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Aromatization and isomerization of 1-hexene over alkali-treated HZSM-5 zeolites: Improved reaction stability

Paper ID Volume ID Publish Year Pages File Format Full-Text
43044 45952 2008 14 PDF Available
Title
Aromatization and isomerization of 1-hexene over alkali-treated HZSM-5 zeolites: Improved reaction stability
Abstract

The HZSM-5 zeolites with micro-mesopore hierarchical porosity have been prepared by the post-synthesis of alkali treatment, and tested in the aromatization and isomerization reactions of 1-hexene in a continuous flow fixed bed. Effects of several variables upon the controlled formation of mesopores have been thoroughly investigated. The results showed that new mesopores could be created and enlarged on ZSM-5 zeolite by increasing the NaOH concentration, temperature and treatment time employed in the alkali treatment, among which the NaOH concentration was the most effective variable in the studied extent. However, excessive high NaOH concentration induced the collapse of zeolite framework, while high temperature and long treatment time induced the backward deposition of amorphous Si onto the zeolite, which would decrease the amount of formed mesopores. When the properly alkali-treated HZSM-5 zeolites were used as catalysts, the reaction activity of 1-hexene was enhanced, and the stabilities of aromatization and isomerization reactions were improved while that of the cracking reaction was deteriorated. These variations of reaction stabilities were associated with the introduction of mesopores over the zeolites, which shortened the diffusion pathlength of the feed/products and reduced the channel blockage.

Graphical abstractA series of HZSM-5 zeolites with micro-mesopore hierarchical porosity were prepared by adjusting the conditions employed in the post-synthesis of alkali treatment, and were found to be highly effective in improving the reaction stability of aromatization and isomerization of 1-hexene. The alkali-treatment conditions for the ZSM-5 zeolite were optimized, and the roles of the introduced mesopores in the improved catalytic performance were studied.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
HZSM-5 zeolite; Alkali treatment; Aromatization; Isomerization; 1-Hexene
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Aromatization and isomerization of 1-hexene over alkali-treated HZSM-5 zeolites: Improved reaction stability
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 338, Issues 1–2, 1 April 2008, Pages 100–113
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us