Ammonia radical, reaction with nitric oxide

Acidic Properties. As a typical acid, it reacts readily with alkaUes, basic oxides, and carbonates to form salts. The largest iadustrial appHcation of nitric acid is the reaction with ammonia to produce ammonium nitrate. However, because of its oxidising nature, nitric acid does not always behave as a typical acid. Bases having metallic radicals ia a reduced state (eg, ferrous and staimous hydroxide becoming ferric and stannic salts) are oxidized by nitric acid. Except for magnesium and manganese ia very dilute acid, nitric acid does not Hberate hydrogen upon reaction with metals. 

Nitric oxide formation from hydroxyurea requires a three-electron oxidation (Scheme 7.15) [114]. Treatment of hydroxyurea with a variety of chemical oxidants produces NO or NO-related species , including nitroxyl (HNO), and these reactions have recently been extensively reviewed [114]. Many of these reactions proceed either through the nitroxide radical (25) or a C-nitroso intermediate (26, Scheme 7.15) [114]. The remainder of the hydroxyurea molecule may decompose into formamide or carbon dioxide and ammonia, depending on the conditions and type of oxidant (one-electron vs. two electron) employed. 

Chemical radicals—such as hydroxyl, peroxyhydroxyl, and various alkyl and aryl species—have either been observed in laboratory studies or have been postulated as photochemical reaction intermediates. Atmospheric photochemical reactions also result in the formation of finely divided suspended particles (secondary aerosols), which create atmospheric haze. Their chemical content is enriched with sulfates (from sulfur dioxide), nitrates (from nitrogen dioxide, nitric oxide, and peroxyacylnitrates), ammonium (from ammonia), chloride (from sea salt), water, and oxygenated, sulfiirated, and nitrated organic compounds (from chemical combination of ozone and oxygen with hydrocarbon, sulfur oxide, and nitrogen oxide fragments). ... 

Inorganic nitrates or nitric acid are formed by several reactions in smog. Among the important reactions forming HNO3 are the reaction of N2O5 with water and the addition of hydroxyl radical to NO2. The oxidation of NO or NO2 to nitrate species may occur after absorption of gas by an aerosol droplet. Nitric acid formed by these reactions reacts with ammonia in the atmosphere to form ammonium nitrate ... 

In a second example, we examine reactions that relate to the Ostwald oxidation process, where NH3 is converted to NO with high selectivity. The reaction is typically run at high temperatures of around 1100 K over Pt/Rh alloy catalysts. The NO that forms is subsequently converted into nitric acid via a series of consecutive reaction steps. At lower temperatures, ammonia reacts to form Ng and NgO instead. The low-temperature conversion of ammonia to N2 would be much more desirable in that it would lower energy costs and, in addition, replace NO, an atmospheric pollutant, with N2, which is environmentally benign. We will describe here the low-temperature catalytic conversion of ammonia to form N2. For a review of high-temperature oxidation, in which coupling with gas-phase radical chemistry plays an important role, we refer to Ref. [50]. 

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