Ammonia formation, nitric oxide

Alternative approaches to nitric oxide formation include irradiation of air in a nuclear reactor (72) and the oxidation of ammonia to nitric oxide in a fuel cell generating energy (73). Both methods indicate some potential for commercial appHcation but require further study and development. 

Dalby studied the flash photolysis of mixtures of ammonia with nitric oxide and observed the formation of nitroxyl, HNO. He reported that Liu, working in the Ottawa laboratory, did not observe HNO when NH3-O2 mixtures were pho-tolyzed. 

The explosive dispersion of aluminum or the release of trimethyl aluminum at high altitude leads to formation of the lower oxide AlO that emits a blue glow useful for temperature measurements. Other studies with different goals involve the release of ammonia or nitric oxide. The subject is lucidly treated, with individual references, in an article by Rosenberg, ... 

Ammonium nitrate is manufactured by reacting ammonia with nitric acid. Consider the process shown by Fig. 9.19. First, namral gas is reformed and converted into hydrogen, nitrogen and carbon dioxide. Hydrogen and nitrogen are separated an fed to the ammonia synthesis plant. A fraction of the produced ammonia is employed in nitric acid formation. Ammonia is first oxidized with compressed air then absorbed in water to form nitric acid. Finally nitric acid is reacted with anunonia to oduce ammonium nitrate. 

Checkel, M. D. et al., J. Loss Prevention, 1995, 8(4), 215 Flammability limits of mixtures of nitric oxide and ammonia were studied. The limits are 15-70% ammonia tenfold pressure rise and explosion are possible. Introduction of oxygen into flammable compositions will produce autoignition, via nitrogen dioxide formation, contamination with air might. 

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). ... 

From the thermodynamic data of Appendix C, show that the product of the reaction of ammonia gas with oxygen would be nitrogen, rather than nitric oxide, under standard conditions and in the absence of kinetic control by, for example, specific catalysis of NO formation by platinum. (Assume the other product to be water vapor.)... 

---