title: Kinetics and Mechanism of the Reaction of Azide with Ozone in Aqueous Solution.
abstract: The stoichiometry of the reaction of aqueous ozone with sodium azide was studied at pH 12 (mainly) where a yellow metastable intermediate is observed. We propose that this is hypoazidite (N3O-), analogous to hypobromite, and that it plays a central role in the azide catalyzed decompostion of ozone. The yellow intermediate is unstable in acid, in which it rapidly decomposes, generating N2and NO2-. The rate of reaction was studied at pH 2.0-3.5, with the ionic strength at 0.6 M and temperature at 3-15 ° C. The intrinsic second-order rate constants were found to be kHN3≤ ≈ 400 M-1sec-1and kN3- = (8.7 ± 0.5) × 105M-1sec-1(3 °C, 0.6 M), both in agreement with the only other previous study. The rate constant at 25 °C was estimated using the following experimentally determined parameters: ln kN3- (M-1sec-1) = (5.73 ± 0.36) × 103/T (K) + (28.34 ± 1.27). The value of kN3- estimated in this way is (2.5 ± 0.1) × 106M-1sec-1at 25 °C and 0.6 M. The enthalpy of reaction (A H) is -48 ± 3 kJ mol-1.
authors.affiliation: a Department of Atmospheric Sciences , University of Arizona , Tucson , Arizona , USA.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Betterton
authors.affiliation: a Department of Atmospheric Sciences , University of Arizona , Tucson , Arizona , USA.
authors.forename: David
authors.initials: D
authors.lastname: Craig