Atmospheric sink of (E)-3-hexen-1-ol, (Z)-3-hepten-1-ol and (Z)-3-octen-1-ol: Rate coefficients, mechanisms and product distribution of the OH-radical initiated degradation

RODRIGO GASTÓN GIBILISCO, MARIA. B BLANCO, IUSTINIAN BEJAN, IAN BARNES, PETER WIESEN AND MARIANO TERUEL

ENVIRONMENTAL SCIENCE & TECHNOLOGY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 49 p. 7717 - 7725

0013-936X

A kinetic study of the gas-phase reactions of OH radicals with three unsaturated biogenic alcohols (E)-3-hexen-1-ol, (Z)-3-hepten-1-ol and (Z)-3-octen-1-ol has been performed. The rate coefficients obtained are (in units of 10-10 cm3 molecule-1 s-1): k1(OH + (E)-CH2(OH)CH2CH=CHCH2CH3) = (1.14 ± 0.14), k2(OH + (Z)-CH2(OH)CH2CH=CHCH2CH2CH3) = (1.28 ± 0.23) and k3(OH + (Z)-CH2(OH)CH2CH=CHCH2CH2CH2CH3) = (1.49 ± 0.35). In addition, a product study on the reactions of OH with (E)-3-hexen-1-ol and (Z)-3-hepten-1-ol is reported. All the experiments were performed at (298 ± 3) K and 1 atm of NOx-free air in a 1080 L photoreactor with in situ FTIR detection of organics.This work constitutes the first kinetic study of the reactions of OH radicals with (Z)-3-hepten-1-ol and (Z)-3-octen-1-ol as well as the first determination of the fate of the hydroxy alkoxy radicals formed in the title reactions.An analysis of the available rates of addition of OH and Cl to the double bond of different unsaturated alcohols at 298 K has shown that they can be related by the expression log kOH = (0.29±0.04) log kCl ? 10.8. The atmospheric lifetimes of the alcohols studies were estimated to be around one hour for reaction with OH radicals. The products formed in the title reactions are mainly carbonylic compounds that can contribute to formation of ozone and PANs-type compounds in the troposphere.