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Urea

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Company Name: Jiangsu Kolod Food Ingredients Co.,Ltd.
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Products Intro: Product Name:UREA ;Carbamide
CAS:57-13-6
Purity:99.0%--101.0% Package:25kg/bag Remarks:Food Grade,Pharmaceutical Grade
Company Name: Shenzhen Sendi Biotechnology Co.Ltd.
Tel: 0755-23311925 18102838259
Email: Abel@chembj.com
Products Intro: Product Name:Urea
CAS:57-13-6
Purity:99% Package:28/KG
Company Name: Henan DaKen Chemical CO.,LTD.
Tel: +86-371-55531817
Email: inquiry@dakenchem.com
Products Intro: Product Name:Urea
CAS:57-13-6
Purity:99% Package:100g,500g,1KG,10KG,100KG
Company Name: Henan Tianfu Chemical Co.,Ltd.
Tel: 0371-55170693
Email: info@tianfuchem.com
Products Intro: CAS:57-13-6
Purity:99% Package:500G;1KG;5KG;25KG
Company Name: Shanghai Time Chemicals CO., Ltd.
Tel: +86-021-57951555
Email: jack.li@time-chemicals.com
Products Intro: Product Name:Urea
CAS:57-13-6

Lastest Price from Urea manufacturers

Urea Chemical Properties
Melting point 132-135 °C(lit.)
Boiling point 332.48°C (estimate)
density 1.335 g/mL at 25 °C(lit.)
refractive index n20/D 1.40
storage temp. 2-8°C
solubility H2O: 8 M at 20 °C
form powder
pka0.10(at 25℃)
color white
PH8.0-10.0 (20℃, 8M in H2O)
Water Solubility 1080 g/L (20 ºC)
Merck 14,9867
BRN 635724
Stability:Substances to be avoided include strong oxidizing agents. Protect from moisture.
CAS DataBase Reference57-13-6(CAS DataBase Reference)
NIST Chemistry ReferenceUrea(57-13-6)
EPA Substance Registry SystemUrea(57-13-6)
Safety Information
Hazard Codes Xn,Xi
Risk Statements 36/37/38-40-38
Safety Statements 26-36-24/25-37
RIDADR Not regulated
WGK Germany 1
RTECS YR6250000
TSCA Yes
HS Code 31021010
Hazardous Substances Data57-13-6(Hazardous Substances Data)
MSDS Information
ProviderLanguage
Carbamide English
SigmaAldrich English
ACROS English
ALFA English
Urea Usage And Synthesis
Chemical structureLewis structure
Ball-and-stick diagram
Space-filling model
Urea, also known as carbamide, is an organic compound with chemical formula CO (NH2)2. This amide has two –NH2 groups joined by a carbonyl (C=O) functional group.
HistoryPure urea was first isolated from urine in 1727 by the Dutch scientist Herman Boerhaave, and he extracted urea from urine by working with the concentated-by-boiling residue. But if only not considering the purity of urea, the discovery of urea should be attributed to the French chemist Hilaire Rouelle, and he prepared urea (or its addition compound with sodium chloride) from urine some time before 1727.
In 1828, just 55 years after its discovery, urea became the first organic compound to be synthetically formulated, this time by a German chemist named Friedrich Wöhler, one of the pioneers of organic chemistry. It was found when Wohler attempted to synthesis ammonium cyanate, to continue a study of cyanates which he had been carrying out for several years. On treating silver cyanate with ammonium chloride solution he obtained a white crystalline material which proved identical to urea obtained from urine.
AgNCO + NH4Cl → (NH2)2CO + AgCl
Synthetic urea is created from synthetic ammonia and carbon dioxide and can be produced as a liquid or a solid. The process of dehydrating ammonium carbamate under conditions of high heat and pressure to produce urea was first implemented in 1870 and is still in use today. Uses of synthetic urea are numerous and therefore production is high. Approximately one million pounds of urea is manufactured in the United States alone each year, most of it used in fertilizers. Nitrogen in urea makes it water soluble, a highly desired property in this application.
OccurrenceUrea is the chief nitrogenous end product of the metabolic breakdown of proteins in all mammals and some fishes. The material occurs not only in the urine of all mammals but also in their blood, bile, milk, and perspiration. In the course of the breakdown of proteins, amino groups (NH2) are removed from the amino acids that partly comprise proteins. These amino groups are converted to ammonia (NH3), which is toxic to the body and thus must be converted to urea by the liver. The urea then passes to the kidneys and is eventually excreted in the urine.


Fig.1 The urea cycle in animals
Physical properties
Fig.2 Urea crystal

It is a colourless, crystalline substance that melts at 132.7°C (271°F) and decomposes before boiling. Its density is 1.32 g/cm3 and It is highly soluble in water and contains 46.7% nitrogen.
Chemical PropertiesThe urea molecule is planar in the crystal structure, but the geometry around the nitrogens is pyramidal in the gas-phase minimum-energy structure. In solid urea, the oxygen center is engaged in two N-H-O hydrogen bonds. The resulting dense and energetically favourable hydrogen-bond network is probably established at the cost of efficient molecular packing: The structure is quite open, the ribbons forming tunnels with square cross-section. The carbon in urea is described as sp2 hybridized, the C-N bonds have significant double bond character, and the carbonyl oxygen is basic compared to, say, formaldehyde. Urea's high aqueous solubility reflects its ability to engage in extensive hydrogen bonding with water.
Urea dissolved in water is in equilibrium with the isomeric ammonium cyanate. The resulting activity of the isocyanic acid ions do result in carbamylation (formation of long-chain carbamides, liberating ammonia molecule as byproduct) of proteins if proteins are present in the solution too. The carbamylation reaction may occurs at elevated temperatures even without catalysts. At room temperature, water solutions of urea are prone to same decomposition reaction in the presence of urease. The isomerization of urea in solution at room temperature without catalysts is a slow process (taking days to reach equilibrium), and freshly prepared, unheated solutions had negligible carbamylation rates.Urea can react with alcohols to form urethanes and react with malonic esters to make barbituric acids.
ProductionsThe primary raw material used to manufacture urea is natural gas, which ties the costs directly to gas prices. Consequently, new plants are only being built in areas with large natural gas reserves where prices are lower. Finished product is transported around the globe in large shipments of 30,000 metric tons. The market price for urea is directly related to the world price of natural gas and the demand for agricultural products. Prices can be very volatile, and at times, unpredictable. TCC is positioned to know the world markets and keep your prices competitive.
Annual production of sulfuric acid
World 164 million tonnes
China 62 million tonnes
India 23 million tonnes
Middle East 20 million tonnes
Rest of Asia 18 million tonnes
FSU 12 million tonnes
North America 9.5 million tonnes
Europe 9.5 million tonnes
It is expected that the global annual production will increase to over 200 million tonnes by 2018.
1. Potash Corporation, 2013
2. International Fertilizer Industry Association, 2014
Production methodsHistorical process
Urea was first noticed by Hermann Boerhaave in the early 18th century from evaporates of urine. In 1773, Hilaire Rouelle obtained crystals containing urea from human urine by evaporating it and treating it with alcohol in successive filtrations. This method was aided by Carl Wilhelm Scheele's discovery that urine treated by concentrated nitric acid precipitated crystals. Antoine François, comte de Fourcroy and Louis Nicolas Vauquelin discovered in 1799 that the nitrated crystals were identical to Rouelle's substance and invented the term "urea." Berzelius made further improvements to its purificationand finally William Prout, in 1817, succeeded in obtaining and determining the chemical composition of the pure substance. In the evolved procedure, urea was precipitated as urea nitrate by adding strong nitric acid to urine. To purify the resulting crystals, they were dissolved in boiling water with charcoal and filtered. After cooling, pure crystals of urea nitrate form. To reconstitute the urea from the nitrate, the crystals are dissolved in warm water, and barium carbonate added. The water is then evaporated and anhydrous alcohol added to extract the urea. This solution is drained off and evaporated, leaving pure urea.

Industrial process
For use in industry, urea is produced from synthetic ammonia and carbon dioxide. As large quantities of carbon dioxide are produced during the ammonia manufacturing process as a byproduct from hydrocarbons (predominantly natural gas, less often petroleum derivatives), or occasionally from coal, urea production plants are almost always located adjacent to the site where the ammonia is manufactured.
Urea can be produced as prills, granules, pellets, crystals, and solutions. The prills are formed by spraying molten urea down a tower up which air is pumped. They are slightly smaller than urea sold as granules and are particularly useful when the fertilizer is being applied by hand. In admixture, the combined solubility of ammonium nitrate and urea is so much higher than that of either component alone that it is possible to obtain a stable solution (known as UAN) with a total nitrogen content (32%) approaching that of solid ammonium nitrate (33.5%), though not, of course, that of urea itself (46%).

Fig.3 Industrial process of urea

Fig.4 An aerial view of a large plant in Alberta, Canada, in which ammonia is synthesized and then converted to urea.( By kind permission of Agrium Inc.)

Fig.5 Prills(small spheres of urea)

Fig.6 UAN(admixture of urea and ammonium nitrate) Laboratory process
Ureas in the more general sense can be accessed in the laboratory by reaction of phosgene with primary or secondary amines, proceeding through an isocyanate intermediate. Non-symmetric ureas can be accessed by reaction of primary or secondary amines with an isocyanate.
Also, urea is produced when phosgene reacts with ammonia:
COCl2 + 4 NH3 → (NH2)2CO + 2 NH4Cl
Urea is byproduct of converting alkyl halides to thiols via a S-alkylation of thiourea. Such reactions proceed via the intermediacy of isothiouronium salts:
RX + CS(NH2)2 → RSCX(NH2)2X
RSCX(NH2)2X + MOH → RSH + (NH2)2CO + MX
In this reaction R is alkyl group, X is halogen and M is alkali metal.
UsesAgriculture uses
More than 90% of world industrial production of urea is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use. Therefore, it has the lowest transportation costs per unit of nitrogen nutrient.
In the soil, it hydrolyses back to ammonia and carbon dioxide. The ammonia is oxidized by bacteria in the soil to nitrate, which can be absorbed by the plants. Urea is also used in many multi-component solid fertilizer formulations. Urea is highly soluble in water, therefore, very suitable for use in fertilizer solutions (in combination with ammonium nitrate: UAN), e.g., in ‘foliar feed’ fertilizers. For fertilizer use, granules are preferred because of their narrower particle size distribution, an advantage for mechanical application. The most common impurity of synthetic urea, biuret, must be present at less than 2 percent of the time, as it impairs plant growth.

Fig.7 Urea fertilizer and farmer’s fertilization process

Pharmacaeutical
Urea and malonic acid react to form barbituric acid. This was discovered by Adolf Bayer in 1864. But the barbiturates were not exploited as hypnotics until the early 1900's.Urea is also used in the production of various acylureas and urethanes for use as sedatives and hypnotics.
Fig.8 Synthesis of barbituric acid

Chemical industry
Urea is a raw material for the manufacture of two main classes of materials: urea-formaldehyde resins and urea-melamine-formaldehyde used in marine plywood. They all have very varied uses including adhesives, laminates, moulding compounds, coatings and textile finishes.
Urea has the ability to trap many organic compounds in the form of clathrates. The organic compounds are held in channels formed by interpenetrating helices comprising of hydrogen-bonded urea molecules. This behavior can be used to separate mixtures, and has been used in the production of aviation fuel and lubricating oils, and in the separation of paraffin.
As the helices are interconnected, all helices in a crystal must have the same molecular handedness. This is determined when the crystal is nucleated and can thus be forced by seeding. The resulting crystals have been used to separate racemic mixtures.

Laboratory uses
Urea in concentrations up to 10 M is a powerful protein denaturant as it disrupts the noncovalent bonds in the proteins. This property can be exploited to increase the solubility of some proteins. A mixture of urea and choline chloride is used as a deep eutectic solvent, a type of ionic liquid.
Urea can in principle serve as a hydrogen source for subsequent power generation in fuel cells. Urea present in urine/wastewater can be used directly (though bacteria normally quickly degrade urea.) Producing hydrogen by electrolysis of urea solution occurs at a lower voltage (0.37 V) and thus consumes less energy than the electrolysis of water (1.2 V).
Urea in concentrations up to 8 M can be used to make fixed brain tissue transparent to visible light while still preserving fluorescent signals from labeled cells. This allows for much deeper imaging of neuronal processes than previously obtainable using conventional one photon or two photon confocal microscopes.

Automobile systems
Urea is used in SNCR and SCR reactions to reduce the NOx pollutants in exhaust gases from combustion, for example, from power plants and diesel engines. The BlueTec system, for example, injects water-based urea solution into the exhaust system. The ammonia produced by decomposition of the urea reacts with the nitrogen oxide emissions and is converted into nitrogen and water within the catalytic converter.

Fig.9 A line diagram of the car above illustrating five key elements in the design of the exhaust system.
1 The oxidation catalyst is used to remove unwanted hydrocarbons, ensuring that they are oxidised to carbon dioxide and water. The catalyst is usually based on platinum or palladium.
2 Known as an NOx catalytic convertor, it contains aluminium oxide on whose surface, platinum and barium oxide are present. It traps the oxides of nitrogen. When the solid is saturated with the oxides, unburnt hydrocarbons are allowed to flow through, converting much of the mixture to nitrogen, carbon dioxide and water vapour.
3 A filter which traps particulates (small pieces of carbon and other solids).
4 A tank containing the solution of urea.
5 The SCR-catalytic convertor which contains another catalyst, for example an oxide of vanadium (or tungsten) on titanium dioxide, which allows the exhaust gases, still containing some nitrogen oxides, to react with ammonia formed from the urea solution, to produce exhaust gases with only traces of the oxides. By kind permission of Daimler AG

Others
A stabilizer in nitrocellulose explosive
A component of animal feed, providing a relatively cheap source of nitrogen to promote growth
A non-corroding alternative to rock salt for road de-icing, and the resurfacing of snowboarding half pipes and terrain parks
A flavor-enhancing additive for cigarettes
A main ingredient in hair removers such as Nair or Veet
A browning agent in factory-produced pretzels
An ingredient in some hair conditioners, facial cleansers, bath oils, skin softeners, and lotions
A reactant in some ready-to-use cold compresses for first-aid use, due to the endothermic reaction it creates when mixed with water
A cloud seeding agent, along with other salts
A flame-proofing agent, commonly used in dry chemical fire extinguisher charges such as the urea-potassium bicarbonate mixture.
An ingredient in many tooth whitening products
An ingredient in dish soap
Along with ammonium phosphate, as a yeast nutrient, for fermentation of sugars into ethanol
A nutrient used by plankton in ocean nourishment experiments for geoengineering purposes
As an additive to extend the working temperature and open time of hide glue
As a solubility-enhancing and moisture-retaining additive to dye baths for textile dyeing or printing
HazardsHealth hazards
Inhalation: 
Causes irritation to the respiratory tract. Symptoms may include coughing, shortness of breath. May be absorbed into the bloodstream with symptoms similar to ingestion. 
Ingestion: 
Causes irritation to the gastrointestinal tract. Symptoms may include nausea, vomiting and diarrhea. May also cause headache, confusion and electrolyte depletion. 
Skin Contact: 
Causes irritation to skin. Symptoms include redness, itching, and pain. 
Eye Contact: 
Causes irritation, redness, and pain. 
Chronic Exposure: 
A study of 67 workers in an environment with high airborne concentrations of urea found a high incidence of protein metabolism disturbances, moderate emphysema, and chronic weight loss. 
Aggravation of Pre-existing Conditions: 
Supersensitive individuals with skin or eye problems, kidney impairment or asthmatic condition should have physician's approval before exposure to urea dust.

Fire Hazards
Behavior in Fire: Melting and decomposing to generate ammonia.
Not combustible. Gives off irritating or toxic fumes (or gases) in a fire.
https://pubchem.ncbi.nlm.nih.gov/compound/urea#section=EPA-Safer-Chemical

Handling and Storage
Keep in a tightly closed container, stored in a cool, dry, ventilated area. Protect against physical damage. Isolate from incompatible substances. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.
Reference
  1. https://en.wikipedia.org/wiki/Urea#Explosives
  2. https://www.chemicalbook.com/ProductChemicalPropertiesCB5853861_EN.htm
  3. https://chemistry.stackexchange.com/questions/54387/extracting-urea-from-urine/60338#60338
  4. http://www.chm.bris.ac.uk/motm/urea/urea.html 
  5. https://thechemco.com/chemical/urea/  
  6. file:///C:/Users/zl/Desktop/kurzer1956.pdf
  7. https://www.britannica.com/science/urea 
  8. http://www.expertsmind.com/topic/biochemistry/urea-cycle-96120.aspx
  9. http://sesl.com.au/blog/what-is-urea/ 
  10. http://www.essentialchemicalindustry.org/chemicals/urea.html 
  11. http://www.atmos.umd.edu/~russ/MSDS/urea.htm 
Chemical PropertiesUrea,CO(HN2)2, also known as carbamide, is a white crystalline powder that has a melting point of l32.7 °C (270 °F). It is a natural product of animal protein metabolism and is the chief nitrogen constituent of urine. Commercially, urea is produced by the reaction of ammonia and carbon dioxide. It is soluble in water, alcohol, and benzene. Although urea is best known for its use in the preparation of fertilizers and plastics, it is used in medicine,adhesives,explosives,and as a flameproofing agent.
UsesUsed for the denaturation of proteins and as a mild solubilization agent for insoluble or denatured proteins. Useful for renaturing proteins from samples already denatured with 6 M guanidine chloride such as inclusion bodies. May be used with guanidine hydrochloride and dithiothreitrol (DTT) in the refolding of denatured proteins into their native or active form.
Usesanticholelithogenic; LD50(rat) 890 mg/kg ip
UsesUrea is a physiological regulator of nitrogen excretion in mammals; synthesized in the liver as an end-product of protein catabolism and excreted in urine. Also occurs normally in skin. Emollient; diu retic.
Uses1) UREA, FCC is an odorless and colorless solid that is an important nitrogen-containing substance found in mammal urine.2) Urea has little or no nutritional value to monogastric mammals but Urea is used in sugar-free chewing gum to adjust the texture
DefinitionChEBI: A carbonyl group with two C-bound amine groups.
General DescriptionSolid odorless white crystals or pellets. Density 1.335 g /cc. Noncombustible.
Air & Water ReactionsWater soluble.
Reactivity ProfileUrea is a weak base. Reacts with hypochlorites to form nitrogen trichloride which explodes spontaneously in air [J. Am. Chem. Soc. 63:3530-32]. Same is true for phosphorus pentachloride. Urea reacts with azo and diazo compounds to generate toxic gases. Reacts with strong reducing agents to form flammable gases (hydrogen). The heating of improper stoichiometric amounts of Urea and sodium nitrite lead to an explosion. Heated mixtures of oxalic acid and Urea yielded rapid evolution of gases, carbon dioxide, carbon monoxide and ammonia (if hot, can be explosive). Titanium tetrachloride and Urea slowly formed a complex during 6 weeks at 80°C., decomposed violently at 90°C., [Chem. Abs., 1966, 64, 9219b]. Urea ignites spontaneously on stirring with nitrosyl perchlorate, (due to the formation of the diazonium perchlorate). Oxalic acid and Urea react at high temperatures to form toxic and flammable ammonia and carbon monoxide gasses, and inert CO2 gas [Von Bentzinger, R. et al., Praxis Naturwiss. Chem., 1987, 36(8), 41-42].
Health HazardMay irritate eyes.
Fire HazardBehavior in Fire: Melts and decomposes, generating ammonia.
Agricultural UsesFertilizer, Fungicide: Used in fertilizers and animal feeds, as a fungicide, in the manufacture of resins and plastics, as a stabilizer in explosives and in medicines, and others. Urea is used to protect against frost and is used in some pesticides as an inert ingredient as a stabilizer, as an inhibitor and as an intensifier for herbicides. Registered for use in EU countries . Registered for use in the U.S.
Trade namePRESPERSION, 75 UREA®; SUPERCEL 3000®; UREAPHIL®; UREOPHIL®; UREVERT®; VARIOFORM II®
Purification MethodsCrystallise urea twice from conductivity water using centrifugal drainage and keeping the temperature below 60o. The crystals are dried under vacuum at 55o for 6hours. Levy and Margouls [J Am Chem Soc 84 1345 1962] prepared a 9M solution in conductivity water (keeping the temperature below 25o) and, after filtering through a medium-porosity glass sinter, added an equal volume of absolute EtOH. The mixture was set aside at -27o for 2-3 days and filtered cold. The precipitate was washed with a small amount of EtOH and dried in air. Crystallisation from 70% EtOH between 40o and -9o has also been used. Ionic impurities such as ammonium isocyanate have been removed by treating the concentrated aqueous solution at 50o with Amberlite MB-1 cation-and anion-exchange resin, and allowing it to crystallise on evaporation. [Benesch et al. J Biol Chem 216 663 1955.] It can also be crystallised from MeOH or EtOH, and is dried under vacuum at room temperature. [Beilstein 3 H 42, 3 I 19, 3 II 35, 3 III 80.]
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