Ureas

Urea, also known as carbamide, is an organic compound with the formula CO(NH2)2. It is the simplest diamide of carbonic acid and a major nitrogen source in fertilizers and chemical syntheses. In industrial and agricultural contexts, urea and related derivatives are sometimes grouped under the informal label ureAs. The compound is a colorless, crystalline solid that is highly soluble in water and decomposes at elevated temperatures. Its melting point is about 133°C.

In mammals, urea is produced in the liver by the urea cycle to detoxify ammonia generated during amino acid metabolism and is excreted in urine. It serves as a primary means of nitrogen excretion and plays a role in maintaining nitrogen balance in the body. Urea is also produced by some microorganisms and can be found in trace amounts in various biological fluids.

Industrial production relies on the Bosch–Meiser urea process, which combines ammonia with carbon dioxide to form ammonium carbamate, subsequently converting it to urea and water. The reaction occurs at high pressure and elevated temperature, followed by purification and granulation to produce solid fertilizer products. Urea contains about 46 percent nitrogen and is among the most widely used nitrogen fertilizers worldwide due to its high nutrient content and ease of handling.

Major uses extend beyond fertilizers: it is a chemical feedstock for the production of urea-formaldehyde resins, melamine, and other nitrogen-containing polymers; it also serves as a humectant in cosmetics and in various drying and moisture-control applications.

Historically, the synthesis of urea by Friedrich Wöhler in 1828 marked a turning point in organic chemistry, proving that organic compounds could be prepared from inorganic precursors.

Safety and environmental considerations include its relatively low toxicity to humans in typical exposures, though concentrated solutions can irritate skin and eyes. Excessive use as a fertilizer can contribute to nutrient pollution in water bodies.