Direct Combination of Nitrogen and Oxygen

As noted in Section 8.4, atmospheric N2 and O2 combine endothermically in small but significant yield and at a sufficiently rapid rate above about 2000 K, but the gases must be quenched rapidly if the high-temperature yield of NO is to be recovered for subsequent conversion to nitric acid  

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The Fixation of Nitrogen as Nitric Oxide. A method (the arc process) formerly used for fixation of atmospheric nitrogen but now abandoned is the direct combination of nitrogen and oxygen to nitric oxide at the high temperature of the electric arc. The reaction... 

Direct combination of nitrogen and oxygen is carried out at 4000°F until equilibrium is attained then the gases are cooled quickly to retard the reverse reaction. The reaction is second order overall in both directions, with the rate equation... 

Nitric oxide, NO, forms in small quantities in the cylinders of internal combustion engines by the direct combination of nitrogen and oxygen ... 

Even though equilibrium is unfavorable at high temperatures, direct combination of nitrogen and oxygen can occur under energy-rich conditions with 5 percent by volume of nitric oxide being formed at 5792T (3200°C) [1, 12]. 

In most zinc enzymes, the metal is tetrahedrally coordinated by either nitrogen atoms alone or by a combination of nitrogen and oxygen atoms. To model zinc enzymes having the much rarer S-donor environments, a number of approaches have been pursued. The most direct routes to such ligands involve the replacement of one or more... 

Titanium triiodide can be made by direct combination of the elements or by reducing the tetraiodide with aluminum at 280°C in a sealed tube. Til reacts with nitrogen, oxygen, and sulfur donor ligands to give the corresponding adducts (148). 

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