols over Fe3+/montmorillonite-K10 using hydrogen peroxide

Oxidation of various primary and secondary alcohols is studied in liquid phase at atmospheric pressure over Fe3+/montmorillonite-K10 catalyst prepared by ion-exchange method at a pH of 4 in an environmentally friendly protocol using hydrogen peroxide. The catalyst and the method are found to be suitable for the selective oxidation of secondary alcohols to the corresponding ketones. Aromatic alcohols form mainly secondary or over oxidation products. Presence of -CH3 group at the -OH bearing carbon is deleterious to the oxidation. The catalyst activity increases with increase in reaction time due to the slow activation of the catalyst. The reaction mechanism is expected to involve the intermediate formation of binuclear, peroxide ion-bridged iron complex by reaction of iron and the activated peroxide followed by oxygen transfer to the alcohol. The catalyst is also found to be easily separable and recyclable. (C) 2002 Elsevier Science B.V All rights reserved.