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Oxidative dehydrogenation of C3–C4 paraffins in the presence of CO2 over CrOx/SiO2 catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
42904 45946 2008 7 PDF Available
Title
Oxidative dehydrogenation of C3–C4 paraffins in the presence of CO2 over CrOx/SiO2 catalysts
Abstract

Oxidative dehydrogenation of propane and isobutane has been investigated over CrOx/silica catalysts prepared by wet impregnation (Cr loading: from 0.5 to 7.5 wt%) using carbon dioxide as oxidant. In particular, reaction conditions were set to attain high conversions, similar to that required in industrial processes. The highest activity, selectivity and stability were exhibited by a catalyst with a Cr loading of 5.0 wt%. DR UV–vis studies indicated that Cr(VI) ions in the form of mono-, di- and polychromates were present in all catalysts, while Cr(III) oxide (α-Cr2O3) was found only for Cr loading higher than 3.0 wt%. The catalyst activity seemed correlated to more dispersed chromates. Introduction of oxygen in the reaction mixture up to 5.0 vol.% resulted in a significant increase of catalysts activity and stability. Some decrease in the propene and isobutene selectivity occurred, but because of the increase of the selectivity towards lighter olefins, the total olefin selectivity increased.

Graphical abstractThis work was targeted to attain high, stable total olefin yields (≥35%) of ODH of propane and isobutane on CrOx/silica catalysts using CO2 as oxidant. The best results were obtained by addition of 5 vol.% of O2 to the feed, and with a chromium loading of 5 wt%. Likely, mono- and di-chromates acted as the most active sites. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
CrOx/SiO2 catalysts; Propane; Isobutane oxidative dehydrogenation; Carbon dioxide as oxidant; Surface chromates; DR UV–vis characterization
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Oxidative dehydrogenation of C3–C4 paraffins in the presence of CO2 over CrOx/SiO2 catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 347, Issue 2, 15 September 2008, Pages 126–132
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
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