Tailoring the pore size of mesoporous sulfated zirconia

In the early 1990s aggregates of surfactant molecules were used as template s to make mesoporous silicate materials, the first of these being MCM-41. T his method is called liquid-crystal templating (LCT). In the work reported here, the LCT method has been applied to zirconia in order to synthesize me soporous sulfated zirconia. The materials have been characterized by X-ray diffraction, infrared spectroscopy and nitrogen-adsorption measurements. Zi rconia treated with sulfuric acid exhibits extremely strong acidity and is capable of catalyzing the isomerization of n-butane at room temperature. Th e conventional preparations of this catalyst lead to microporous material o f high catalytic activity for reactions of small molecules in the vapor pha se; this material is less suited for liquid-phase reactions of larger molec ules. By using the neutral templating method it is possible to synthesize m esoporous sulfated zirconia, and by changing synthetic parameters, such as surfactant concentration and cosolvent, it is possible to alter the size of the mesopores. Preliminary catalytic testing has shown that the diameter o f the pores of the catalyst does affect the reaction rate for a specific la rge-molecule alkylation reaction in the liquid phase. (C) 2000 Elsevier Sci ence B.V. All rights reserved.