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Method for preparing 1-methyl-4-nitropyrazole

A technology for nitropyrazole and methylpyrazole, which is applied in the field of preparation of 1-methyl-4-nitropyrazole, can solve the problems of pollution, excessive waste acid environment, a large amount of nitrogen oxide gas and the like, and achieves Abundant sources of raw materials, less environmental pollution, and low requirements for reaction equipment

Inactive Publication Date: 2018-01-26
ZHONGBEI UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the nitrating agent used in this method, fuming nitric acid-concentrated sulfuric acid, will produce a large amount of nitrogen oxide gas and too much waste acid, which will cause environmental pollution.

Method used

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  • Method for preparing 1-methyl-4-nitropyrazole
  • Method for preparing 1-methyl-4-nitropyrazole
  • Method for preparing 1-methyl-4-nitropyrazole

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preparation example Construction

[0030] The invention provides a kind of preparation method of 1-methyl-4-nitropyrazole, comprises the following steps:

[0031] Mix 1-methylpyrazole, N-nitropyrazole and sulfuric acid solution for nitration reaction to obtain 1-methyl-4-nitropyrazole.

[0032] In the present invention, the molar ratio of the 1-methylpyrazole, N-nitropyrazole and sulfuric acid in the sulfuric acid solution is preferably 1:1~3:7.5~12.5, more preferably 1:1.5~2.5 : 9~11; The mass concentration of described sulfuric acid solution is preferably 40%~98%, more preferably 75%~90%, most preferably 85~90%. In the present invention, sulfuric acid can protonate the unsubstituted nitrogen atom of N-nitropyrazole, so that the nitro group on its adjacent nitrogen atom is activated to produce nitroxyl ion (NO 2 + ), nitric oxide ion (NO 2 + ) further undergoes C-nitration reaction with N-methylpyrazole.

[0033] In the present invention, the temperature of the nitration reaction is preferably 20-80° C., ...

Embodiment 1

[0055] Take 1.4g (0.012mol) of N-nitropyrazole and 1g (0.012mol) of 1-methylpyrazole respectively for later use, add 8mL of 98% concentrated sulfuric acid into a 100mL four-necked bottle equipped with mechanical stirring, a thermometer, and an addition funnel 1-Methylpyrazole was added dropwise to concentrated sulfuric acid at 20°C with an addition funnel, and the water bath was heated to 60°C after the addition was completed. At this temperature, N-nitropyrazole was added in 10 times, and the amount added each time was 0.0012mol, the feeding is completed, keep stirring and reacting at constant temperature for 6 hours, after the reaction is completed, pour the reaction solution into a beaker with ice cubes while it is hot and stir, white fine crystalline solids are precipitated, the ice cubes are completely melted, suction filtration, and white Solid I and filtrate; the filtrate was extracted with ether, the solvents were combined, and the solvent was removed by rotary evaporat...

Embodiment 2

[0070] Take 4.1g (0.036mol) of N-nitropyrazole and 1g (0.012mol) of 1-methylpyrazole respectively for later use, and add 6mL of 98% concentrated sulfuric acid into a 100mL four-port container equipped with mechanical stirring, a thermometer, and an addition funnel In the bottle, add 1-methylpyrazole dropwise to the concentrated sulfuric acid with a constant pressure dropping funnel at 20°C. After the addition, the water bath is heated to 80°C. At this temperature, N-nitropyrazole is added in 12 times. Add 0.003mol at a time. After the addition is complete, react at a constant temperature of 20°C for 4 hours. Pour the reaction solution into a beaker filled with ice cubes while it is hot and stir. White fine crystalline solids precipitate out. After the ice cubes are completely melted, filter them with suction. A white solid I was obtained; the filtrate was extracted with ether, the solvents were combined, and the solvent was removed by rotary evaporation under reduced pressure t...

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Abstract

The invention provides a method for preparing 1-methyl-4-nitropyrazole. According to the invention, 1-methylpyrazole, N-nitropyrazole and a sulfuric acid solution are mixed and subjected to nitrationto obtain the 1-methyl-4-nitropyrazole. The method takes N-nitropyrazole and sulfuric acid as nitrated reagents, 1-methylpyrazole is directly nitrated to obtain the 1-methyl-4-nitropyrazole, the raw material source is abundant, the cost is low, usage of mixed acid of nitric acid and sulfuric acid as the nitrated agent is avoided, no polluted gas nitrogen oxide is generated during a reaction process, waste acid is not generated, environment pollution is little, furtherly, the reaction condition of the preparation method is mild, long time reaction at high temperature is not required, requirement on reaction equipment is low, purification is easy, and purity of the obtained product is high.

Description

technical field [0001] The invention relates to the field of synthesis of organic compounds, in particular to a preparation method of 1-methyl-4-nitropyrazole. Background technique [0002] 1-Methyl-4-nitropyrazole is a typical nitrogen heterocyclic compound, the structure contains high enthalpy C=C double bond and N-N single bond, it has high formation enthalpy, high density and environmental friendly characteristics, has very considerable energy, and has good prospects in the fields of high-energy explosives, safety insensitivity, and low-sensitivity additives. It is a new type of energetic material 1-methyl-3,4,5-trinitropyrazole intermediate. [0003] The nitration of pyrazole or methylpyrazole generally uses fuming nitric acid-acetic anhydride or fuming nitric acid-concentrated sulfuric acid as the nitrating reagent, and the N-nitration of the pyrazole ring uses fuming nitric acid-acetic anhydride as the nitrating reagent. C-nitration uses fuming nitric acid-concentra...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/16
Inventor 李永祥陈军王建龙杨峰方克雄潘红霞李军龚磊常雯宇胡志勇
Owner ZHONGBEI UNIV
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