Mesoporous nanocrystaline zeolite composition and preparation from amorphous colloidal metalosilicates

Abstract

Mesoporous ZSM compositions and methods of preparing same are provided. The starting material is an amorphous metallosilicate which is processed into ZSM-type nanocrystals. Upon calcinations, meso-ZSM-nanaocrystals are prepared.

Description

FIELD OF THE INVENTION [0001] A mesoporous zeolite material having microporous crystalline mesopore walls and a process of preparing same is described. BACKGROUND OF THE INVENTION [0002] Crystalline molecular sieves are widely used as catalysts in the industry since they possess catalytically active sites as well as uniformly sized and shaped micropores, that allow for their use as shaped selective catalysts in, for instance, oil refining, petrochemistry and organic synthesis. However, due to the pore size constraints, the unique catalytic properties of zeolites are limited to reactant molecules having kinetic diameters below 10 .angrostoms. [0003] A series of mesoporous molecular sieves with increased diameters were disclosed in U.S. Pat. Nos. 5,057,296 and 5,102,643. These molecular sieves overcome the limitation of microporous zeolites and allow the diffusion of larger molecules. These materials, however, are amorphous solids. Amorphous silica-aluminas have much weaker acid sites...

AI Technical Summary

Problems solved by technology

However, due to the pore size constraints, the unique catalytic properties of zeolites are limited to reactant molecules having kinetic diameters below 10 .angrostoms.

Amorphous silica-aluminas have much weaker acid sites than zeolites and thus do not exhibit the spectacular catalytic properties of acidic zeolites.

Moreover, their hydrothermal stability is low and, as a consequence, their industrial use as catalysts is very limited