Carbamide or Urea . Colorless crystalline chemical compound. Its chemical formula is NH 2 – CO – NH 2 . It is also known as carbonyldiamide or arbamidic acid. The IUPAC name is diaminoketone.
It is a nitrogenous substance produced by various living beings as a means of eliminating ammonia, which is highly toxic to them. In animals it is found in blood, urine, bile, and sweat.
It has hygroscopic properties and when dissolving in water it absorbs heat, making it cold and wet to the touch. It is the most valuable nitrogen fertilizer without ballast, it contains up to 46% nitrogen. It is also used as an additive in livestock feed and serves as a raw material for the plastic materials, synthetic glues, textile, and pharmaceutical industries; hence its industrial production reaches several tens of millions of tons per year.
Urea is formed in animal tissues as the end product of protein metabolism, concentrating in the kidneys and being expelled in the urine where it accounts for 80% of the dissolved nitrogen.
Summary
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- 1 Physical and chemical properties
- 2 Structure
- 3 Obtaining
- 4 Applications
- 5 Related Links
- 6 Sources
Physical and chemical properties
Global formula: CON 2 H 4
Semi-developed formula: NH 2 – CO – NH 2
Molecular mass: 60.06 g mol-1
Aggregation state: solid.
Density: 1.34 g / cm³
Melting temperature: 132.7 ºC
Heat of fusion: 24.18J / g
Heat of combustion: 10590 J / g
Heat of dissolution in water: 241.8 J / g
It has an acid character, requiring 84 parts of carbonate of calcium to neutralize the acidifying effect of 100 parts of urea.
It is highly corrosive to carbon steel, slightly corrosive to aluminum, zinc and copper and not to special steels and glass. It is very soluble in water, alcohol and ammonia.
Structure
The central carbon atom of the carbamide molecule to which an oxygen atom is attached through a double bond and two amino groups, which gives the molecule a flat structure.
Obtaining
Carbamide is synthetically obtained from Ammonia (NH 3 ) and Carbon Dioxide (CO 2 ) whose interaction comprises two stages. In the first, the formation of ammonium carbamate takes place according to the reaction:
2NH 3 + CO 2 = NH 2 COONH 4 + 159.1 kJ
In the second stage, dehydration of the carbamate occurs, forming the carbamide:
NH 2 COONH 4 = (NH 2 ) 2 CO + H 2 O – 285kJ
These reactions are verified in industrial processes at temperatures of 180 to 200 ºC and pressure of 18 ∙ 106 – 2 ∙ 107 N / m2 (200 atmospheres)
Applications
More than 90% of the world production of carbamide is destined for its use as a fertilizer, which is applied to both the soil and the leaf surface of plants through irrigation.
The easy solubility in water allows it to be absorbed by plant roots. Its use in livestock feed is based on the fact that bacteria in the stomachs of ruminant mammals are able to metabolize urea and supply nitrogen to the body, which results in higher protein yield.
From carbamide, resins are obtained to produce valuable plastic materials such as so-called amine plastics, wood chip slabs, synthetic glues and compounds to impregnate fabrics. It is also used in the manufacture of synthetic fibers known as Urilón . Carbamide has a wide application in the pharmaceutical industry, being present in the chemical composition of drugs such as Carbamazepine and others.
