Delaminated zeolites:: Combining the benefits of zeolites and mesoporous materials for catalytic uses

The delamination of the layered precursor of the MCM-22 zeolite (MWW structure) affords monolayers of a crystalline aluminosilicate with more than 700 m(2) g(-1) of a well defined external surface formed by cups of 0.7 x 0.7 nm. In this layered structure the circular 10-member-ring microporous system is preserved. The resultant material presents the strong acidity and stability characteristic of the zeolites but, at the same time, offers the high accessibility to large molecules characteristic of the amorphous aluminosilicates. The cracking behavior during the process of small and large molecules has been compared with that of the zeolite MCM-22 and pillared laminar precursor MCM-36. (C) 1999 Academic Press.