Title: Cyanic Acid
CAS Registry Number: 420-05-3
Additional Names: Hydrogen cyanate
Molecular Formula: CHNO
Molecular Weight: 43.02
Percent Composition: C 27.92%, H 2.34%, N 32.56%, O 37.19%
Literature References: Best prepd in the laboratory by dry distillation of cyanuric acid: Linhard, Z. Anorg. Allg. Chem. 236, 200 (1938). See also Isocyanic Acid.
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 liq 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.
Melting point: mp -86°
Boiling point: bp760 23.5°
pKa: pK (20°) 3.66
Density: d420 1.140; d4-20 1.156
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. |