Carbamide, also called urea, is a solid organic compound that has no color or odor. It’s highly water-soluble and melts at 132.7 degrees Celsius or 271 degrees Fahrenheit, decomposing prior to boiling. Structurally, carbamide comprises a couple of nitrogen atoms bonding to carbon atom, which is double bonded to oxygen atom. A carbonyl group is formed courtesy the double bond between an oxygen and carbon atom.
Urea is found in the urine of animals and amphibians. It occurs naturally after protein metabolism. When protein breakdown happens, amino groups are separated from amino acids. The amino groups get converted to ammonia, a toxic substance, and therefore should be converted by the liver to carbamide, which isn’t toxic. The carbamide then moves to the kidneys, eventually getting excreted via urine. In the case of water-based animals, which includes fish, the urea is expelled directly into the water.
As aforementioned, carbamide is commonly found in the urine of mammals. It’s also prepared on a large-scale commercially from liquid carbon dioxide and liquid ammonia. These substances are merged at increased temperatures and under high pressures to make ammonium carbamate, which later get decomposed at significantly reduced lower pressures, churning out water and urea.
Carbamide is used as fertilizer, thanks to its high nitrogen content and ability to readily transform into ammonia when in the soil. Of all important nutrients, plants require nitrogen the most and is quite often the factor affecting crop productivity. Proper nitrogen management is essential since it’s usually the most restricted nutrient in the production of crops and gets lost easily from the soil.
Carbamide has many other applications too. For example, in veterinary medicine, it’s used as a diuretic and topical antiseptic. Carbamide is used in animal feed as well, at times used for enhancing the feed’s protein content. In the manufacturing setup, carbamide helps make carbamide resin and urea-formaldehyde plastics. It’s also used for stabilizing explosives, and mitigates acid rain impact when applied in combination with barium hydroxide to limestone monuments. Carbamide is also used in the dental (teeth whitening) and cosmetic industry (skin creams, hair conditioners, moisturizers, etc.).