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Titanium and cerium-containing mesoporous silicate materials as catalysts for oxidative cleavage of cyclohexene with H2O2: A comparative study of catalytic activity and stability

Paper ID Volume ID Publish Year Pages File Format Full-Text
43698 45983 2008 6 PDF Available
Title
Titanium and cerium-containing mesoporous silicate materials as catalysts for oxidative cleavage of cyclohexene with H2O2: A comparative study of catalytic activity and stability
Abstract

Catalytic properties of transition-metal-containing silicate materials with hexagonally packed mesopore-channels, Ti-MMM-2 and Ce-SBA-15, have been studied in oxidative cleavage of cyclohexene (CyH) to adipic acid using aqueous H2O2 as oxidant. In a solvent-free system, the yield of adipic acid reached 10–15% at H2O2/CyH 3.6 mol mol−1 and 80 °C after 72 h. The stepwise addition of the oxidant to the reaction mixture allowed increasing the yield of the target product up to 33 and 18% for Ti-MMM-2 and Ce-SBA-15, respectively. For both catalysts, the yield of adipic acid decreased significantly in the second run despite CyH conversion attained 100%. The catalyst stability and the reasons of the deactivation have been explored. For both catalytic materials, partial decrease of the mesopore surface area and mesopore volume was observed after the CyH oxidation run. DRS–UV–vis study revealed irreversible formation of oligomerized TiO2-like species on the Ti-MMM-2 surface due to interaction of Ti centres with the oxidant and the reaction products. The elemental analysis data showed that adipic acid causes leaching of titanium from Ti-MMM-2 into solution. Ce-SBA-15 was found to be more stable with respect to the active metal leaching but prone to deactivation due to agglomeration of cerium ions to form cerium oxide nanocrystallites; partial reduction of Ce(IV) to Ce(III) also occurred.

Graphical abstractAdipic acid can be obtained with the yield of 18 and 33% over transition-metal-containing silicate materials Ti-MMM-2 and Ce-SBA-15, respectively, via oxidative cleavage of cyclohexene with aqueous H2O2. Both high concentration of the oxidant and polar reaction products lead to irreversible catalysts deactivation. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Cyclohexene; Oxidation; Hydrogen peroxide; Adipic acid; Titanium; Cerium; Mesoporous silicate materials
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Titanium and cerium-containing mesoporous silicate materials as catalysts for oxidative cleavage of cyclohexene with H2O2: A comparative study of catalytic activity and stability
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 345, Issue 2, 1 August 2008, Pages 195–200
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