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Industrial preparation process for 3,4-difluorobenzonitrile

A technology of difluorobenzonitrile and preparation process, applied in 3 fields, can solve the problems of inability to meet industrial production needs, strict reaction requirements, complex preparation process, etc., and achieves the possibility of reducing fluorine loss and coking, short reaction process flow, and improved performance. Effect of Reaction Yield

Inactive Publication Date: 2012-09-26
TAIXING YUANDONG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] In order to solve the problems in the prior art of synthesizing 3,4-difluorobenzonitrile with complex preparation process, strict reaction requirements, long cycle time and low yield, which cannot meet the needs of industrial production, the invention provides a simple process, mild reaction, Industrial preparation process of 3,4-difluorobenzonitrile with short cycle time and high yield

Method used

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  • Industrial preparation process for 3,4-difluorobenzonitrile
  • Industrial preparation process for 3,4-difluorobenzonitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] 1. Add 456Kg solvent and 150L toluene from solvent DMI head tank and toluene head tank respectively to 2000L fluorination kettle with rectification tower;

[0032] 2. Turn on the fluorination kettle to stir, open the feeding port and put 139.2Kg of anhydrous potassium fluoride and 20Kg of catalyst into the fluorination kettle, close the feeding port, and check whether the seal is intact;

[0033] 3. Turn on the vacuum system so that the gauge pressure of the fluorination kettle is -0.1Mpa. After the vacuum is stable, open the cooling water system of the top condenser of the fluorination kettle, start the hot oil pump, and slowly raise the temperature; when the temperature in the kettle rises to 110°C , the rectifying tower is in the total reflux state, and the discharge flow rate is controlled at 55kg / h, the discharge ends, the clear cut toluene is finished, and the discharge valve is closed so that the tower is in the total reflux state;

[0034] 4. Open the vent valve...

Embodiment 2

[0040] 1. Add 342Kg solvent and 150L toluene from the solvent DMI head tank and toluene head tank respectively to the 2000L fluorination kettle with rectification tower;

[0041] 2. Turn on the fluorination kettle to stir, open the feeding port and put 127.6Kg of anhydrous potassium fluoride and 12.5Kg of catalyst into the fluorination kettle, close the feeding port, and check whether the seal is intact;

[0042] 3. Turn on the vacuum system so that the gauge pressure of the fluorination kettle is -0.1Mpa. After the vacuum is stable, open the cooling water system of the top condenser of the fluorination kettle, start the hot oil pump, and slowly raise the temperature; when the temperature in the kettle rises to 110°C , the rectifying tower is in the total reflux state, and the discharge flow rate is controlled at 55kg / h, the discharge ends, the clear cut toluene is finished, and the discharge valve is closed so that the tower is in the total reflux state;

[0043]4. Open the v...

Embodiment 3

[0049] 1. Add 912Kg solvent and 150L toluene from solvent DMI head tank and toluene head tank respectively to 2000L fluorination kettle with rectification tower;

[0050] 2. Turn on the fluorination kettle to stir, open the feeding port and put 232Kg of anhydrous potassium fluoride and 25Kg of catalyst into the fluorination kettle, close the feeding port, and check whether the seal is intact;

[0051] 3. Turn on the vacuum system so that the gauge pressure of the fluorination kettle is -0.1Mpa. After the vacuum is stable, open the cooling water system of the top condenser of the fluorination kettle, start the hot oil pump, and slowly raise the temperature; when the temperature in the kettle rises to 110°C , the rectifying tower is in the total reflux state, and the discharge flow rate is controlled at 55kg / h, the discharge ends, the clear cut toluene is finished, and the discharge valve is closed so that the tower is in the total reflux state;

[0052] 4. Open the vent valve t...

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Abstract

The invention relates to an industrial preparation process for 3,4-difluorobenzonitrile. The method comprises the following steps of: reacting 3,4-dichlorobenzonitrile and anhydrous potassium fluoride under the protection of nitrogen by taking 1.3-dimethyl-2-imidazolone as a reaction solvent and N-bis(dimethylamino)methylene-1.3-dimethyl imidazoline-2-ammonium chloride salt as a catalyst at the temperature of between 200 and 230 DEG C for 20 hours, reacting with rectifying to obtain a 3,4-dichlorobenzonitrile crude product, rectifying the 3,4-dichlorobenzonitrile to obtain high-purity 3,4-dichlorobenzonitrile, and distilling the solvent and recycling. The method has the advantages of simplicity, mild reaction, short period, and high yield.

Description

technical field [0001] The invention relates to a preparation method of a pesticide intermediate, in particular to an industrial preparation process of 3,4-difluorobenzonitrile. Background technique [0002] 3,4-difluorobenzonitrile can be used in the synthesis of pesticides, medicines and fluorine-containing liquid crystal display materials. The pesticide synthesized with it has strong selectivity, less usage, low toxicity to humans, and low residue. It is the safest rice herbicide at present. It is a pesticide with a very broad development prospect. Therefore, how to efficiently synthesize 3,4- Difluorobenzonitrile has received great attention from people, and there are three methods reported in the literature for 3,4-difluorobenzonitrile. [0003] 1) 3,4-difluorobenzonitrile can be obtained by amidation and dehydration of 3,4-dichloroformyl chloride, which can be fluorinated to obtain 3,4-difluorobenzonitrile. [0004] [0005] 2) 3,4-difluoroacetophenone is obtained...

Claims

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Application Information

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IPC IPC(8): C07C255/50C07C253/30
Inventor 陈小明赵炳南杨新生任爱国
Owner TAIXING YUANDONG CHEM
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