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Method for preparing high-purity 2,4'-difluorobenzophenone

A difluorobenzophenone, high-purity technology, applied in the direction of condensation to prepare carbonyl compounds, organic chemistry, etc., can solve the problems of high production cost, difficulty in controlling the content of individual impurities, and low purity

Active Publication Date: 2015-03-11
南京美茵生命科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the problems that 2,4'-difluorobenzophenone has high production cost, low purity and difficult control of single impurity content

Method used

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  • Method for preparing high-purity 2,4'-difluorobenzophenone
  • Method for preparing high-purity 2,4'-difluorobenzophenone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Synthesis of 2,4'-difluorobenzophenone (fluorobenzene as solvent)

[0020] Add 360.0g of fluorobenzene and 120.0g of aluminum trichloride to a 500ml reaction bottle, control the system temperature to about 10°C under ice bath, add 118.9g of o-fluorobenzoyl chloride dropwise, and control the system temperature at 25°C during the dropping process , dropwise, react at room temperature, follow the gas phase until the end of the reaction, then add the reaction solution to 260ml of ice water and 90ml of concentrated hydrochloric acid, separate the organic phase, wash the organic phase with 100ml of water, separate the organic layer, and then use 100ml of Wash the organic layer with 10% sodium hydroxide solution and 200ml water to neutrality, recover fluorobenzene by atmospheric distillation, and rectify to obtain the product with a yield of 92.5% and a content of 98.5%. Individual impurity content ≤ 1.1%.

Embodiment 2

[0022] Synthesis of 2,4'-difluorobenzophenone (n-hexane as solvent)

[0023] In n-hexane solvent, use o-fluorobenzoyl chloride and fluorobenzene as raw materials, and anhydrous aluminum trichloride as a catalyst for reaction. After the reaction, pour the reaction solution into 2mol L -1 hydrochloric acid solution, adjust the pH to 3, then adjust the pH to 12 with 5% sodium hydroxide solution, separate the organic phase, extract the water phase with solvent several times, combine the organic phase, remove the organic solvent by distillation, and rectify Obtain 2,4'-difluorobenzophenone or cooling and crystallization to obtain 2,4'-difluorobenzophenone; wherein the molar ratio of o-fluorobenzoyl chloride, fluorobenzene and anhydrous aluminum trichloride The ratio is 1:1:3. The minimum content of single impurity is 0.45%.

Embodiment 3

[0025] In dichloroethane solvent, use o-fluorobenzoyl chloride and fluorobenzene as raw materials, anhydrous aluminum trichloride as catalyst for reaction, after the reaction, pour the reaction solution into 4mol L -1 hydrochloric acid solution, adjust the pH to 2, then adjust the pH to 13 with 8% sodium hydroxide solution, separate the organic phase, extract the aqueous phase with a solvent several times, combine the organic phases, and obtain the product 2,4' after post-treatment - Difluorobenzophenone; the solvent used for recrystallization is petroleum ether. Among them, the molar ratio of o-fluorobenzoyl chloride, fluorobenzene and anhydrous aluminum trichloride is 1: 3: 1, and the single impurity content is less than 0.46%.

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Abstract

The invention discloses a method for preparing high-purity 2,4'-difluorobenzophenone. The method for preparing the high-purity 2,4'-difluorobenzophenone is characterized in that one or more kinds of compound solvent such as fluorobenzene, dichloromethane, dichloroethane, normal hexane and nitrobenzene are used during a synthesis process, fluorobenzoyl chloride and the fluorobenzene are used as raw materials, and aluminium trichloride is used as the catalyst; after the reaction is finished, hydrolysis and desolventizing are conducted, aftertreatment and recrystallizatoin are conducted and then a high-purity target object is obtained, wherein the mass part ratio of raw materials which are the fluorobenzoyl chloride and the fluorobenzene and the aluminium trichloride is 1:1 to 3:0.5-1.5. The method for preparing the high-purity 2,4'-difluorobenzophenone is simple in synthetic route, environmentally friendly, low in cost, high in productive rate, and suitable for industrialized production.

Description

technical field [0001] The invention belongs to the technical fields of clean production and chemistry and chemical engineering, and relates to the synthesis of a high-purity triazol intermediate, more specifically a method for preparing 2,4'-difluorobenzophenone. Background technique [0002] Triconazole, developed by the British company Zeneca, is a sterol demethylation inhibitor and a broad-spectrum fungicide for plant leaves and ears. It is effective against cereal powdery mildew, cloud disease, leaf spot and rust. At present, the method for synthesizing triazol mainly contains two kinds: one is the Grignard reaction method, the Grignard reagent is not easy to prepare, and the yield is low, and the reaction yield of the Grignard reagent and the ketone is also lower due to steric hindrance. Gradually eliminated; the other is the carbonyl reduction method, through the synthesis of 2,4'-difluorobenzophenone, reduction and other steps to prepare fuconazole, the preparation m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C45/46C07C49/813
Inventor 沈文通朱其军赵世雄殷剑
Owner 南京美茵生命科技有限公司