Direct Detection of Supramolecular Reaction Centers in the Methanol-to-Olefins Conversion over Zeolite H-ZSM-5 by 13C–27Al Solid-State NMR Spectroscopy

CATEGORY: METHANOL TO OLEFINS
Direct Detection of Supramolecular Reaction Centers in the Methanol-to-Olefins Conversion over Zeolite H-ZSM-5 by 13C–27Al Solid-State NMR Spectroscopy

Type	Journal Article
Author	Chao Wang
Author	Qiang Wang
URL	http://onlinelibrary.wiley.com/doi/10.1002/ange.201510920/abstract
Volume	128
Issue	7
Pages	2553-2557
Publication	Angewandte Chemie
Date	February 12, 2016
Abstract	Hydrocarbon-pool chemistry is important in methanol to olefins (MTO) conversion on acidic zeolite catalysts. The hydrocarbon-pool (HP) species, including methylbenzenes and cyclic carbocations, confined in zeolite channels during the reaction are critical in determining the reaction pathway. Authors experimentally prove the formation of supramolecular reaction centers composed of organic hydrocarbon species and the inorganic zeolite framework in H-ZSM-5 zeolite by advanced 13C–27Al double-resonance solid-state NMR spectroscopy. Methylbenzenes and cyclic carbocations located near Brønsted acid/base sites form the supramolecular reaction centers in the zeolite channel. The internuclear spatial interaction/proximity between the 13C nuclei (associated with HP species) and the 27Al nuclei (associated with Brønsted acid/base sites) determines the reactivity of the HP species. The closer the HP species are to the zeolite framework Al, the higher their reactivity in the MTO reaction.