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Abstract:
n-Butane conversion was used as a probe reaction to investigate the influence of acidity and topology of zeolites on the reaction properties at low temperatures. The results show that the number of catalytic Brønsted acid sites determines the reaction rates. The bimolecular pathway of n-butane reaction requires two adjacent acid sites, while the monomolecular reaction occurs on the isolated Brønsted sites. The contribution of bimolecular reaction primarily affected by the number of catalytic Brønsted sites and secondly influenced by the zeolite topology. The zeolites with larger cavity provide enough space for the formation and the transformation of bulky C8 intermediates in bimolecular pathway and give rise to the higher contribution of bimolecular pathway. The distribution of bimolecular products strongly depends on the maximum free sphere diameter of zeolites, while has no direct relationship with the volume of the zeolite cavities. This can be explained by a molecular sieve effect of zeolite channels on the diffusion rates of propane, isobutane, and pentane from cavities to external surface of zeolites. This improved understanding of the molecular sieve effect allows one to design and select appropriate zeolites for a special reaction. © 2019 Elsevier Inc.
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Microporous and Mesoporous Materials
ISSN: 1387-1811
Year: 2020
Volume: 292
5 . 4 5 5
JCR@2020
4 . 8 0 0
JCR@2023
ESI HC Threshold:196
JCR Journal Grade:1
CAS Journal Grade:2
Cited Count:
SCOPUS Cited Count: 24
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 2
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