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A kind of method of synthesizing 2,3,5,6-tetrafluorophenol

A technology of tetrafluorophenol and pentafluorobenzoic acid, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as complicated operation, high cost, increased energy consumption, etc., and achieve convenient operation and environmental pollution. small effect

Active Publication Date: 2022-07-19
宁夏忠同生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method realizes 2,3,5,6-tetrafluorophenol through a two-step reaction, the operation is cumbersome, and solvent extraction is used in the preparation of 4-hydroxy-2,3,5,6-tetrafluorobenzoic acid, and the cost is relatively high; More N,N-dimethylaniline is used in the decarboxylation of 4-hydroxy-2,3,5,6-tetrafluorobenzoic acid, and the decarboxylation reaction is carried out at 160°C, which not only increases the cost but also consumes a certain amount of energy. Increase

Method used

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  • A kind of method of synthesizing 2,3,5,6-tetrafluorophenol

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Comparison scheme
Effect test

Embodiment 1

[0024] 404 grams of DMF and 202.3 grams of sodium acetate were placed in a 1 L glass reactor. Add 106.0 g of pentafluorobenzoic acid at a temperature of 50-55 °C. The temperature was raised and refluxed for 6 hours. HPLC detects that the raw material content of the reaction solution is lower than 1.0% and drops below 80°C, and 350.0 grams of 30% concentrated hydrochloric acid is added to the kettle to adjust the pH to less than 1. Then, the temperature was raised and refluxed for 5 hours. After refluxing, steam distillation was performed to separate the lower organic matter. The lower organic matter was rectified to obtain 74.0 g of 2,3,5,6-tetrafluorophenol, which turned into white crystals after cooling down, the yield was 89%, and the HPLC purity was 99.9%.

Embodiment 2

[0026] 305 grams of DMSO and 202.3 grams of sodium acetate were placed in a 1 L glass reactor. Add 106.0 g of pentafluorobenzoic acid at a temperature of 50-55 °C. The temperature was raised and refluxed for 2 hours. HPLC detects that the raw material content of the reaction solution is lower than 1.0% and drops below 80°C, and 350.0 grams of 30% concentrated hydrochloric acid is added to the kettle to adjust the pH to less than 1. Then, the temperature was raised and refluxed for 5 hours. After refluxing, steam distillation was performed to separate the lower organic matter. The lower organic matter was rectified to obtain 76.6 g of 2,3,5,6-tetrafluorophenol, which turned into white crystals after cooling down, the yield was 92%, and the HPLC purity was 99.8%.

Embodiment 3

[0028] 800 grams of water and 202.3 grams of sodium acetate were put into a 1 L glass reactor. Add 106.0 g of pentafluorobenzoic acid at a temperature of 55-60 °C. The reaction was carried out under reflux for 40 hours. HPLC detects that the raw material content of the reaction solution is lower than 1.0% and drops below 80°C, and 350.0 grams of 30% concentrated hydrochloric acid is added to the kettle to adjust the pH to less than 1. Then, the temperature was raised and refluxed for 5 hours. After refluxing, steam distillation was performed to separate the lower organic matter. The lower organic matter was rectified to obtain 73.2 g of 2,3,5,6-tetrafluorophenol, which turned into white crystals after cooling down, the yield was 88%, and the HPLC purity was 99.8%.

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Abstract

The invention discloses a method for synthesizing 2,3,5,6-tetrafluorophenol, which belongs to the field of fine chemicals. The sterically hindered short-chain fatty acid sodium and pentafluorobenzoic acid are used for reflux reaction in a polar solvent; after the reaction is completed, the strong acid is hydrolyzed and decarboxylated and then steam distilled; the steam distillation product is rectified to obtain 2,3,5,6-tetrafluoroethylene Fluorophenol, the purity is over 99.8%, and the yield is over 88%. The process has the remarkable features of easy operation and little environmental pollution, and has good economic value in preparing 2,3,5,6-tetrafluorophenol products.

Description

technical field [0001] The invention relates to a method for synthesizing 2,3,5,6-tetrafluorophenol, belonging to the technical field of fine chemicals. Background technique [0002] 2,3,5,6-Tetrafluorophenol is a widely used fine chemical intermediate, mainly used in the field of pharmaceutical intermediates and new materials. There are two main synthesis processes at present. [0003] CN104926617A reported that 1,2,4,5-tetrafluorobenzene reacted with borate ester under the action of organolithium reagent to obtain 2,3,5,6-tetrafluorobenzeneboronic acid / ester; then under the action of hydrogen peroxide to obtain 2,3 ,5,6-tetrafluorophenol, the total yield is 86%, and the purity is 99.7%. This method needs to control the temperature below -50°C to carry out the reaction in an anhydrous and oxygen-free environment, and at the same time uses an organolithium reagent that has a fire risk in the synthesis, so the synthesis cost of this method is high and there is a potential s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/055C07C37/50C07C37/76C07C39/27C07C67/11C07C69/63
CPCC07C37/0555C07C37/50C07C37/76C07C67/11C07C69/63C07C39/27
Inventor 张同斌刘英亮王涛李锋耿艺文孙艳萍姜殿平
Owner 宁夏忠同生物科技有限公司
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