Hydrothermal incorporation of manganese in the framework of SBA-15

Manganese incorporated SBA-15 was synthesised by pre-hydrolyzing tetraethyl orthosilicate and manganese acetate above the isoelectric point of silica using tri-block copolymer as the template. The synthesised material was characterised by XRD, N2 adsorption, ESR, SEM and AAS techniques. XRD results revealed well-ordered hexagonal array of the materials. ESR spectral studies confirmed the incorporation of manganese in the framework of assynthesised and calcined materials. Synthesis gel of higher pH favoured better incorporation of manganese in the framework. Manganese exists in bivalent and trivalent states in all the materials. Their catalytic activity was examined in the liquid phase oxidation of ethylbenzene using tert-butyl hydroperoxide as the oxidant. Acetophenone, 2-phenylethanol and 1-phenylethanol were obtained as the major products. Ethylbenzene conversion increases with increase of manganese content in the catalyst.