Urea

Urea is a white, crystalline solid also known as carbamide. It is highly soluble in water and is the major molecule used by mammals and amphibians as a means of excreting nitrogenous waste (which generally comes from proteins). It is used in making fertilizers (where it serves as source of nitrogen) and in cattle feed, where it also raises the nitrogen levels. Urea is also used in the manufacturing of barbiturates and in manufacturing some plastics such as urethanes. Urea melts at 271°F (133°C). Solutions of urea in water are slightly basic. The formula of urea is shown in Figure 1.

The NH₂ groups are derived from nitrogen containing portions of proteins. Urea was first isolated from urine in 1773 by Hillaire-Malin Rouelle. In 1828 urea became the first organic (carbon based) molecule to be synthesized from inorganic components. This was accomplished by Freidrich Wolher by heating ammonium cyanate, forming urea. This synthesis began the decline of a "vital force" theory which held that only living things could make organic compounds.