Synthesis, characterization and catalytic activity of cubic Ia3d and hexagonal p6mm mesoporous aluminosilicates with enhanced acidity

Abstract

Through a two-step crystallization procedure, an ordered mesoporous aluminosilicate with cubic Ia3d structure denoted as MB48 has been synthesized from the assembly of preformed zeolite beta precursors, utilizing cetyltrimethylammonium bromide (CTAB) as a template. By adjusting the alkalinity during the second crystallization step, an ordered mesoporous aluminosilicate with hexagonal p6mm structure named as MB41 has also been prepared. MB48 and MB41 were characterized with PXRD, FTIR, ²⁷Al-MAS NMR, N₂ adsorption–desorption and NH₃-TPD techniques, etc. Experiments show that both MB48 and MB41 are pure mesoporous phases, containing the secondary structural units of zeolite beta. Compared with conventional mesoporous aluminosilicates, MB48 and MB41 have enhanced acidity and show higher catalytic activity in the cracking of cumene and the phenol alkylation with tert-butanol.