title: Gas-phase kinetics of hydroxyl radical reactions with C3H6 and C4H8: product branching ratios and OH addition site-specificity.
abstract: Products of the reaction of OH radicals with propene, trans-2-butene, and 1-butene have been investigated in a fast flow reactor, coupled with time-of-flight mass spectrometry, at pressures between 0.8 and 3.0 Torr. The product determination includes H atom abstraction channels as well as site-specific OH addition. The OH radicals are produced by the H + NO(2) → OH + NO reaction or by the F + H(2)O → OH + HF reaction, the H or F atoms being produced in a microwave discharge. The gas mixture is ionized using single photon ionization (SPI at 10.54 eV), and products are detected using time-of-flight mass spectrometry (TOF-MS). The H atom abstraction channels are measured to be <2% for OH + propene, 8 ± 3% for OH + 1-butene, and 3 ± 1% for OH + trans-2-butene. Analysis of ion fragmentation patterns leads to 72 ± 16% OH addition to the propene terminal C atom and 71 ± 16% OH addition to the 1-butene terminal C atom. The errors bars represent 95% confidence intervals and include estimated uncertainties in photoionization cross sections.
authors.affiliation: Institut des Sciences Moléculaires, CNRS UMR 5255, Université Bordeaux I, 351 Cours de la Libération, 33405 Talence cedex, France. jc.loison@ism.u-bordeaux1.fr
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Loison
authors.forename: Julien
authors.initials: J
authors.lastname: Daranlot
authors.forename: Astrid
authors.initials: A
authors.lastname: Bergeat
authors.forename: Françoise
authors.initials: F
authors.lastname: Caralp
authors.forename: Raphaël
authors.initials: R
authors.lastname: Mereau
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Hickson