Journal of Physical Chemistry A, Vol.103, No.30, 5959-5966, 1999
Atmospheric chemistry of 1,3-dioxolane: Kinetic, mechanistic, and modeling study of OH radical initiated oxidation
An absolute rate pulse radiolysis technique was used to measure k(OH + 1,3-dioxolane) = (8.8 +/- 0.9) x 10(-12) cm(3) 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) x 10(-11), k(Cl+ 1,3-dioxolane) = (1.6 +/- 0.3) x 10(-10), k(CI + ethylene carbonate) = (7.1 +/- 1.7) x 10(-12), and k(C1 $ methylene glycol diformate) = (5.6 +/- 0.7) x 10(-13) cm3 molecule(-1) s(-1). OH radical and chlorine atom initiated oxidation of 1,3-dioxolane in 1 bar of N-2/O-2 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 O-2 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.