Cyanic acid is prepared in the laboratory by dry distillation of cyanuric acid, C3N3(OH)3.
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Reaction
Cyanic acid decomposes on heating. Rapid heating may cause explosion. When heated to high temperatures, it decomposes forming carbon dioxide, water, and nitrogen oxides:
4NCOH + 7O2 4CO2 + 4NO2 + 2H2O
It dissolves in water decomposing to carbon dioxide and ammonia. Although the reaction occurs at ordinary temperatures, it is slow in dilute aqueous solutions at ice temperature.
NCOH + H2O → CO2 + NH3
The compound polymerizes on standing, forming cyanuric acid, an oxygen heterocylic compound, 1,3,5-trioxane-2,4,6-triimine, C3H3N3O3.
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