Manufacturing Method of Nitrobenzene
Nitrobenzene is an important raw material for the production of chemicals, which is widely used in dyestuffs, pharmaceuticals, pesticides and other fields. In this article, we will introduce the manufacturing methods of nitrobenzene, including mixed acid nitrification method, atmospheric pressure intermittent nitrification method, pressurized continuous nitrification method and so on.
I. Mixed Acid Nitrification
Mixed Acid Nitrification is a common manufacturing method of nitrobenzene, and the process is as follows:
1. Dosing: Benzene, concentrated sulfuric acid and concentrated nitric acid are dosed according to a certain ratio, and the general use of benzene and mixed acid mass ratio is 1:0.7~0.8.
2. Mixed Acid Preparation: Mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid.
3. Nitrification reaction: Add the ingredients into the nitrification reactor and carry out the nitrification reaction under certain temperature and pressure to produce a mixture of nitrobenzene and water.
4. Separation: the nitrobenzene and water mixture is separated to obtain the nitrobenzene product.
The advantages of mixed acid nitrification method are simple process and easy operation, but the disadvantage is that the production process produces more waste acid, which needs to be disposed of.
II. Atmospheric Pressure Intermittent Nitrification
Atmospheric Pressure Intermittent Nitrification is a more traditional method of manufacturing nitrobenzene, and its process is as follows:
1. Dosing: Benzene, concentrated sulfuric acid and concentrated nitric acid are dosed according to a certain proportion.
2. Nitrification reaction: Add the ingredients into the nitrification reactor and heat to a certain temperature under normal pressure to carry out the nitrification reaction.
3. Cooling and crystallization: The reaction solution is cooled to a certain temperature and nitrobenzene crystals are precipitated.
4. Filtration and washing: filter out the nitrobenzene crystals and wash them with water.
5. Drying: Dry the nitrobenzene crystals to obtain nitrobenzene product.
The advantages of atmospheric pressure batch nitrification are simple operation and less investment, but the disadvantages are lower production efficiency and the need for a large number of manual operations.
III. Pressurized continuous nitrification method
Pressurized continuous nitrification method is a modern method of manufacturing nitrobenzene, and its process is as follows:
1. Dosing: Benzene, concentrated sulfuric acid and concentrated nitric acid are dosed according to a certain proportion.
2. Mixed Acid Preparation: Mix concentrated sulfuric acid and concentrated nitric acid to prepare mixed acid.
3. Pressurized Nitrification: Add the dosage and the mixed acid into the pressurized nitrification reactor and carry out the nitrification reaction under a certain pressure and temperature.
4. Separation: The reaction solution is separated to obtain nitrobenzene and water mixture.
5. Distillation: The nitrobenzene and water mixture are separated to obtain pure nitrobenzene product by distillation treatment.
The advantages of pressurized continuous nitrification method are high production efficiency, stable product quality, and automated production can be realized, but the disadvantage is the higher investment in equipment.
Four, other manufacturing methods
In addition to the above three methods, there are some other nitrobenzene manufacturing methods, such as gas-phase nitrification, electrolytic nitrification and so on. The process and advantages and disadvantages of these methods are not the same, you can choose the suitable method according to the specific production needs and conditions.
In conclusion, there are various manufacturing methods for nitrobenzene, and different methods have different process flow and advantages and disadvantages. When choosing the manufacturing method, it is necessary to make comprehensive consideration according to the specific production needs and conditions, and choose the suitable method. At the same time, attention needs to be paid to safety, environmental protection and quality control during the manufacturing process to ensure product quality and production safety.
