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Preparation method of 2, 4-dichloro-5-fluoroacetophenone

A technology of fluoroacetophenone and dichlorofluorobenzene, which is applied in the field of preparation of 2,4-dichloro-5-fluoroacetophenone, can solve the problems of difficult wastewater treatment, inability to reuse, complex components of hydrolyzed mother liquor, etc.

Active Publication Date: 2021-08-13
SHANDONG GUOBANG PHARMA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Because the carbonyl group present in acetyl chloride will complex with aluminum chloride, it is theoretically determined that in the Friedel-Crafts acetylation reaction, the amount of aluminum chloride used is far greater than the catalytic amount, and in actual industrialization, the amount of aluminum chloride The use of equivalents has reached the level of more than 2 equivalents, that is, about 1.5 tons of anhydrous aluminum chloride will be consumed for every 1 ton of 2,4-dichloro-5-fluoroacetophenone produced, and this part of aluminum chloride will eventually be consumed. In the presence of a large amount of water, hydrolysis decomplexation enters the hydrolysis mother liquor and cannot be reused, resulting in a high cost of anhydrous aluminum chloride in the Friedel-Crafts reaction
The characteristics of the Friedel-Crafts reaction determine that the acylating reagent acetyl chloride is difficult to react completely, and the residual acetyl chloride aluminum chloride complex will also be hydrolyzed to generate acetic acid during the hydrolysis and decomplexation process, and the Friedel-Crafts reaction itself will produce a large amount of organic impurities. This part of impurities will also enter the hydrolysis mother liquor, resulting in complex components of the hydrolysis mother liquor and difficult treatment of wastewater. The Friedel-Crafts reaction mother liquor has always been one of the core problems restricting the Friedel-Crafts reaction.

Method used

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  • Preparation method of 2, 4-dichloro-5-fluoroacetophenone

Examples

Experimental program
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Effect test

Embodiment 1

[0021] (1) Take 330g (2mol) of 2,4-dichlorofluorobenzene and add it to the reaction kettle with mechanical stirring, slowly pass in 0.73g (0.02mol) of hydrogen chloride, and put in 53.4g (0.4mol) of anhydrous aluminum chloride and 97g (1mol) of vinylidene chloride, tighten the lid of the kettle, start stirring and gradually heat up to 150°C, and keep the temperature for 2 hours;

[0022] (2) After the heat preservation is over, cool down to 75°C, use 1-5min to slowly open the exhaust valve, and the exhaust gas will be cooled through the condenser tube, and the cooled material is vinylidene chloride;

[0023] (3) Transfer the materials in the reaction kettle to a glass reaction bottle, raise the temperature to 130°C, slowly add an appropriate amount of water to keep the temperature at 130°C, and use it for 1-2 hours to slowly add dropwise until the temperature cannot be maintained, which means the hydrolysis reaction It is basically over, keep warm for 0.5 hours;

[0024] (4) ...

Embodiment 2

[0035] The difference between this implementation method and Example 1 is that in order to improve efficiency, no water layer is added after the hydrolysis reaction, and the internal standard is directly sampled to detect 2,4-dichlorofluorobenzene and 2,4-dichloro-5-fluorophenylethyl Ketone amount, its transformation rate is 41.5%, and selectivity is 81.8%.

Embodiment 3

[0037] The difference between this implementation method and Example 2 is that the Friedel-Crafts reaction temperature in step (1) is 130°C, the other steps are the same, the conversion rate is 40.7%, and the selectivity is 87.5%.

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Abstract

The invention provides a preparation method of 2, 4-dichloro-5-fluoroacetophenone. The method comprises the following steps: by taking 2, 4-dichlorofluorobenzene as a raw material, carrying out Friedel-Crafts reaction on 2, 4-dichlorofluorobenzene and vinylidene chloride in the presence of anhydrous aluminum chloride and protonic acid at the same time to generate 1-(1, 1-dichloroethyl)-2, 4-dichloro-5-fluoroacetophenone benzene, carrying out hydrolysis reaction on the intermediate product under the catalysis of Lewis acid to generate 2, 4-dichloro-5-fluoroacetophenone and hydrogen chloride, adding a proper amount of water for layering after the reaction is finished, and rectifying an organic layer to obtain the product. According to the method, the cost of raw materials and auxiliary materials is greatly reduced, the post-treatment pressure is relieved, the yield can reach 85% or above, and the method belongs to the technical field of organic chemical industry.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry and relates to a preparation method of 2,4-dichloro-5-fluoroacetophenone. Background technique [0002] 2,4-dichloro-5-fluoroacetophenone is an important chemical raw material, used as a pharmaceutical intermediate, and the main intermediate of the third-generation broad-spectrum high-efficiency quinolone antibacterial agents ciprofloxacin and anthranofloxacin body. [0003] At present, fluorochloroacetophenones are generally produced in the industry by acetylation of 2,4-dichlorofluorobenzene. According to the different acylating agents, it can be roughly divided into three routes: 1. use acetic acid as an acylating agent, react with aluminum chloride in DMF and thionyl chloride, and the resulting yield is about 84%. Eliminated; ②Using acetic anhydride as an acylating agent and aluminum chloride as a catalyst for Friedel-Crafts reaction, the yield is only 29%, which is not sui...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/43C07C45/82C07C49/807C07C17/32C07C25/13
CPCC07C45/43C07C45/82C07C17/32C07C25/13C07C49/807
Inventor 张小垒刘聪王兴国潘燕朋孟德伟
Owner SHANDONG GUOBANG PHARMA
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