Biuret

Chembox new
Name = Biuret
ImageFileL1 = Biuret-2D-skeletal.png ImageSizeL1 = 120px
ImageFileR1 = Biuret-3D-vdW.png ImageSizeR1 = 100px
ImageName = Space-filling model of biuret
IUPACName = 2-Imidodicarbonic diamide
OtherNames = Carbamylurea, imidodicarbonic diamide, allophanamide
Section1 = Chembox Identifiers
SMILES = NC(=O)NC(N)=O
CASNo = 108-19-0
Section2 = Chembox Properties
C=2|H=5|N=3|O=2
Density =
MeltingPt = 186–189 °C (decomposes)
BoilingPt =
Section7 = Chembox Hazards
External MSDS = [http://physchem.ox.ac.uk/MSDS/BI/biuret.html External MSDS]

Biuret is a condensation compound of urea, equivalent to two molecules of urea less one of ammonia. It is a white solid soluble in hot water and decomposes at 186–189 °C. The parent compound can be prepared by heating urea above the melting point at which temperature ammonia is expelled.

: 2 CO(NH₂)₂ → H₂N-CO-NH-CO-NH₂ + NH₃ ↑

The term biuret can also apply to the functional group and class of organic compounds with the general structure RHN-CO-NR-CO-NHR where R is an organic residue. Biurets can be prepared by trimerization of isocyanates. For example the trimer of 1,6-hexamethylene diisocyanate is also known as HDI-biuret.

The biuret reagent is used in the biuret protein assay, a chemical test for proteins not because the reagent contains biuret but because both biuret and proteins have the same response to copper. However, the biuret test will also return a positive result in contact with polypeptides as it detects the peptide bonds.

The liquid form of biuret is usually blue but turns violet when it comes in contact with protein or a substance with peptide bonds.

Biuret is also used as a non-protein nitrogen source in ruminant feed, [ [http://www.britannica.com/eb/article-67947/livestock-farming Beef cattle feed] , Encyclopedia Brittanica Online] where it is converted into protein by gut microbia. [ [http://edis.ifas.ufl.edu/AN117 Florida Cow-Calf Management, 2nd Edition - Feeding the Cow Herd] , IFAS Extension, University of Florida] It is less favored than urea, due to its lower digestibilitycite journal |author=Oltjen RR, Williams EE, Slyter LL, Richardson GV |title=Urea versus biuret in a roughage diet for steers |journal=J. Anim. Sci. |volume=29 |issue=5 |pages=816–22 |year=1969 |month=November |pmid=5391979 |doi= |url=http://jas.fass.org/cgi/pmidlookup?view=long&pmid=5391979] and higher cost, but is digested more slowly, decreasing the risk of ammonia toxicity. [cite journal | author = Paul V. Fonnesbeck, Leonard C. Kearl and Lorin E. Harris| title =Feed Grade Biuret as a Protein Replacement for Ruminants. A Review | journal = J. Anim Sci. | year =1975 | volume =40 | issue = | pages =1150–1184 | doi = | url = http://jas.fass.org/cgi/content/abstract/40/6/1150]

ee also

Related compounds:
* Triuret
* Cyanuric acid

References