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dc.contributor.authorBadra, Jihad
dc.contributor.authorElwardani, Ahmed Elsaid
dc.contributor.authorFarooq, Aamir
dc.date.accessioned2015-08-03T11:38:07Z
dc.date.available2015-08-03T11:38:07Z
dc.date.issued2014
dc.identifier.issn14639076
dc.identifier.pmid24817270
dc.identifier.doi10.1039/c4cp01253d
dc.identifier.urihttp://hdl.handle.net/10754/563205
dc.description.abstractReaction rate constants of the reaction of four large ketones with hydroxyl (OH) are investigated behind reflected shock waves using OH laser absorption. The studied ketones are isomers of hexanone and include 2-hexanone, 3-hexanone, 3-methyl-2-pentanone, and 4-methl-2-pentanone. Rate constants are measured under pseudo-first-order kinetics at temperatures ranging from 866 K to 1375 K and pressures near 1.5 atm. The reported high-temperature rate constant measurements are the first direct measurements for these ketones under combustion-relevant conditions. The effects of the position of the carbonyl group (CO) and methyl (CH3) branching on the overall rate constant with OH are examined. Using previously published data, rate constant expressions covering, low-to-high temperatures, are developed for acetone, 2-butanone, 3-pentanone, and the hexanone isomers studied here. These Arrhenius expressions are used to devise rate rules for H-abstraction from various sites. Specifically, the current scheme is applied with good success to H-abstraction by OH from a series of n-ketones. Finally, general expressions for primary and secondary site-specific H-abstraction by OH from ketones are proposed as follows (the subscript numbers indicate the number of carbon atoms bonded to the next-nearest-neighbor carbon atom, the subscript CO indicates that the abstraction is from a site next to the carbonyl group (CO), and the prime is used to differentiate different neighboring environments of a methylene group):P1,CO = 7.38 × 10-14 exp(-274 K/T) + 9.17 × 10-12 exp(-2499 K/T) (285-1355 K)S10,CO = 1.20 × 10-11 exp(-2046 K/T) + 2.20 × 10-13 exp(160 K/T) (222-1464 K)S11,CO = 4.50 × 10-11 exp(-3000 K/T) + 8.50 × 10-15 exp(1440 K/T) (248-1302 K)S11′,CO = 3.80 × 10-11 exp(-2500 K/T) + 8.50 × 10-15 exp(1550 K/T) (263-1370 K)S 21,CO = 5.00 × 10-11 exp(-2500 K/T) + 4.00 × 10-13 exp(775 K/T) (297-1376 K) © 2014 the Partner Organisations.
dc.description.sponsorshipWe would like to acknowledge the funding support from Saudi Aramco under the FUELCOM program. We are also thankful for the financial support provided by the Clean Combustion Research Center (CCRC) and King Abdullah University of Science and Technology (KAUST).
dc.publisherRoyal Society of Chemistry (RSC)
dc.titleReaction rate constants of H-abstraction by OH from large ketones: Measurements and site-specific rate rules
dc.typeArticle
dc.contributor.departmentClean Combustion Research Center
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Division
dc.contributor.departmentMechanical Engineering Program
dc.contributor.departmentChemical Kinetics & Laser Sensors Laboratory
dc.identifier.journalPhysical Chemistry Chemical Physics
dc.contributor.institutionSaudi Aramco Research and Development Center, Fuel Technology RandD Division, Dhahran 31311, Saudi Arabia
kaust.personBadra, Jihad
kaust.personElwardani, Ahmed Elsaid
kaust.personFarooq, Aamir


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