Biuret
| Biuret | |
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2-Imidodicarbonic diamide |
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Other names
Carbamylurea, imidodicarbonic diamide, allophanamide |
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| Identifiers | |
| CAS number | 108-19-0  |
| ChemSpider | 7625 |
| KEGG | C06555 |
| ChEBI | CHEBI:18138 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C2H5N3O2 |
| Molar mass | 103.08 g mol−1 |
| Melting point |
186–189 °C (decomposes) |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Biuret is a chemical compound with the chemical formula H2NC(O)NHC(O)NH2. It is the result of condensation of two molecules of urea and is a problematic impurity in urea-based fertilizers. This white solid is soluble in hot water.[1]
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.
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[edit] Biuret test
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.
[edit] Preparation
The parent compound can be prepared by heating urea above the melting point at which temperature ammonia is expelled:[2]
- 2 CO(NH2)2 → H2N-CO-NH-CO-NH2 + NH3 ↑
In general, organic biurets are prepared by trimerization of isocyanates. For example the trimer of 1,6-hexamethylene diisocyanate is also known as HDI-biuret.
[edit] Applications
Biuret is also used as a non-protein nitrogen source in ruminant feed,[3] where it is converted into protein by gut microorganisms.[4] It is less favored than urea, due to its higher cost and lower digestibility[5] but this characteristic also slows down its digestion and so decreases the risk of ammonia toxicity.[5][6]
[edit] Related compounds
[edit] References
- ^ 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: (1) "Neues Zersetzungsproduct des Harnstoffs" (New decomposition product of urea) Journal für praktische Chemie, vol. 42, pages 255-256 (1847). [This notice reports that biuret reacts with alkaline copper sulfate to produce a red solution -- the so-called "Biuret test".]; (2) Gustav Wiedemann (1848) "Über eine neue, aus dem Harnstoff entstehende Verbindung" (On a new compound arising from urea) Journal für praktische Chemie, vol. 43, page 271-280; (3) G. Wiedemann (1848) "Biuret. Zersetzungsprodukt des Harnstoffs" (Biuret: decomposition product of urea), Liebig's Annalen der Chemie und Pharmacie, vol. 68, pages 323-326.
- ^ Jozef H. Meessen and Harro Petersen “Urea” in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a27_333
- ^ Beef cattle feed, Encyclopædia Britannica Online
- ^ Florida Cow-Calf Management, 2nd Edition - Feeding the Cow Herd, IFAS Extension, University of Florida
- ^ a b Oltjen RR, Williams EE, Slyter LL, Richardson GV (November 1969). "Urea versus biuret in a roughage diet for steers". J. Anim. Sci. 29 (5): 816–22. PMID 5391979. http://jas.fass.org/cgi/pmidlookup?view=long&pmid=5391979.
- ^ Paul V. Fonnesbeck, Leonard C. Kearl and Lorin E. Harris (1975). "Feed Grade Biuret as a Protein Replacement for Ruminants. A Review". J. Anim Sci. 40 (6): 1150–1184. http://jas.fass.org/cgi/content/abstract/40/6/1150.
