ATMOSPHERIC CHEMISTRY OF 1,4-DIOXANE - LABORATORY STUDIES

A pulse radiolysis technique was used to measure the UV absorption spe ctra of c-C4H7O2 and (c-C4H7O2)O-2 radicals over the range 220-320 nm, sigma(c-C4H7O2)(250 nm) = (5.9 +/- 0.6) x 10(-18) and sigma[(c-C4H7O2 )O-2](240 nm) = (4.8 x 0.8) x 10(-18) cm(2) molecule(-1). The observed self-reaction rate constants for the c-C4H7O2 and (c-C4H7O2)O-2 radic als, defined as -d[c-C4H7O2]/dt = 2k(4)[C-C4H7O](2) and -d[(c-C4H7O2)O -2]/dt = 2k(5 obs)[(c-C4H7O2)O-2](2) were k(4) = (3.3 +/- 0.4) x 10(-1 1) and k(5 obs) = (7.3 +/- 1.2) x 10(-12) cm(3) molecule(-1)s(-1). The rate constants for reactions of c-C4H7O2 radicals with NO and NO2 wer e k(6) (1.2 +/- 0.3) x 10(-11) and k(7) = (1.3 +/- 0.3) x 10(-11) cm(3 ) molecule(-1)s(-)1, respectively. The rate constants for the reaction of F atoms with 1,4-dioxane and the reaction of c-C4H7O2 radicals wit h O-2, were k(3) = (2.4 +/- 0.7) x 10(-10) and k(2) = (8.8 +/- 0.9) x 10(-12) cm(3) molecule(-1)s(-1) respectively. A relative rate techniqu e was used to measure the rate constant for the reaction of Cl atoms w ith 1,4-dioxane, k(17) = (2.0 +/- 0.3) x 10(-10) cm(3) molecule(-1)s(- 1). A long-pathlength FTIR spectrometer coupled to a smog chamber syst em was used to show that the sole atmospheric fate of the alkoxy radic al (c-C4H7O2)O is decomposition via C-C bond scission leading to the f ormation of H(O)COCH2CH2OC(O)H (ethylene glycol diformate).