Urea
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
Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. It is a colorless, odorless solid, highly soluble in water, and practically non-toxic (LD50 is 15 g/kg for rats). 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 ammoniamolecules (NH3) with a carbon dioxide (CO2) molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry.
Friedrich Wöhler's discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry. It 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
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
Urea is used in SNCR and SCR reactions to reduce the NOx pollutants in exhaust gases from combustion from Diesel, dual fuel, and lean-burn natural gas engines. The BlueTec system, for example, injects a water-based urea solution into the exhaust system. The ammonia produced by the hydrolysis of the urea reacts with the nitrogen oxide emissions and is converted into nitrogen and water within the catalytic converter. Trucks and cars using these catalytic converters need to carry a supply of diesel exhaust