Process for synthesizing 2,3-difluoroaniline

A kind of technology of difluoroaniline and synthesis method, applied in 2 fields, can solve problems such as difficult source of raw materials, high price, unsuitable for industrialized production and the like

Active Publication Date: 2011-08-03
ZHEJIANG YONGTAI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The known methods for producing 2,3-difluoroaniline include: a, 1,2,3-trifluoroaniline amination, but this method has the disadvantages of difficult source of raw materials, high price, and low amination yield, and is not suitable for industrial production

Method used

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  • Process for synthesizing 2,3-difluoroaniline
  • Process for synthesizing 2,3-difluoroaniline
  • Process for synthesizing 2,3-difluoroaniline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0005] 1), the preparation of 3-chloro-2-fluoronitrobenzene

[0006] Add 192g (1.0mol) of 2,3-dichloronitrobenzene, 69.6g (1.2mol) of anhydrous KF and 200g of dimethyl sulfoxide (DMSO) into a 500ml four-necked reaction flask for fluorination reaction. Reaction at 170-175°C for 8 hours, cooling to 50°C, filtering, washing the filter cake with 150ml of toluene, combining the filtrates, recovering the solvent by distillation, and then rectifying under reduced pressure to obtain 142.2g of 3-chloro-2-fluoronitrobenzene , yield 81%, content > 99.5%.

[0007] Reaction equation:

[0008]

[0009] 2), the preparation of 3-chloro-2-fluoroaniline

[0010] In a 1000ml pressure-resistant reaction kettle, add 230g (1.31mol) of 3-chloro-2-fluoronitrobenzene, 460ml of methanol, and 7g of Raney nickel catalyst, replace the air in the kettle with nitrogen and replace it with hydrogen for 3 times, and then fill H2 to 1.5MPa, carry out reduction reaction at 35-45°C until no hydrogen is abso...

Embodiment 2

[0024] This embodiment provides a group of embodiments of the fluorination reaction of the present invention. In this embodiment, except for the reaction temperature, other conditions are the same as step "1)" in Example 1. The following table is a statistical table of experimental data:

[0025] DMSO (g)

[0026] 200

[0027] 200

[0028] Conclusion: In the selection of the reaction temperature of the fluorination reaction of the present invention, 170-175° C. has the best effect.

Embodiment 3

[0029] Example 3, the selection of strong polar aprotic solvent in the fluorination reaction of the present invention.

[0030] The fluorination reaction of the present invention is preferably carried out in a strong polar aprotic solvent, and the described strong polar aprotic solvent is preferably with the following substances: N, N-dimethylformamide (DMF), dimethyl Sulfoxide (DMSO), sulfolane or 1,3-dimethyl-2-imidazolidinone (DMI).

[0031] In this example, N, N-dimethylformamide (DMF), sulfolane or 1,3-dimethyl-2-imidazolidinone (DMI) are used to replace the Dimethyl sulfoxide (DMSO), carry out fluorination reaction at 170~175 DEG C respectively, other reaction conditions are identical with the step "1)" among the embodiment 1,

[0032] The following table is the statistical table of the experimental data:

[0033] solvent

[0034] Conclusion: In the synthetic method of the present invention, the effect of choosing dimethyl sulfoxide (DMSO) as the solvent for ...

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Abstract

The invention provides a method for synthesizing 2,3-difluroaniline, which adopts 2,3-dichloronitrobenzene to be reaction initiators, 2,3-difluorochlorobenzene is obtained after a fluorination reaction, a reduction reaction, and a heman reaction in order, then the 2,3-difluroaniline is obtained after an amination reaction; the synthesizing method can use the cheap 2,3-dichloronitrobenzene as initial materials to obtain high-yield 2,3-difluroaniline through the technique with low cost.

Description

technical field [0001] The present invention relates to the synthetic method of 2,3-difluoroaniline. Background technique [0002] 2,3-Difluoroaniline has many uses and can be used as an intermediate in the production of pharmaceuticals and liquid crystal products. The known methods for producing 2,3-difluoroaniline include: a, 1,2,3-trifluoroaniline amination, but this method has the disadvantages of difficult source of raw materials, high price, and low amination yield, and is not suitable for industrial production . Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a low-cost synthesis method of 2,3-difluoroaniline. For this reason, the present invention adopts following technical scheme: it is reaction initiator with 2,3-dichloronitrobenzene, obtains 2 through fluorination reaction, reduction reaction, Schiemann reaction successively, and then After amination reaction, 2,3-difluoroaniline can be obtained. D...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C211/52C07C209/10
Inventor 何人宝钟建新王莺妹章正秋
Owner ZHEJIANG YONGTAI TECH CO LTD
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