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Chemical synthesis method of 2, 3, 4, 5-tetrafluoro-benzoic acid

A tetrafluorobenzoic acid, chemical synthesis technology, applied in chemical instruments and methods, organic chemistry, carboxylate preparation and other directions, can solve the problems of large acid and alkali usage, large waste water discharge, etc., to reduce waste water discharge, The three wastes are small and the product purity is good.

Active Publication Date: 2014-12-10
ZHEJIANG UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The method uses tri-n-butylamine as a solvent to carry out decarboxylation reaction. After the reaction, tributylamine and product 2,3,4,5-tetrafluorobenzoic acid form a salt, and acid-base (sodium hydroxide solution and Hydrochloric acid) is used in large quantities, and the discharge of waste water is large

Method used

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  • Chemical synthesis method of 2, 3, 4, 5-tetrafluoro-benzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Tetrafluorophthalic acid: The molar ratio of the catalyst is 1:0.01, the catalyst is tri-n-butylammonium trifluoromethanesulfonate, the solvent is water, and the amount used is twice the mass of tetrafluorophthalic acid.

[0017] Weigh 23.8g (0.1mol) of tetrafluorophthalic acid and 0.33g (1mmol) of catalyst tri-n-butylammonium trifluoromethanesulfonate and feed them into the autoclave, add 48ml of water, after the addition is complete, heat up to 150-155°C React under pressure for 6 hours, when the pressure in the autoclave exceeds 10 atm, exhaust once to maintain the pressure in the autoclave at about 8-10 atm, cool down after the reaction, open the autoclave to take out the material, and filter to obtain 2,3,4,5-tetrafluoro Benzoic acid 16.49g, product yield 85%, melting point 87.5-88.0°C, purity 99.3% (HPLC).

Embodiment 2

[0019] Tetrafluorophthalic acid: The molar ratio of the catalyst is 1:0.10, the catalyst is tri-n-butylammonium trifluoromethanesulfonate, the solvent is water, and the amount used is 3 times the mass of tetrafluorophthalic acid.

[0020] Weigh 23.8g (0.1mol) of tetrafluorophthalic acid and 3.34g (10mmol) of catalyst tri-n-butylammonium trifluoromethanesulfonate and feed them into the autoclave, add 71ml of water, and heat up to 156-160°C React for 5 hours. When the pressure in the autoclave exceeds 10 atm, exhaust once to maintain the pressure in the autoclave at about 8-10 atm. After the reaction, cool down, open the autoclave to take out the material, and filter to obtain 2,3,4,5-tetrafluoro Benzoic acid 17.46g, product yield 90%, melting point 87.8-88.2°C, purity 99.7% (HPLC).

Embodiment 3

[0022] Tetrafluorophthalic acid: The molar ratio of the catalyst is 1:0.02, the catalyst is tri-n-butylammonium trifluoromethanesulfonate, the solvent is water, and the amount used is 2.5 times the mass of tetrafluorophthalic acid.

[0023] Weigh 23.8g (0.1mol) of tetrafluorophthalic acid and 0.67g (2mmol) of catalyst tri-n-butylammonium trifluoromethanesulfonate and feed them into the autoclave, add 60ml of water, after the addition is complete, heat up to 156-160°C React for 5 hours. When the pressure in the autoclave exceeds 10 atm, exhaust once to maintain the pressure in the autoclave at about 8-10 atm. After the reaction, cool down, open the autoclave to take out the material, and filter to obtain 2,3,4,5-tetrafluoro Benzoic acid 16.68g, product yield 86%, melting point 87.5-88.0°C, purity 99.3% (HPLC).

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Abstract

The invention discloses a chemical synthesis method of 2, 3, 4, 5-tetrafluoro-benzoic acid, which comprises the steps of: adding tetrafluoro-phthalic acid, tri-n-butyl ammonium trifluoromethanesulfonate as a catalyst and water as a medium into a reactor, making the temperature rise to 140-170 DEG C, performing selective decarboxylation reaction for 3-10h, cooling after the reaction, and filtering reaction materials, thereby obtaining the 2, 3, 4, 5-tetrafluoro-benzoic acid. The chemical synthesis method of 2, 3, 4, 5-tetrafluoro-benzoic acid has the advantages of high reaction yield, high product purity, small quantities of three wastes, low cost and the like, and has high implementation value and social and economic benefits.

Description

(1) Technical field [0001] The present invention relates to a chemical synthesis method of 2,3,4,5-tetrafluorobenzoic acid, in particular to the selective decarboxylation of tetrafluorophthalic acid as raw material to prepare 2,3,4,5-tetrafluorobenzoic acid chemical synthesis method. (2) Background technology [0002] 2,3,4,5-Tetrafluorobenzoic acid is an important intermediate for the synthesis of chemical raw materials, an important intermediate for the preparation of fluorine-containing silazolone antibacterial drugs such as ofloxacin, and can also be used for pesticides and liquid crystals preparation etc. [0003] Before the present invention is given, the chemical synthesis method of 2,3,4,5-tetrafluorobenzoic acid in the prior art is mainly prepared by selective decarboxylation of tetrafluorophthalic acid. As reported in EP021 811 1A, 2,3,4,5-tetrafluorobenzoic acid was prepared by dissolving tetrafluorophthalic acid in DMSO and raising the temperature to 115-120°C ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C63/10C07C51/377
Inventor 陈志卫苏为科王晓冬袁其亮王超陈寅镐
Owner ZHEJIANG UNIV OF TECH