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Preparation method of 2, 6-difluorobenzamide

A kind of technology of difluorobenzamide and difluorobenzonitrile

Pending Publication Date: 2021-11-16
南京硕达生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because one of these two methods uses strong acid and the other uses strong alkali, so the post-treatment needs to use a large amount of acid and alkali for neutralization, which not only wastes a lot of acid and alkali, but also produces a large amount of waste salt to pollute the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] A kind of preparation method of 2,6-difluorobenzamide, operation steps are as follows in sequence:

[0022] S1: Prepare the raw material solution: add deionized water and 2,6-difluorobenzonitrile respectively in the reaction kettle, the mass ratio of ionized water and 2,6-difluorobenzonitrile is 2:1, stir evenly and prepare a solution for later use;

[0023] S2: Set up equipment: connect the high-pressure plunger pump to the stainless steel insert reactor, set the temperature of the reactor to 240°C, set the reaction pressure to 4Mpa, and set the flow rate of the plunger pump to 2.5ml / min;

[0024] S3: High-temperature hydrolysis: After the temperature and pressure are stabilized, the raw material liquid is pumped into the stainless steel insert type coil reactor with a plunger pump for reaction, and then flows out into the post-treatment tank through the cooling section and the back pressure valve;

[0025] S4: Post-treatment: Add sodium chloride solution to salt out i...

Embodiment 2

[0028] A kind of preparation method of 2,6-difluorobenzamide, operation steps are as follows in sequence:

[0029] S1: Prepare the raw material solution: add deionized water and 2,6-difluorobenzonitrile respectively in the reaction kettle, the mass ratio of ionized water and 2,6-difluorobenzonitrile is 2:1, stir evenly and prepare a solution for later use;

[0030] S2: Set up equipment: connect the high-pressure plunger pump to the stainless steel insert reactor, set the temperature of the reactor to 280°C, the reaction pressure to 4Mpa, and the flow rate of the plunger pump to 5ml / min;

[0031] S3: High-temperature hydrolysis: After the temperature and pressure are stabilized, the raw material liquid is pumped into the stainless steel insert type coil reactor with a plunger pump for reaction, and then flows out into the post-treatment tank through the cooling section and the back pressure valve;

[0032] S4: Post-treatment: Add sodium chloride solution to salt out in the trea...

Embodiment 3

[0035] A kind of preparation method of 2,6-difluorobenzamide, operation steps are as follows in sequence:

[0036] S1: Prepare the raw material solution: add deionized water and 2,6-difluorobenzonitrile respectively in the reaction kettle, the mass ratio of ionized water and 2,6-difluorobenzonitrile is 3:1, stir evenly and prepare a solution for later use;

[0037] S2: Set up equipment: connect the high-pressure plunger pump to the stainless steel insert reactor, set the temperature of the reactor to 240°C, set the reaction pressure to 4Mpa, and set the flow rate of the plunger pump to 2.5ml / min;

[0038] S3: High-temperature hydrolysis: After the temperature and pressure are stabilized, the raw material liquid is pumped into the stainless steel insert type coil reactor with a plunger pump for reaction, and then flows out into the post-treatment tank through the cooling section and the back pressure valve;

[0039] S4: Salt-out treatment: Add sodium chloride solution to salt-o...

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PUM

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Abstract

The invention discloses a preparation method of 2, 6-difluorobenzamide. 2, 6-difluorobenzonitrile is prepared by pyrohydrolysis through a micro-channel reactor. The preparation method comprises the following steps of: S1, preparing a raw material solution: preparing a 2, 6-difluorobenzonitrile aqueous solution for later use; S2, setting up equipment which is composed of a high-pressure plunger pump and a stainless steel insert type reactor; S3, carrying out pyrohydrolysis: pumping the raw material solution into the stainless steel insert type reactor through the plunger pump for reaction, and enabling the raw material solution to flow into a post-treatment kettle for post-treatment; and S4, carrying out post-treatment: adding a sodium chloride solution into the treatment kettle for salting-out, and then filtering, washing and drying to obtain difluorobenzamide. No catalyst needs to be added in the hydrolysis process, acid-base neutralization is not needed in post-treatment, the process is simple, the purity is good, and the yield is high. A continuous flow process instead of a traditional high-pressure reaction kettle process is used, so that the reaction process is more controllable, safer and more efficient.

Description

technical field [0001] The invention relates to the field of pesticide preparation, in particular to a preparation method of 2,6-difluorobenzamide. Background technique [0002] 2,6-Difluorobenzamide is a key intermediate in the synthesis of benzoylurea insecticides. Benzoylurea insecticides belong to chitin synthesis inhibitors. By inhibiting the biogenesis of chitin in insects, Synthesized to kill insects, it has the characteristics of high insecticidal activity, broad insecticidal activity, low residue, strong selectivity, and safety to humans and animals. Therefore, the demand for high-quality 2,6-difluorobenzamide in domestic and foreign markets is increasing. [0003] The reported synthetic methods are mainly divided into two categories: (1) ammonolysis of difluorobenzoic acid and its derivatives; (2) hydrolysis of difluorobenzonitrile. Wherein the hydrolysis method of difluorobenzonitrile is further divided into: (1) acid catalyzed hydrolysis; (2) strong base cataly...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C231/06C07C233/65
CPCC07C231/06C07C233/65
Inventor 席亚男张俊
Owner 南京硕达生物科技有限公司
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