Comparison on the Catalytic Cracking and Alkylation Activities between MSU-SMFI and MCM-41 Aluminosilicates

Abstract

Mesoporous aluminosilicates MSU-SMFI with well-ordered hexagonal symmetry were assembled from MFI zeolitic precursors containing abundant protozeolitic nanoclusters. Normal MCM-41 was synthesized by using tetraethyl orthosilicate (TEOS) and sodium aluminate as silica source and aluminum source,respectively. The pore diameter of MSU-SMFI sample and normal MCM-41 both are 2.70 nm, and their BET specific surface areas and pore volumes are comparable as seen from XRD and N2 sorption results. Although both MSU-SMFI and MCM-41 possess weak acidic sites and medium strong acidic sites in NH3-TPD profiles, the density of weak acidic sites and medium strong acidic sites in MSU-SMFI are much higher than that of MCM-41.The catalytic cracking conversion of cumene on MSU-SMFI is 31% higher than that on MCM-41 with the same Si/Al ratio, and the butylation conversion of naphthalene over MSU-SMFI is 15% higher than that on the MCM-41 sample. Incorporation of MFI zeolitic nanoclusters into the mesostructured framework of MSU-SMFI led to enhanced acidity.