Manufacturing method of o-toluidine
I. Introduction
o-toluidine (o-toluidine) is an important organic chemical raw material, which is widely used in the fields of dyestuffs, pharmaceuticals, pesticides, rubber auxiliaries and so on. With the continuous development of industrial production, the manufacturing method of o-toluidine has been improved and optimized. In this paper, we will introduce the manufacturing method of o-toluidine, including raw materials, process flow, reaction principle, equipment, operation steps, control methods and safe production.
II. Raw materials
The raw materials for the manufacture of o-toluidine are mainly o-nitrotoluene and hydrogen. Among them, o-nitrotoluene can be produced through the reaction of toluene and nitric acid, and hydrogen can be produced through natural gas, water gas and other methods.
Third, process flow
The manufacturing process of o-toluidine mainly includes reduction reaction, distillation, crystallization and other steps. The specific process is as follows:
1. Add o-nitrotoluene and hydrogen into the reactor to carry out the reduction reaction;
2. After the completion of the reaction, carry out the distillation to separate the unreacted raw materials and impurities;
3. Crystallize the o-toluidine obtained from the distillation to get the product with higher purity.
Four, reaction principle
o-nitrotoluene under the action of hydrogen, after the reduction reaction to produce o-toluidine. The principle of reduction reaction is that under certain temperature and pressure, hydrogen gas and nitro in o-nitrotoluene undergo addition reaction to generate hydroxyl amine group, and then undergo dehydration reaction to generate o-toluidine.
V. Equipment
The manufacturing equipment of o-toluidine mainly includes reactor, distillation tower, crystallization tank and so on. Among them, the reactor needs to have the functions of heating, stirring and cooling to ensure the smooth progress of the reaction; the distillation tower is used to separate the raw materials and impurities, and needs to have a high separation efficiency; the crystallization tank is used to crystallize o-toluidine, and needs to have the functions of stirring and cooling. VI. Operation steps
The operation steps for manufacturing o-toluidine are as follows:
1. Add o-nitrotoluene and hydrogen into the reactor, start the stirring and heating system;
2. Control the reaction temperature and pressure to keep the reaction stable;
3. After the reaction is finished, stop the heating and stirring, and transfer the reaction liquid to the distillation tower;
4. Start the distillation system, and separate out the un-reacted raw materials and impurities;
5. Transfer the o-toluidine obtained by distillation to the crystallization tank, start the stirring and cooling system;
6. Control the crystallization temperature and stirring speed, so that the o-toluidine crystals precipitated;
7. After the crystallization is completed, centrifugal separation is carried out, and the o-toluidine product with higher purity is obtained.
7. Control method
In order to ensure the manufacturing quality and yield of o-toluidine, the manufacturing process needs to be strictly controlled. The specific control methods are as follows:
1. Control the temperature and pressure of the reduction reaction to maintain the stability of the reaction;
2. Control the temperature and pressure of the distillation process to ensure the separation effect;
3. Control the temperature and stirring speed of the crystallization process to get the appropriate crystal size;
4. Conduct regular tests on the quality of raw materials and products to ensure that they meet the standard requirements.
VIII. Safe production
There are certain safety risks in the manufacturing process of o-toluidine, which need to be prevented by corresponding safety measures. Specific production safety requirements are as follows:
1. Strictly implement production safety regulations to ensure that employees have safety awareness;
2. Regular inspection and maintenance of equipment to ensure normal operation;
3. Monitoring of the production process to detect and deal with abnormalities in a timely manner;
4. Equipped with complete fire-fighting and first-aid facilities to ensure the ability to deal with emergencies.
IX. Conclusion
o-Toluidine, as an important organic chemical raw material, has been gradually matured through continuous improvement and optimization of its manufacturing method. In the actual production process, the process parameters and equipment operating conditions need to be strictly controlled to ensure product quality and production safety. At the same time, it is also necessary to pay constant attention to the development and application of new technologies to improve the production efficiency and reduce the cost, so as to contribute to the sustainable development of the enterprise.
