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 th e preparation of TS-1, a material showing a narrow pore size distribution i n the mesopore region (approximate to 30 A mean pore diameter) is obtained. The catalytic features, tested in the epoxidation of a series of unsaturat ed terpenic alcohols, were compared with those of an ordered mesoporous mat erial as Ti-containing MCM-41. MST displayed mainly a higher activity than [Ti]-MCM-41 and a progressive increase in epoxidation rate was observed pas sing from bishomoallylic to allylic alcohols. Under these conditions, a glo bal improvement in alkene conversion was achieved using methylacetate as so lvent, without a remarkable loss in epoxide selectivity. During repeated re cycles no significant changes in both catalytic performances and active met al content were recorded. (C) 2001 Elsevier Science B.V. All rights reserve d.