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
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[0012] A preparation method of 2,3-difluoro-4-bromophenethyl ether has the following process steps:
[0013] a) Bromination: Using 2,3-difluorophenol as raw material, halogenated alkane in the first solvent, (preferably dichloroethane or dichloromethane), add organic acid additives (preferably butyric acid, valeric acid or acetic acid), At low temperature, preferably -10~-15℃, use Br 2 Bromination to obtain 2,3-difluoro-4-bromophenol with a main content of more than 95% and 2,3-difluoro-6-bromophenol with a main content of about 3%, and pass through the second solvent halogenated alkane (preferably chloroform or dichloromethane). Chloromethyl) was recrystallized to obtain more than 99% of 2,3-difluoro-4-bromophenol.
[0014] b) Use acetone or alcohol solvents (preferably methanol or ethanol) in the presence of potassium carbonate to etherify 2,3-difluoro-4-bromophenol and bromoethane; or diethyl sulfate in potassium hydroxide ( It is etherified with 2,3-difluoro-4-bromophenol in t...
Example Embodiment
[0015] Example 1.
[0016] A preparation method of 2,3-difluoro-4-bromophenethyl ether has the following process steps:
[0017] a) Bromination: In a 500ml four-necked flask with a stirrer, add 180ml of dichloroethane, 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 temperature below -13℃ in the kettle. After dripping, react at -10°C for 1 hour. Insert the liquid phase tube at room temperature, use N 2 Catch up the remaining Br 2 And HBr gas.
[0018] The solvent was evaporated under normal pressure, cooled and filtered to obtain a crude product with a main content of 95.3%. Then use 100 g of dichloromethane and about 130 g of crude product, recrystallize it, let it 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-necked flask, add 300ml of acetone, 53g of anhydrous potassium carbonat...
Example Embodiment
[0021] Example two.
[0022] A preparation method of 2,3-difluoro-4-bromophenethyl ether has the following process steps:
[0023] a) Bromination: In a 500ml four-necked 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 temperature below -13℃ in the kettle. After dripping, react at -10°C for 1 hour. Insert the liquid phase tube at room temperature, use N 2 Catch up the remaining Br 2 And HBr gas.
[0024] The solvent was evaporated under normal pressure, cooled and filtered to obtain a crude product with a main content of 95.7%. Then use 100 g of dichloromethane and about 130 g of crude product, recrystallize it, let it 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 1000 ml four-necked flask, add 300 ml of methanol, 53 g of anhydrous pota...
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