Urea is one of the components of urine. It is an organic chemical compound that dissolves in alcohol and water and has the ability to crystallize.
The chemical formula of urea is CO(NH2) 2 . This diamide (its molecule has two amide groups) of carbonic acid lacks color and odor: therefore, urea can be said to be colorless and odorless. In addition to urine, urea is present in fecal matter, blood, semen, and lymph, among other fluids and substances. It also appears in the bones, lungs, liver and heart. Urea is produced when proteins are metabolized and nitrogen-containing elements are degraded.
The process that results in the formation of this chemical compound is known as the urea cycle. Animals that develop excretion of amino nitrogen as urea are classified as ureotelic. On the other hand, if the expulsion of amine nitrogen occurs as ammonia, the organisms are called ammonotelic, whereas if they do so as uric acid, they are classified as uricotelic. The discovery of urea in urine took place in 1727, by the scientist Herman Boerhaave, a native of Holland, although some attribute it to Hilaire Rouelle, a French chemist. Just a century later, a German chemist named Friedrich Wöhler managed to obtain urea artificially, by combining ammonium chloride and silver cyanate; It is worth mentioning that never before has an organic compound been synthesized with inorganic materials and without the use of living organisms. Importantly, urea can be used in different contexts. Urea is used in the production of resins, plastics, paints, cosmetics and adhesives, among other substances. Most of the urea, anyway, is used as a fertilizer. When applied in the field, crops receive nitrogen. Urea can also be mixed with cattle feed as a supplement to help build proteins. As mentioned in the previous paragraph, almost all the urea produced – 91% – is used to manufacture fertilizers. In addition to applying it to the soil to supply nitrogen to the plants, there is a fertilizer for foliar use, which is obtained with the low content of urea biuret, a reagent used to detect the presence of compounds with at least two peptide bonds, such as short peptides and proteins. It is necessary to dissolve the foliar fertilizer before applying it to the leaves; the plants in which it is used are usually fruit trees, mainly citrus. Nitrogen is essential for plant metabolism, as it directly affects the number of leaves and stems that develop, whose presence is essential for photosynthesis.
This type of fertilizer can be used in different types of crops, being always necessary to neutralize the great loss of nitrogen that the harvest entails. It is important to correctly apply the urea to the soil, preventing it from remaining on the surface. Regarding the use of urea for the industrial production of certain materials, such as plastics, we can also mention finishes for textiles, metal or paper articles and pharmaceutical products. A specific example is urea-formaldehyde, a type of adhesive or resin that does not soften with heat after molding. On the other hand, urea can be used as an adulterant for the manufacture of drugs, and among them is methamphetamine, a highly potent psychostimulant, indicated to treat attention deficit, narcolepsy and obesity.