Atmospheric Chemistry of 1,3,5-Trioxane: UV Spectra of c-C3H5O3(•) and (c-C3H5O3)O2(•) Radicals, Kinetics of the Reactions of (c-C3H5O3)O2(•) Radicals with NO and NO2, and Atmospheric Fate of the Alkoxy Radical (c-C3H5O3)O(•)

A pulse radiolysis technique was used to measure the UV absorption spectra of c-C 3 H 5 O 3 (•) and (c-C 3 H 5 O 3 )O 2 (•) radicals over the range 220−300 nm, with σ(c-C 3 H 5 O 3 (•)) 250 nm = (5.2 ± 0.7) × 10 -18 and σ((c-C 3 H 5 O 3 )O 2 (•)) 250 nm = (3.7 ± 0.4) × 10 -18 cm 2 molecule -1 . The self-reaction rate constant for the c-C 3 H 5 O 3 (•) radicals, defined as d[c-C 3 H 5 O 3 (•)]/d t = 2 k 4 [c-C 3 H 5 O 3 (•)] 2, was k 4 = (3.1 ± 0.6) × 10 -11 cm 3 molecule -1 s -1 . The rate constants for reactions of (c-C 3 H 5 O 3 )O 2 (•) radicals with NO and NO 2 were k 6 = (5.8 ± 1.4) × 10 -12 and k 7 = (1.1 ± 0.2) × 10 -11 cm 3 molecule -1 s -1, respectively. The rate constants for the reaction of F atoms with 1,3,5-trioxane and the reaction of c-C 3 H 5 O 3 (•) radicals with O 2 were k 3 = (1.1 ± 0.4) × 10 -10 and k 2 = (7.4 ± 1.1) × 10 -12 cm 3 molecule -1 s -1, respectively. Relative rate techniques were used to measure the rate constants for the reactions of OH radicals and Cl atoms with 1,3,5-trioxane and Cl atoms with H(O)COCH 2 OC(O)H, k 20 = (6.0 ± 1.0) × 10 -12, k 24 = (1.0 ± 0.2) × 10 -10, and k 25 = (5.1 ± 1.0) × 10 -13 cm 3 molecule -1 s -1, respectively. FTIR−smog chamber systems were used to show that the atmospheric fate of the alkoxy radical (c-C 3 H 5 O 3 )O(•) is decomposition via C−O bond scission leading to the formation of H(O)COCH 2 OC(O)H (methylene glycol diformate). The IR spectrum of the peroxynitrate (c-C 3 H 5 O 3 )O 2 NO 2 is presented. The results are discussed with respect to the atmospheric chemistry of 1,3,5-trioxane.