Kinetic study of the OH-initiated photo-oxidation of four unsaturated (allyl and vinyl) ethers under simulated atmospheric conditions

Abstract

Using the relative rate technique, rate constants for the gas-phase reactions of hydroxyl radicals with n-propyl vinyl ether (k1), 2-chloroethyl vinyl ether (k2), allyl ether (k3) and allyl ethyl ether (k4) have been measured. Experiments were carried out at (298 ± 2) K and atmospheric pressure using N2 and ultra pure air as bath gas. Using isoprene, 1-methyl-1-cyclohexene, 2-methyl-2-butene, 3-buten-1-ol and 2-methyl-2-propen-1-ol as reference compounds, the following rate constants were derived: k1 = (11.0 ± 0.4) × 10−11, k2 = (9 ± 1) × 10−11, k3 = (6.8 ± 0.7) × 10−11 and k4 = (4.2 ± 0.7) × 10−11, in units of cm3 molecule−1 s−1. This is the first experimental detcermination of k2–k4. The rate constants obtained are compared with the previous literature data for corresponding alkenes reactions with OH and the observed reactivity trends are discussed. The atmospheric implications of the results are considered.