HR: 1340h
AN: A43A-0881    [Abstracts]
TI: Experimental Studies of the Kinetics of the OH-initiated Oxidation of Hydroxyacetone
AU: * Baasandorj, M
EM: mbaasand@indiana.edu
AF: School of Public and Environmental Affairs, Indiana University, 1315 East Tenth Street, Bloomington, IN 47405, United States
AU: Stevens, P
EM: pstevens@indiana.edu
AF: School of Public and Environmental Affairs, Indiana University, 1315 East Tenth Street, Bloomington, IN 47405, United States
AB: Hydroxyacetone is mainly produced in the atmosphere from the reaction of the OH radical with methacrolein, which is a major product of photooxidation of isoprene. Given the abundance of isoprene throughout the troposphere, a detailed understanding of the chemistry of hydroxyacetone is required in order to fully assess the contribution of isoprene oxidation to atmospheric chemistry. Although the room temperature rate coefficient of the reaction of hydroxyacetone with OH has been investigated by several groups, there have been few measurements of the temperature dependence for this reaction. We studied the temperature dependence of the rate constant for the hydroxyacetone + OH reaction at 5 torr and between 273 and 355 K using a discharge-flow system coupled with resonance fluorescence (RF) detection of OH. Our results show that the reaction displays positive temperature dependence in contrast to recent measurements at higher pressures. The observed temperature dependence is consistent with a hydrogen abstraction reaction that proceeds through a hydrogen-bonded pre-reactive complex, similar to the OH + acetone reaction.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere: composition and chemistry
DE: 0399 General or miscellaneous
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting