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Synthesis method of 3, 5-difluorophenol

A technology of difluorophenol and synthesis method, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., and can solve problems such as unsatisfactory yield, high price and difficult availability, large amount of waste water, etc.

Active Publication Date: 2021-04-06
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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  • Synthesis method of 3, 5-difluorophenol
  • Synthesis method of 3, 5-difluorophenol
  • Synthesis method of 3, 5-difluorophenol

Examples

Experimental program
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Effect test

Embodiment 1

[0043] In a 1-liter pressure-resistant reactor, 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 reactor, and heat up to 160-165°C The reaction was stirred for 10 hours, and the reaction was stopped. The reaction system was lowered to room temperature, the reaction solution was taken out, the pH was adjusted to 1-2 with concentrated hydrochloric acid, the layers were allowed to stand, 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 reactor, 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 reactor, raise the temperature to 150-155°C and stir for 15 hours , stop responding. The reaction system was lowered to room temperature, the reaction solution was taken out, stirred at room temperature, adjusted to strong acidity with 10% hydrochloric acid, extracted with chloroform, combined organic phases, dried, concentrated, and rectified to obtain 3,5-difluorophenol 111.46 grams, yield 94.3%, purity 99.6%.

Embodiment 3

[0047] In a 1-liter pressure-resistant reactor, 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 reactor, and heat up to 80-85°C Stir the reaction for 30 hours, raise the temperature to 140-145° C. and continue the reaction for 10 hours, then stop the reaction. The reaction system was lowered to room temperature, the reaction liquid was taken out, the pH was adjusted to 1-2 with 50% sulfuric acid solution, the layers were allowed to stand, 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 was obtained with a yield of 95.5% and a purity of 99.8%.

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Abstract

The invention discloses a synthetic method of 3, 5-difluorophenol, and belongs to the technical field of chemical synthesis. According to the method, 3,5-difluorophenolate is obtained through a one-pot reaction of 2,4,6-trifluorobenzoic acid in a solvent under the action of alkali, 3,5-difluorophenol is obtained after acid regulation and dissociation, and the method has the advantages of cheap and easily available raw materials, short synthesis steps, simple operation, mild reaction conditions, high synthesis yield, good product quality, suitability for industrial production and the like. According to the method, cheap and easily available pentachloronitrile is taken as a raw material, 2, 4, 6-trifluoro-3, 5-dichlorobenzonitrile is obtained through a fluorination reaction, 2, 4, 6-trifluoro-3, 5-dichlorobenzoic acid is obtained through a hydrolysis reaction, and finally, the raw material 2, 4, 6-trifluoro-3, 5-dichlorobenzoic acid is synthesized through a selective dechlorination reaction, so that simple, cheap and efficient preparation of the raw material 2, 4, 6-trifluorobenzoic acid is realized, and the industrial application value of the synthesis process is improved.

Description

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

Claims

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Application Information

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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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