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Process for preparing 1,5-difluoro-2,4-dinitrobenzene

A technology of dinitrobenzene and fuming nitric acid, which is applied in chemical instruments and methods, preparation of nitro compounds, preparation of organic compounds, etc., can solve problems such as low product yield and purity, difficult industrialization, and complicated process. Achieve the effects of low production cost, improved yield and purity, and simple process

Active Publication Date: 2019-04-16
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In summary, the prior art has the following deficiencies in the preparation of 1,5-difluoro-2,4-dinitrobenzene: 1. The process is more complicated and industrialization is more difficult; 2. The raw materials are more expensive; 3. .The yield and purity of the product are low, and recrystallization operation must be used to improve the purity of the target product

Method used

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  • Process for preparing 1,5-difluoro-2,4-dinitrobenzene
  • Process for preparing 1,5-difluoro-2,4-dinitrobenzene

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Under magnetic stirring, add 220mL of 98% concentrated sulfuric acid to the 1000mL reaction flask, and after cooling completely with an ice-water bath, slowly add 220mL (5.0mol) of 95% fuming nitric acid, which is the concentration of concentrated sulfuric acid and concentrated nitric acid in the nitrating reagent. The volume ratio is 1:1. After the fuming nitric acid has been added, continue stirring for 15min under an ice-water bath (the fuming nitric acid is completely dissolved in sulfuric acid), then slowly add 114g (1.0mol) of m-difluorobenzene dropwise (the temperature of the system during the dropping process is not over 10°C), after the dropwise addition was completed, the system was kept in an ice-water bath and continued to stir for 3h. Then gradually raise the reaction temperature to room temperature and continue to stir. Utilize the TLC plate to monitor the reaction, wherein the developer is ethyl acetate:petroleum ether=1:20, at this time R f =0.6, it wa...

Embodiment 2

[0032] The difference between this example and Example 1 is that the amount of concentrated sulfuric acid added is 440mL, and the volume ratio of the amount of concentrated sulfuric acid to the amount of concentrated nitric acid is 2:1. Other steps are the same as in Embodiment 1, and the yield reaches 94.5% pure, 98.0% pure

Embodiment 3

[0034] The difference between this example and Example 1 is that the amount of concentrated sulfuric acid added is 145mL, and the volume ratio of the amount of concentrated sulfuric acid to the amount of concentrated nitric acid is 2:3. Other steps are the same as in Embodiment 1, and the yield reaches The purity is 91.3%, and the purity is 96.8%.

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Abstract

The invention discloses a method of preparing 1,5-difluoro-2,4-dinitrobenzene. According to the method, 1,5-difluoro-2,4-dinitrobenzene is prepared via nitration in a concentrated sulfuric acid and fuming nitric acid mixed system by taking m-difluorobenzene as a starting raw material. A synthesis process is very simple and convenient; reaction conditions are mild; the raw material is cheap and easy to obtain; fewer byproducts are generated in a preparation process; the productivity is higher; a product with higher purity can be obtained without recrystallization operation; and industrial production can be performed.

Description

technical field [0001] The invention relates to a preparation method of a compound, in particular to a preparation method for obtaining 1,5-difluoro-2,4-dinitrobenzene by nitrating m-difluorobenzene. Background technique [0002] 1,5-difluoro-2,4-dinitrobenzene is an important intermediate in the synthesis of the herbicide flumechlor propargyl, which can undergo etherification, hydrogenation reduction ring closure, and sequential reaction with bromopropylamine and acid anhydride Obtained fluramid propargyl. At the same time, because its structure contains two nitro groups and two fluorine groups, the nitro group is an energetic group, and the fluorine group can be further modified into other energy-containing groups, so 1,5-difluoro-2, 4-Dinitrobenzene is also an intermediate that can be widely used in the field of energetic materials. [0003] At present, due to the complicated synthetic route, low purity and low yield of the product, its application in industry is limite...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C201/08C07C201/16C07C205/12
CPCC07C201/08C07C201/16C07C205/12
Inventor 程广斌黄丽萍张行程杨红伟
Owner NANJING UNIV OF SCI & TECH