Atmospheric Chemistry of 1,3-Dioxolane: Kinetic, Mechanistic, and Modeling Study of OH Radical Initiated Oxidation

Abstract

An absolute rate pulse radiolysis technique was used to measure k(OH + 1,3-dioxolane) = (8.8 ± 0.9) × 10-12 cm3 molecule-1 s-1 at 295 K in 1000 mbar of Ar. Relative rate techniques were used to study the reactions of OH radicals and Cl atoms with 1,3-dioxolane and Cl atoms with ethylene carbonate and methylene glycol diformate at 300 K in 1 bar of synthetic air. Rate coefficients were k(OH + 1,3-dioxolane) = (1.04 ± 0.16) × 10-11, k(Cl + 1,3-dioxolane) = (1.6 ± 0.3) × 10-10, k(Cl + ethylene carbonate) = (7.1 ± 1.7) × 10-12, and k(Cl + methylene glycol diformate) = (5.6 ± 0.7) × 10-13 cm3 molecule-1 s-1. OH radical and chlorine atom initiated oxidation of 1,3-dioxolane in 1 bar of N2/O2 mixtures at 298 K in the presence of NOx gives ethylene carbonate and methylene glycol diformate. Molar yields of ethylene carbonate and methylene glycol diformate were 0.48 ± 0.07 and 0.50 ± 0.14 for OH radical initiation and 0.43 ± 0.07 and 0.53 ± 0.07 for Cl atom initiation. Product yields were independent of O2 partial pressure over the range studied (60−800 mbar). A photochemical mechanism was developed to describe the OH-initiated degradation of 1,3-dioxolane in the presence of NOx. The results are discussed with respect to the available literature data concerning the atmospheric chemistry of ethers.