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Desilication of a TON zeolite with NaOH: Influence on porosity, acidity and catalytic properties

Paper ID Volume ID Publish Year Pages File Format Full-Text
41434 45889 2011 10 PDF Available
Title
Desilication of a TON zeolite with NaOH: Influence on porosity, acidity and catalytic properties
Abstract

A TON zeolite (Si/Al = 31) was treated at 353 K with NaOH solutions of different concentrations C (0.05–0.4 M) and for different times t (30–300 min). The resulting samples were characterized by various techniques: SEM, XRD, nitrogen adsorption–desorption, pyridine chemisorption followed by FTIR and 1-butene isomerisation at 333 K. The filtrate analysis shows a simultaneous dissolution of Si and Al with a large preference for Si (Si/Al from 35 to 150), especially at high t and low C values. The increase with t of the filtrate Si/Al ratio was related to the redeposition of Al on the zeolite under the form of extraframework species with Lewis acidity. The alkali treatment caused the creation of mesopores with ∼20 nm diameter, a limited decrease in the Brønsted acidity and a significant increase in the Lewis acidity. With all samples, 1-butene double bond shift selectively occurred but with a fast deactivation due to carbonaceous deposits which can be eliminated from the zeolite through nitrogen sweeping. Desilication had no effect on the catalyst stability but increased the initial activity. The activity per protonic site (TOF) was shown to be correlated with the volume of created mesopores, which shows that these mesopores facilitate the access of 1-butene molecules to the active sites.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (86 K)Download as PowerPoint slideHighlights► NaOH treatment conditions influence on the desilication of TON zeolite. ► Porosity modification of intermediate pore size zeolite TON. ► Influence of TON desilication on the 1-butene double bond shift reaction. ► Influence of TON desilication on the acidity. ► Active sites accessibility in desilicated TON zeolite.

Keywords
Desilication; TON zeolite; Mesopore; Acidity; 1-Butene isomerisation
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Desilication of a TON zeolite with NaOH: Influence on porosity, acidity and catalytic properties
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 399, Issues 1–2, 31 May 2011, Pages 100–109
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
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Any Questions? feel free to contact us