What is the melting point range of urea benzoic acid?

UreaThe initial melting point is 160. Urea will decompose when the heating temperature exceeds the melting point, and urea has a certain hygroscopicity, which is closely related to the change of temperature and humidity: at room temperatureRelative humidityWhen it is less than 70%, the hygroscopicity is not large, but when the temperature exceeds 20 and the relative humidity is greater than 80%, it will melt and turn into a liquid within 1 month.

Urea can undergo a condensation reaction at high temperature to produce biuret, triuret and cyanuric acid. Heat to 160 degrees to decompose to produce ammonia.

At the same time, it becomes isocyanic acid. Because it contains this substance in human urine, it is named urea. The nitrogen content of urea (N) is 46%, which is the highest nitrogen content among solid nitrogen fertilizers. Hu Kai talks.

Precautions for urea use

1. Avoid ammonium carbonate.

Mixed use: It should be noted that the mixed application of ammonium carbonate and urea in farmland will greatly slow down the speed of the conversion of urea into ammonia, which is easy to cause urea loss and volatile loss.

2. Avoid surface sprinkling: urea is sprinkled on the surface, and it can only be used after 4 to 5 days of transformation at room temperature, and most of the nitrogen is easy to volatilize in the process of ammoniation, and the general actual utilization rate is only about 30%.

3. Avoid seed fertilizer: urea often produces a small amount of biuret in the production process, and when the content of biuret exceeds 2%, it will poison seeds and seedlings, affecting seed germination and seedling growth, so it is not suitable for seed fertilizer.

The above content refers to Encyclopedia-Urea.

UreaThe melting point of benzoic acid is that the initial and full melting of urea and benzoic acid mixture is between 60 and 90.

In the field of organic chemistry, pure organic compounds generally have a fixed melting point. That is, under a certain pressure, the changes between the solid-liquid phases are very keen, and the temperature from initial melting to full melting does not exceed the melting point range or melting distance and melting range).

The melting range of urea and benzoic acid mixtures depends on their molar ratio. A mixture of urea and benzoic acid can form a solid mixture with different melting points. In general, the theoretical eutectic point of urea and benzoic acid is 132°C, but in practice, the melting point of the wheel roll varies depending on the composition of the mixture.

In a mixture of urea and benzoic acid, when the molar ratio of urea is higher, its melting range increases because a hydrogen bond is formed between urea and benzoic acid and the melting point of urea is higher than that of benzoic acid. For example, when the molar ratio of urea to benzoic acid is 1:1, its melting point is 70-71°C, while when the molar ratio of urea is 2:

At 1, its melting point is 97-99 °C, and when the molar ratio is 3:1, its Qitong slag melting point is 116-118 °C.

In summary, the melting range of the urea and benzoic acid mixture can be controlled by the molar ratio of urea and benzoic acid in the mixture, and the specific value needs to be determined by experimental altimetry.

The melting range of urea and benzoic acid mixtures depends on factors such as the proportion of urea and benzoic acid and the purity of the mixture, which is generally around 120-130 degrees Celsius. The specific melting range depends on the composition of the mixture and the preparation conditions, and different mixtures may have different melting ranges. At the same time, benzoic acid and urea will interact with each other when they are mixed, forming chemical bonds such as hydrogen bonds, which will affect the melting range and properties of the mixture.

Therefore, in practice, it is necessary to determine the melting range according to the specific composition of the mixture and the preparation conditions.

UreaThe initial melting point is 160.

Urea decomposes when heated above the melting point. Urea has a certain hygroscopicity, which is closely related to the change of temperature and humidity: at room temperature, relative humidity.

When it is less than 70%, it is not very hygroscopic, but when the temperature exceeds 20 and the relative humidity is greater than 80%, it will dissolve into a liquid within 1 month.

Urea can undergo a condensation reaction at high temperature, and it will be deamidated to biuret when heated to 150-160; If heated rapidly, it will be deaminate into a six-membered cyclic compound, cyanuric acid. Urea reacts with acid to form salts, which can be hydrolyzed to form ammonia and carbon dioxide under the action of acids, alkalis and enzymes.