Catalysts from MCM-41: Framework modification, pore size engineering, and organic-inorganic hybrid materials

Abstract

The mesoporous material, MCM-41, is characterized by an extremely high surface area and a one-dimensional system of cylindrical pores with a narrow size distribution in the mesopore range. Adjustment of the pore size over the range 2.0-4.0 nm can be easily achieved by selection of a templating agent. However, the material has little intrinsic catalytic activity. In order to take advantage of the unique opportunities inherent in the defined porosity, catalytic activity has to be introduced. This can be done by inorganic ions, or by affixing organic/metal-organic active groups on the material. We describe catalysts for high temperature gas-phase reactions where functionalization has been achieved by the introduction of framework alumina and platinum. For liquid-phase reactions, we developed solid bases as well as solid Lewis acids based upon modified MCM-41. Through pore size engineering, i.e. matching the pore size to the size of the reacting molecules, the selectivity of the catalyst can be increased, as shown for the preparation of linear alkyl benzenes. © 2002 Elsevier Science B.V. All rights reserved.