What Is Urea Nitrate?
Urea, also known as carbamide, is an organic compound composed of carbon, nitrogen, oxygen, and hydrogen. It is a white crystal. One of the simplest organic compounds is the main nitrogen-containing end product of protein metabolism in mammals and certain fish. It is also the nitrogen fertilizer with the highest nitrogen content.
- In 1773, Hilaire Rouelle discovered urea. In 1828, the German chemist Friedrich Weiler for the first time artificially synthesized urea using ammonium cyanate (NH 4 CNO, an inorganic compound produced by the reaction of ammonium chloride and silver cyanate) and ammonium sulfate. He originally planned to synthesize ammonium cyanate, but got urea. The synthesis of urea opened the curtain of synthetic organic matter. This proves the error of the vitality theory and actually opens up organic chemistry (the vitality theory believes that there is a fundamental difference between inorganic substances and organic substances, so inorganic substances cannot become organic substances, and organic compounds can only be changed by biological cells in a special Strength-generated under the action of vitality, artificial synthesis is impossible. Urine is contained in the urine of mammals, amphibians and some fish; uric acid is emitted by birds and reptiles because their nitrogen metabolism process uses less water) . [1]
- Method 1 Ammonium carbamate is synthesized from carbon dioxide and ammonia at high temperature and pressure. After decomposition, absorption and conversion, it is crystallized, separated, and dried.
- Method 2 < br The preparation method is to mix purified ammonia and carbon dioxide at a molar ratio of 2.8 to 4.5 into the synthesis tower. The pressure in the tower is 13.8 to 24.6 MPa, the temperature is 180 to 200 ° C, and the residence time of the reaction material is 25. 40min, get excess ammonia and
- 1. If urea is not stored properly, it will easily absorb moisture and agglomerate, which will affect the original quality of urea and bring certain economic losses to farmers. This requires the majority of farmers to properly store urea. Be sure to keep the urea packaging bag intact before use. Handle it with care during transportation, protect it from rain, and store it in a dry, well-ventilated place with a temperature below 20 degrees.
- 2.If it is a large amount
- It can be used as raw materials for the production of melamine, urea-formaldehyde resin, hydrazine hydrate, tetracycline, phenobarbital, caffeine, reduced brown BR, phthalocyanine blue B, phthalocyanine blue Bx, monosodium glutamate and other products in large quantities.
- Adjust flower amount
- In order to overcome the size of the apple field, at the young age, 5-6 weeks after flowering (the critical period of apple flower bud differentiation, the new shoot growth is slow or stopped, and the leaf nitrogen content shows a downward trend). If sprayed twice, it can increase the nitrogen content in the leaves, accelerate the growth of new shoots, inhibit the flower bud differentiation, and make the annual flower amount suitable.
- Sparse flower
- The flower organs of peach trees are more sensitive to urea but the glutinous response is slower. Therefore, experiments on sparse flowers and fruits of peaches and nectarines using urea were conducted abroad. The results show that the sparse flowers and fruits of peaches and nectarines require a greater concentration (7.4%) can show good results, the most suitable concentration is 8% -12%, within 1-2 weeks after spraying, the purpose of thinning flowers and fruits can be achieved. However, under different land conditions, the response of different periods and different varieties needs further testing.
- Rice seed production
- In the hybrid rice seed production technology, in order to increase the parental outcrossing rate, in order to increase the amount of hybrid rice seed production or the sterile line, the female parent is generally sprayed with red toxin to reduce the female parent's necking or make Extract it completely; or spray the parent, adjust the growth of the two, so that the flowering period is synchronized. Because gibberellin is more expensive, its seed production cost is high. People use urea instead of gibberellin for experiments. 1.5% -2% urea is used in the booting stage and heading stage (20% heading). Its breeding effect is similar to gibberellin and it does not increase plant height.
- Pest Control
- Use urea, washing powder, and clean water at 4: 1: 400. Stir and mix to prevent pests such as aphids, red spiders, and cabbage worms on fruit trees, vegetables, and cotton. The insecticidal effect is over 90%.
- Urea iron fertilizer
- Urea forms chelated iron with Fe 2+ in the form of a complex. This organic iron fertilizer has a low cost and has a good effect in preventing iron deficiency and chlorosis. In addition, 0.3% urea is added when foliar spray of 0.3% ferrous sulfate, and the effect of preventing green loss is better than that of single spray of 0.3% ferrous sulfate.
- Urea is an excellent dye solvent / hygroscopic agent / viscose fiber bulking agent in the textile industry because urea has excellent dissolving dye properties, as well as mild reducing / oxidizing resistance and extremely good hygroscopicity (see attached table). , Resin finishing agent, has a wide range of uses.
- Comparison of hygroscopicity of urea with other hygroscopic agents in the textile industry: weight ratio to itself.
- Industrial applications
- It has a brightening effect on chemical polishing of steel and stainless steel. It is used as a corrosion inhibitor in metal pickling and also used in the preparation of palladium activating solution.
- It is also used industrially as a raw material for the production of urea-formaldehyde resin, polyurethane, and melamine-formaldehyde resin. When urea is heated to 200 ° C, solid melamine (ie, cyanuric acid) is formed. Derivatives of cyanuric acid Trichloroisocyanuric acid, sodium dichloroisocyanate, tris (2-hydroxyethyl) isocyanurate, tris (allyl) isocyanurate, tris (3,5-di Tert-butyl-4-hydroxybenzyl) isocyanate, triglycidyl isocyanurate, melamine cyanurate complex, etc. have many important applications. The former two are new high-end disinfection and bleaching agents. The total production capacity of trichloroisocyanuric acid in the world exceeds 80,000 tons.
- Selective reducing agent for denitration of combustion exhaust gas, and urea for vehicles. Its composition is 32.5% high-purity urea and 67.5% deionized water.
- Selective catalytic reduction (SCR) exhaust aftertreatment is a technology that uses the ammonia produced by the pyrolysis reaction of urea in the combustion exhaust gas to perform selective catalytic reduction reaction with nitrogen oxides (NOx) in automobile exhaust. The key and mainstream technology to reduce NOx, which is a harmful substance in combustion exhaust gases such as combustion boilers and diesel engines. The SCR system is an indispensable system to meet the strict emission regulations of modern automobiles such as Euro IV / Euro V / Euro VI (China IV / National V / National VI) regulations. Vehicle urea is called AdBlue in Europe, and DEF (diesel exhaust treatment fluid) in the United States.
- Commercial areas
- Raw materials for special plastics, especially urea formaldehyde resins;
- Certain gum raw materials;
- Fertilizer and feed ingredients;
- Instead of spraying antifreeze on the street, the advantage is that it does not corrode the metal;
- Enhance the smell of cigarettes;
- Gives industrially produced pretzels a brown color;
- Ingredients of certain shampoos and cleansers;
- Components of a refrigeration kit for emergency use, because the reaction between urea and water will absorb heat;
- The treatment of exhaust gas from diesel engines, engines, and thermal power plants with urea in vehicles can reduce nitrogen oxides in particular;
- The composition of the rain-proofing agent (combined salt);
- Used to separate paraffin, because urea can form inclusion complexes;
- Refractory
- Composition of environmentally friendly engine fuel;
- Ingredients for whitening dental products;
- Chemical fertilizer
- An important adjuvant for dyeing and printing.
- Laboratory applications:
- Urea can denature proteins very effectively, especially can destroy non-covalently bound proteins very effectively. This feature can increase the solubility of certain proteins, and its concentration can reach 10 moles / volume. Urea can also be used to make urea nitrate. [2]
- Method name: Urea-Determination of Urea-Neutralization Titration
- Application: This method uses the titration method to determine the urea content in urea.
- This method is applicable to urea.
Urea classification
- Circulatory Drugs> Antihypertensive Drugs> Diuretic Antihypertensive Drugs
Urea dosage form
- 1. Ointment: 10%, 20%;
- 2. Compound preparation: Triamcinolone urea urea cream;
- 3. Injection: 30mg (100ml), 60g (250ml).
Urea pharmacological action
- Urea has basically the same effect as sorbitol and is an osmotic diuretic. Since some urea can enter the brain tissue through the blood-cerebrospinal fluid barrier, when the urea in the blood is eliminated by the kidney and the concentration drops rapidly, the urea that has entered the brain tissue cannot be removed in time, and water can re-enter the brain tissue, causing the skull Increased internal pressure, even worsening cerebral edema, the phenomenon of "bounce", so it should be used alternately with other dehydrating drugs. In addition to its rapid and powerful dehydration, urea can also dissolve and denature proteins. High-concentration urea can change the structure of amino acid side chains and the polypeptide backbone of proteins, solubilize proteins, increase the moisture content of the stratum corneum, and promote keratin The layer of hydration makes the skin soft and has antibacterial (including fungal), antipruritic, and granulation growth effects.
Urea biological metabolism
- The urea cycle is also known as the "ornithine cycle", proposed by H.Crebs and K.Henseleit in 1932.
- Urea is incorporated into the blood after it is produced by the liver (the concentration in the human body is between 2.5 and 7.5 micromoles per liter), and is finally excreted by the urine through the kidneys. A small amount of urea is excreted by sweat.
- Biology synthesizes urea with chemicals such as carbon dioxide, water, aspartic acid and ammonia. The metabolic pathway that promotes urea synthesis is an anabolic called the urea cycle. This process consumes energy but is necessary. Because ammonia is toxic and a common metabolic product, it must be eliminated. When the liver synthesizes urea, N-acetylglutamic acid is required for regulation.
- Nitrogen-containing wastes are toxic and arise from the catabolism of proteins and amino acids (ie,
- Urea structure
- Mammals produce urea in a circulatory response in the liver. This cycle was first proposed in 1932, and its starting point was the decomposition of ammonia. After the effects of citrulline and arginine succinic acid were clarified in the 1940s, it was fully understood. In this cycle, the amino groups from ammonia and L-aspartic acid are converted to urea, and the mediators are L-ornithine, citrulline, L-arginine-succinic acid, and L-arginine .
- Urea cycle is the main way for mammals and amphibians to excrete nitrogen-containing metabolic waste. But so are other organisms, such as birds, invertebrates, insects, plants, yeast, fungi, and microorganisms.
- Urea is basically waste to living things, but still has positive value. For example, urea in the renal tubules is introduced into the renal cortex to increase its osmotic concentration, which promotes the penetration of water from the renal tubules back to the body for reuse. [2]
Urea pharmacokinetics
- After intravenous infusion, it is filtered by the glomerulus, and about 50% is reabsorbed from the renal tubules, and the remaining 50% is excreted by the renal tubules. If a larger dose is given, it can increase the plasma osmotic pressure and produce dehydration and diuretic effects. Its effect is rapid and powerful. It takes effect 15 to 30 minutes after administration. The effect reaches a peak in 1 to 2 hours and is maintained for 3 to 6 hours.
Urea indication
- It is clinically used for cerebral edema, intracranial hypertension syndrome (increased intracranial pressure), glaucoma, and also for oliguria after burn, postoperative and posttraumatic, and it can promote urination after prostate operation. Topical application can treat certain skin diseases, such as making ointments or creams, which can soften the skin, prevent chapped hands and feet, and can also be used to relieve itching. 15% to 20% ointment is suitable for ichthyosis, cleft palate, etc. High-concentration ointments and plasters can be used to treat onychomycosis. Not suitable for mucosal sites.
Urea contraindications
- Because urea can increase non-protein nitrogen in the blood, patients with severe liver and kidney dysfunction, severe shock and significant dehydration, patients with active intracranial hemorrhage and high blood urea nitrogen levels are contraindicated.
Urea precautions
- 1. The urea solution is unstable in nature. The injection must be dissolved in 10% glucose solution immediately before use, and it must be used up within 24 hours to prevent decomposition and release of ammonia, which will cause toxicity. Cannot be used more than 24h.
- 2. Urea alone has hemolytic effect. It must be diluted by adding 5% or 10% glucose injection or 10% invert sugar solution. It must not be diluted with sterilized water for injection.
- 3. Do not spill into the subcutaneous tissue when instilling urea. When spilling, it should be closed locally with 0.25% procaine injection, and treated with heat or 50% magnesium sulfate wet compress.
- 4. Urea has many shortcomings and is rarely used clinically. [2]
Urea adverse reactions
- 1. Urea is stored for too long or the temperature of the medicinal solution is too low, which can cause flushing, mental excitement, irritability and other symptoms after injection.
- 2. Urea is highly irritating, and venous spasm pain, phlebitis, or venous thrombosis may occur in the injection area; subcutaneous leakage may cause local swelling, blistering, and even tissue necrosis. Occasionally mild local irritation.
Urea usage and dosage
- Adults 0.5 to 1 g / kg once, instilled within 20 to 30 minutes. Dosage can be repeated after 12 hours, 1 or 2 times a day, usually 1 to 3 days in a row. External use: 1 to 2 times a day, the dosage should be adjusted according to the doctor's advice according to the area of the lesion. [2]
Urea drug interaction
- Hydrochlorothiazide
Urea poisoning
- Urea is a diuretic and dehydrating drug, and its effect is similar to that of mannitol. It is mainly used to treat cerebral edema and glaucoma. The usual dose of this medicine is 0.5 1g / kg for intravenous injection or rapid intravenous drip, and the infusion is completed within 20 30min.
- Clinical manifestation
- Fewer adverse reactions, such as long storage of the drug or low temperature of the liquid, can cause facial flushing, mental excitement, irritability, headache and gastrointestinal reactions. Liquid leakage from the blood vessel can cause local swelling and blisters.
- treatment
- The main points of treatment for urea poisoning are:
- 1. Local leakage of medicinal solution can be closed with 0.25% procaine, hot compress, or treated with Ruyi golden powder, 50% magnesium sulfate.
- 2. Symptomatic treatment [4] .