Site-specific reaction rate constant measurements for various secondary and tertiary H-abstraction by OH radicals

Handle URI:
http://hdl.handle.net/10754/347279
Title:
Site-specific reaction rate constant measurements for various secondary and tertiary H-abstraction by OH radicals
Authors:
Badra, Jihad; Farooq, Aamir ( 0000-0001-5296-2197 )
Abstract:
Reaction rate constants for nine site-specific hydrogen atom (H) abstraction by hydroxyl radicals (OH) have been determined using experimental measurements of the rate constants of Alkane+OH→Products reactions. Seven secondary (S 20, S 21, S 22, S 30, S 31, S 32, and S 33) and two tertiary (T 100 and T 101) site-specific rate constants, where the subscripts refer to the number of carbon atoms (C) connected to the next-nearest-neighbor (N-N-N) C atom, were obtained for a wide temperature range (250-1450K). This was done by measuring the reaction rate constants for H abstraction by OH from a series of carefully selected large branched alkanes. The rate constant of OH with four different alkanes, namely 2,2-dimethyl-pentane, 2,4-dimethyl-pentane, 2,2,4-trimethyl-pentane (iso-octane), and 2,2,4,4-tetramethyl-pentane were measured at high temperatures (822-1367K) using a shock tube and OH absorption diagnostic. Hydroxyl radicals were detected using the narrow-line-width ring-dye laser absorption of the R1(5) transition of OH spectrum near 306.69nm.Previous low-temperature rate constant measurements are added to the current data to generate three-parameter rate expressions that successfully represent the available direct measurements over a wide temperature range (250-1450. K). Similarly, literature values of the low-temperature rate constants for the reaction of OH with seven normal and branched alkanes are combined with the recently measured high-temperature rate constants from our group [1]. Subsequent to that, site-specific rate constants for abstractions from various types of secondary and tertiary H atoms by OH radicals are derived and have the following modified Arrhenius expressions:. S20=8.49×10-17T1.52exp(73.4K/T)cm3molecule-1s-1(250-1450K) S21=1.07×10-15T1.07exp(208.3K/T)cm3molecule-1s-1(296-1440K) S22=2.88×10-13T0.41exp(-291.5K/T)cm3molecule-1s-1(272-1311K) S30=3.35×10-18T1.97exp(323.1K/T)cm3molecule-1s-1(250-1366K) S31=1.60×10-18T2.0exp(500.0K/T)cm3molecule-1s-1(250-1351K) S32=9.65×10-17T1.45exp(180.0K/T)cm3molecule-1s-1(297-1367K) S33=2.83×10-19T2.25exp(501.3K/T)cm3molecule-1s-1(250-1365K) T100=5.69×10-16T1.32exp(76.8K/T)cm3molecule-1s-1(297-1375K) T101=1.05×10-16T1.38exp(577.9K/T)cm3molecule-1s-1(297-1362K)
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division
Citation:
Site-specific reaction rate constant measurements for various secondary and tertiary H-abstraction by OH radicals 2015 Combustion and Flame
Publisher:
Elsevier
Journal:
Combustion and Flame
Issue Date:
Feb-2015
DOI:
10.1016/j.combustflame.2015.01.001
Type:
Article
ISSN:
00102180
Additional Links:
http://linkinghub.elsevier.com/retrieve/pii/S0010218015000048
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorBadra, Jihaden
dc.contributor.authorFarooq, Aamiren
dc.date.accessioned2015-03-30T06:33:07Zen
dc.date.available2015-03-30T06:33:07Zen
dc.date.issued2015-02en
dc.identifier.citationSite-specific reaction rate constant measurements for various secondary and tertiary H-abstraction by OH radicals 2015 Combustion and Flameen
dc.identifier.issn00102180en
dc.identifier.doi10.1016/j.combustflame.2015.01.001en
dc.identifier.urihttp://hdl.handle.net/10754/347279en
dc.description.abstractReaction rate constants for nine site-specific hydrogen atom (H) abstraction by hydroxyl radicals (OH) have been determined using experimental measurements of the rate constants of Alkane+OH→Products reactions. Seven secondary (S 20, S 21, S 22, S 30, S 31, S 32, and S 33) and two tertiary (T 100 and T 101) site-specific rate constants, where the subscripts refer to the number of carbon atoms (C) connected to the next-nearest-neighbor (N-N-N) C atom, were obtained for a wide temperature range (250-1450K). This was done by measuring the reaction rate constants for H abstraction by OH from a series of carefully selected large branched alkanes. The rate constant of OH with four different alkanes, namely 2,2-dimethyl-pentane, 2,4-dimethyl-pentane, 2,2,4-trimethyl-pentane (iso-octane), and 2,2,4,4-tetramethyl-pentane were measured at high temperatures (822-1367K) using a shock tube and OH absorption diagnostic. Hydroxyl radicals were detected using the narrow-line-width ring-dye laser absorption of the R1(5) transition of OH spectrum near 306.69nm.Previous low-temperature rate constant measurements are added to the current data to generate three-parameter rate expressions that successfully represent the available direct measurements over a wide temperature range (250-1450. K). Similarly, literature values of the low-temperature rate constants for the reaction of OH with seven normal and branched alkanes are combined with the recently measured high-temperature rate constants from our group [1]. Subsequent to that, site-specific rate constants for abstractions from various types of secondary and tertiary H atoms by OH radicals are derived and have the following modified Arrhenius expressions:. S20=8.49×10-17T1.52exp(73.4K/T)cm3molecule-1s-1(250-1450K) S21=1.07×10-15T1.07exp(208.3K/T)cm3molecule-1s-1(296-1440K) S22=2.88×10-13T0.41exp(-291.5K/T)cm3molecule-1s-1(272-1311K) S30=3.35×10-18T1.97exp(323.1K/T)cm3molecule-1s-1(250-1366K) S31=1.60×10-18T2.0exp(500.0K/T)cm3molecule-1s-1(250-1351K) S32=9.65×10-17T1.45exp(180.0K/T)cm3molecule-1s-1(297-1367K) S33=2.83×10-19T2.25exp(501.3K/T)cm3molecule-1s-1(250-1365K) T100=5.69×10-16T1.32exp(76.8K/T)cm3molecule-1s-1(297-1375K) T101=1.05×10-16T1.38exp(577.9K/T)cm3molecule-1s-1(297-1362K)en
dc.publisherElsevieren
dc.relation.urlhttp://linkinghub.elsevier.com/retrieve/pii/S0010218015000048en
dc.rightsArchived with thanks to Combustion and Flame. Copyright © 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.en
dc.titleSite-specific reaction rate constant measurements for various secondary and tertiary H-abstraction by OH radicalsen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalCombustion and Flameen
dc.eprint.versionPost-printen
dc.contributor.institutionSaudi Aramco Research and Development Center, Fuel Technology R&D Division, Dhahran 31311, Saudi Arabiaen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorBadra, Jihaden
kaust.authorFarooq, Aamiren
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