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Elucidating Zeolite Channel Geometry–Reaction Intermediate Relationships for the Methanol‐to‐Hydrocarbon Process
Author(s) -
Fu Donglong,
Lucini Paioni Alessandra,
Lian Cheng,
Heijden Onno,
Baldus Marc,
Weckhuysen Bert M.
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202009139
Subject(s) - zeolite , magic angle spinning , olefin fiber , spectroscopy , methanol , nuclear magnetic resonance spectroscopy , chemistry , hydrocarbon , alkylation , selectivity , solid state nuclear magnetic resonance , catalysis , materials science , chemical physics , chemical engineering , organic chemistry , nuclear magnetic resonance , quantum mechanics , engineering , physics
The chemical industry has exploited zeolite shape selectivity for more than 50 years, yet our fundamental understanding remains incomplete. Herein, the zeolite channel geometry–reactive intermediate relationships are studied in detail using anisotropic zeolite ZSM‐5 crystals for the methanol‐to‐hydrocarbon (MTH) process, and advanced magic‐angle spinning solid‐state NMR (ssNMR) spectroscopy. The utilization of anisotropic ZSM‐5 crystals enabled the preferential formation of reaction intermediates in single‐orientation zeolite channels, as revealed by molecular dynamics simulations and in situ UV/Vis diffuse‐reflectance spectroscopy. The ssNMR results show that the slightly more constrained sinusoidal zeolite channels favor the olefin cycle by promoting the homologation of alkanes, whereas the more extended straight zeolite channels facilitate the aromatic cycle with a higher degree of alkylation of aromatics. Dynamic nuclear polarization experiments further indicate the preferential formation of heavy aromatics at the zeolite surface dominated by the sinusoidal channels, providing further insight into catalyst deactivation.