Introduction
Urea's behavior is greatly influenced by temperature and humidity. Below 20℃ and with a relative humidity below 70%, urea does not absorb moisture. On the contrary, it promotes water evaporation and reduces its own water content. However, as the temperature rises above 20℃ and the relative humidity exceeds 80%, urea begins to absorb moisture. In severe cases, it can become mushy. Furthermore, when the surrounding air becomes dry, urea tends to re-agglomerate, second only to ammonium nitrate in its moisture-absorbing properties.
Urea's Affinity for Compound Formation
Urea exhibits interesting reactions when combined with nitric acid and formaldehyde. When urea reacts with nitric acid, relaxed urea nitrate is produced: CO(NH2)2+HNO3→CO(NH2)2·HNO3. On the other hand, urea can form compounds with formaldehyde, particularly urea formaldehyde compounds, also known as urate gum. Among these compounds, urea resin has a high formaldehyde ratio, while urea itself has a low formaldehyde ratio.
CAS: 57-13-6
EINECS number 200-315-5
Density 1.335g/mLat25°C(lit.)
Storage conditions 2-8°C
Acidity coefficient (pKa)0.10(at25℃)
PH 8.0-10.0(20℃,8MinH2O)
Maximum wavelength (λmax)λ:260nmAmax:0.03λ:280nmAmax:0.02
Stability substances to be avoided include strong oxidizing agents. Protect from moisture.
Urea stands as a vital nitrogen fertilizer renowned for its superior quality and efficiency. Initially utilized in Germany as a fertilizer after World War I, urea has proven to be highly beneficial for all crops. Its high nitrogen content and absence of side components contribute to significant yield increases. Over time, urea has emerged as a prominent nitrogen fertilizer variety, surpassing ammonium nitrate in popularity. In this article, we will delve into the properties, application, and advantages of urea as a nitrogen fertilizer.
Urea possesses several advantages that make it an ideal choice for topdressing applications outside the root zone. Firstly, urea does not contain any harmful ingredients that could adversely affect crops. It maintains a neutral pH, thereby preventing any burning of stems and leaves. Additionally, urea exhibits hygroscopic properties, enabling it to penetrate leaves easily when accompanied by water. This promotes rapid absorption by crops, enhancing their nutrient uptake. The recommended concentration for topdressing outside the root zone generally ranges from 0.5% to 2%.
Precautions and Considerations
Apart from its significance as a nitrogen fertilizer, urea finds application in various industries. It serves as a crucial raw material for the synthesis of ureaaldehyde, melamine-formaldehyde resin, and other industrial compounds. In the pharmaceutical field, urea plays a role in the production of drugs such as tetracycline, phenobarbital, and caffeine. The dye industry utilizes urea in the manufacturing process of reduced brown BR and phthalein blue B. Moreover, urea is commonly packaged in plastic film-lined woven bags and should be stored in dry warehouses, away from any acid materials.
more information
