Aromatic amines reactions with hydroxyl radical

On the other hand, the indirect type of ozonation is due to the reactions of free radical species, especially the hydroxyl radical, with the organic matter present in water. These free radicals come from reaction mechanisms of ozone decomposition in water that can be initiated by the hydroxyl ion or, to be more precise, by the hydroperoxide ion as shown in reactions (4) and (5). Ozone reacts very selectively through direct reactions with compounds with specific functional groups in their molecules. Examples are unsaturated and aromatic hydrocarbons with substituents such as hydroxyl, methyl, amine groups, etc. [45,46],... 

Peter Griess, 1858.—Diazo compounds were discovered and first prepared by Peter Griess in 1858. The historical method used by him is the same in general as is now used widely in dyestuff manufacture. It has already been described and consists in the action of nitrous acid on an aromatic primary amine, e.g., aniline. When this reaction takes place, at ordinary or slightly raised temperatures, the same products are obtained as with aliphatic primary amines, viz., the hydroxyl compound of the hydrocarbon radical, free nitrogen and water. 

The kinetics of the reactions of many xenobiotics with hydroxyl and nitrate radicals have been examined under simulated atmospheric conditions and include (1) aliphatic and aromatic hydrocarbons (Tuazon et al. 1986) and substituted monocyclic aromatic compounds (Atkinson et al. 1987c) (2) terpenes (Atkinson et al. 1985a) (3) amines (Atkinson et al. 1987a) (4) heterocyclic compounds (Atkinson et al. 1985b) and (5) chlorinated aromatic hydrocarbons (Kwok et al. 1995). For PCBs (Anderson and Hites 1996), rate constants were highly dependent on the number of chlorine atoms, and calculated atmospheric lifetimes varied from 2 days for 3-chlorobiphenyl to 34 days for 2,2, 3,5, 6-pentachlorbiphenyl. It was estimated that loss by hydroxylation in the atmosphere was a primary process for removal of PCBs from the environment. It was later shown that the products were chlorinated benzoic acids produced by initial reaction with a... 

Aromatic nitroxides were found to attack both alkyl and alkylperoxy radicals, but aliphatic nitroxides attacked only alkyl radicals, the rate obeying equation (IX) above. The kinetics of reaction involving nitroxide B were close to predictions made on the basis of equation (VII) and it is interesting to note that the rate of reaction was affected by solvent, possibly via the formation of a loose solvent—nitroxide complex. Hydroxyl-amines A and B reacted only with peroxy radicals, but hydroxylamine C was involved in a complex reaction sequence producing first strong inhibition and then equally strong catalysis of autoxidation ... 

Nitrations are highly exothermic, ie, ca 126 kj/mol (30 kcal/mol). However, the heat of reaction varies with the hydrocarbon that is nitrated. The mechanism of a nitration depends on the reactants and the operating conditions. The reactions usually are either ionic or free-radical. Ionic nitrations are commonly used for aromatics many heterocycHcs hydroxyl compounds, eg, simple alcohols, glycols, glycerol, and cellulose and amines. Nitration of paraffins, cycloparaffins, and olefins frequentiy involves a free-radical reaction. Aromatic compounds and other hydrocarbons sometimes can be nitrated by free-radical reactions, but generally such reactions are less successful. 

With nitrous acid. The reaction of the aromatic primary amines with nitrous acid is different from that of the aliphatic primary amines with the same reagent, and serves to distinguish the two groups of compounds. When a primary alkyl amine is treated with nitrous acid the hydroxyl compound of the radical is formed and all of the nitrogen of the amine is given off as free nitrogen. The reaction is as follows ... 

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