Facile synthesis and catalytic properties of titanium containing silica-pillared clay derivatives with ordered mesoporous structure through a novel intra-gallery templating method

Facile synthesis of titanium containing silica-pillared clay derivatives with ordered mesoporous structure from a novel intra-gallery templating route is successfully established. The ordered mesoporous titanium containing silica-pillared clay materials obtained by a surfactant-directed assembly of silica species in the interlayer space of natural montmorillonite, are characterized by a mesoporous structure with uniform pores (2.7 nm) between the layers. These results indicate that surfactant plays a decisive role in pore formation, because it acts as a micelle-like template during the hydrolysis of organic precursor. The main titanium species was tetrahedrally coordinated in the gallery silica framework. The increase of Ti content leads to a gradual reduction of quality of pore structure and of the pore volumes. Up to a Ti loading corresponding to Si/Ti = 20 the titanium is mainly tetracoordinated and the highest conversions of cyclohexene with anhydrous tert-butylhydroperoxide are obtained, with excellent selectivity for the epoxide. However, a further increase of Ti content to Si/Ti of 10 and 5, leads to an undesirable decrease of conversion and selectivity.