Catalysis by Crystalline Mesoporous Molecular Sieves

Abstract

Crystalline mesoporous molecular sieves may be prepared under a wide range of conditions in the presence of cationic, anionic, gemini, or neutral surfactants. These mesostructured materials include pure and modified silicates, other metallic oxides and sulfides as well as aluminophosphates. Air calcination of silicate-based mesoporous molecular sieves with stable frameworks (MCM-41, MCM-48, SBA- n, MSU- n ) affords materials with extremely high surface areas. Their pore size may be adjusted from ca. 20 to more than 100 Å using different strategies. Because of their unique flexibility in terms of synthesis conditions, pore size tuning, and framework composition, these materials have been targeted for a number of potential applications, particularly in catalysis. The present review deals with the fast-growing area of catalysis by crystalline mesoporous materials. Three topics are discussed separately: (i) acid catalysis, (ii) redox catalysis, and (iii) miscellaneous applications. Particular attention is put on the patent literature, and some opportunities in the field of catalysis over these materials are pointed out.