Carbamide

Carbamide

Carbamide, also known as urea, is an organic compound with the chemical formula (NH₂)₂CO. It is a colorless, odorless solid, highly soluble in water, and practically non-toxic. Urea is the primary nitrogen-containing substance in the urine of mammals and is an important compound in the metabolism of nitrogen-containing compounds by animals.

History

Carbamide was first discovered in 1773 by the French chemist Hilaire Marin Rouelle. It was the first organic compound to be synthesized from inorganic materials, a landmark event in the history of chemistry, achieved by Friedrich Wöhler in 1828. This synthesis, known as the Wöhler synthesis, involved the reaction of potassium cyanate with ammonium sulfate to produce urea, challenging the vitalism theory that organic compounds could only be produced by living organisms.

Structure and Properties

Carbamide is a simple organic compound composed of two amine groups (-NH₂) joined by a carbonyl functional group (C=O). It is highly soluble in water due to its ability to form hydrogen bonds with water molecules. The solubility of urea in water is about 108 g/100 mL at 20 °C.

Biological Role

In the human body, urea is produced in the liver through the urea cycle, a process that converts ammonia, which is toxic, into urea, which is then excreted in the urine. This process is crucial for the removal of excess nitrogen from the body.

Industrial Production

Carbamide is produced on an industrial scale from ammonia and carbon dioxide. The process involves the reaction of these two gases under high pressure and temperature to form ammonium carbamate, which is then dehydrated to form urea. This process is known as the Bosch-Meiser urea process.

Applications

Carbamide has a wide range of applications:

• Agriculture: It is widely used as a nitrogen-release fertilizer. Urea fertilizers have the highest nitrogen content of all solid nitrogenous fertilizers in common use.
• Chemical Industry: Urea is a raw material for the manufacture of many important chemical compounds, such as urea-formaldehyde resins.
• Medical Uses: Urea is used in dermatology as a topical cream to rehydrate the skin.
• Automotive: It is used in selective catalytic reduction (SCR) systems to reduce nitrogen oxide emissions from diesel engines.

Safety and Environmental Impact

Carbamide is generally considered safe and non-toxic. However, its use in large quantities as a fertilizer can lead to environmental issues such as eutrophication of water bodies.

See Also

• Urea cycle
• Friedrich Wöhler
• Ammonia
• Nitrogen cycle