Method for preparing 2,3 difluoro - 4 - Bromoethyl phenyl ether

A technology of bromophenethyl ether and bromophenol, which is applied in the field of preparation of fluorine-containing organic intermediates, can solve the problems that the synthesis method has not been reported yet, and achieve the effects of low cost, scientific process, and low viscoelastic coefficient

Inactive Publication Date: 2007-07-25
YETAI FINE CHEM INST CHANGZHOU CITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But the synthetic method of 2,3-difluoro-4-bromophenetole has not been reported yet

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0012] A kind of preparation method of 2,3-difluoro-4-bromophenetole, has following processing steps:

[0013] a) Bromination: use 2,3-difluorophenol as raw material, add organic acid auxiliary agent (preferably butyric acid, valeric acid or acetic acid) in the first solvent haloalkane (preferably dichloroethane or dichloromethane), At low temperature, preferably -10~-15°C, use Br 2 Bromination to obtain 2,3-difluoro-4-bromophenol with a main content greater than 95% and 2,3-difluoro-6-bromophenol with a main content of about 3%, through a second solvent halide (preferably trichloromethane or dichloromethane) Chloromethane) recrystallized to obtain more than 99% of 2,3-difluoro-4-bromophenol.

[0014] b) etherification of 2,3-difluoro-4-bromophenol with ethyl bromide with acetone or alcohol solvent (preferably methanol or ethanol) in the presence of potassium carbonate; or diethyl sulfate in potassium hydroxide ( Etherification with 2,3-difluoro-4-bromophenol in the presence...

Embodiment 1

[0016] A kind of preparation method of 2,3-difluoro-4-bromophenetole, has following processing steps:

[0017] a) Bromination: In a 500ml four-necked flask with a stirrer, add 180ml of dichloroethane and 91g of 2,3-difluorophenol, 10ml of butyric acid, stir, cool with salt ice water, slowly use a dropping funnel Drop in 127g Br 2 , Keep the kettle below -13°C. After dropping, react at -10°C for 1 hour. Insert the liquid phase tube at room temperature, use N 2 Get rid of the remaining Br 2 and HBr gas.

[0018] Evaporate the solvent under normal pressure, cool and filter to obtain a crude product with a main content of 95.3%. Then use 100 g of dichloromethane, about 130 g of the crude product, recrystallize, let stand overnight, and filter with suction to obtain 99.45% of 2,3-difluoro-4-bromophenol. The yield is about 88%.

[0019] b) Etherification: In a 1000ml four-neck flask, add 300ml of acetone, 53g of anhydrous potassium carbonate, 21g of bromoethane, 35.5g of 3-di...

Embodiment 2

[0022] A kind of preparation method of 2,3-difluoro-4-bromophenetole, has following processing steps:

[0023] a) Bromination: In a 500ml four-neck flask with a stirrer, add 180ml of dichloromethane, 91g of 2,3-difluorophenol, 10ml of valeric acid, stir, cool with salt ice water, and slowly drop with a dropping funnel Into 127g Br 2 , Keep the kettle below -13°C. After dropping, react at -10°C for 1 hour. Insert the liquid phase tube at room temperature, use N 2 Get rid of the remaining Br 2 and HBr gas.

[0024] Evaporate the solvent under normal pressure, cool and filter to obtain a crude product with a main content of 95.7%. Then use 100 g of dichloromethane, about 130 g of the crude product, recrystallize, let stand overnight, and filter with suction to obtain 99.45% of 2,3-difluoro-4-bromophenol. The yield is about 89%.

[0025] b) Etherification: In a 1000ml four-neck flask, add 300ml of methanol, 53g of anhydrous potassium carbonate, 21g of bromoethane, 35.5g of ...

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Abstract

This invention relates to a method for preparing a fluorine-containing organic intermediate, more specifically, 2, 3-difluoro-4-bromophenetole. The method comprises: bromating 2, 3-difluorophenol by Br2 in the presence of solvent and organic acid to obtain 2,3-difluoro-4-bromophenol with content higher than 95%, recrystallizing to obtain 2,3-difluoro-4-bromophenol with a content higher than 99%, and etherifying with bromoethane or diethyl sulfate to obtain 2,3-difluoro-4-bromophenetole. The method has such advantages as abundant raw materials, reasonable process, easy operation, low cost, and high yield. The prepared 2,3-difluoro-4-bromophenetole can be used in the formula of liquid crystal material with high negative dielectric anisotropy, appropriate double refraction, wide nematic range, and low viscoelasticity.

Description

technical field [0001] The invention relates to the technical field of preparation of fluorine-containing organic intermediates, in particular to a preparation method of 2,3-difluoro-4-bromophenetole. Background technique [0002] Liquid crystal is an organic compound with a certain order between solid and liquid. Liquid crystal is used in many fields, especially in the field of flat panel display. Liquid crystal has been widely used. With the rapid development of information industry, liquid crystal display devices The demand for liquid crystal displays is increasing year by year, and the requirements for liquid crystal display technology and liquid crystal materials are also constantly increasing. According to display technology and application requirements, compounds or compositions used as liquid crystal materials are required to have high resistivity, low viscosity in the low temperature range, large negative dielectric anisotropy, wide operating temperature range, and ...

Claims

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Application Information

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IPC IPC(8): C07C41/01C07C43/225
Inventor 柳建华
Owner YETAI FINE CHEM INST CHANGZHOU CITY
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