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Production method of p-toluidine

A technology of p-toluidine and a production method, applied in the field of production technology of p-toluidine, can solve the problems of large amount of sewage, low product yield, difficult sewage treatment, etc., and achieves high conversion rate, good control of reaction process, The effect of reducing production costs

Inactive Publication Date: 2011-09-14
GAOYOU AUXILIARY FACTORY
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  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

Catalytic hydrogenation is divided into liquid phase hydrogenation method and gas phase hydrogenation method. Although this method is suitable for continuous large-scale production, the production process requires solvent reduction, which has the disadvantages of high production cost and low product yield.
The alkali sulfide reduction method is currently widely used by domestic manufacturers, but the production cost is also high, the amount of sewage generated is large and the sewage is difficult to treat, and the product yield is low. The data shows that the yield is 88.9%

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0017] 1. Weighing:

[0018] Weigh 1000 kg p-nitrotoluene and 0.51 kg palladium carbon catalyst respectively.

[0019] Mix 0.51kg of palladium-carbon catalyst and 5kg of water evenly and set aside.

[0020] 2. Production of p-toluidine:

[0021] 1. Dissolve p-nitrotoluene in a liquid state by raising the temperature and add it to the reaction kettle, add the carbon catalyst aqueous solution, and seal the reaction kettle.

[0022] 2. Use 0.3Mpa nitrogen to replace the air in the kettle once.

[0023] 3. Use 0.3Mpa nitrogen to replace the gas in the kettle for the second time.

[0024] 4. Use 0.3Mpa hydrogen to continuously replace the gas in the kettle twice.

[0025] 5. Close the reaction kettle, raise the temperature to 45°C and turn on the stirrer.

[0026] 6. Introduce hydrogen, control the temperature in the kettle to 80-85°C, and the pressure to 0.55-0.6Mpa to carry out hydrogenation reduction, and the reaction time is about 4-5 hours.

[0027] 7. After confirming t...

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Abstract

The invention provides a production method of p-toluidine and relates to the technical field of chemical production. In the production method, liquid phase hydrogenation reduction is directly carried out on p-nitrotoluene in the presence of a palladium-carbon catalyst so as to produce the p-toluidine. The production method has the advantages of low reaction temperature, low reaction pressure and high reaction conversion rate; and the product performs water distribution and crystallization after hermetic filtration, the yield of the product is up to 98.3%, and no three wastes are basically emitted. Because no other byproducts are generated in the production process of the produce, the purity of the product is up to 98.6%, and the next generation products can be directly produced.

Description

technical field [0001] The invention relates to the technical field of chemical production, in particular to the production process of p-toluidine. Background technique [0002] P-toluidine is mainly used as a dye intermediate for the manufacture of pigment red 122, red base GL, methylamine red lake, basic fuchsin, methyl peri-acid and 4-aminotoluene-3-sulfonic acid, triphenyl Intermediates of methane dyes, etc., can also be used as intermediates of pharmaceutical pyrimethamine, pesticide trimeturon and other products. Pure p-toluidine is a colorless flaky crystal. The melting point is 44-45°C, the boiling point is 200.2°C, and the flash point is 87.2°C. Slightly soluble in water, soluble in ethanol, ether, carbon disulfide and oils, soluble in dilute inorganic acids and forming salts, and can volatilize with water vapor. [0003] The existing production of p-toluidine mainly uses p-nitrotoluene as raw material, and p-toluidine is obtained through reduction reaction. The ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/47C07C209/36
Inventor 秦政琦秦国儒吕桂栋
Owner GAOYOU AUXILIARY FACTORY
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