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The preparation method of methylnitrosamine

A technology of metronitramine and concentrated nitric acid, which is applied in the preparation of organic compounds, preparation of urea derivatives, chemical instruments and methods, etc. It can solve problems such as harsh hydrolysis conditions, incomplete nitration of dimethyl urea, and complicated reaction steps , to achieve the effect of increasing the yield

Active Publication Date: 2021-02-26
XIAN MODERN CHEM RES INST
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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 deficiencies and defects in the preparation process of metronitroamine in the background technology, such as complex reaction steps, incomplete nitration of N,N'-dimethylurea, harsh hydrolysis conditions, and low yield, and provide A method for preparing metronitramine with complete nitration, simple post-treatment operation, mild hydrolysis conditions and high yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Dissolve 100g of N,N'-dimethylurea in 200mL of dichloromethane to prepare a solution, slowly add it to 278g of concentrated nitric acid with a mass concentration of 98% and 233g of 20% oleum to form a mixed acid for nitration reaction, the reaction temperature -5°C to 0°C. After the addition, the reaction mixture was poured into 400 g of ice water for dilution.

[0018] The diluted liquid was heated to 20°C for hydrolysis reaction, the hydrolysis time was 60min, after the reaction was terminated, the hydrolyzed liquid phase was separated, the dichloromethane phase was dried with anhydrous magnesium sulfate, and concentrated to obtain 154g of metronitroamine, with a yield of 89.2% and a purity of ≥99.4%.

[0019] Structural Identification of Metronitramine:

[0020] Elemental Analysis:CH 4 N 2 o 2 , calculated: C 15.79, H 5.263, N 36.84;

[0021] Found: C 16.16, H 5.312, N 37.28.

[0022] IR(KBr),υ / cm -1 : 2950, ​​2898, 1574, 1336, 775, 738.

[0023] 1 H NMR (CD...

Embodiment 2

[0026] Dissolve 100g of N,N'-dimethylurea in 200mL of dichloromethane to prepare a solution, slowly add it to 201g of concentrated nitric acid with a mass concentration of 98% and 169g of 20% oleum to form a mixed acid for nitration reaction, the reaction temperature -5°C to 0°C. After the addition, the reaction mixture was poured into 400 g of ice water for dilution.

[0027] The dilute liquid was heated to 5°C for hydrolysis reaction, the hydrolysis time was 30min, after the reaction was terminated, the hydrolyzed liquid phase was separated, the dichloromethane phase was dried with anhydrous magnesium sulfate, and concentrated to obtain 119g of metronitroamine with a yield of 68.9% and a purity of ≥98.7%.

Embodiment 3

[0029] Dissolve 100g of N,N'-dimethylurea in 200mL of dichloromethane to prepare a solution, slowly add 260g of concentrated nitric acid with a mass concentration of 98% and 218g of 20% oleum to form a mixed acid for nitration reaction, the reaction temperature -5°C to 0°C. After the addition, the reaction mixture was poured into 400 g of ice water for dilution.

[0030] The diluted liquid was heated to 25°C for hydrolysis reaction, the hydrolysis time was 80min, after the reaction was terminated, the hydrolyzed liquid phase was separated, the dichloromethane phase was dried with anhydrous magnesium sulfate, and concentrated to obtain 150g of metronitroamine with a yield of 86.9% and a purity of ≥99.4%.

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Abstract

The invention discloses a method for preparing metronitroamine. The method uses N,N'-dimethylurea as a raw material, and comprises the following steps: (1) dissolving N,N'-dimethylurea in dichloromethane to prepare into a solution, slowly added to a mass concentration of 98% concentrated nitric acid and 20% fuming sulfuric acid in the mixed acid composed of nitration reaction, the reaction temperature -5 ℃ ~ 0 ℃, after the addition, the reaction mixture is poured into ice water for dilution; ( 2) Warm up the diluted solution obtained in (1) above to 5°C to 30°C for hydrolysis reaction, the hydrolysis time is 30min to 120min, after the reaction is terminated, the hydrolysis liquid phase is separated, and the dichloromethane phase is dried with anhydrous magnesium sulfate, Concentrated to obtain metronidramine. The invention aims to solve the problems of complicated reaction operation steps, incomplete nitration of N,N'-dimethylurea, harsh hydrolysis conditions, low yield and the like in the preparation process of metronitroamine. It is mainly used in the preparation of methylnitrosamine.

Description

technical field [0001] The invention relates to the nitration and hydrolysis of N,N'-dimethylurea, specifically a method for preparing metronitroamine, which belongs to organic synthesis. Background technique [0002] Metronitroamine is an important organic compound, which can be used not only as a simple substance explosive, but also as an intermediate for the synthesis of nitramine energetic materials. [0003] The synthesis method of metronitramine is mainly based on N,N'-dimethylurea as raw material, first synthesize N,N'-dimethyl-N,N'-dinitrourea, and then carry out hydrolysis reaction to obtain the target things. U.S. Patents US4418212A and US4476322A disclose a method for synthesizing metronitroamine. N,N'-dimethylurea is dissolved in dichloromethane to prepare a solution, and nitric acid mixed acid is added for nitration. After the reaction is completed, pour ice water and use Extracted with dichloromethane, washed with alkali and water to obtain a dichloromethane ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C243/02C07C273/18C07C275/66
CPCC07C243/02C07C273/1863C07C275/66
Inventor 陈斌汪营磊丁峰刘卫孝刘亚静马玲
Owner XIAN MODERN CHEM RES INST