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Impact of Zeolite Framework Composition and Flexibility on Methanol‐To‐Olefins Selectivity: Confinement or Diffusion?
Author(s) -
Ferri Pau,
Li Chengeng,
Millán Reisel,
MartínezTriguero Joaquín,
Moliner Manuel,
Boronat Mercedes,
Corma Avelino
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202007609
Subject(s) - chemistry , propene , selectivity , olefin fiber , zeolite , product distribution , diffusion , catalysis , cationic polymerization , methanol , hydrocarbon , butene , molecular dynamics , computational chemistry , chemical engineering , organic chemistry , thermodynamics , ethylene , physics , engineering
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 the 8r windows 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.