Urea

Urea or Nitrogen 46%

Urea or Nitrogen 46% ( N 46% ) is a white, solid, odor-free substance also known as carbamide in which has many usages in technical grade and industry. It is supplied in both granular and prilled form (The prills are formed by spraying molten urea down a tower up which air is pumped. They are slightly smaller than urea sold as granules and are particularly useful when the fertilizer is being applied by hand), and is organic compound of Oxygen, Nitrogen, Carbon, and Hydrogen with the following chemical formula:Â Â Â Â

Ammonia and carbon dioxide are heated together at 450 K and 200 atm pressure. First ammonium carbamate is formed, which rapidly decomposes to form urea.

Urea is the world's most commonly used nitrogen fertilizer and indeed more urea is manufactured by mass than any other organic chemical. Containing 46% N, it is the most concentrated nitrogen fertilizer, and is readily available as free-flowing prills (granules). It is the cheapest form of nitrogen fertilizer to transport and it is also the least likely to 'cake'. It is therefore favored in developing countries.

While over 90% of urea produced is used as a fertilizer, it has other uses, which include the manufacture of the melamine, used in melamine-methanal resins. Urea itself also forms important resins.

An increasingly important use of urea is in reducing air pollution from diesel engines in cars, buses and lorries. Diesel engines run at high temperatures and nitrogen and oxygen, from the air, are able to react together under these conditions to produce high concentrations of nitric oxide. One way to remove this pollutant is to allow it to react with ammonia to form nitrogen.

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