Urea

Urea
Names
Pronunciation urea /jʊəˈrə/, carbamide /ˈkɑːrbəmd/
Preferred IUPAC name
Urea[1]
Systematic IUPAC name
Carbonic diamide[1]
Other names
  • Carbamide
  • Carbonyldiamide
  • Carbonyldiamine
  • Diaminomethanal
  • Diaminomethanone
Identifiers
3D model (JSmol)
635724
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.286 Edit this at Wikidata
E number E927b (glazing agents, ...)
1378
KEGG
RTECS number
  • YR6250000
UNII
  • InChI=1S/CH4N2O/c2-1(3)4/h(H4,2,3,4) checkY
    Key: XSQUKJJJFZCRTK-UHFFFAOYSA-N checkY
  • InChI=1/CH4N2O/c2-1(3)4/h(H4,2,3,4)
    Key: XSQUKJJJFZCRTK-UHFFFAOYAF
  • C(=O)(N)N
Properties
CO(NH2)2
Molar mass 60.06 g/mol
Appearance White solid
Density 1.32 g/cm3
Melting point 133 to 135 °C (271 to 275 °F; 406 to 408 K)
Boiling point decomposes
545 g/L (at 25 °C)[2]
Solubility 500 g/L glycerol[3]

  50 g/L ethanol
  ~4 g/L acetonitrile[4]

Basicity (pKb) 13.9[5]
Conjugate acid Uronium
−33.4·10−6 cm3/mol
Structure
4.56 D
ThermochemistryCRC Handbook
−333.19 kJ/mol
−197.15 kJ/mol
Pharmacology
B05BC02 (WHO) D02AE01 (WHO)
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
1
0
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
8500 mg/kg (oral, rat)
Safety data sheet (SDS) ICSC 0595
Related compounds
Related ureas
Thiourea
Hydroxycarbamide
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula CO(NH2)2. This amide has two amino groups (–NH2) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid.[6]

Urea serves an important role in the cellular metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. Urea is Neo-Latin, from French urée, from Ancient Greek οὖρον (oûron) 'urine', itself from Proto-Indo-European *h₂worsom.

It is a colorless, odorless solid, highly soluble in water, and practically non-toxic (LD50 is 15 g/kg for rats).[7] Dissolved in water, it is neither acidic nor alkaline. The body uses it in many processes, most notably nitrogen excretion. The liver forms it by combining two ammonia molecules (NH3) with a carbon dioxide (CO2) molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen (N) and is an important raw material for the chemical industry.

In 1828, Friedrich Wöhler discovered that urea can be produced from inorganic starting materials, which was an important conceptual milestone in chemistry. This showed for the first time that a substance previously known only as a byproduct of life could be synthesized in the laboratory without biological starting materials, thereby contradicting the widely held doctrine of vitalism, which stated that only living organisms could produce the chemicals of life.

  1. ^ a b Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 416, 860–861. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The compound H2N-CO-NH2 has the retained name 'urea', which is the preferred IUPAC name, with locants N and N′, as shown above the structure below. The systematic name is 'carbonic diamide', (…).
  2. ^ Yalkowsky, Samuel H.; He, Yan; Jain, Parijat (19 April 2016). Handbook of Aqueous Solubility Data. CRC Press. ISBN 9781439802465.
  3. ^ "Solubility of Various Compounds in Glycerine" (PDF). msdssearch.dow.com. Archived from the original (PDF) on 13 April 2014. Retrieved 12 April 2014.
  4. ^ Loeser E, DelaCruz M, Madappalli V (9 June 2011). "Solubility of Urea in Acetonitrile–Water Mixtures and Liquid–Liquid Phase Separation of Urea-Saturated Acetonitrile–Water Mixtures". Journal of Chemical & Engineering Data. 56 (6): 2909–2913. doi:10.1021/je200122b.
  5. ^ Calculated from 14−pKa. The value of pKa is given as 0.10 by the CRC Handbook of Chemistry and Physics, 49th edition (1968–1969). A value of 0.18 is given by Williams, R. (24 October 2001). "pKa Data" (PDF). Archived from the original (PDF) on 24 August 2003.
  6. ^ "Carbamic acid".
  7. ^ "Urea - Registration Dossier - ECHA". echa.europa.eu.