A kind of synthetic method of 3,5-difluorophenol

A technology for difluorophenol and a synthesis method, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of expensive and difficult to obtain raw materials, high price and difficult to obtain, and unsatisfactory yield, and achieves improvement The effect of industrial application value, efficient preparation and good product quality

Active Publication Date: 2022-06-07
ZHEJIANG ZHONGXIN FLUORIDE MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages are that the raw material 3,5-difluoroaniline is expensive and difficult to obtain, the diazo / hydrolysis reaction has certain safety risks, the amount of wastewater in the synthesis process is large, it is not friendly to the environment, and the yield is not ideal
[0012] The raw materials used in this method are expensive and difficult to obtain. The etherification reaction uses cuprous halide as a catalyst and double enthalpy ligands such as nitrogen and phosphorus. The synthesis cost is relatively high, and the hydrolysis reaction produces a large amount of acidic wastewater, which is not friendly to the environment.

Method used

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  • A kind of synthetic method of 3,5-difluorophenol
  • A kind of synthetic method of 3,5-difluorophenol
  • A kind of synthetic method of 3,5-difluorophenol

Examples

Experimental program
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Effect test

Embodiment 1

[0043] In a 1-liter pressure-resistant reaction kettle, add 300 grams of water, 300 grams of xylene, and 113 grams of sodium carbonate, stir at room temperature, add 75 grams of 2,4,6-trifluorobenzoic acid, seal the reaction kettle, and heat up to 160-165°C The reaction was stirred for 10 hours, and the reaction was stopped. The reaction system was cooled to room temperature, the reaction solution was taken out, the pH was adjusted to 1-2 with concentrated hydrochloric acid, left to stand for layers, the organic phase was separated, the aqueous phase was extracted with xylene, the organic phases were combined, dried, concentrated and rectified to obtain 51.81 g of 3,5-difluorophenol, yield 93.5%, purity 99.7%.

Embodiment 2

[0045] In a 1-liter pressure-resistant reaction kettle, add 480 grams of water and 110 grams of sodium hydroxide, stir at room temperature, add 160 grams of 2,4,6-trifluorobenzoic acid, seal the reaction kettle, and heat up to 150-155 °C and stir for 15 hours , stop the reaction. The reaction system was cooled to room temperature, the reaction solution was taken out, stirred at room temperature, adjusted to pH strongly acidic with 10% hydrochloric acid, extracted with chloroform, combined with organic phases, dried, concentrated and rectified to obtain 3,5-difluorophenol 111.46 g, yield 94.3%, purity 99.6%.

Embodiment 3

[0047] In a 1-liter pressure-resistant reaction kettle, add 210 grams of water, 280 grams of toluene, and 110 grams of potassium hydroxide, stir at room temperature, add 70 grams of 2,4,6-trifluorobenzoic acid, seal the reaction kettle, and heat up to 80-85°C The reaction was stirred for 30 hours, the temperature was raised to 140-145° C., the reaction was continued for 10 hours, and the reaction was stopped. The reaction system was lowered to room temperature, the reaction solution was taken out, adjusted to pH 1-2 with 50% sulfuric acid solution, left to stand for layers, the organic phase was separated, the aqueous phase was extracted with toluene, the organic phases were combined, dried, concentrated and rectified, 49.38 g of 3,5-difluorophenol were obtained with a yield of 95.5% and a purity of 99.8%.

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Abstract

The invention discloses a synthesis method of 3,5-difluorophenol, which belongs to the technical field of chemical synthesis. 2,4,6-trifluorobenzoic acid in a solvent, under the action of alkali, obtains 3,5-difluorophenolate through one-pot reaction, and obtains 3,5-difluorophenol after adjusting the acid for free. This method has raw materials It has the advantages of cheap and easy to obtain, short synthesis steps, simple operation, mild reaction conditions, high synthesis yield, good product quality, and suitable for industrial production. 2,4,6-trifluorobenzoic acid uses cheap and easy-to-obtain pentachlorobenzonitrile as a raw material, first undergoes fluorination reaction to obtain 2,4,6-trifluoro-3,5-dichlorobenzonitrile, and then undergoes hydrolysis The reaction obtains 2,4,6-trifluoro-3,5-dichlorobenzoic acid, which is finally synthesized by selective dechlorination reaction, realizing the simple, cheap and efficient preparation of raw material 2,4,6-trifluorobenzoic acid, Improve the industrial application value of the synthesis process.

Description

Technical field: [0001] The invention belongs to the technical field of chemical synthesis, in particular to a method for synthesizing 3,5-difluorophenol. Background technique: [0002] 3,5-Difluorophenol is a very important fluorine-containing fine chemical, which is widely used in medicine, pesticides, new materials and other fields. body. [0003] There are mainly three kinds of synthetic methods reported publicly for 3,5-difluorophenol. [0004] (1) Using 3,5-difluoroaniline as raw material, synthesizing 3,5-difluorophenol through diazo and hydrolysis reaction: [0005] [0006] This method is a traditional method for synthesizing phenolic compounds. The disadvantage is that the raw material 3,5-difluoroaniline is expensive and difficult to obtain, the diazo / hydrolysis reaction has certain safety risks, the amount of waste water in the synthesis process is large, it is not friendly to the environment, and the yield is not ideal. [0007] (2) Using 3,5-difluorobrom...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/02C07C37/64C07C37/055C07C39/27
CPCC07C37/02C07C37/64C07C37/055C07C39/27C07C39/34
Inventor 袁其亮鹿威威陈建王超竺坚飞陈寅镐
Owner ZHEJIANG ZHONGXIN FLUORIDE MATERIALS CO LTD
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