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Role of Cr and V on the stability of potassium-promoted iron oxides used as catalysts in ethylbenzene dehydrogenation

Paper ID Volume ID Publish Year Pages File Format Full-Text
41364 45886 2011 7 PDF Available
Title
Role of Cr and V on the stability of potassium-promoted iron oxides used as catalysts in ethylbenzene dehydrogenation
Abstract

Potassium-promoted iron oxides are the most widely used catalysts for catalytic dehydrogenation of ethylbenzene to styrene. Besides potassium, other minor promoters are also added into the catalyst for different purposes, either enhancing catalyst stability or activity/selectivity. Chromium (Cr) and vanadium (V) are two historically used promoters. Cr is widely accepted to be a structure stabilizer and V can increase the selectivity to styrene but with detrimental effect on stability and activity of the catalysts. Since the effects of these two promoters are known and opposite, the effects of Cr and V on the solid state phase behavior of K-promoted iron oxide were investigated. Gas environments consisting of H2, CO2, ethylbenzene and steam were used to explore the interaction between the gas composition and the phase behavior of the doped iron oxides. The experiments were performed in a thermogravimetric analyzer under various gas environments and X-ray powder diffraction was used to quantitatively characterize the phase changes. The Cr and V promoted K–promoted iron oxide had very different responses to the different gas phase environments, but in the presence of steam and ethylbenzene Cr stabilized the iron oxide against reduction whereas V destabilized the iron oxide. These data support the idea that the promoters influence K-promoted iron oxide stability under low steam-to-ethylbenzene operation via modifying the phase behavior of the iron oxide.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (133 K)Download as PowerPoint slideHighlights► K-promoted iron oxide stability impacted by gas phase species. ► Cr stabilizes K–Fe2O3 against reduction. ► V destabilizes K–Fe2O3 oxide via interaction with the K. ► Phase change behavior of K–Fe2O3 correlates with reaction performance.

Keywords
Iron oxide catalysts; Potassium-promoted iron oxide ethylbenzene dehydrogenation; Mixed metal oxide materials
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Role of Cr and V on the stability of potassium-promoted iron oxides used as catalysts in ethylbenzene dehydrogenation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 405, Issues 1–2, 3 October 2011, Pages 101–107
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