Nitrogen Dioxide, NO

Nitrogen dioxide (NO,) is a reddish-brown gas that is formed through the oxidation of nitrogen oxide (NO). The term nitrogen oxides, or NO is used to encompass NO, as well as NO and the other oxides of nitrogen that lead to NO, production. 

Nitrogen dioxide (NO ) reacts with a wide variety of functional groups and it is the reagent of choice for a number of synthetic transformations. For example, the selective oxidation of sulfide to sulfoxide by NO forms the basis for the commercial production of dimethyl sulfoxide (from dimethyl sulfide) via a catalytic procedure (see below).250 Some representative examples of oxidative transformations carried out with NO are presented in Chart 8. 

Catalytic oxidation with dioxygen. The well-known aerial oxidation of the nitric oxide (NO ) produced in the stoichiometric oxidations in equation (90) to nitrogen dioxide (NO ) forms the basis for the NO -catalyzed oxidation of various donors with dioxygen251-253 (equation 96). 

FIGURE 4-7 Ozone, nitrogen dioxide, NO, and nonmethane hydrocarbon concentrations in pollution episode at Tunney s Pasture, Ontario. Redrawn from Quickert et al. ... 

When benzo[a]pyrene adsorbed from the vapor phase onto coal fly ash, silica, and alumina was exposed to nitrogen dioxide, no reaction occurred. However, in the presence of nitric acid, nitrated compounds were produced (Yokley et al, 1985). Chlorination of benzo [a] pyrene in polluted humus poor lake water gave ll,12-dichlorobenzo[a]pyrene and 1,11,12-, 3,11,12- or 3,6,11-... 

Tn recent years, a number of reaction models have been proposed to account for the chemical features of photochemical smog observed in atmospheric and laboratory studies (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11). Because of the complexity of smog chemistry and a lack of detailed knowledge of many relevant elementary reactions, numerous assumptions and simplifications are made in these mechanistic interpretations. A model for the chemistry of smog is presented here with a critical evaluation of the factors that control the major course of the reactions. The photooxidation of propylene (CsHq) in the presence of nitric oxide and nitrogen dioxide (NO + NO2 = NO, ) is used as a prototype for this study. 

The reversible gas-phase decomposition of nitrogen tetroxide, N2O4, to nitrogen dioxide, NO,... 

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