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Impact of Zeolite Framework Composition and Flexibility on Methanol-To-Olefins Selectivity: Confinement or Diffusion?

Área de investigaciónQuímica y Ciencia y Tecnología de los Materiales
TítuloImpact of Zeolite Framework Composition and Flexibility on Methanol-To-Olefins Selectivity: Confinement or Diffusion?
Tipo de publicaciónArtículo de revista
Año de publicación2020
AutoresFerri, P., C. Li, R. Millán, J. Martinez-Triguero, M. Moliner, M. Boronat, y A. Corma
RevistaANGEWANDTE CHEMIE-INTERNATIONAL EDITION
Type of ArticleArticle; Early Access
Keywordsdiffusion, MTO, reaction mechanism, structure-selectivity relationship}, {ab initio calculations
Abstract

The methanol-to-olefins reaction catalyzed by small-pore cage-based acid zeolites and zeotypes produces a mixture of short chain olefins, whose selectivity to ethene, propene and butene varies with the cavity architecture and with the framework composition. The product distribution of aluminosilicates and silicoaluminophosphates with the CHA and AEI structures (H-SSZ-13, H-SAPO-34, H-SSZ-39 and H-SAPO-18) has been experimentally determined, and the impact of acidity and framework flexibility on the stability of the key cationic intermediates involved in the mechanism and on the diffusion of the olefin products through the8rwindows of the catalysts has been evaluated by means of periodic DFT calculations and ab initio molecular dynamics simulations. The preferential stabilization by confinement of fully methylated hydrocarbon pool intermediates favoring the paring pathway is the main factor controlling the final olefin product distribution.

DOI10.1002/anie.202007609