title: Measurements of Rate Coefficients for Reactions of OH with Ethanol and Propan-2-ol at Very Low Temperatures.
abstract: The low temperature kinetics of the reactions of OH with ethanol and propan-2-ol have been studied using a pulsed Laval nozzle apparatus coupled with pulsed laser photolysis-laser-induced fluorescence (PLP-LIF) spectroscopy. The rate coefficients for both reactions have been found to increase significantly as the temperature is lowered, by approximately a factor of 18 between 293 and 54 K for ethanol, and by ∼10 between 298 and 88 K for OH + propan-2-ol. The pressure dependence of the rate coefficients provides evidence for two reaction channels: a zero pressure bimolecular abstraction channel leading to products and collisional stabilization of a weakly bound OH-alcohol complex. The presence of the abstraction channel at low temperatures is rationalized by a quantum mechanical tunneling mechanism, most likely through the barrier to hydrogen abstraction from the OH moiety on the alcohol.
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Caravan
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Shannon
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lewis
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Blitz
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Dwayne E
authors.initials: DE
authors.lastname: Heard
mesh_terms: D000431:Ethanol / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D016018:Least-Squares Analysis; D016014:Linear Models; D017711:Nonlinear Dynamics; D010782:Photolysis; D011312:Pressure; D020005:Propanols / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D005740:Gases; D020005:Propanols; D017665:Hydroxyl Radical; D000431:Ethanol