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2-nitro-4-trifluoromethyl-benzoic acid and preparation method of isomer thereof

A technology of trifluoromethylbenzoic acid and trifluoromethylbenzonitrile is applied in the field of preparation of 2-nitro-4-trifluoromethylbenzoic acid and isomers thereof, and can solve the problems of low yield, 2 -Nitro-4-trifluoromethylbenzoic acid and its isomers have problems such as expensive raw materials, and achieve the effects of high yield, cheap raw materials and easy operation

Active Publication Date: 2018-09-21
LIER CHEM CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] What the present invention will solve is the problem that prior art produces 2-nitro-4-trifluoromethylbenzoic acid and its isomer raw material expensive, and yield is on the low side

Method used

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  • 2-nitro-4-trifluoromethyl-benzoic acid and preparation method of isomer thereof

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preparation example Construction

[0020] Concrete, the preparation method of 2-nitro-4-trifluoromethylbenzoic acid and its isomers, the method comprises: with 4-trifluoromethylbenzonitrile raw material, under the action of nitrating agent, one-step reaction obtains 2-nitro-4-trifluoromethylbenzoic acid and 3-nitro-4-trifluoromethylbenzoic acid.

[0021] Reaction formula of the present invention is as follows:

[0022]

[0023] The present invention is with 4-trifluoromethyl benzonitrile as raw material, because there is reaction selectivity problem, cyano group is hydrolyzed to be carboxyl group in acidic condition and is usually comparatively difficult, promptly obtains the mixture of amide and carboxylic acid under normal circumstances, and To improve the selectivity of carboxylic acid formation, harsh hydrolysis conditions, such as high concentration of strong acid or high temperature, are required. Experiments have found that if 4-trifluoromethylbenzonitrile and concentrated sulfuric acid are reacted u...

Embodiment 1

[0037] Add 5g of 4-trifluoromethylbenzonitrile and 30mL of dichloromethane to the three-necked flask, then dropwise add 10mL of nitrating agent, raise the temperature to 40°C, stir magnetically for 7h, and end the reaction; add 30mL of water, separate the liquids, and take the organic layer, The aqueous layer was extracted once with 30 mL of ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, and rotary evaporated to obtain 5.2 g of viscous liquid, which was detected at 215 nm in the liquid phase, and the content of 2-nitro-4-trifluoromethylbenzoic acid was 14 %, 3-nitro-4-trifluoromethylbenzoic acid content 10%.

Embodiment 2

[0039] Add 5g of 4-trifluoromethylbenzonitrile and 30mL of 1,2-dichloroethane to the three-necked flask, then dropwise add 10mL of nitrating agent, raise the temperature to 40°C, stir for 7h with magnetic force, and end the reaction; add 30mL of water, separate the liquid , the organic layer was taken, the aqueous layer was extracted once with 30 mL of ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, and rotary evaporated to obtain 5.3 g of viscous liquid, which was detected at 215 nm in the liquid phase, 2-nitro-4-trifluoroform The content of benzoic acid is 15%, and the content of 3-nitro-4-trifluoromethylbenzoic acid is 11%.

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Abstract

The invention discloses a 2-nitro-4-trifluoromethyl-benzoic acid and a preparation method of an isomer thereof, belongs to the technical field of organic synthesis, and solves the problems that in theprior art, raw materials for preparing a 2-nitro-4-trifluoromethyl-benzoic acid and the isomer thereof are expensive and the yield is slightly low. In order to solve the problems, the invention provides the 2-nitro-4-trifluoromethyl-benzoic acid and the preparation method of the isomer thereof. The preparation method comprises the following steps: with 4-(trifluoromethyl)benzonitrile as a raw material, performing a one-step reaction under the effect of a nitrating agent to obtain the 2-nitro-4-trifluoromethyl-benzoic acid and a 3-nitro-4-trifluoromethyl-benzoic acid. The preparation method has the advantages that the 2-nitro-4-trifluoromethyl-benzoic acid and the isomer thereof can be obtained only through the one-step reaction, the operation is simple and convenient, the reaction steps are short, the yield is high, and the 2-nitro-4-trifluoromethyl-benzoic acid and the isomer thereof are suitable for industrialized production.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and relates to a preparation method of 2-nitro-4-trifluoromethylbenzoic acid and its isomers. Background technique [0002] 2-nitro-4-trifluoromethylbenzoic acid is an important pharmaceutical and pesticide intermediate, and its isomer 4-trifluoromethyl-3-nitrobenzoic acid also has potential similar value. [0003] US4845279 discloses a method for preparing 4-trifluoromethyl-2-nitrobenzoic acid and its isomer 4-trifluoromethyl-3-nitrobenzoic acid. The method takes 4-trifluoromethyl-benzoyl halide or 4-trifluoromethyl-trihalotoluene as raw material, nitrates the starting material by nitrating agent, and simultaneously hydrolyzes formyl halide or trihalomethyl to carboxyl , to prepare 4-trifluoromethyl-2-nitrobenzoic acid and its isomer 4-trifluoromethyl-3-nitrobenzoic acid. This method raw material is expensive, and can only make the total yield of 4-trifluoromethyl-2-nitrobenzoic acid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C205/58C07C201/08
CPCC07C201/08C07C205/58
Inventor 梁维平曾伟徐勇姚中伟左翔程柯
Owner LIER CHEM CO LTD