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Oxidative bromination of methane on silica-supported non-noble metal oxide catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
43083 45954 2009 6 PDF Available
Title
Oxidative bromination of methane on silica-supported non-noble metal oxide catalysts
Abstract

Oxidative bromination of methane, mediated by HBr/H2O (solution), provides an original route for the production of oxygenates and gasoline directly from natural gas. However, the reported catalysts for this reaction all involved noble metals. From the consideration of replacing noble metal catalysts with cheaper oxides, various silica-supported oxide catalysts were surveyed. It was found that the redox ability of different metals had a strong impact on the product distribution. On the catalysts with metals that lack facile redox ability, such as BaO/SiO2, both CH3Br and CO were main products. Otherwise, deep oxidation proceeded. Moreover, methanol was firstly reported in this system. In order to obtain a molar ratio of (CH3OH + CH3Br): CO = 1, which can provide a perfect feedstock for the synthesis of acetic acid, the process variables were optimized on BaO/SiO2. It was demonstrated that 44.0% methane conversion and 95% total selectivity of CH3Br, CH3OH and CO could be achieved at 620 °C, and the molar ratio of (CH3Br + CH3OH): CO was close to 1. Time-on-stream tests showed declined catalytic performance after 30 h. The results from N2-adsorption, XRF and XRD implied that aggregation of barium particles occurred, making the metathesis between BaO and BaBr2 difficult. The functions of BaO were also proposed. Additionally, the activity data were compared with those of noble metal catalysts.

Graphical abstractVarious silica-supported non-noble metal oxide catalysts were investigated for the oxidative bromination of methane, mediated by HBr/H2O. BaO/SiO2 showed good activity for its lack of facile redox capacity, but suffered deactivation after 30 h. The characterization results implied that aggregation of barium particles occurred, which made the metathesis between BaO and BaBr2 difficult. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Methane oxidative bromination; Non-noble metal oxide; BaO/SiO2; (CH3OH + CH3Br): CO; Metathesis; Deactivation mechanism
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Oxidative bromination of methane on silica-supported non-noble metal oxide catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 353, Issue 1, 31 January 2009, Pages 87–92
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