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Transient kinetic modeling of the oxidative dehydrogenation of propane over a vanadia-based catalyst in the absence of O2

Paper ID Volume ID Publish Year Pages File Format Full-Text
42382 45923 2009 12 PDF Available
Title
Transient kinetic modeling of the oxidative dehydrogenation of propane over a vanadia-based catalyst in the absence of O2
Abstract

The oxidative dehydrogenation of propane in the absence of O2 over the vanadia-based EL10V1 Eurocat catalyst is investigated in a Temporal Analysis of Products (TAP) reactor over a completely oxidized catalyst and at reduction degrees up to 0.47. Only CO2 and propene are detected as reaction products at temperatures from 723 to 823 K. The reduction of the catalyst with propane occurs through the formation of propene, the consecutive oxidation of propene to CO2 and the parallel total oxidation of propane. Four elementary reactions are considered as kinetically relevant: (1) the methyl C–H bond dissociation in propane during the formation of propene, (2) the methylene C–H bond breaking in propane to form surface isopropoxide, which finally transforms into CO2, (3) the CC double bond breaking in propene in the formation of surface formate species and (4) the oxidation of these surface formate species to CO2. The formation of propene via (1) is favored at the investigated conditions, while CO2 is largely produced by the sequential oxidation of propene (3–4), and to a lesser extent by the parallel route of the direct total oxidation of propane (2). Both the oxidative dehydrogenation and the direct total oxidation of propane reaction paths involve only one kinetically relevant step, (1) respectively (2), with an activation energy of 36 and 74 kJ mol−1 over a completely oxidized catalyst and of 15 and 40 kJ mol−1 over a partially reduced catalyst. The further oxidation of propene involves two kinetically relevant steps (3–4) of which only the double bond breaking (3) is slightly activated (5 kJ mol−1) over the completely oxidized catalyst, while both steps are non-activated when the catalyst is partially reduced.

Graphical abstractThe oxidative dehydrogenation of propane in the absence of O2 over the vanadia-based EL10V1 Eurocat catalyst is shown to occur through three reaction paths: αα (propane → propene), ββ (propane → CO2) and γγ (propene → CO2), in which four steps are found to be kinetically significant with parameters k1, k2, k4 and k13. The constructed kinetic model can quantitatively describe the interaction of propane with the catalyst at different reduction degrees and at different temperatures.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Vanadia-based catalyst; Reduction; Propane; TAP; Kinetic modeling
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Transient kinetic modeling of the oxidative dehydrogenation of propane over a vanadia-based catalyst in the absence of O2
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 371, Issues 1–2, 15 December 2009, Pages 31–42
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Price was $35.95
You save - $31
Price after discount Only $4.95
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