Shape Selectivity in Catalysis

Morphology Induced Shape Selectivity in Zeolite Catalysis

Understanding zeolite catalysis: inverse shape selectivity revised.

Anyone who has experience in moving house [the Angewandte team has just done this!] knows that those boxes filled with small books are the heaviest, because these small objects pack so easily. The same entropy effect explains the catalytic selectivity towards the formation of branched hydrocarbons in zeolites. The pink tubes represent the zeolite pores at high loading in which effective size di...

Shape selectivity in primate frontal eye field.

Previous neurophysiological studies of the frontal eye field (FEF) in monkeys have focused on its role in saccade target selection and gaze shift control. It has been argued that FEF neurons indicate the locations of behaviorally significant visual stimuli and are not inherently sensitive to specific features of the visual stimuli per se. Here, for the first time, we directly examined single ce...

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...

Shape selectivity extending to ordered supermicroporous aluminosilicates.

In the synthesis of polyoxymethylene dimethyl ethers (PODEn) catalyzed by ordered supermicroporous aluminosilicates, shape selectivity was observed and the high selectivity for target products (PODE3-8) was attributed to the particular pore diameter.