420-05-3

Basic information

• Product Name: cyanic acid
• Synonyms: cyanic acid;CPD-69;hydrogen cyanate
• CAS NO: 420-05-3
• Molecular Formula: CHNO
• Molecular Weight: 43.02474
• Mol File: 420-05-3.mol
• Article Data: 14

Chemical Properties

• Melting Point: -86°
• Boiling Point: bp760 23.5°
• Flash Point: °C
• Appearance: /
• Density: d420 1.140; d4-20 1.156
• Vapor Pressure: 813mmHg at 25°C
• Refractive Index: 1.4300 (estimate)
• PKA: 3.7(at 25℃)
• CAS DataBase Reference: cyanic acid(CAS DataBase Reference)
• NIST Chemistry Reference: cyanic acid(420-05-3)
• EPA Substance Registry System: cyanic acid(420-05-3)

Safety Data

• Hazardous Substances Data: 420-05-3(Hazardous Substances Data)

Usage

Preparation

Cyanic acid is prepared in the laboratory by dry distillation of cyanuric acid, C3N3(OH)3.

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.

Chemical Properties

Colorless liquid or gas with an acrid smell; mp -86°C (-122.8°F); bp 23.5°C (74.3°F); density 1.140 at 20°C (68°F); soluble in water, alcohol, ether, benzene, and toluene.

Uses

Different sources of media describe the Uses of 420-05-3 differently. You can refer to the following data:
1. In formation of some cyanates.
2. Hydrogen cyanate is used in the preparation of cyanates.

Definition

cyanic acid: An unstable explosiveacid, HOCN. The compound has thestructure H–O–C≡N, and is also calledfulminic acid. Its salts and esters arecyanates (or fulminates). The compoundis a volatile liquid, whichreadily polymerizes. In water it hydrolysesto ammonia and carbondioxide. It is isomeric with anotheracid, H–N=C=O, which is known asisocyanic acid. Its salts and esters areisocyanates.

Health Hazard

Hydrogen cyanate is a severe irritant to the eyes, skin, and mucous membranes. Exposure to this compound can cause severe lacrimation. Inhalation can produce irritation and injury to the respiratory tract. LD50 values are not reported.

Fire Hazard

Flammable; the liquid can explode when heated rapidly.

Waste Disposal

Hydrogen cyanate can be disposed of in the drain in small amounts. It decomposes in water forming CO2 and NH3.

InChI:InChI=1/CHNO/c2-1-3/h3H

Upstream product

• 50-00-0 formaldehyd 
• 941-87-7 2-hydroxy-2H-quinoline-1-carbonitrile 
• 107-97-1 sarcosine 
• 64-17-5 ethanol 
• 4412-24-2 phenothiazine-10-carboxamide 
• 16898-71-8 bis-benzothiazol-2-yl tetrasulfide 
• 151-50-8 potassium cyanide 
• 3315-16-0 silver cyanate 
• 56-81-5 glycerol 
• 917-61-3 sodium isocyanate 
• 497-58-5 3,4-dioxo-3,4-dihydro-2H-pyran-2,6-dicarboxylic acid 
• 7697-37-2 nitric acid 
• 108-80-5 cyanuric acid 
• 7732-18-5 water 

Downstream Products

• 108-19-0 BIURET 
• 626-36-8 ethyl allophanate 
• 96314-56-6 allophanic acid-(3-hydroxy-phenyl ester) 
• 3147-85-1 allophanic acid butyl ester 
• 592-35-8 butyl carbamate 
• 55-21-0 benzamide 
• 622-46-8 carbamic acid phenyl ester 
• 1192-34-3 4-methyl-1,3-dihydro-imidazol-2-one 
• 625-52-5 N-Ethylurea 
• 598-94-7 1,1-Dimethylurea 
• 1118-12-3 1,1-dimethylethylurea 
• 557-11-9 allylurea 
• 634-95-7 N,N-diethylurea 
• 462-60-2 N-carbamoylglycine 

Relevant articles and documents

The crystal structure of carbamoyl fluoride, NH2COF

Although first synthesized in 1940, the X-ray crystal structure of carbamoyl fluoride, NH2COF, has until now remained unknown. [1] NH2COF crystallizes in the orthorhombic space group Ibam, is planar, and exhibits a short C-N bond length, 1.3168(13) ?, implying a significant degree of donation from the nitrogen lone pair. The structure features one molecule in the asymmetric unit and eight molecules in the unit cell. There are four molecules in two planar layers that are connected by a network of NH·O hydrogen bonds with N·O distances of 2.987(2) ? and 2.945(2) ?. The compound was also studied by quantum chemical calculations at both the ab initio (MP2) and density functional theory (B3LYP) level.

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Thermal reactivity of HNCO with water ice: An infrared and theoretical study

The structure and energy of the 1:1 complexes between isocyanic acid (HNCO) and H2O are investigated using FTIR matrix isolation spectroscopy and quantum calculations at the MP2/6-31G(d,p) level. Calculations yield two stable complexes. The first and most stable one (ΔE = 23.3 kJ/mol) corresponds a form which involves a hydrogen bond between the acid hydrogen of HNCO and the oxygen of water. The second form involves a hydrogen bond between the terminal oxygen of HNCO and hydrogen of water. In an argon matrix at 10 K, only the first form is observed. Adsorption on amorphous ice water at 10 K shows the formation of only one adsorption site between HNCO and ice. It is comparable to the complex observed in matrix and involves an interaction with the dangling oxygen site of ice. Modeling using computer code indicates the formation of polymeric structure on ice surface. Warming of HNCO, adsorbed on H2O ice film or co-deposited with H2O samples above 110 K, induces the formation of isocyanate ion (OCN-) characterized by its vasNCO infrared absorption band near 2170 cm-1. OCN- can be produced by purely solvation-induced HNCO dissociative ionization. The transition state of this process is calculated 42 kJ/mol above the initial state, using the ONIOM model in B3LYP/6-31g(d,p).

Determination of the rate constant and product channels for the radical-radical reaction NCO(X 2Π) + C2H5(X 2A″) at 293 K

The rate constant and product branching ratios for the reaction of the cyanato radical, NCO(X 2Π), with the ethyl radical, C 2H5(X 2A″), have been measured over the pressure range of 0.28 to 0.59 kPa and at a temperature of 293 ± 2 K. The total rate constant, k1, increased with pressure, P(kPa), described by k1 = (1.25 ± 0.16) × 10-10 + (4.22 ± 0.35) × 10-10 P cm3 molecule-1 s-1. Three product channels were observed that were not pressure dependent: (1a) HNCO + C2H4, k1a = (1.1 ± 0.16) × 10-10, (1b) HONC + C2H4, k1b = (2.9 ± 1.3) × 10-11, (1c) HCN + C 2H4O, k1c = (8.7 ± 1.5) × 10 -13, with units cm3 molecule-1 s-1 and uncertainties of one-standard deviation in the scatter of the data. The pressure dependence was attributed to a forth channel, (1d), forming recombination products C2H5NCO and/or C2H 5OCN, with pressure dependence: (1d) k1d = (0.090 ± 1.3) × 10-11 + (3.91 ± 0.27) × 10-10 P cm3 molecule-1 s-1. The radicals were generated by the 248 nm photolysis of ClNCO in an excess of C2H 6. Quantitative infrared time-resolved absorption spectrophotometry was used to follow the temporal dependence of the reactants and the appearance of the products. Five species were monitored, HCl, NCO, HCN, HNCO, and C 2H4, providing a detailed picture of the chemistry occurring in the system. Other rate constants were also measured: ClNCO + C 2H5, k10 = (2.3 ± 1.2) × 10 -13, NCO + C2H6, k2 = (1.6 ± 0.11) × 10-14, NCO + C4H10, k4 = (5.3 ± 0.51) × 10-13, with units cm3 molecule-1 s-1 and uncertainties of one-standard deviation in the scatter of the data. the Owner Societies.