Biuret

Biuret

Names
Preferred IUPAC name 2-Imidodicarbonic diamide
Systematic IUPAC name (Carbamoylamino)methanamide
Other names Allophanamide Carbamylurea Allophanic acid amide Allophanimidic acid N-Carbamoylaminomethanamide Ureidoformamide Imidodicarbonic diamide Diurea
Identifiers
CAS Number	108-19-0 Y
3D model (Jmol)	Interactive image Interactive image
3DMet	B00969
Beilstein Reference	1703510
ChEBI	CHEBI:18138 Y
ChemSpider	7625 Y
ECHA InfoCard	100.003.236
EC Number	203-559-0
Gmelin Reference	49702
KEGG	C06555 Y
MeSH	Biuret
PubChem CID	7913
UNII	89LJ369D1H N
InChI InChI=1S/C2H5N3O2/c3-1(6)5-2(4)7/h(H5,3,4,5,6,7) Y Key: OHJMTUPIZMNBFR-UHFFFAOYSA-N Y
SMILES [nH2]:c(:[o]):[nH]:c(:[nH2]):[o] NC(=O)NC(N)=O
Properties
Chemical formula	C2H5N3O2
Molar mass	103.08 g·mol−1
Appearance	White crystals
Odor	Odourless
Density	1.467 g/cm3
Melting point	190 °C (decomposes)
Thermochemistry
Specific heat capacity (C)	131.3 J K−1 mol−1
Std molar entropy (So298)	146.1 J K−1 mol−1
Std enthalpy of formation (ΔfHo298)	−565.8–−561.6 kJ mol−1
Std enthalpy of combustion (ΔcHo298)	−940.1–−935.9 kJ mol−1
Hazards
GHS pictograms
GHS signal word	WARNING
GHS hazard statements	H315, H319, H335
GHS precautionary statements	P261, P305+351+338
EU classification (DSD)	Xi
R-phrases	R36/37/38
S-phrases	S26, S36
Related compounds
Related compounds	urea, triuret, cyanuric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Biuret is a chemical compound with the chemical formula C₂H₅N₃O₂. It is also known as carbamylurea. It is the result of condensation of two molecules of urea and is an impurity in urea-based fertilizers. This white solid is soluble in hot water. Biuret was first prepared and studied by Gustav Heinrich Wiedemann (1826 - 1899) for his doctoral dissertation, which was submitted in 1847. His findings were reported in several articles.

The term "biuret" also describes a family of organic compounds with the functional group -(HN-CO-)₂N-. Thus dimethyl biuret is CH₃HN-CO-NR'-CO-NHCH₃. A variety of organic derivatives are possible.

The parent compound can be prepared by heating urea above the melting point at which temperature ammonia is expelled:

Under related conditions, pyrolysis of urea affords triuret ((H₂N-CO-NH)₂CO). In general, organic biurets (those with alkyl or aryl groups in place of one or more H atoms) are prepared by trimerization of isocyanates. For example, the trimer of 1,6-hexamethylene diisocyanate is also known as HDI-biuret.

Biuret is also used as a non-protein nitrogen source in ruminant feed, where it is converted into protein by gut microorganisms. It is less favored than urea, due to its higher cost and lower digestibility but this characteristic also slows down its digestion and so decreases the risk of ammonia toxicity.

The biuret test is a chemical test for proteins and polypeptides. It is based on the biuret reagent, a blue solution that turns violet upon contact with proteins, or any substance with peptide bonds. The test and reagent do not actually contain biuret; they are so named because both biuret and proteins have the same response to the test.