Atmospheric Autoxidation Chemistry of Diethyl Ether

We report estimates of the rate coefficients for atmospheric autoxidation chemistry of diethyl ether (DE), a simple aliphatic ether, as a representative for the ether family, an important class of volatile chemical products (VCPs). We perform chamber experiments to estimate the rate coefficients of the H-shift reactions of peroxy radicals (RO 2 ) formed by hydroxyl radical (OH) oxidation of DE relative to the rate coefficients of their reaction with HO 2 . We also estimate these rate coefficients for the fully deuterated version, diethyl ether- d 10 (DE-d10). Computational methods based on multi-conformer transition state theory are used to guide our interpretation of these rate coefficients. At ambient temperature (294 ± 1 K), H-shift rate coefficients of DE RO 2 are estimated to be ∼0.09 ± 0.06 s –1, while those of DE-d10 RO 2 are ∼8–15 times smaller due primarily to reduction in quantum tunneling. Our estimates agree well with theoretical predictions. The RO 2 autoxidation rate coefficients are sufficiently fast to be competitive with their bimolecular reactions when NO levels are less than ∼1 ppb─common urban atmospheric conditions following the controls of NO x emissions, indicating efficient formation of highly oxygenated organic molecules (HOMs), which can be important secondary organic aerosol (SOA) contributors, from volatile ether compounds.