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Improved synthesis technology of 3,4,5-trifluorophenol

A technology for the synthesis of trifluorophenol, which is applied in the field of improvement of the synthesis process of 3,4,5-trifluorophenol, which can solve problems such as high equipment requirements, hidden dangers, and difficult control of the reaction, and achieve the effect of improving reaction efficiency

Active Publication Date: 2020-04-10
BENGBU CHINA SYNCHEM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the first step, the author added the Grignard reagent dropwise to the raw material, the reaction is difficult to control, the risk factor is high, and the post-treatment requires a large amount of solvent extraction. The second step uses dichloromethane as the solvent for the oxidation reaction, which has potential safety hazards and is not suitable for industrial production. At the same time, the fluorine drop of the synthesized product is not introduced in detail
[0006] CN1861554 patent uses 1-halo-3,4,5-trifluorobenzene as raw material to synthesize 3,4,5-trifluorophenol through ammoniation, diazotization, and hydrolysis. This method requires high temperature and high pressure conditions, and the equipment The requirements are high, and the amount of reaction wastewater is difficult to handle, which is not conducive to industrial production

Method used

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  • Improved synthesis technology of 3,4,5-trifluorophenol
  • Improved synthesis technology of 3,4,5-trifluorophenol

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Experimental program
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Effect test

Embodiment 1

[0030] The first step: 1000mL four-neck flask, equipped with thermometer and condenser, under the protection of nitrogen, put in 3,4,5-trifluorobromobenzene 105.5g (0.5mol), tetrahydrofuran 470mL, turn on the stirring, and cool the low temperature bath to -85 ~-75°C, slowly add 220 mL (0.55 mol) of n-butyl lithium n-hexane solution (2.5 mol / L) dropwise, after the dropwise addition is completed, control the temperature and stir for 2.0 hours. At the end of heat preservation, control the temperature from -85 to -75°C to start adding 77.9 g (0.75 mol) of trimethyl borate dropwise, and keep the temperature for 2.0 hours after the dropping. Sample delivery liquid phase detection 3,4,5-trifluorobromobenzene raw material residue <0.5%. After the reaction is completed, desolvate tetrahydrofuran under negative pressure until the temperature of the reaction flask reaches 50℃ and no flow, stop desolventization, cool to 20-25℃, add 630mL pure water, control the temperature at 20-25℃, add 3...

Embodiment 2

[0033] The first step: 1000mL four-neck flask, equipped with thermometer and condenser, under the protection of nitrogen, put in 3,4,5-trifluorobromobenzene 105.5g (0.5mol), 2-methyltetrahydrofuran 490mL, start stirring, low temperature bath The temperature was lowered to -70°C to -60°C, and 220 mL (0.55 mol) of a cyclohexane solution (2.5 mol / L) of n-butyl lithium was slowly added dropwise. After the dropwise addition was completed, the temperature was controlled and stirred for 2.0 hours. At the end of the heat preservation, control the temperature from -85 to -75°C to start adding 109.5 g (0.75 mol) of triethyl borate dropwise, and keep the temperature for 2.0 hours after the dropping. Sample delivery liquid phase detection 3,4,5-trifluorobromobenzene raw material residue <0.5%. After the reaction is completed, desolve 2-methyltetrahydrofuran under negative pressure until the temperature of the reaction flask reaches 50℃ and no flow, stop desolventization, cool to 20-25℃, ad...

Embodiment 3

[0036] The first step: 1000mL four-neck flask, equipped with thermometer and condenser, under the protection of nitrogen, put in 3,4,5-trifluorobromobenzene 105.5g (0.5mol), tetrahydrofuran 470mL, turn on the stirring, and cool the low temperature bath to -70 At ~-60°C, 220 mL (0.55 mol) of a cyclohexane solution (2.5 mol / L) of n-butyl lithium was slowly added dropwise. After the addition was completed, the temperature was controlled and stirred for 2.0 hours. At the end of the heat preservation, control the temperature from -85°C to -75°C to start adding 141.0g (0.75mol) isopropyl borate dropwise, and keep the temperature for 2.0 hours after the dropping. Sample delivery liquid phase detection 3,4,5-trifluorobromobenzene raw material residue <0.5%. After the reaction is completed, desolvate tetrahydrofuran under negative pressure until the temperature of the reaction flask reaches 50℃ and no flow, stop desolventization, cool to 20-25℃, add 630mL pure water, control the tempera...

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Abstract

The invention discloses a synthesis technology of 3,4,5-trifluorophenol, and belongs to the technical field of organic synthesis. The method comprises the following steps: 3,4,5-trifluorobromobenzeneused as a raw material is lithiated by using n-butyllithium under an ultralow temperature condition, and then reacts with boric acid ester, an alkali is added for quenching to obtain 3,4,5-trifluorophenylborate, the 3,4,5-trifluorophenylborate is oxidized in the presence of hydrogen peroxide, and then undergoes acidolysis to obtain 3,4,5-trifluorophenol, and the obtained 3,4,5-trifluorophenol is simply distilled to obtain the product having a purity reaching 99.9% or above, having a defluorination matter content of below 50 ppm and meeting the requirements of electronic products. The technology adopting lithiation / boronation and the oxidation reaction in a water system has the advantages of mild reaction conditions, few defluorination byproducts, high product purity, and easiness in realization of industrial production.

Description

Technical field [0001] The invention relates to the technical field of organic synthesis, in particular to an improvement in the synthesis process of 3,4,5-trifluorophenol. Background technique [0002] The fluorine atom increases the width of the molecule, destroys the coplanarity of the molecule itself, and decreases the intermolecular force. The fluorine-containing intermediate 3,4,5-trifluorophenol has become an important fine chemical intermediate, which is widely used in liquid crystal materials. , Pharmaceutical intermediates and pesticide intermediates. In terms of pesticides, it is an important prerequisite for a new type of fungicide fluconazole, which is a broad-spectrum, specific effect, strong selectivity, and excellent systemic conductivity. It is a compound II for the mitochondrial respiratory chain. Its inhibitory effect on succinate dehydrogenase. Its molecular structure is as follows: [0003] [0004] For the synthesis of 3,4,5-trifluorophenol, the literature ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C37/01C07C39/27C07C37/74
CPCC07C37/01C07F5/02C07C37/74C07C39/27
Inventor 徐剑霄刘洪强赵士民魏佳玉王松松朱克明
Owner BENGBU CHINA SYNCHEM TECH CO LTD
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