Experimental and theoretical investigations of the rate constant for the reaction of the hydroxyl radical with methyl ethyl ketone

HR: 0800h
AN: A21E-0795 [Abstracts]
TI: Experimental and theoretical investigations of the rate constant for the reaction of the hydroxyl radical with methyl ethyl ketone
AU: * Vimal, D
EM: dvimal@indiana.edu
AF: Center for Environmental Science Research, School of Public & Environmental Affairs, 1315 E 10th St, Bloomington, IN 47408, United States
AU: Stevens, P S
EM: pstevens@indiana.edu
AF: Center for Environmental Science Research, School of Public & Environmental Affairs, 1315 E 10th St, Bloomington, IN 47408, United States
AU: Stevens, P S
EM: pstevens@indiana.edu
AF: Department of Chemistry, 500, E Kirkwood Ave, Bloomington, IN 47405, United States
AB: Methyl ethyl ketone (MEK) or 2-butanone is a high-volume industrial solvent with a production rate greater than 70 million lbs yr^-1. It is also a photo-oxidation product of several volatile organic compounds (VOCs) in the atmosphere. MEK is removed from the atmosphere primarily by its reaction with hydroxyl (OH) radical. As a result, knowledge of the chemical mechanism and temperature dependence of this reaction is important as MEK may be transported to the upper troposphere and influence the chemistry of this region of the atmosphere. We present absolute measurements of the rate constant and the kinetic isotope effect for the reaction of MEK with OH radicals at low pressure and over the temperature range 263-388 K using a discharge-flow technique coupled with resonance fluorescence detection of OH radicals. Theoretical studies of the potential energy surface suggest that the reaction of MEK and OH proceeds by H-abstraction mediated by the formation of a 7- membered hydrogen-bonded complex. This mechanism is similar to that of several other atmospherically relevant oxygenated VOCs such as acetone, acetic acid and hydroxyacetone. The influence of the pre-reactive complex on the temperature dependence for this reaction will be discussed.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting