CATALYSIS BY CRYSTALLINE MESOPOROUS MOLECULAR-SIEVES

Crystalline mesoporous molecular sieves may be prepared under a wide r ange of conditions in the presence of cationic, anionic, gemini, or ne utral surfactants. These mesostructured materials include pure and mod ified silicates, other metallic oxides and sulfides as well as alumino phosphates. Air calcination of silicate-based mesoporous molecular sie ves with stable frameworks (MCM-41, MCM-48, SBA-n, MSU-n) affords mate rials with extremely high surface areas. Their pore size may be adjust ed from ca. 20 to more than 100 Angstrom using different strategies. B ecause of their unique flexibility in terms of synthesis conditions, p ore size tuning, and framework composition, these materials have been targeted for a number of potential applications, particularly in catal ysis. The present review deals with the fast-growing area of catalysis by crystalline mesoporous materials. Three topics are discussed separ ately: (i) acid catalysis, (ii) redox catalysis, and (iii) miscellaneo us applications. Particular attention is put on the patent literature, and some opportunities in the field of catalysis over these materials are pointed out.