Formation of acid sites in ordered pores of FSM-16 by modification with sulfated zirconia

A mesoporous solid acid with ordered mesopores was prepared by modification of FSM-16 with sulfated zirconia (SO42-/ZrO2/FSM-16); FSM-16 precalcined a t 1123 K was soaked with an ethanol solution of zirconyl chloride, followed by exposing to 0.5 mol dm(-3) H2SO4 and calcining in air at 873 K. Measure ments of XRD and nitrogen adsorption isothermo showed the structure to cont ain the ordered pores, though its surface area and total pore volume were r educed to 619 m(2) g(-1) and 376 cm(3) g(-1) compared with 886 m(2) g(-1) a nd 490 cm(3) g(-1) for the unmodified FSM-16. The acid sites of zirconia pr omoted by sulfate ions were formed inside of the ordered pores. The activit y of (SO42-/ZrO2/FSM-16) for 1-butene isomerization was nine times larger t han that of the unmodified FSM-16. Two more acid-catalyzed reactions produc ing relatively large molecules were examined and catalytic activities of SO 42-/ZrO2/FSM-16 were compared with those of sulfated zirconia (SO42-/ZrO2) which is one of the solid superacids. The activities for Mukaiyama aldol co ndensation of 1 trimethylsilyloxycyclohexene with benzaldehyde were compara ble to each other, but the Friedel-Crafts benzoylation of toluene with benz oyl chloride or benzoic anhydride revealed the present catalyst to be much inferior to the sulfated zirconia for lack of superacidity. (C) 2001 Elsevi er Science B.V. All rights reserved.