Reactions with Nitrogen-Hydrogen Bonds

Figure 5.16 Photoactivation of a phenyl azide group with UV light results in the formation of a short-lived nitrene. Nitrenes may undergo a number of reactions, including insertion into active carbon-hydrogen or nitrogen-hydrogen bonds and addition to points of unsaturation in carbon chains. The most likely route of reaction, however, is to ring-expand to a dehydroazepine intermediate. This group is highly reactive toward nucleophiles, especially amines.

The manufacture of reaction-bonded Si3N4 begins with a preform of silicon. This preform is nitrided in an atmosphere of pure nitrogen or of nitrogen/hydrogen. The reaction proceeds without volume change, but the products have a minimum porosity of 10%. 98% of the theoretical density can be achieved by postsintering. 

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