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Acid catalyzed organic transformations by heteropoly tungstophosphoric acid supported on MCM-41

Paper ID Volume ID Publish Year Pages File Format Full-Text
41272 45883 2012 10 PDF Available
Title
Acid catalyzed organic transformations by heteropoly tungstophosphoric acid supported on MCM-41
Abstract

In this work, solid acid catalysts of the Keggin-type 12-tungstophosphoric acid (H3PW12O40, HPW) incorporated within the mesochannels of MCM-41 are prepared through a simple and effective impregnation method. The catalysts are characterized by various techniques such as XRD, FTIR, TEM, N2 adsorption and thermal analysis. The surface acidities are measured by non-aqueous titration of n-butyl amine in acetonitrile and FTIR spectra of chemisorbed pyridine. The acidity and the textural parameters of the nanocomposites can be controlled simply by changing the loading of HPW on the MCM-41. The results indicate that the surface saturation coverage of MCM-41 is reached with 60 wt% HPW. The high saturation coverage is indicative of the well-dispersion of HPW within the mesochannels of MCM-41. The catalytic activities of the HPW/MCM-41 catalysts for the Pechmann, esterification reaction and Friedel–Crafts acylation reactions are studied in detail. Both the surface acidity and the catalytic activity sharply increase with the modification of MCM-41 by HPW. The sample with 60 wt% HPW shows the highest acidity and catalytic activity. The reusability tests of the catalysts show that the catalysts can be used several times without significant loss in activity. The HPW/MCM-41 catalysts have great potential for applications as commercial catalysts in promoting acid-catalyzed organic transformations under environmental friendly conditions and processes.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (220 K)Download as PowerPoint slideHighlights► MCM-41-suppported 12-tungstophosphoric acid was used as catalyst. Catalysts show high acidity and surface saturation conerage up to 60 HPW wt%. ► The catalysts exhibit high activity towards many organic reactions. The catalysts can be recycled several times without significant loss in activity.

Keywords
Solid acid catalyst; MCM-41; Heteropoly acid; Pechmann; Esterification; Friedel–Crafts acylation reactions
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Acid catalyzed organic transformations by heteropoly tungstophosphoric acid supported on MCM-41
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 411–412, 16 January 2012, Pages 77–86
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