Gas-phase reaction of ozone with trans-2-hexenal, trans-2-hexenyl acetate, ethylvinyl ketone, and 6-methyl-5-hepten-2-one

Article abstract of DOI:10.1002/(SICI)1097-4601(1996)28:5<373::AID-KIN6>3.0.CO;2-S

The gas-phase reaction of ozone with the unsaturated oxygenates trans-2-hexenal, trans-2-hexenyl acetate, ethylvinyl ketone, and 6-methyl-5-hepten-2-one, which are components of biogenic emissions and/or close structural homologues thereof, has been investigated at atmospheric pressure and ambient temperature (286-291 K) and humidity (RH = 55 ± 10%). Reaction rate constants, in units of 10^-18 cm³ molecule^-1 s^-1, are 1.28 ± 0.28 for trans2-hexenal, 21.8 ± 2.8 for trans-2-hexenyl acetate, and 394 ± 40 for 6-methyl-5-hepten-2-one. Carbonyl product formation yields, measured with sufficient cyclohexane added to scavenge the hydroxyl radical, are 0.53 ± 0.06 for n-butanal and 0.56 ± 0.04 for glyoxal from trans-2-hexenal, 0.47 ± 0.02 for n-butanal and 0.58 ± 0.14 for 1-oxoethyl acetate from trans-2-hexenyl acetate, 0.55 ± 0.07 for formaldehyde and 0.44 ± 0.03 for 2-oxobutanal from ethylvinyl ketone, and 0.28 ± 0.02 for acetone from 6-methyl-5-hepten-2-one. Reaction mechanisms are outlined and the atmospheric persistence of the compounds studied is briefly discussed.