Wink D A, Darbyshire J F, Nims R W, Saavedra J E, Ford P C
Chemistry Section, National Cancer Institute, Frederick Cancer Research and Development Center, Maryland 21702.
Chem Res Toxicol. 1993 Jan-Feb;6(1):23-7. doi: 10.1021/tx00031a003.
The reaction kinetics of nitric oxide autoxidation in aerobic solutions were investigated by direct observation of the nitrite ion product and by trapping the strongly oxidizing and nitrosating intermediates formed in this reaction. The rate behavior observed for nitrite formation [rate = k3[O2][NO]2, k3 = (6 +/- 1.5) x 10(6) M-2 s-1 at 22 degrees C] was the same as found for oxidation of Fe(CN)6(4-) and of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and as for the nitrosation of sulfanilamide. There was a slight decrease in k3 to (3.5 +/- 0.7) x 10(6) M-2 s-1 at 37 degrees C. The second-order dependency for NO was observed at NO concentrations as low as 3 microM. The results of the competitive kinetics studies suggest that the key oxidizing intermediates, species which are both strong oxidants and nitrosating agents, are not one of those commonly proposed (NO2, N2O3, NO+, or O2NO-) but are one or more as yet uncharacterized NOx species.
通过直接观察亚硝酸根离子产物以及捕获该反应中形成的强氧化性和亚硝化中间体，研究了有氧溶液中一氧化氮自氧化的反应动力学。观察到的亚硝酸盐形成的速率行为[速率 = k3[O2][NO]2，在22℃时k3 = (6±1.5)×10(6) M-2 s-1]与Fe(CN)6(4-)和2,2'-联氮双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)的氧化以及磺胺的亚硝化所发现的速率行为相同。在37℃时，k3略有下降至(3.5±0.7)×10(6) M-2 s-1。在低至3 microM的NO浓度下观察到对NO的二级依赖性。竞争动力学研究结果表明，关键的氧化中间体，即既是强氧化剂又是亚硝化剂的物种，不是那些常见的物种(NO2、N2O3、NO+或O¬2NO-)，而是一种或多种尚未表征的NOx物种。
