A tetranitroisoxazole energetic compound and a synthesis method and application thereof

Abstract

The application discloses a tetranitroisoxazole energetic compound, and a structural formula of the tetranitroisoxazole energetic compound is shown in the following formula . 3 The tetranitroisoxazole energetic compound has a density of 1.75 g / cm 3 , a melting point of 51.3 DEG C, a thermal decomposition temperature of 201.3 DEG C, a calculated detonation velocity of 8534 m / s and a detonation pressure of 31.7 GPa. The application further provides a synthesis method of the compound. The tetranitroisoxazole energetic compound disclosed by the application has the characteristics of high energy and simple synthesis method, and has good application potential in melt-cast explosives and energetic plasticizers.

Description

Technical Field

[0001] This invention belongs to the field of novel energetic materials technology, specifically relating to a tetranitroisoxazole energetic compound, its synthesis method, and its application. Background Technology

[0002] Low-melting-point energetic compounds are mainly used as carrier explosives and energetic plasticizers in the field of energetic materials, showing broad application prospects. Improving energy levels is a perpetual theme in the development of energetic materials technology; to enhance the combat effectiveness of weapons and ammunition, future energetic materials must possess even higher energies. Therefore, the creation of novel high-energy, low-melting-point energetic compounds is of great significance.

[0003] In recent years, nitrogen-based heterocyclic energetic compounds have become a research hotspot in the field of low-melting-point energetic compounds. Among them, 3,4-dinitrofurazanyloxyfurazan (DNTF), 1-methyl-3,4,5-trinitropyrazole (MTNP), and 1-methyl-2,4,5-trinitroimidazole (MTNI) all exhibit superior properties. However, these substances also have some drawbacks, such as high sensitivity, poor thermal stability, and long synthetic routes.

[0004] The isoxazole ring exhibits typical aromatic hydrocarbon characteristics, possessing three active sites that facilitate the introduction of various functional groups to modify its overall properties. Furthermore, the asymmetric nature of the isoxazole ring is advantageous for constructing low-melting-point compounds. Currently, there are relatively few reported low-melting-point energetic isoxazole-based compounds. Typical examples include 3,3'-bisisoxaazole-5,5'-bismethylene dinitrate (Chempluschem., 2017, 195) and isoxazole-3,5-dimethylbis(methylene) dinitrate (Eur. J. Org. Chem., 2018, 6724), both reported by American scientists in 2017. However, these energetic isoxazole compounds suffer from poor detonation performance due to the scarcity of oxygen-rich detonating groups, and their complex synthetic steps hinder industrial-scale production.

[0005] In summary, there is an urgent need in this field to develop an energetic compound with a low melting point, good detonation performance, and few reaction steps, and the development and production of such novel compounds has become a pressing technical problem to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a tetranitroisoxazole energetic compound, its synthesis method, and its applications, thereby solving the problems of multiple synthesis steps, unfavorable for industrial production, and poor detonation performance of existing reported isoxazole energetic compounds.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0008] One objective of this invention is to provide a tetranitroisoxazole energetic compound with a density of 1.75 g / cm³. 3 The melting point is 51.3℃, the thermal decomposition temperature is 201.3℃, the calculated detonation velocity is 8534 m / s, and the detonation pressure is 31.7 GPa. The tetranitroisoxazole energetic compound provided by this invention is mainly used in the field of energetic materials, and its structural formula is shown in formula <Ⅰ> below:

[0009]

[0010] Another object of the present invention is to provide a method for synthesizing the above-mentioned tetranitroisoxazole energetic compound, the method comprising the following steps:

[0011] (1) Mix concentrated sulfuric acid and nitrifying agent evenly, and then add 2-(3-methylisoxazol-5-yl)-acetic acid to react;

[0012] (2) Transfer the reaction solution obtained in step (1) to room temperature and continue the reaction;

[0013] (3) Quench the reaction solution obtained in step (2) in ice;

[0014] (4) The quenched reaction solution is filtered, and the solid phase is washed and dried to obtain solid product A. The filtrate is extracted and recrystallized to obtain solid product B. Solid product A and solid product B are combined to obtain the tetranitroisoxazole energetic compound.

[0015] As a preferred embodiment of the present invention, when performing step (1), the weight ratio of concentrated sulfuric acid to nitrifying agent is 2 to 6:1.

[0016] As a preferred embodiment of the present invention, when performing step (1), the nitrifying agent includes any one of fuming nitric acid, potassium nitrate, sodium nitrate, and ammonium nitrate.

[0017] As a preferred embodiment of the present invention, in step (1), the molar ratio of nitrifying agent to 2-(3-methylisoxazol-5-yl)-acetic acid is 5.0 to 9.0:1.

[0018] As a preferred embodiment of the present invention, step (1) is carried out in a low temperature bath, the reaction temperature is not higher than -5°C, and the reaction time is 2 to 5 hours;

[0019] As a preferred embodiment of the present invention, step (2) is carried out at room temperature for 10 to 12 hours;

[0020] As a preferred embodiment of the present invention, when performing step (3), the reaction temperature is 0 to 25°C and the reaction time is 0.5 to 1 hour.

[0021] As a preferred embodiment of the present invention, when performing step (4), the extractant used for extraction is any one of diethyl ether, ethyl acetate, dichloromethane, and 1,2-dichloroethane, preferably ethyl acetate.

[0022] As a preferred embodiment of the present invention, when performing step (4), the solvent used for recrystallization is any one of methanol, ethanol, isopropanol, and n-propanol, preferably ethanol.

[0023] A third objective of this invention is to provide the application of the above-mentioned tetranitroisoxazole energetic compound in cast explosives and energetic plasticizers.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention provides a tetranitroisoxazole energetic compound and its synthesis method, wherein the density of the tetranitroisoxazole energetic compound is 1.75 g·cm³. -3 The melting point is 51.3℃, the thermal decomposition temperature is 201.3℃, the calculated detonation velocity is 8534 m / s, and the detonation pressure is 31.7 GPa. Compared with existing reported isoxazole energetic compounds, the tetranitroisoxazole energetic compound provided by this invention has the advantages of excellent detonation performance, fewer synthesis steps, and is conducive to industrial-scale production. Attached Figure Description

[0026] Figure 1 The single-crystal molecular structure diagram of the tetranitroisoxazole energetic compound provided by the present invention. Detailed Implementation

[0027] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are still within the scope of protection of the present invention.

[0028] Example 1

[0029] 12 mL of concentrated sulfuric acid was added to a three-necked flask, followed by the dropwise addition of 8 mL of fuming nitric acid, maintaining the temperature below -5 °C. After the addition was complete, the mixture was stirred for ten minutes to ensure homogeneity. Then, 2.005 g (14.17 mmol) of 2-(3-methylisoxazol-5-yl)-acetic acid was added, maintaining the temperature below 0 °C. After the addition was complete, the reaction was continued under ice bath conditions for 2 hours, and then the reaction was transferred to room temperature and continued for 10 hours. After the reaction was complete, the reaction solution was poured into a beaker containing ice. After half an hour, the solid product was filtered under reduced pressure, washed three times with 30 mL of distilled water, and dried to obtain a white solid. The filtrate was extracted with ethyl acetate, and the solvent was removed by rotary evaporation. The resulting solid was recrystallized from ethanol. The two solid products were combined to obtain a white solid with a yield of 84% and a purity of 99.5% (HPLC).

[0030] 1. The product structure was identified as follows:

[0031] Infrared spectroscopy: FT-IR (cm) -1 ),υ:2884,1595,1540,1378,1358,1279,1174,961,842,823,795,761,601.

[0032] Mass spectrometry: MS: ESI negative: m / z = 276 [MH]

[0033] Nuclear magnetic resonance spectroscopy: 1 H NMR (DMSO-d6, 600MHz), δ: 2.66 (s, 3H); 13 CNMR (DMSO-d6, 150MHz), δ: 168.86, 159.42, 149.38, 125.35, 13.39. The above structural identification data confirm that the obtained substance is a tetranitroisoxazole energetic compound.

[0034] 2. The properties of the product, tetranitroisoxazole, are as follows:

[0035] Appearance: White powdery solid;

[0036] Melting point: 51.3℃;

[0037] Peak decomposition temperature: 201.3℃;

[0038] Actual impact sensitivity: 5J;

[0039] Calculated detonation velocity: 8534 m / s -1 ;

[0040] Calculated burst pressure: 31.7 GPa.

[0041] Example 2

[0042] 16 mL of concentrated sulfuric acid was added to a three-necked flask, followed by the dropwise addition of 8 mL of fuming nitric acid, maintaining the temperature below -5 °C. After the addition was complete, the mixture was stirred for ten minutes to ensure homogeneity. Then, 2.005 g (14.17 mmol) of 2-(3-methylisoxazol-5-yl)-acetic acid was added, maintaining the temperature below 0 °C. After the addition was complete, the reaction was continued under ice bath conditions for 2 hours, and then the reaction was transferred to room temperature and continued for 10 hours. After the reaction was complete, the reaction solution was poured into a beaker containing ice. After half an hour, the solid product was filtered under reduced pressure, washed three times with 30 mL of distilled water, and dried to obtain a white solid. The filtrate was extracted with diethyl ether, and the solvent was removed by rotary evaporation. The resulting solid was recrystallized from ethanol. The two solid products were combined to obtain a white solid with a yield of 86% and a purity of 99.6% (HPLC).

[0043] The reaction phenomena observed during the preparation process in this embodiment are the same as those in Example 1.

[0044] The structural identification results of the product obtained in this embodiment are the same as those in Example 1.

[0045] Example 3

[0046] 12 mL of concentrated sulfuric acid was added to a three-necked flask, followed by 7.23 g (85.02 mmol) of sodium nitrate, maintaining the temperature below -5 °C. After the addition was complete, the mixture was stirred for ten minutes to ensure homogeneity. Then, 2.005 g (14.17 mmol) of 2-(3-methylisoxazol-5-yl)-acetic acid was added, maintaining the temperature below 0 °C. After the addition was complete, the reaction was continued in an ice bath for 2 hours, then transferred to room temperature and continued for another 10 hours. After the reaction was complete, the reaction mixture was poured into a beaker containing ice. After half an hour, the solid product was filtered under reduced pressure, washed three times with 30 mL of distilled water, and dried to obtain a white solid. The filtrate was extracted with ethyl acetate, and the solvent was removed by rotary evaporation. The resulting solid was recrystallized from isopropanol. The two solid products were combined to obtain a white solid with a yield of 85% and a purity of 99.6% (HPLC).

[0047] The reaction phenomena observed during the preparation process in this embodiment are the same as those in Example 1.

[0048] The structural identification results of the product obtained in this embodiment are the same as those in Example 1.

[0049] Example 4

[0050] 12 mL of concentrated sulfuric acid was added to a three-necked flask, followed by 8.50 g (106.28 mmol) of ammonium nitrate, maintaining the temperature below -5 °C. After the addition was complete, the mixture was stirred for ten minutes to ensure homogeneity. Then, 2.01 g (14.17 mmol) of 2-(3-methylisoxazol-5-yl)-acetic acid was added, maintaining the temperature below 0 °C. After the addition was complete, the reaction was continued under ice bath conditions for 2 hours, and then the reaction was transferred to room temperature and continued for 10 hours. After the reaction was complete, the reaction solution was poured into a beaker containing ice. After half an hour, the solid product was filtered under reduced pressure, washed three times with 30 mL of distilled water, and dried to obtain a white solid. The filtrate was extracted with dichloromethane, and the solvent was removed by rotary evaporation. The resulting solid was recrystallized from n-propanol. The two solid products were combined to obtain a white solid with a yield of 87% and a purity of 99.4% (HPLC).

[0051] The reaction phenomena observed during the preparation process in this embodiment are the same as those in Example 1.

[0052] The structural identification results of the product obtained in this embodiment are the same as those in Example 1.

[0053] Example 5

[0054] 12 mL of concentrated sulfuric acid was added to a three-necked flask, followed by 7.16 g (70.85 mmol) of potassium nitrate, maintaining the temperature below -5 °C. After the addition was complete, the mixture was stirred for ten minutes to ensure homogeneity. Then, 2.01 g (14.17 mmol) of 2-(3-methylisoxazol-5-yl)-acetic acid was added, maintaining the temperature below 0 °C. After the addition was complete, the reaction was continued under ice bath conditions for 2 hours, and then the reaction was transferred to room temperature and continued for 10 hours. After the reaction was complete, the reaction solution was poured into a beaker containing ice. After half an hour, the solid product was filtered under reduced pressure, washed three times with 30 mL of distilled water, and dried to obtain a white solid. The filtrate was extracted with ethyl acetate, and the solvent was removed by rotary evaporation. The resulting solid was recrystallized from ethanol. The two solid products were combined to obtain a white solid with a yield of 87% and a purity of 99.7% (HPLC).

[0055] The reaction phenomena observed during the preparation process in this embodiment are the same as those in Example 1.

[0056] The structural identification results of the product obtained in this embodiment are the same as those in Example 1.

Claims

1. A tetranitroisoxazole energetic compound, characterized in that, The chemical structural formula of the tetranitroisoxazole energetic compound is shown in Formula <Ⅰ> below:

2. The method for synthesizing the tetranitroisoxazole energetic compound according to claim 1, characterized in that, The method includes the following steps: (1) Mix concentrated sulfuric acid and nitrifying agent evenly, and then add 2-(3-methylisoxazol-5-yl)-acetic acid to react; (2) The reaction solution obtained in step (1) is further reacted at room temperature; (3) Quench the reaction solution obtained in step (2) in ice; (4) The quenched reaction solution is filtered, and the solid phase is washed and dried to obtain solid product A; the filtrate is extracted and recrystallized to obtain solid product B. Solid product A and solid product B are combined to obtain the tetranitroisoxazole energetic compound.

3. The synthesis method according to claim 2, characterized in that, The weight ratio of concentrated sulfuric acid to nitrifying agent in step (1) is 2 to 6:

1.

4. The synthesis method according to claim 2, characterized in that, The nitrifying agent mentioned in step (1) includes any one of fuming nitric acid, potassium nitrate, sodium nitrate, and ammonium nitrate.

5. The synthesis method according to claim 2, characterized in that, In step (1), the molar ratio of nitrifying agent to 2-(3-methylisoxazol-5-yl)-acetic acid is 5.0 to 9.0:

1.

6. The synthesis method according to claim 2, characterized in that, The reaction in step (1) is carried out in a low-temperature bath, with the reaction temperature not exceeding 5°C and the reaction time being 2 to 5 hours.

7. The synthesis method according to claim 2, characterized in that, The reaction time for step (2) is 10 to 12 hours.

8. The synthesis method according to claim 2, characterized in that, The reaction temperature in step (3) is 0 to 25°C, and the reaction time is 0.5 to 1 hour.

9. The synthesis method according to claim 2, characterized in that, The extractant used in step (4) is any one of diethyl ether, ethyl acetate, dichloromethane, and 1,2-dichloroethane; the solvent used for recrystallization is any one of methanol, ethanol, isopropanol, and n-propanol.

10. The use of the tetranitroisoxazole energetic compound of claim 1 or the tetranitroisoxazole energetic compound prepared by the synthetic method of any one of claims 2-9 in cast explosives or energetic plasticizers.

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