Manufacturing method of o-nitroaniline
I. Introduction
o-nitroaniline is an important organic chemical raw material, which is widely used in dyestuffs, pharmaceuticals, pesticides and other fields. Therefore, it is of great significance to study the manufacturing method of o-nitroaniline to improve the production efficiency, reduce the cost and improve the product quality. In this paper, we will introduce the manufacturing method of o-nitroaniline, including raw material preparation, reaction conditions, operation steps and so on.
II. Raw material preparation
The main raw materials for manufacturing o-nitroaniline are aniline and nitric acid. Aniline is a colorless or slightly yellow liquid with a special odor. Nitric acid is a strong acid with strong oxidizing and corrosive properties. In the preparation of o-nitroaniline, aniline and nitric acid need to be mixed according to a certain ratio, and the molar ratio usually used is 1:1.2-1.5.
Three, the reaction conditions
The preparation of o-nitroaniline needs to be carried out at a certain temperature, pressure and acidity conditions. Usually the reaction temperature used is 50-60°C, the reaction pressure is 0.8-1.0MPa, and the acidity is controlled at pH 2-3. Under such conditions, aniline and nitric acid can undergo nitration reaction to produce o-nitroaniline.
4. Operation steps
1. Add aniline into the reaction kettle, turn on the stirrer and keep the stirring speed uniform.
2. Gradually add nitric acid dropwise into the reactor, control the rate of dropwise acceleration so that the reaction temperature does not exceed 60℃.
3. After dropping, continue stirring for a period of time, so that the reaction is fully carried out.
4. At the end of the reaction, cool the reaction solution to room temperature and precipitate o-nitroaniline crystals.
5. Filter, wash and dry to obtain pure o-nitroaniline product.
5. Precautions
1. During operation, the reaction temperature and pressure should be strictly controlled to prevent the reaction from getting out of control.
2. Nitric acid is strongly corrosive, protective measures should be taken to avoid contact with skin.
3. When precipitating o-nitroaniline crystals, slow cooling should be used to avoid agglomeration of the product.
VI. Yield and purity
The yield and purity of o-nitroaniline are affected by many factors, such as the quality of raw materials, reaction conditions, operation techniques, etc.. In actual production, the yield and purity of the product should be improved by optimizing the process parameters and improving the operation level. Generally speaking, the yield of o-nitroaniline can reach more than 80% and the purity can reach more than 98%.
VII. Waste treatment
In the process of manufacturing o-nitroaniline, some waste will be generated, such as waste acid and waste water. These wastes should be disposed of properly to avoid pollution to the environment. The methods usually used include neutralization treatment, biological treatment, and physicochemical treatment.
VIII.CONCLUSION
o-nitroaniline is an important organic chemical raw material, and its manufacturing method involves a number of links and precautions. In the actual production, it should be carried out in strict accordance with the operating procedures to ensure the quality and safety of the products. Meanwhile, waste treatment should be enhanced to protect the environment. By continuously optimizing the process parameters and improving the operation level, the yield and purity of o-nitroaniline can be further improved, the production cost can be reduced, and greater economic and social benefits can be created for the enterprise.
