Reactions of C2 and C4. alpha.-hydroxy radicals with oxygen

T H E J O U R N A L OF

PHYSICAL CHEMISTRY Registered in U.S. Patent Office 0 Copyright, 1979, by the American Chemical Society ~

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SEPTEMBER 6,1979

VOLUME 83, NUMBER 18

Reactions of C2 and C4 a-Hydroxy Radicals with Oxygen Wllllam P. L. Carter," Karen R. Darnall, Rlchard A. Graham, Arthur

M. Winer,

and James N. Pltts, Jr.

Statewide Air Pollution Research Center, University of California, Riverside, California 9252 1 (Received February 2, 1979; Revised Manuscript Received May 11, 1979) Publication costs assisted by the University of California, Riverside

To determine the relative importance of addition vs. H-atom abstraction in the reaction of oxygen with a-hydroxy radicals, we irradiated ethanol or %butanol in NO,-air or Clz-NO,-air mixtures under simulated atmospheric conditions in a 5800-L evacuable environmental chamber. Products from the reactions of a-hydroxy radicals, formed via initial OH or C1-atom abstraction of hydrogen from the alcohols, were identified and measured. The major primary products were acetaldehyde (80 f 15%) in the ethanol experiments and methyl ethyl ketone (7540%) and acetaldehyde (12-16%) in the 2-butanol experiments. Other products measured were formaldehyde, propionaldehyde, PAN, formic acid, and acetic acid as well as methyl, ethyl, and 2-butyl nitrates. The total organic acid yields were (3 and