Nitro compounds reaction with hydroxyl radical

Aliphatic nitro compounds are characterized by another interesting and mechanistically important property. Based on tautomeric and protolytic equilibria the stable form of nitromethane in basic solution is that of a double bonded ac/-nitromethane anion, CH2=N02 , which becomes ready target for electrophilic radical additions. An example, studied by pulse radiolysis, is its reaction with hydroxyl radicals as formulated in eq. 3."... 

Some of the main reactions of aromatic nitro compounds with free radicals given here [116]. Nitrobenzene reacts with hydroxyl produced by hydrogen iroxide ferrous salt reaction (28)... 

Gasoline hydrocarbons volatilized to the atmosphere quickly undergo photochemical oxidation. The hydrocarbons are oxidized by reaction with molecular oxygen (which attacks the ring structure of aromatics), ozone (which reacts rapidly with alkenes but slowly with aromatics), and hydroxyl and nitrate radicals (which initiate side-chain oxidation reactions) (Stephens 1973). Alkanes, isoalkanes, and cycloalkanes have half-lives on the order of 1-10 days, whereas alkenes, cycloalkenes, and substituted benzenes have half- lives of less than 1 day (EPA 1979a). Photochemical oxidation products include aldehydes, hydroxy compounds, nitro compounds, and peroxyacyl nitrates (Cupitt 1980 EPA 1979a Stephens 1973). 

Nitration of phenols by peroxidases can occur through two different mechanisms. The reaction requires phenol, nitrite, and hydrogen peroxide. In the principal mechanisms, compound I and compound II are formed. Upon one-electron oxidation of the substrates, phenoxy radical and nitrogen dioxide are produced. Coupling of these species gives the nitrophenol derivatives, where the nitro group is in the ortho or para position with respect to the phenol hydroxyl group. This reaction will be described in more detail in Sect. 6.1.5. 

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