2686. Cyanic Acid

Nomenclature

CAS number: 420-05-3
Hydrogen cyanate.
CHNO; mol wt 43.02.
C 27.92%, H 2.34%, N 32.56%, O 37.19%.

Description and references

Best prepd in the laboratory by dry distillation of cyanuric acid: Linhard, Z. Anorg. Allg. Chem. 236, 200 (1938). See also Isocyanic Acid.

Chemical structure

Properties

Liquid. Acrid odor, strong lacrimator and vesicant. d420 1.140; d4-20 1.156. mp -86°. bp760 23.5°. Heat of formation -36.5 kcal/mol. Dipole moment 1.592. pK (20°) 3.66. Rapid heating of the liquid may result in an explosion. Polymerizes on standing forming cyamelide and cyanuric acid. Sol in water with decompn to carbon dioxide and ammonia. Dil solns in ice water may be kept for several hours. Dil solns in ether, benzene, toluene can be kept for several weeks.

Caution

Highly irritating to eyes, skin, and mucous membranes. See Clinical Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins, Baltimore, 5th ed., 1984) Section II, p 110.

Use

In formation of some cyanates.