Atmospheric Chemistry of 1,3,5-Trioxane:  UV Spectra of c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>(•) and (c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O<INF>2</INF>(•) Radicals, Kinetics of the Reactions of (c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O<INF>2</INF>(•) Radicals with NO and NO<INF>2</INF>, and Atmospheric Fate of the Alkoxy Radical (c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O(•)

A pulse radiolysis technique was used to measure the UV absorption spectra of c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>(•) and (c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O<INF>2</INF>(•) radicals over the range 220−300 nm, with σ(c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>(•))<INF>250 nm</INF> = (5.2 ± 0.7) × 10^-18 and σ((c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O<INF>2</INF>(•))<INF>250 nm</INF> = (3.7 ± 0.4) × 10^-18 cm² molecule^-1. The self-reaction rate constant for the c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>(•) radicals, defined as d[c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>(•)]/dt = 2k<INF>4</INF>[c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>(•)]², was k<INF>4</INF> = (3.1 ± 0.6) × 10^-11 cm³ molecule^-1 s^-1. The rate constants for reactions of (c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O<INF>2</INF>(•) radicals with NO and NO<INF>2</INF> were k<INF>6</INF> = (5.8 ± 1.4) × 10^-12 and k<INF>7</INF> = (1.1 ± 0.2) × 10^-11 cm³ 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<INF>3</INF>H<INF>5</INF>O<INF>3</INF>(•) radicals with O<INF>2</INF> were k<INF>3</INF> = (1.1 ± 0.4) × 10^-10 and k<INF>2</INF> = (7.4 ± 1.1) × 10^-12 cm³ 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<INF>2</INF>OC(O)H, k<INF>20</INF> = (6.0 ± 1.0) × 10^-12, k<INF>24</INF> = (1.0 ± 0.2) × 10^-10, and k<INF>25</INF> = (5.1 ± 1.0) × 10^-13 cm³ molecule^-1 s^-1, respectively. FTIR−smog chamber systems were used to show that the atmospheric fate of the alkoxy radical (c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O(•) is decomposition via C−O bond scission leading to the formation of H(O)COCH<INF>2</INF>OC(O)H (methylene glycol diformate). The IR spectrum of the peroxynitrate (c-C<INF>3</INF>H<INF>5</INF>O<INF>3</INF>)O<INF>2</INF>NO<INF>2</INF> is presented. The results are discussed with respect to the atmospheric chemistry of 1,3,5-trioxane.