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Aging investigation on catalysts for hydrofluorocarbons synthesis

Paper ID Volume ID Publish Year Pages File Format Full-Text
44328 46015 2007 7 PDF Available
Title
Aging investigation on catalysts for hydrofluorocarbons synthesis
Abstract

This study aims to verify whether the thermal effects occurring during catalyst oxidative regeneration may have to do with the irreversible catalyst deactivation industrially observed for CrOxFy-AlF3-based catalysts. Deactivation phenomena can be due to modifications occurring on both the active phase and the support; therefore, the aging treatment effects on the support (AlF3) and fresh and stabilized catalysts CrOxFy/AlF3 were compared. It was proved that at temperatures higher than 600 °C, the support undergoes to release of HF molecules and sintering phenomena correlated with the irreversible evolution to the thermally stable α-phase. The presence of Cr ions has an inhibiting effect on the support crystals growth, but strongly catalyses the surface area decrease at a relatively low temperature. In addition, the evolution of HF from chromium-containing catalysts starts at a very low temperature and is related to the formation of the crystalline Cr2O3 phase. Moreover, UV–vis and TPR analysis demonstrated that, due to aging treatments, chromium ions tend to interact with the support, and lead to the formation of less reducible chromium species, which are probably responsible for the irreversible catalytic activity degradation observed in commercial processes.

Graphical abstractThis study is aimed at verifying whether the thermal effects occurring during the catalyst oxidative regeneration may deal with the irreversible catalyst deactivation industrially observed for Cr-AlF3-based catalysts. It was proved that due to the aging treatments, Cr3+ ions interact with the support, and lead to the formation of less reducible Cr3+ species.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Catalyst aging; Chromium; Aluminum-trifluoride; TPR; DR–UV–vis
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Aging investigation on catalysts for hydrofluorocarbons synthesis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 326, Issue 1, 30 June 2007, Pages 48–54
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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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