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Pillared MWW zeolites MCM-36 prepared by swelling MCM-22P in concentrated surfactant solutions

Paper ID Volume ID Publish Year Pages File Format Full-Text
55611 47059 2012 8 PDF Available
Title
Pillared MWW zeolites MCM-36 prepared by swelling MCM-22P in concentrated surfactant solutions
Abstract

Lamellar zeolite forms like layered MCM-22 precursor, MCM-22P, offer unprecedented opportunities for creating diversity of more open zeolite structures prepared post-synthesis by expanding and modifying the interlamellar space. This is a relatively unexplored area with regard to procedures ensuring easy, least destructive and most efficient expansion of layered zeolites. Herein we explore concentrated surfactant solutions with high pH for their ability to provide swollen MCM-22 that can be converted to the pillared MCM-36. High pH of the swelling solutions was obtained by addition of tetrapropylammonium hydroxide and by partial conversion of the surfactant chloride into hydroxide by ion exchange. The products were evaluated based on their X-ray diffraction characteristics, sorption properties, scanning electron microscopy and IR spectra as indicators of catalytic potential. The swelling/pillaring efficiency was judged based on BET surface area and depended on swelling conditions, especially the apparent basicity. There was an overall decrease in acid site concentration due to incorporation of inert silica pillars. The MCM-36 zeolite with the highest BET showed increased uptake of 2,6-di-tert-butyl-pyridine by 75% compared to the parent MCM-22 suggesting enhanced accessibility of acid sites for bulky probe molecules. We conclude that concentrated surfactant solutions can be effective in swelling MCM-22P even at room temperature but an optimal approach must balance many factors including yield and activity of the final product.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (147 K)Download as PowerPoint slideHighlights► The expanded range of swelling conditions for MCM-22P was studied. ► The suitability of such swollen zeolites for pillaring treatment leading to MCM-36 was studied. ► We concluded that the concentrated surfactant solutions are effective in swelling MCM-22P even at room temperature. ► These swollen materials are appropriate for pillaring resulted in MCM-36.

Keywords
MCM-22 family; MCM-36; MWW structure; X-ray powder diffraction
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Pillared MWW zeolites MCM-36 prepared by swelling MCM-22P in concentrated surfactant solutions
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 179, Issue 1, 5 January 2012, Pages 35–42
Authors
, , , , ,
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