Description
It can react with acids to form salts. There is hydrolysis. The condensation reaction can be carried out at high temperature to generate biuret, triuret and cyanuric acid. heated to
It is decomposed at 160°C, producing turning into cyanic acid at the same time. Because it is contained in human urine, it is named urea. Urea contains 46% nitrogen (N), which is the highest nitrogen content among solid nitrogen fertilizers.
Under the action of acid, alkali and enzyme (acid and alkali need to be heated), urea can be hydrolyzed to carbon dioxide.
Instable to heat, it will be deaminated into biuret when heated to 150~160ºC. If heated rapidly, it will be deaminated and trimerized into a six-membered ring compound cyanuric acid. (Mechanism: first deamination generates isocyanic acid (HN=C=O), and then trimerization.)
generate acetyl urea
it reacts with diethyl malonate to form malonyl urea (also known as barbituric acid because it has a certain acidity).
Under the action of basic catalysts such , it can react with formaldehyde to form urea-formaldehyde resin by polycondensation.
It reacts with generate semicarbazide.
Urea is easily soluble in water, 105 grams can be dissolved in 100 ml of water at 20°C, and the aqueous solution is neutral. There are two types of urea products. Crystalline urea is white needle-like or prism-like crystal form, and has strong hygroscopicity. Granular urea is a translucent particle with a particle size of 1 to 2 mm, with a smooth appearance and significantly improved hygroscopicity. The critical moisture absorption point at 20°C is 80% relative humidity, but at 30°C, the critical moisture absorption point drops to 72.5%, so urea should be kept open in humid climates in midsummer. At present, hydrophobic substances such as paraffin are added in urea production, and their hygroscopicity is greatly reduced
Commercial application:
Medical Applications:
Dermatologists use certain agents containing urea to increase skin moisture. Occlusive dressings for non-surgically removed nails contain 40% urea.
A carbon-14-breath test to test for the presence of Helicobacter pylori uses urea containing either a carbon 14 or carbon 13 label. Because H. pylori's urease uses urea to make to raise the pH in its surrounding stomach. The same principle can be used to test similar bacteria living in the stomach of animals.
Agricultural applications:
Urea is a high-concentration nitrogen fertilizer, a neutral quick-acting fertilizer, and can also be used to produce a variety of compound fertilizers. No harmful substances remain in the soil, and long-term application has no adverse effects. Animal husbandry can be used as feed for ruminants. However, if the temperature is too high in granulation, a small amount of biuret, also known as biuret, will be produced, which has an inhibitory effect on crops. my country stipulates that the content of urea biuret in fertilizers should be less than 0.5%. When the biuret content exceeds 1%, it cannot 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 can be absorbed and utilized by crops after being hydrolyzed into ammonium carbonate or ammonium bicarbonate by the action of urease in the soil. Therefore, urea should be applied 4 to 8 days before the fertilization period of crops.
Raw material for special plastics, especially urea formaldehyde resin
raw materials for certain glues
Composition of Fertilizers and Feeds
Instead of freezing salt sprinkled on the street, the advantage is that it does not corrode the metal
Enhance the smell of cigarettes
Gives industrially produced pretzels brown
ingredient in certain shampoos and cleansers
Composition of first aid refrigeration kits, as urea reacts with water to absorb heat
Treatment of exhaust gases from diesel engines, engines, thermal power plants, especially reducing their nitrogen oxides
The ingredients of the rain booster <compounded salt>
Used in the past to separate paraffins because urea can form clathrates
Refractory
Composition of Eco-Friendly Engine Fuels
Ingredients in Teeth Whitening Products
for chemical fertilizers
Important auxiliaries for dyeing and printing
Complaint
