title: Experimental and Kinetic Modeling Study of 2-Methyl-2-Butene: Allylic Hydrocarbon Kinetics.
abstract: Two experimental studies have been carried out on the oxidation of 2-methyl-2-butene, one measuring ignition delay times behind reflected shock waves in a stainless steel shock tube, and the other measuring fuel, intermediate, and product species mole fractions in a jet-stirred reactor (JSR). The shock tube ignition experiments were carried out at three different pressures, approximately 1.7, 11.2, and 31 atm, and at each pressure, fuel-lean (ϕ = 0.5), stoichiometric (ϕ = 1.0), and fuel-rich (ϕ = 2.0) mixtures were examined, with each fuel/oxygen mixture diluted in 99% Ar, for initial postshock temperatures between 1330 and 1730 K. The JSR experiments were performed at nearly atmospheric pressure (800 Torr), with stoichiometric fuel/oxygen mixtures with 0.01 mole fraction of 2M2B fuel, a residence time in the reactor of 1.5 s, and mole fractions of 36 different chemical species were measured over a temperature range from 600 to 1150 K. These JSR experiments represent the first such study reporting detailed species measurements for an unsaturated, branched hydrocarbon fuel larger than iso-butene. A detailed chemical kinetic reaction mechanism was developed to study the important reaction pathways in these experiments, with particular attention on the role played by allylic C-H bonds and allylic pentenyl radicals. The results show that, at high temperatures, this olefinic fuel reacts rapidly, similar to related alkane fuels, but the pronounced thermal stability of the allylic pentenyl species inhibits low temperature reactivity, so 2M2B does not produce "cool flames" or negative temperature coefficient behavior. The connections between olefin hydrocarbon fuels, resulting allylic fuel radicals, the resulting lack of low-temperature reactivity, and the gasoline engine concept of octane sensitivity are discussed.
authors.affiliation: †Lawrence Livermore National Laboratory, Livermore, California 94550, United States.
authors.forename: Charles K
authors.initials: CK
authors.lastname: Westbrook
authors.affiliation: †Lawrence Livermore National Laboratory, Livermore, California 94550, United States.
authors.forename: William J
authors.initials: WJ
authors.lastname: Pitz
authors.affiliation: †Lawrence Livermore National Laboratory, Livermore, California 94550, United States.
authors.forename: Marco
authors.initials: M
authors.lastname: Mehl
authors.affiliation: ‡Laboratoire Réactions et Génie des Procédés, CNRS, Universite de Lorraine, Nancy, France.
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Glaude
authors.affiliation: ‡Laboratoire Réactions et Génie des Procédés, CNRS, Universite de Lorraine, Nancy, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Herbinet
authors.affiliation: ‡Laboratoire Réactions et Génie des Procédés, CNRS, Universite de Lorraine, Nancy, France.
authors.forename: Sarah
authors.initials: S
authors.lastname: Bax
authors.affiliation: ‡Laboratoire Réactions et Génie des Procédés, CNRS, Universite de Lorraine, Nancy, France.
authors.forename: Frederique
authors.initials: F
authors.lastname: Battin-Leclerc
authors.forename: Olivier
authors.initials: O
authors.lastname: Mathieu
authors.forename: Eric L
authors.initials: EL
authors.lastname: Petersen
authors.affiliation: ∥School of Chemistry, National University of Ireland, Galway, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Bugler
authors.affiliation: ∥School of Chemistry, National University of Ireland, Galway, Ireland.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Curran