Understanding zeolite catalysis: inverse shape selectivity revised.

Morphology Induced Shape Selectivity in Zeolite Catalysis

Methylation of Naphthalene with Methanol over SAPO-11 Zeolite

Shape-selective methylation of naphthalene (NAPH) over SAPO-11 zeolite was carried out in a fixed-bed flow reactor under atmospheric pressure. Some zeolites, such as H-beta (Hβ), HUSY and ZSM-5 were also evaluated for comparison with SAPO-11 zeolite.The results showed that SAPO-11 exhibited higher stability, higher selectivity of  2,6-dimethylnaphthalene (2,6-DMN), and higher 2,6-/2,7-DMN r...

Solvent Polarity-Induced Pore Selectivity in H-ZSM-5 Catalysis

Molecular-sized micropores of ZSM-5 zeolite catalysts provide spatial restrictions around catalytic sites that allow for shape-selective catalysis. However, the fact that ZSM-5 has two main pore systems with different geometries is relatively unexploited as a potential source of additional shape selectivity. Here, we use confocal laser-scanning microscopy to show that by changing the polarity o...

Phosphorus promotion and poisoning in zeolite-based materials: synthesis, characterisation and catalysis

Phosphorus and microporous aluminosilicates, better known as zeolites, have a unique but poorly understood relationship. For example, phosphatation of the industrially important zeolite H-ZSM-5 is a well-known, relatively inexpensive and seemingly straightforward post-synthetic modification applied by the chemical industry not only to alter its hydrothermal stability and acidity, but also to in...

The catalytic diversity of zeolites: confinement and solvation effects within voids of molecular dimensions.

The ability of molecular sieves to control the access and egress of certain reactants and products and to preferentially contain certain transition states while excluding others based on size were captured as shape selectivity concepts early in the history of zeolite catalysis. The marked consequences for reactivity and selectivity, specifically in acid catalysis, have since inspired and sustai...