HR: 15:24h
AN: A43F-07 [Abstracts]
TI: Temperature Dependent Rate Coefficients for the OH + Pinonaldehyde Reaction
AU: * Davis, M E
EM: maxine.e.davis@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80303
United States
AU: * Davis, M E
EM: maxine.e.davis@noaa.gov
AF: Cooperative Institute fro Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
United States
AU: Talukdar, R
EM: Ranajit.K.Talukdar@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80303
United States
AU: Notte, G
EM: Gregory.Notte@Colorado.edu
AF: Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
United States
AU: Ellison, G B
EM: barney@jila.colorado.edu
AF: Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
United States
AU: Ravishankara, A R
EM: A.R.Ravishankara@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80303
United States
AU: Ravishankara, A R
EM: A.R.Ravishankara@noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
United States
AU: Ravishankara, A R
EM: A.R.Ravishankara@noaa.gov
AF: Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
United States
AU: Burkholder, J B
EM: James.B.Burkholder@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80303
United States
AB:
The biogenic emission of monoterpenes is an important source of volatile organic compounds (VOCs) to the atmosphere,
approximately 10% of the biogenic hydrocarbons emitted yearly. The oxidation of alpha-pinene, the most abundant monoterpene
in the atmosphere, by OH leads to the formation of pinonaldehyde (3-acetyl-2,2-dimethyl-cyclobutyl-ethanal) as a major
oxidation product formed in yields > 50%. The atmospheric oxidation of pinonaldehyde will impact radical cycling, ozone
formation and air quality on a regional scale. Previous laboratory studies of the OH + pinonaldehyde rate coefficient have
used relative rate methods and were limited to room temperature. The reported rate coefficients are in poor agreement with
values ranging from 4.0 to 9.1 × 10-11 cm#3 molecule-1 s-1. In this study we have measured
absolute rate coefficients to resolve these discrepancies and have extended the measurements to include the temperature
dependence. The rate coefficient for the gas phase reaction of OH with pinonaldehyde was measured over the temperature range
297 to 374 K and between 55 and 96 Torr under pseudo first order conditions in OH. Laser-induced fluorescence (LIF) was used
to monitor the OH radical which was produced by pulsed laser photolysis. The pinonaldehyde concentration was determined in
situ using Fourier transform infrared (FTIR) and UV (185 nm) absorption spectroscopy. The rate coefficient for the OH +
pinonaldehyde reaction will be presented. Our results will be compared with previous rate coefficient measurements and the
discrepancies and the atmospheric implications of these measurements will be discussed.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
DE: 3307 Boundary layer processes
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005