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Method for continuously producing 3,4-dichloroaniline

A technology of dichloroaniline and dichloronitrobenzene, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as complicated operation, large amount of hydrogen feed, hydrogen loss, etc., and achieve a control method The effect of simplicity, simplified process flow, and low hydrogen consumption

Inactive Publication Date: 2013-10-09
QINGDAO UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] 2. During the batch reaction process, due to the need for pressure relief, purging and other operations such as feeding, discharging, and additional catalyst, hydrogen loss is caused and product costs are increased
[0009] 3. When the production scale is large, the batch reaction process generally uses multiple sets of reactors, and the equipment cost is high
[0010] 4. At the beginning of the batch reactor reaction, the amount of hydrogen feed is large, the reaction heat is large, the heat needs to be removed, and the amount of circulating water that needs to be introduced is large; the heat released at the end of the reaction is small, the heat that needs to be removed is small, and the amount of circulating water should be reduced. , it is difficult to achieve stable temperature control during the whole process, and the energy consumption is high
[0011] 5. The catalyst settles intermittently in the reactor for a long time
[0012] 6. The batch reaction process requires feeding, heating, boosting, reaction, cooling, pressure relief, purging, catalyst sedimentation, and discharge operations in sequence. The labor intensity of workers is high and the operation is complicated, so it is difficult to realize large-scale industrial production.

Method used

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  • Method for continuously producing 3,4-dichloroaniline
  • Method for continuously producing 3,4-dichloroaniline
  • Method for continuously producing 3,4-dichloroaniline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] The stirred tank reactor 1 has a size of 1 L and is made of carbon steel. The reaction pressure is 1MPa, controlled by the flow of hydrogen; the temperature is 65°C, controlled by the flow of circulating water in the jacket 12 of the stirred tank reactor 1, the catalyst is Raney nickel, and the mass concentration is 1.3%. The stirred tank reactor 1 adopts a self-priming stirring paddle 3, and the stirring speed is 550 rpm. The dechlorination inhibitor is ethanolamine, and the mass concentration of the inhibitor in the kettle is 500ppm. The solvent was methanol, the feed was 3,4-dichloronitrobenzene in methanol solution, the mass concentration of 3,4-dichloronitrobenzene was 15%, and the feed rate was 10 mL / min. The effective volume of the reactor is 0.6L, and the residence time is 1h. The reaction product enters the inclined plate separator 2 through overflow, and the length of the straight plates in the inclined plate separator 2 is 0.2m, the width is 0.07m, the plat...

Embodiment 2

[0053] The stirred tank reactor 1 has a size of 1 L and is made of carbon steel. The reaction pressure is 0.8MPa, controlled by the flow of hydrogen; the temperature is 100°C, controlled by the flow of circulating water in the jacket 12 of the stirred tank reactor 1, and the catalyst is a diatomite nickel catalyst with a mass concentration of 2%. The stirred tank reactor 1 adopts a self-priming stirring paddle 3, and the stirring speed is 800 rpm. The dechlorination inhibitor is sodium sulfite, and the mass concentration of the inhibitor in the kettle is 800ppm. The solvent is ethanol, and the feed is an ethanol solution of 3,4-dichloronitrobenzene, the mass concentration of 3,4-dichloronitrobenzene is 5%, and the feed rate is 6.7mL / min. The effective volume of the reactor is 0.6L, and the residence time is 1.5h. The reaction product enters the inclined plate separator 2 through overflow, and the length of the straight plate in the inclined plate separator 2 is 0.1m, the wid...

Embodiment 3

[0057] The size of the stirred tank reactor 1 is 1m 3 , the material is carbon steel. The reaction pressure is 1.2MPa, controlled by the flow of hydrogen; the temperature is 90°C, controlled by the flow of circulating water in the jacket 12 of the stirred tank reactor 1, and the catalyst is activated carbon nickel catalyst with a mass concentration of 1.8%. The stirred tank reactor 1 adopts a self-priming stirring paddle 3, and the stirring speed is 200 rpm. The dechlorination inhibitor is thiourea, and the mass concentration of the inhibitor in the kettle is 1000ppm. Solvent adopts ethylene glycol, and feed is the ethylene glycol solution of 3,4-dichloronitrobenzene, and the mass concentration of 3,4-dichloronitrobenzene is 12%, and feed rate is 0.3m 3 / h. The effective volume of the reactor is 0.6m 3 , the residence time is 2h. Reaction product enters inclined plate separator 2 by overflowing, and the straight plate length in inclined plate separator 2 is 1m, and width ...

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Abstract

The invention relates to a method for continuously producing 3,4-dichloroaniline. The method comprises the following steps of: continuously putting a 3,4-dichloronitrobenzene solution into a stirred tank reactor, wherein the pressure of the stirred tank reactor is 0.5-2Mpa, the temperature is 60-120 DEG C, and the pH value in a stirred tank is controlled to be between 8 and 12; performing catalytic hydrogenation reaction on the 3,4-dichloronitrobenzene in the stirred tank reactor in the presence of a nickel catalyst, a dechlorination inhibitor, hydrogen and a solvent to generate 3,4-dichloroaniline; overflowing the reaction product into a tilted plate separator, and continuously separating a catalyst concentrated solution and a product clear solution in the tilted plate separator; and continuously returning the catalyst concentrated solution to the stirred tank reactor. According to the method, the yield of the product obtained by the method is more than 99%, the dechlorination mass fraction is less than 0.5%, the loss of the catalyst is low, the consumption of the hydrogen is small, and the operation is stable and easy to control, so that the method is suitable for industrial large-scale production.

Description

Technical field: [0001] The invention relates to a production method of 3,4-dichloroaniline, in particular to a continuous production method for generating 3,4-dichloroaniline through hydrogenation reaction of 3,4-dichloronitrobenzene. Background technique: [0002] 3,4-Dichloroaniline is an important intermediate, such as used in the synthesis of ricotine, NMDA and dichlorophenylthiourea in the pharmaceutical industry, and can be used in the synthesis of propanil and rituron in the pesticide industry , Mielingcao and other pesticides. In the dye industry, it can be used to synthesize azo dyes, such as C.I. Disperse Red 152 and C.I. Disperse Red 153. In addition, it can also be used to prepare 3,4-dichlorophenol and mothproof agent for woolen fabrics, and has broad market prospects. [0003] The initial industrial production method of 3,4-dichloroaniline is the iron powder reduction method under acidic conditions. This method has relatively low cost, relatively mature proc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/36
Inventor 程华农齐学正张兵岳金彩李玉刚谭心舜郑世清
Owner QINGDAO UNIV OF SCI & TECH
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