[Chemical Knowledge]：Production and manufacturing method and process flow of o-toluidine

The manufacturing method
of o-toluidine
1. Introduction

o-toluidine (o-toluidine) is an important organic chemical raw material, widely used in dyes, pharmaceuticals, pesticides, rubber additives and other fields. With the continuous development of industrial production, the manufacturing method of o-toluidine has been continuously improved and optimized. This paper will introduce the manufacturing method of o-toluidine, including raw materials, process flow, reaction principle, equipment, operation steps, control method and safety production.

2. raw material

o-toluidine manufacturing raw materials are mainly o-nitrotoluene and hydrogen. Among them, o-nitrotoluene can be produced by the reaction of toluene and nitric acid, and hydrogen can be produced by natural gas, water gas and other methods.

3. Process
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 perform a reduction reaction;
2. After the reaction is completed, perform distillation to separate unreacted raw materials and impurities;
3. Crystallize the o-toluidine obtained by distillation to obtain a product with higher purity.

4. reaction principle

o-nitrotoluene in the role of hydrogen, through the reduction reaction of o-toluidine. The principle of reduction reaction is that under a certain temperature and pressure, hydrogen and nitro in o-nitrotoluene occur addition reaction to generate hydroxylamine, and then through dehydration reaction to generate o-toluidine.

5. equipment

o-toluidine manufacturing equipment mainly includes reactors, distillation columns, crystallization tanks, etc. Among them, the reactor needs to have heating, stirring, cooling and other functions to ensure the smooth progress of the reaction; the distillation column is used to separate raw materials and impurities, and needs to have high separation efficiency; the crystallization tank is used to crystallize o-toluidine, and needs to have functions such as stirring and cooling.

6. operation steps
the manufacturing operation steps of
o-toluidine are as follows:

1. Add o-nitrotoluene and hydrogen into the reactor, and start the stirring and heating system;
2. Control the reaction temperature and pressure to keep the reaction stable;
3. After the reaction is completed, stop heating and stirring, and transfer the reaction liquid to the distillation tower;
4. Start the distillation system, separate unreacted raw materials and impurities;
5. Transfer the distilled o-toluidine to the crystallization tank, start the stirring and cooling system;
6. Control the crystallization temperature and stirring speed to crystallize the o-toluidine;
7. After the crystallization is completed, perform centrifugal separation to obtain the o-toluidine product with higher purity.

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 obtain the appropriate crystal size;
4. Regularly check the quality of raw materials and products to ensure that they meet the standard requirements.

8. safety production

there are certain safety risks in the manufacturing process of o-toluidine, and corresponding safety measures should be taken to prevent it. The specific safety production requirements are as follows:

1. Strictly implement safety production rules and regulations to ensure that employees have safety awareness;
2. Regular inspection and maintenance of equipment to ensure normal operation of equipment;
3. Monitoring the production process, timely detection and handling of abnormal situations;
4. Equipped with complete fire and first aid facilities to ensure the ability to respond to emergencies.

9. conclusion

o-toluidine as an important organic chemical raw material, its manufacturing method has been gradually mature after continuous improvement and optimization. In the actual production process, it is necessary to strictly control the process parameters and equipment operation status to ensure product quality and production safety. At the same time, it is also necessary to constantly pay attention to the development and application of new technologies, improve production efficiency and reduce costs, and contribute to the sustainable development of enterprises.