Journal de Medecine, de Chirurgie Et de Pharmacie, Volume 56… PDF

Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. Friedrich Journal de Medecine, de Chirurgie Et de Pharmacie, Volume 56… PDF’s discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry. A process plant in Bangladesh that commercially produces urea as fertilizer by using methane as the main raw material. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use.


Therefore, it has the lowest transportation costs per unit of nitrogen nutrient. Thus urea fertilizers rapidly transform to the ammonium form in soils. The most common impurity of synthetic urea is biuret, which impairs plant growth. Smaller applications incur lower losses due to leaching.

Because of the high nitrogen concentration in urea, it is very important to achieve an even spread. The application equipment must be correctly calibrated and properly used. Drilling must not occur on contact with or close to seed, due to the risk of germination damage. Urea dissolves in water for application as a spray or through irrigation systems. In grain and cotton crops, urea is often applied at the time of the last cultivation before planting. Top-dressing is also popular on pasture and forage crops. In irrigated crops, urea can be applied dry to the soil, or dissolved and applied through the irrigation water.

Urea dissolves in its own weight in water, but becomes increasingly difficult to dissolve as the concentration increases. Dissolving urea in water is endothermic—the solution temperature falls when urea dissolves. 3 g urea per 1 L water. In foliar sprays, urea concentrations of between 0. Low-biuret grades of urea are often indicated.

Urea absorbs moisture from the atmosphere and therefore is typically stored either in closed or sealed bags on pallets or, if stored in bulk, under cover with a tarpaulin. As with most solid fertilizers, storage in a cool, dry, well-ventilated area is recommended. Overdose or placing urea near seed is harmful. Urea is a raw material for the manufacture of two main classes of materials: urea-formaldehyde resins and urea-melamine-formaldehyde used in marine plywood. Urea can be used to make urea nitrate, a high explosive that is used industrially and as part of some improvised explosive devices. Urea in concentrations up to 10 M is a powerful protein denaturant as it disrupts the noncovalent bonds in the proteins. This property can be exploited to increase the solubility of some proteins.