The reactions of the azide radical (X̃ 2Πg), produced by the reaction of F atoms with HN3, with F, Cl, NO,
NO2, O2, CO, CO2, Cl2, and propylene have been examined in a room-temperature flow reactor. The relative
concentration of N3 was monitored under pseudo-first-order conditions using laser-induced fluorescence. A
microwave discharge applied to a dilute flow of CF4 in argon served as the F atom source for the F + HN3
reaction. Using reactant concentrations of (0.5−4.0) × 1012 and (1.0−4.0) × 1012 molecules cm-3 for CF4
and HN3, respectively, the rate constant for the N3 + F reaction was found to be (4.1 ± 0.3) × 10-11 cm3
molecule-1 s-1, which compares favorably with the accepted value of (5 ± 2) × 10-11 cm3 molecule-1 s-1.
The reaction with Cl atoms was examined using reactant concentrations of (5.5−9.4) × 1011, (2.0−4.0) ×
1012, and (1.0−22.0) × 1012 molecules cm-3 for CF4, HN3, and Cl2, respectively, and the rate constant is
× 10-11 cm3 molecule-1 s-1. The rate constants for the reactions of N3 with NO, NO2, and CO were
determined to be (2.9 ± 0.3) × 10-12, (1.9 ± 0.2) × 10-12, and (1.8 ± 0.2) × 10-12 cm3 molecule-1 s-1,
respectively. The reactions between azide radicals and Cl2, CO2, O2, and propylene all occur with rate constants
less than 5 × 10-13 cm3 molecule-1 s-1, indicating that N3 is not an especially reactive radical. The bimolecular
self-destruction rate for azide radical was also examined. An upper bound on the rate constant was determined
to be ≤1−2 × 10-12 cm3 molecule-1 s-1. The possible products and the reaction mechanisms of these reactions
are discussed.