Method for preparing 2, 6-difluorobenzonitrile

A technology of difluorobenzonitrile and dichlorobenzonitrile, which is applied in the field of pesticide preparation, can solve problems such as low yield, cumbersome process, complicated post-treatment, etc., achieve high melting point, increase reaction yield, and good catalytic effect

Active Publication Date: 2015-07-22
SHANGHAI TAIHE INT TRADE CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] Of the above-mentioned synthesis processes, the yields of process 1 and 2 are relatively low, process 3 uses high temperature and high pressure conditions, and process 4 is tedious and complex, and the post-treatment is complicated; therefore, the industry has a mild and efficient method for preparing 2,6-difluorobenzonitrile the need is very urgent

Method used

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  • Method for preparing 2, 6-difluorobenzonitrile
  • Method for preparing 2, 6-difluorobenzonitrile
  • Method for preparing 2, 6-difluorobenzonitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] In a 1000ml mechanically stirred reaction flask equipped with a condenser and a water separator, 1,3-dimethyl-2-imidazolinone 450g, toluene 100g, 2,6-dichlorobenzonitrile 150g (content 99.5% , 0.868mol), N-ethylpyridine chloride 9g, stirred and heated to 110°C, refluxed for 2 hours, then continued to heat up to remove toluene, and recovered 99g of toluene.

[0036] Turn off the heating, lower the reaction temperature to 90°C, add 122g of anhydrous potassium fluoride (99% content, 2.08mol) into the reaction flask, heat to raise the reaction temperature to 150°C, keep the reaction for 15 hours, then turn off the heating.

[0037] Lower the reaction temperature to 40°C, filter with suction, transfer the filtrate to a rectifying bottle, turn on the vacuum, the vacuum degree is -0.1MPa, collect 105-108°C fractions, and obtain 118.8g of finished product 2,6-difluorobenzonitrile (content 99.5%, 0.85mol), yield 98%. The rectification raffinate is recovered and applied mechanic...

Embodiment 2

[0039] In a 1000ml mechanically stirred reaction flask equipped with a condenser and a water separator, 1,3-dimethyl-2-imidazolinone 450g, toluene 100g, 2,6-dichlorobenzonitrile 150g (content 99.5% , 0.868mol), 9g of N-propylpyridine chloride, stirred and heated up to 110°C, refluxed and separated for 2 hours, then continued to heat up to remove toluene, and recovered 99g of toluene.

[0040] Turn off the heating, lower the reaction temperature to 90°C, add 122g of anhydrous potassium fluoride (99% content, 2.08mol) into the reaction flask, heat to raise the reaction temperature to 150°C, keep the reaction for 15 hours, then turn off the heating.

[0041] Lower the reaction temperature to 40°C, filter with suction, transfer the filtrate to a rectifying bottle, turn on the vacuum, the vacuum degree is -0.1MPa, collect fractions at 105-108°C, and obtain 119g of finished product 2,6-difluorobenzonitrile (content 99.5 %, 0.852mol), yield 98.17%. The rectification raffinate is rec...

Embodiment 3

[0043] In a 1000ml mechanically stirred reaction flask equipped with a condenser and a water separator, dimethylsulfoxide, 100g of toluene, 150g of 2,6-dichlorobenzonitrile (content 99.5%, 0.868mol), N-chlorinated Ethylpyridine 9g, stirred and heated up to 110°C, refluxed to separate water for 2 hours, then continued to heat up to remove toluene, and recovered 99g of toluene.

[0044] Turn off the heating, lower the reaction temperature to 90°C, add 122g of anhydrous potassium fluoride (99% content, 2.08mol) into the reaction flask, heat to raise the reaction temperature to 150°C, keep the reaction for 15 hours, then turn off the heating.

[0045] Lower the reaction temperature to 40°C, filter with suction, transfer the filtrate to a rectifying bottle, turn on the vacuum, the vacuum degree is -0.1MPa, collect the fraction at 105-108°C, and obtain 119.2g of the finished product 2,6-difluorobenzonitrile (content 99.5%, 0.853mol), yield 98.34%. The rectification raffinate is rec...

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Abstract

The invention relates to a method for preparing 2, 6-difluorobenzonitrile. The method comprises the following steps: adding an aprotic strong polar solvent, toluene, 2,6-dichlorobenzonitrile and a catalyst, controlling temperature to 110-150 DEG C, carrying out reflux and dehydration and removing methylbenzene; cooling to 90-100 DEG C and adding potassium fluoride into a reaction container; controlling reaction temperature to 150-250 DEG C, and reacting for 15-20 h; reducing temperature of the reaction container to below 50 DEG C, carrying out suction filtration to obtain a filtrate and transferring the filtrate into a rectification bottle, starting a vacuum pump with the vacuum degree being -0.1 MPa, and collecting a fraction of 105-108 DEG C so as to obtain a finished product 2, 6-difluorobenzonitrile. In comparison with the prior art, the invention has advantages as follows: reaction conditions are mild; the preparation technology is simple; and reaction yield can reach up to 98%.

Description

technical field [0001] The invention relates to a method for preparing pesticides, in particular to a method for preparing 2,6-difluorobenzonitrile. Background technique [0002] 2,6-Difluorobenzonitrile is an essential intermediate for specific insect growth regulators: diflubenzuron, diflunuron and other benzoylurea pesticides. It can also be used in the synthesis of drugs and liquid crystal materials, and has a wide range of applications. market prospects. Therefore, how to efficiently synthesize 2,6-difluorobenzonitrile is widely concerned by people, and the synthetic methods of 2,6-difluorobenzonitrile mainly contain the following types: [0003] 1. Before 1980, the synthesis of 2,6-difluorobenzonitrile mainly adopted the method of fluorination reaction of chlorinated aromatic hydrocarbons and anhydrous potassium fluoride in various solvents (see GC, Fing, et al., chem .commn, 1965, (18), [0004] [0005] 2. Phase-transfer catalyst method: Phase-transfer catalyst...

Claims

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Application Information

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IPC IPC(8): C07C255/50C07C253/30
Inventor 周庆江吴勇谢思勉田晓宏
Owner SHANGHAI TAIHE INT TRADE CO LTD
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