Catalytic epoxidation of unsaturated alcohols on Ti-MCM-41

The catalytic epoxidation of a series of unsaturated terpenic alcohols was carried out on titanium-containing MCM-41 mesoporous materials with tert-butylhydroperoxide. A direct comparison between in-framework Ti-MCM-41 and Ti-grafted MCM-41 showed a better performance of the latter, even if the difference between them becomes lower as the alcoholic group approaches the C=C double bond. At 358 K and in both acetonitrile and ethyl acetate, the epoxidation rate of the double bond is ruled, on these catalysts, mainly by electronic factors, which cause the preferential oxidation of internal unsaturations instead of the terminal ones. It is also governed by the OH-function position, so that, particularly in ethyl acetate, the closer the hydroxyl group to the unsaturation, the higher is the conversion rate of the terpene. (C) 2000 Elsevier Science B.V. All rights reserved.