A comparison between [Ti]-MCM-41 and amorphous mesoporous silica-titania as catalysts for the epoxidation of bulky unsaturated alcohols

The preparation of a new amorphous mesoporous silica-titania (MST) is here reported. Following a modification of the standard procedure employed in the preparation of TS-1, a material showing a narrow pore size distribution in the mesopore region (approximate to 30 A mean pore diameter) is obtained. The catalytic features, tested in the epoxidation of a series of unsaturated terpenic alcohols, were compared with those of an ordered mesoporous material as Ti-containing MCM-41. MST displayed mainly a higher activity than [Ti]-MCM-41 and a progressive increase in epoxidation rate was observed passing from bishomoallylic to allylic alcohols. Under these conditions, a global improvement in alkene conversion was achieved using methylacetate as solvent, without a remarkable loss in epoxide selectivity. During repeated recycles no significant changes in both catalytic performances and active metal content were recorded. (C) 2001 Elsevier Science B.V. All rights reserved.