triuret
{{chembox
| ImageFile = TriuretHbond.png
| ImageSize = 260px
| ImageName = Structure of triuret
| Name = Triuret
| PIN = 2,4-Diimidotricarbonic diamide{{cite book |author=International Union of Pure and Applied Chemistry |date=2014 |title=Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 |publisher=The Royal Society of Chemistry |page=866 |doi=10.1039/9781849733069 |isbn=978-0-85404-182-4}}
| OtherNames = Carbonyldiurea
1,3-Dicarbamylurea
Dicarbamylurea
Diimidotricarbonic diamide
Tricarbonodiimidic diamide
|Section1={{Chembox Identifiers
| CASNo = 556-99-0
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII = 6ID4233C3S
| UNII_Ref = {{fdacite|correct|FDA}}
| EINECS = 209-147-7
| PubChem = 68400
| ChemSpiderID = 61685
| SMILES = C(=O)(N)NC(=O)NC(=O)N
| StdInChI = 1S/C3H6N4O3/c4-1(8)6-3(10)7-2(5)9/h(H6,4,5,6,7,8,9,10)
| StdInChIKey = WNVQBUHCOYRLPA-UHFFFAOYSA-N
| MeSHName = C017781
| ChEBI = 36955}}
|Section2={{Chembox Properties
| C=3 | H=6 | N=4 | O=3
| Density = 1.547 g/cm3
}}
}}
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.D. Carlström and H. Ringertz "The molecular and crystal structure of triuret" Acta Crystallogr. (1965. vol. 18, 307-313. {{doi|10.1107/S0365110X65000737}}
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:{{ Ullmann |author=C. Nitschke |author2=G. Scherr | title = Urea Derivatives | year = 2012| doi = 10.1002/14356007.o27_o04}}
:2 (H2N)2CO + COCl2 → [H2NC(O)NH]2CO + 2 HCl
A similar synthesis employs urea and dimethyl carbonate with potassium methoxide as a catalyst:{{cite journal|last1=Chen|first1=Jianchao|last2=Zhao|first2=Peihua|last3=Liu|first3=Yaqing|last4=Liu|first4=Hua|last5=Zhu|first5=Futian|title=Clean and facile synthesis of triuret from urea and dimethyl carbonate (DMC) under mild conditions|journal=Korean Journal of Chemical Engineering|date=2012|volume=29|issue=3|pages=288–290|doi=10.1007/s11814-011-0172-8|s2cid=94537937}}
:2 (H2N)2CO + CO(OCH3)2 → [H2NC(O)NH]2CO + 2 MeOH
The original synthesis entailed oxidation of uric acid with hydrogen peroxide.Alfred Schittenhelm, Karl Wiener "Carbonyldiharnstoff als Oxydationsprodukt der Harnsäure" Zeitschrift für Physiologische Chemie 1909, volume 62, 100 ff.
Triuret is a complicating by-product in the industrial synthesis of melamine from urea.