Reactivity of hydrohaloethers with OH radicals and chlorine atoms: Correlation with molecular properties

Abstract

The reactivity of halogenated ethers, especially hydrochloroethers, with hydroxyl radicals and chlorine atoms was studied by correlating the room-temperature rate coefficients with both the C–H bond dissociation energies and the vertical ionization potentials of the parent molecules. These molecular properties were estimated at the composite G3B3 level of theory. The results suggest that Cl-substituted ethyl-methyl-ethers and ethyl-ethyl-ethers at the β-position tend to raise the activating effect of the ether linkage –O– and to enhance the possibility of the abstraction of H atoms bonded to α-carbon. Derived relationships between the rate coefficients (in cm3 molecule−1 s−1) and ionization potentials (in eV): log kOH = −(1.248 ± 0.065) IP + (1.06 ± 0.73) and log kCl = −(1.46 ± 0.12) IP + (4.5 ± 1.3) allows, in average, to estimate rate coefficients within a factor of 2–3. The atmospheric implications of halogenated and hydrogenated ethers are briefly discussed on the basis of their estimated global lifetimes.