English Name: urea
Alternative name: carboamide
Chemical formula: ch4n2o
CAS accession number: 57-13-6
EINECS accession number: 200-315-5
Melting point: 131-135 ℃
Boiling point: 196.6 ° cat760mmhg
Main applications
Medical application:
Dermatology uses certain agents containing urea to increase skin moisture. The closed dressing for non-surgical nail removal contains 40% urea.
The carbon-14-breath test to test the presence of Helicobacter pylori uses urea containing carbon 14 or carbon 13. Because H. pylori's urease uses urea to make ammonia to raise the pH in the stomach around it. The same principle can be used to test similar bacteria that live in the stomach of animals.
Agricultural applications:
Urea is a kind of high concentration nitrogen fertilizer, which belongs to neutral quick acting fertilizer. It can also be used to produce a variety of compound fertilizers. No harmful substances remained in the soil, and long-term application had no adverse effects. Animal husbandry can be used as feed for ruminants. However, a small amount of biuret, also known as biuret, will be produced when the temperature is too high in granulation, which has inhibitory effect on crops. The content of biuret in urea for fertilizer should be less than 0.5%. When biuret content is more than 1%, it can not be used as seed fertilizer, seedling fertilizer and foliar fertilizer, and the urea content in other application periods should not be too much or too concentrated.
Urea is an organic nitrogen fertilizer, which is hydrolyzed into ammonium carbonate or ammonium bicarbonate by the action of urease in soil before it can be absorbed and used by crops. Therefore, urea should be applied 4-8 days before the fertilizer requirement period of crops.
Commercial applications:
Raw material of special plastics, especially urea formaldehyde resin
Raw materials of some adhesives
Composition of fertilizer and feed
Instead of antifreeze salt sprinkled on the street, the advantage is not to make metal corrosion
Enhance the smell of cigarettes
Brown for industrial Pretzels
Ingredients of some shampoos and detergents
Ingredients of the first aid refrigeration package, because urea reacts with water to absorb heat
The treatment of diesel engine, engine, thermal power plant exhaust gas, especially can reduce its nitrogen oxide
Composition of precipitant
It was used to separate paraffin because urea can form inclusion compounds
Refractory
Composition of environmentally friendly engine fuel
Ingredients of tooth whitening products
Chemical fertilizer
Important auxiliaries in dyeing and printing
Laboratory application:
Urea is very effective in denaturing proteins, especially in destroying non covalently bound proteins. This characteristic can improve the solubility of some proteins, and its concentration can reach 10 moles / volume. Urea can also be used to make urea nitrate.
Feed additives:
The shortage of human food resources and protein also causes a big problem in feed industry. The industry is actively looking for new sources of protein and expanding to nitrogen sources other than protein, such as urea with high nitrogen content.
In 1897, waesk et al. Proposed the idea that ruminants could transform non protein nitrogen into bacterial protein. In 1949, C. J. Watson et al. Fed sheep with N15 labeled urea capsules. Four days later, the protein containing N15 was detected in sheep blood, liver and kidney. This confirms that ruminants can use non protein nitrogen. In the same year, J. K. looli et al. Fed sheep with urea as the only nitrogen source, and found that sheep could have positive nitrogen balance, which indicated that the microorganisms in sheep rumen could synthesize 10 kinds of essential amino acids for their growth by using urea. Since then, urea and urea compounds have become feed additives for ruminants.
Application in cosmetics:
Urea is a good moisturizing ingredient, which exists in the cuticle of the skin, and is the main component of NMF. For the skin, urea has the effect of moisturizing and softening cuticle, so it can also prevent the cuticle from blocking the pores, so as to improve the acne problem. It is used for moisturizing ingredients in mask, skin care, cream, hand cream and other products. The addition ratio is 3-5%.
Industrial applications:
It can be used as corrosion inhibitor in metal pickling and preparation of palladium activation solution.
