| 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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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.
The parent compound can be prepared by heating urea above the melting point at which temperature ammonia is expelled:[2]
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.
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]