Reactivity of Nitric Oxide with Simple Short-Lived Radicals in Aqueous Solutions

The kinetic parameters and spectral properties of the products of the reaction of nitric oxide (NO) with (SCN)[sub 2][sup [minus]], Br[sub 2][sup [minus]], CO[sub 2][sup [minus]], CO[sub 3][sup [minus]], and ethyl alcohol radicals were studied by the pulse radiolysis technique. The rate constants for the reaction of NO with these radicals are k[NO + (SCN)[sub 2][sup [minus]]] = (4.3 [+-] 0.1) x 10[sup 9] M[sup [minus]1] s[sup [minus]1], k[NO + CO[sub 2][sup [minus]]] = (2.9 [+-] 0.5) x 10[sup 9] M[sup [minus]1] s[sup [minus]1], k[NO + CO[sub 3][sup [minus]]] = (3.5 [+-] 0.5) x 10[sup 9] M[sup [minus]1] s[sup [minus]1], and k[NO + ethanol radicals] = (3.0 [+-] 1.0) x 10[sup 9] M[sup [minus]1] s[sup [minus]1]. (SCN)[sub 2][sup [minus]] radical forms an adduct that decomposes by first-order processes to yield ultimately NO[sub 2][sup [minus]]. The CO[sub 3][sup [minus]] radical reacts with NO by O[sup [minus]] transfer with the direct formation of NO[sub 2][sup [minus]]. The CO[sub 2] radical reacts with NO forming the NOCO[sub 2][sup [minus]] transient which reacts with excess NO yielding N[sub 2]O[sub 2][sup [minus]]. The ethanol radical-NO adducts rearrange to yield ultimately oximes/hydroxamic acids. 25 refs., 4 figs., 1 tab.