title: H-Abstraction by OH from Large Branched Alkanes: Overall Rate Measurements and Site-Specific Tertiary Rate Calculations.
abstract: Reaction rate coefficients for the reaction of hydroxyl (OH) radicals with nine large branched alkanes (i.e., 2-methyl-3-ethyl-pentane, 2,3-dimethyl-pentane, 2,2,3-trimethylbutane, 2,2,3-trimethyl-pentane, 2,3,4-trimethyl-pentane, 3-ethyl-pentane, 2,2,3,4-tetramethyl-pentane, 2,2-dimethyl-3-ethyl-pentane, and 2,4-dimethyl-3-ethyl-pentane) are measured at high temperatures (900-1300 K) using a shock tube and narrow-line-width OH absorption diagnostic in the UV region. In addition, room-temperature measurements of six out of these nine rate coefficients are performed in a photolysis cell using high repetition laser-induced fluorescence of OH radicals. Our experimental results are combined with previous literature measurements to obtain three-parameter Arrhenius expressions valid over a wide temperature range (300-1300 K). The rate coefficients are analyzed using the next-nearest-neighbor (N-N-N) methodology to derive nine tertiary (T003, T012, T013, T022, T023, T111, T112, T113, and T122) site-specific rate coefficients for the abstraction of H atoms by OH radicals from branched alkanes. Derived Arrhenius expressions, valid over 950-1300 K, are given as (the subscripts denote the number of carbon atoms connected to the next-nearest-neighbor carbon): T003= 1.80 × 10-10exp(-2971 K/T) cm3molecule-1s-1; T012= 9.36 × 10-11exp(-3024 K/T) cm3molecule-1s-1; T013= 4.40 × 10-10exp(-4162 K/T) cm3molecule-1s-1; T022= 1.47 × 10-10exp(-3587 K/T) cm3molecule-1s-1; T023= 6.06 × 10-11exp(-3010 K/T) cm3molecule-1s-1; T111= 3.98 × 10-11exp(-1617 K/T) cm3molecule-1s-1; T112= 9.08 × 10-12exp(-3661 K/T) cm3molecule-1s-1; T113= 6.74 × 10-9exp(-7547 K/T) cm3molecule-1s-1; T122= 3.47 × 10-11exp(-1802 K/T) cm3molecule-1s-1.
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal 23955, Kingdom of Saudi Arabia.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Liu
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal 23955, Kingdom of Saudi Arabia.
authors.forename: Fethi
authors.initials: F
authors.lastname: Khaled
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal 23955, Kingdom of Saudi Arabia.
authors.forename: Binod R
authors.initials: BR
authors.lastname: Giri
authors.affiliation: Université Lille , CNRS, UMR 8522 - PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Assaf
authors.affiliation: Université Lille , CNRS, UMR 8522 - PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
authors.forename: Christa
authors.initials: C
authors.lastname: Fittschen
authors.affiliation: Clean Combustion Research Center, King Abdullah University of Science and Technology , Thuwal 23955, Kingdom of Saudi Arabia.
authors.forename: Aamir
authors.identifier: http://orcid.org/0000-0001-5296-2197
authors.initials: A
authors.lastname: Farooq