Sodium cyanate
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| Identifiers | |
|---|---|
3D model (JSmol)
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| 3655041 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.011.846 |
| EC Number |
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| MeSH | C009281 |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| NaOCN | |
| Molar mass | 65.01 g/mol |
| Appearance | white crystalline solid |
| Odor | odorless |
| Density | 1.893 g/cm3 |
| Melting point | 550 °C (1,022 °F; 823 K) |
| 11.6 g/100 mL (25 °C) | |
| Solubility | ethanol: 0.22 g/100 mL (0 °C) dimethylformamide: 0.05 g/100 mL (25 °C) slightly soluble in ammonia, benzene insoluble in diethyl ether |
| Structure | |
| body centered rhombohedral | |
| Thermochemistry | |
Heat capacity (C)
|
86.6 J/mol K |
Std molar
entropy (S⦵298) |
119.2 J/mol K |
Std enthalpy of
formation (ΔfH⦵298) |
−400 kJ/mol |
| Hazards | |
| GHS labelling: | |
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| Warning | |
| H302, H412 | |
| P264, P270, P273, P301+P312, P330, P501 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
|
1500 mg/kg (rat, oral) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium cyanate is the inorganic compound with the formula NaOCN. A white solid, it is the sodium salt of the cyanate anion.
Structure
The anion is described by two resonance structures: N≡C−O− and −N=C=O
The salt adopts a body centered rhombohedral crystal lattice structure (trigonal crystal system) at room temperature.[1]
Preparation
Sodium cyanate is prepared industrially by the reaction of urea with sodium carbonate at elevated temperature.
- 2OC(NH2)2 + Na2CO3 → 2Na(NCO) + CO2 + 2NH3 + H2O
Sodium allophanate is observed as an intermediate:[2]
- H2NC(O)NHCO2Na → NaOCN + NH3 + CO2
It can also be prepared in the laboratory by oxidation of a cyanide in aqueous solution by a mild oxidizing agent such as lead oxide.[3]
Uses and reactions
The main use of sodium cyanate is for steel hardening.[2]
Sodium cyanate is used to produce cyanic acid, often in situ:
- NaOCN + HCl → HOCN + NaCl
This approach is exploited for condensation with amines to give unsymmetrical ureas:
- HOCN + RNH2 → RNHC(O)NH2
Such urea derivatives have a range of biological activity.[4]
See also
References
- ^ Waddington, T.C. "Journal of the Chemical Society (Resumed)." 499. Lattice Parameters and Infrared Spectra of Some Inorganic Cyanates - (RSC Publishing). N.p., n.d. Web. 09 Nov. 2014.
- ^ a b Schalke, Peter M. (2006). "Cyanates, Inorganic Salts". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a08_157.pub2. ISBN 3527306730.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 324. ISBN 978-0-08-037941-8.
- ^ Vinogradova, Ekaterina V.; Fors, Brett P.; Buchwald, Stephen L. (11 July 2012). "Palladium-Catalyzed Cross-Coupling of Aryl Chlorides and Triflates with Sodium Cyanate: A Practical Synthesis of Unsymmetrical Ureas". Journal of the American Chemical Society. 134 (27): 11132–11135. doi:10.1021/ja305212v. PMC 3472423. PMID 22716197.
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