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Flow-synthesis of mesoporous silicas and their use in the preparation of magnetic catalysts for Knoevenagel condensation reactions

Paper ID Volume ID Publish Year Pages File Format Full-Text
54901 47030 2013 8 PDF Available
Title
Flow-synthesis of mesoporous silicas and their use in the preparation of magnetic catalysts for Knoevenagel condensation reactions
Abstract

Mesoporous silica MCM-41 was successfully prepared by flow synthesis in a microreactor at shorter reaction times (i.e., minutes versus day) at high yield (i.e., 60% calcined sample) to give particles of more uniform size and shape compared to MCM-41 prepared by conventional batch synthesis. Magnetic iron oxide nanoparticles were incorporated and organic amines (i.e., propylamine and propyl diethylene amine) were grafted to obtain magnetic mesoporous catalysts for the Knoevenagel condensation reactions of benzaldehyde with ethyl cyanoacetate, ethyl acetoacetate and diethyl malonate. The incorporation of magnetic nanoparticles and large organic amines can hinder reactants access to the catalyst resulting in lower reactivity. NH2-magMCM-41 showed superb catalyst activity and selectivity for the all three Knoevenagel condensation reactions studied. The catalyst can be easily dispersed into solution and rapidly removed by a magnet for recovery and reuse.

Graphical abstractFlow-synthesis of MCM-41 in a microfluidic reactor produces small spherical MCM-41 particles (0.5 ± 0.1 μm) with narrow particle size distribution that could be converted into high active magnetic mesoporous base catalysts for Knoevenagel condensation reactions.Figure optionsDownload full-size imageDownload high-quality image (175 K)Download as PowerPoint slideHighlights► Flow-synthesis of MCM-41 was successfully implemented in a microfluidic reactor. ► MCM-41 with smaller particle size and narrow PSD was obtained by flow-synthesis at 2 min residence time. ► The MCM-41 was successfully converted into magnetic mesoporous base catalysts after incorporating magnetic nanoparticles and grafting organic amines. ► NH2-magMCM-41 with grafted propylamines have superb catalytic activity and selectivity for Knoevenagel condensation reaction. ► NH2-magMCM-41 is easily dispersed into the reaction mixture and can be readily recovered using a magnet.

Keywords
Catalyst; Mesoporous silica; Flow synthesis; Knoevenagel reaction; Magnetic
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Flow-synthesis of mesoporous silicas and their use in the preparation of magnetic catalysts for Knoevenagel condensation reactions
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 204, 15 April 2013, Pages 140–147
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
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Online Support
Any Questions? feel free to contact us