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Direct Evidence for the Nonrandom Nature of Al Substitution in Zeolite ZSM‐5: An Investigation by 27 Al MAS and MQ MAS NMR
Author(s) -
Han Oc Hee,
Kim ChangSam,
Hong Suk Bong
Publication year - 2002
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 - 10.1002/1521-3773(20020201)41:3<469::aid-anie469>3.0.co;2-k
Subject(s) - zeolite , substitution (logic) , crystallization , zsm 5 , content (measure theory) , diffraction , nmr spectra database , tetrahedron , crystallography , chemistry , spectral line , computer science , physics , mathematics , organic chemistry , catalysis , mathematical analysis , astronomy , optics , programming language
Incorporation of Al atoms in particular sites in the ZSM‐5 structure is governed by the Si/Al ratio during synthesis, and their distribution over the twelve types of tetrahedral sites (T1–T12) during crystallization occurs in a nonrandom manner according to the results of 27 Al MAS NMR measurements on a series of as‐made ZSM‐5 zeolites with Si/Al=14–250. Further support for this conclusion was provided by 27 Al MQMAS spectra (see picture) simulated with X‐ray diffraction data.