A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction

Handle URI:
http://hdl.handle.net/10754/622267
Title:
A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction
Authors:
Khaled, Fathi; Giri, Binod; Farooq, Aamir ( 0000-0001-5296-2197 )
Abstract:
Isobutene is an important intermediate formed during the oxidation of branched alkanes. It also appears as a byproduct during the combustion of methyl-tert-butyl-ether (MTBE) which is used as octane enhancer in gasolines. To understand better the oxidation kinetics of isobutene, we have measured the rate coefficients for the reaction of OH radicals with isobutene (HCC(CH)) behind reflected shock waves over the temperature range of 830-1289K and pressures near 1.5atm. The reaction progress was followed by measuring mole fraction of OH radicals near 306.7nm using UV laser absorption technique. Three deuterated isotopes, isobutene-1-d2 (DCC(CH)), isobutene-3-d6 (HCC(CD)) and isobutene-d8 (DCC(CD)) were employed to elucidate branching ratios of the allylic and vinylic H-abstraction from isobutene by OH radicals. H-abstraction from the allylic sites was found to be dominant and constituted about 75% of the total rate in the entire temperature range of the current work. The derived three-parameter Arrhenius expressions for site-specific H- and D- abstraction rates over 830-1289K are (units:cm mol s):k3,H=6.98×106(TK)1.77exp(-136.6KT) k3,D=4.42×106(TK)1.8exp(-361.7KT) k1,H=6.25×105(TK)2.16exp(-711.6KT) k1,D=3.13×107(TK)1.67exp(-1814KT) The subscript of . k identifies the position of H or D atom in isobutene according to the IUPAC nomenclature of alkenes.
KAUST Department:
Clean Combustion Research Center
Citation:
Khaled F, Giri BR, Farooq A (2016) A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction. Proceedings of the Combustion Institute. Available: http://dx.doi.org/10.1016/j.proci.2016.07.107.
Publisher:
Elsevier BV
Journal:
Proceedings of the Combustion Institute
Issue Date:
11-Oct-2016
DOI:
10.1016/j.proci.2016.07.107
Type:
Article
ISSN:
1540-7489
Sponsors:
King Abdullah University of Science and Technology; Saudi Aramco
Appears in Collections:
Articles; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorKhaled, Fathien
dc.contributor.authorGiri, Binoden
dc.contributor.authorFarooq, Aamiren
dc.date.accessioned2017-01-02T09:08:23Z-
dc.date.available2017-01-02T09:08:23Z-
dc.date.issued2016-10-11en
dc.identifier.citationKhaled F, Giri BR, Farooq A (2016) A high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reaction. Proceedings of the Combustion Institute. Available: http://dx.doi.org/10.1016/j.proci.2016.07.107.en
dc.identifier.issn1540-7489en
dc.identifier.doi10.1016/j.proci.2016.07.107en
dc.identifier.urihttp://hdl.handle.net/10754/622267-
dc.description.abstractIsobutene is an important intermediate formed during the oxidation of branched alkanes. It also appears as a byproduct during the combustion of methyl-tert-butyl-ether (MTBE) which is used as octane enhancer in gasolines. To understand better the oxidation kinetics of isobutene, we have measured the rate coefficients for the reaction of OH radicals with isobutene (HCC(CH)) behind reflected shock waves over the temperature range of 830-1289K and pressures near 1.5atm. The reaction progress was followed by measuring mole fraction of OH radicals near 306.7nm using UV laser absorption technique. Three deuterated isotopes, isobutene-1-d2 (DCC(CH)), isobutene-3-d6 (HCC(CD)) and isobutene-d8 (DCC(CD)) were employed to elucidate branching ratios of the allylic and vinylic H-abstraction from isobutene by OH radicals. H-abstraction from the allylic sites was found to be dominant and constituted about 75% of the total rate in the entire temperature range of the current work. The derived three-parameter Arrhenius expressions for site-specific H- and D- abstraction rates over 830-1289K are (units:cm mol s):k3,H=6.98×106(TK)1.77exp(-136.6KT) k3,D=4.42×106(TK)1.8exp(-361.7KT) k1,H=6.25×105(TK)2.16exp(-711.6KT) k1,D=3.13×107(TK)1.67exp(-1814KT) The subscript of . k identifies the position of H or D atom in isobutene according to the IUPAC nomenclature of alkenes.en
dc.description.sponsorshipKing Abdullah University of Science and Technologyen
dc.description.sponsorshipSaudi Aramcoen
dc.publisherElsevier BVen
dc.subjectBranching ratioen
dc.subjectHydroxyl radicalsen
dc.subjectIsobuteneen
dc.subjectRate coefficientsen
dc.subjectShock tubeen
dc.titleA high-temperature shock tube kinetic study for the branching ratios of isobutene+OH reactionen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.identifier.journalProceedings of the Combustion Instituteen
kaust.authorKhaled, Fathien
kaust.authorGiri, Binoden
kaust.authorFarooq, Aamiren
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