Triuret

Triuret is an organic compound with the formula (H₂NC(O)NH)₂CO. It is a product from the pyrolysis of urea. Triuret is a colorless, crystalline, hygroscopic solid, slightly soluble in cold water or ether, and more soluble in hot water. It is a planar molecule. The central carbonyl is hydrogen-bonded to both terminal amino groups.^[2]

Triuret

Names
Preferred IUPAC name 2,4-Diimidotricarbonic diamide[1]
Other names Carbonyldiurea 1,3-Dicarbamylurea Dicarbamylurea Diimidotricarbonic diamide Tricarbonodiimidic diamide
Identifiers
CAS Number	556-99-0 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:36955
ChemSpider	61685
ECHA InfoCard	100.008.317
EC Number	209-147-7
MeSH	C017781
PubChem CID	68400
UNII	6ID4233C3S Y
CompTox Dashboard (EPA)	DTXSID9060314
InChI InChI=1S/C3H6N4O3/c4-1(8)6-3(10)7-2(5)9/h(H6,4,5,6,7,8,9,10) Key: WNVQBUHCOYRLPA-UHFFFAOYSA-N
SMILES C(=O)(N)NC(=O)NC(=O)N
Properties
Chemical formula	C3H6N4O3
Molar mass	146.106 g·mol−1
Density	1.547 g/cm3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

The compound is typically prepared by heating thin layers of urea, the thin layers facilitating escape of ammonia:

3 (H₂N)₂CO → [H₂NC(O)NH]₂CO + 2 NH₃

It can also prepared by treatment of urea with phosgene:^[3]

2 (H₂N)₂CO + COCl₂ → [H₂NC(O)NH]₂CO + 2 HCl

A similar synthesis employs urea and dimethyl carbonate with potassium methoxide as a catalyst:^[4]

2 (H₂N)₂CO + CO(OCH₃)₂ → [H₂NC(O)NH]₂CO + 2 MeOH

The original synthesis entailed oxidation of uric acid with hydrogen peroxide.^[5]

Triuret is a complicating by-product in the industrial synthesis of melamine from urea.

Related compounds

• Urea
• Biuret
• Cyanuric acid

References

1. International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 866. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
2. D. Carlström and H. Ringertz "The molecular and crystal structure of triuret" Acta Crystallogr. (1965. vol. 18, 307-313. doi:10.1107/S0365110X65000737
3. C. Nitschke; G. Scherr (2012). "Urea Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.o27_o04. ISBN 978-3527306732.
4. Chen, Jianchao; Zhao, Peihua; Liu, Yaqing; Liu, Hua; Zhu, Futian (2012). "Clean and facile synthesis of triuret from urea and dimethyl carbonate (DMC) under mild conditions". Korean Journal of Chemical Engineering. 29 (3): 288–290. doi:10.1007/s11814-011-0172-8. S2CID 94537937.
5. Alfred Schittenhelm, Karl Wiener "Carbonyldiharnstoff als Oxydationsprodukt der Harnsäure" Zeitschrift für Physiologische Chemie 1909, volume 62, 100 ff.