Novel multi-nitromethyl green energetic compound and preparation method thereof

Abstract

The invention discloses a novel multi-nitromethyl green energetic compound, and belongs to the technical field of energetic material synthesis and preparation. The compound is 5-(3, 4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1, 2, 4-triazole dipotassium salt, and the structural formula of the compound is shown in the specification. The compound can be 9, 10-dinitro-2-(trinitromethyl)-pyrazol [1, 5-d] [1, 2, 4] triazole [5, 1-f] [1, 2, 3, 4] tetrazine. According to the invention, the multi-nitromethyl group is introduced into a pyrazole-triazole skeleton and a tetrazine fused ring skeleton as an energy group, so that the oxygen balance of molecules is improved, and the detonation performance of the energetic material is improved.

Description

Technical Field

[0001] This invention belongs to the field of energetic material synthesis and preparation technology, specifically relating to novel polynitromethyl green energetic compounds and their preparation methods. Background Technology

[0002] Energetic materials, composed of fuels and oxidizers, undergo violent redox reactions under specific conditions, producing high temperatures, high pressures, and large quantities of gas. They are a class of substances capable of rapidly releasing large amounts of energy through combustion or explosion, typically including explosives, propellants, and pyrotechnics. Energetic materials are widely used in military, aerospace, and civilian fields, such as in ammunition, rocket propellants, and blasting engineering, playing an irreplaceable role in national defense and the national economy. Research on high-energy-density energetic materials is currently one of the key areas of exploration in the field.

[0003] With the changing global landscape and peace and development becoming the central themes of the world today, research into weaponry is increasingly focused on high performance, reliability, and environmental friendliness. Primary and secondary explosives are high-energy-density energetic materials used in military, civilian, and industrial blasting applications, characterized by efficient energy release and controllability. However, the performance of traditional detonators can fluctuate due to environmental temperature and humidity, leading to decreased reliability and limiting their application. Furthermore, the use of heavy metals (such as lead and mercury) and other toxic substances in their chemical composition causes significant environmental problems.

[0004] Green initiators, typically based on environmentally friendly materials such as nitrogen-rich compounds, are a class of environmentally friendly, low-toxicity, and low-pollution initiators. Their preparation and use minimize harm to the environment and human health, while possessing good initiation performance and stability. However, ammonium perchlorate is still widely used in solid propellants. Although it has advantages such as low cost, excellent oxygen balance, good thermal stability, and good compatibility with other components of solid propellants, the environmental problems caused by the large amount of hydrogen chloride produced during its combustion cannot be ignored, limiting its applicability. Therefore, exploring new green energetic compounds is an urgent task.

[0005] In recent years, metal-organic framework (MOF) green initiators have emerged as a novel type of environmentally friendly energetic material. These materials are formed by the self-assembly of metal ions and organic ligands into porous crystal structures. This porous structure can support high-energy materials, improving energy release efficiency. Initiation performance can be precisely controlled by adjusting different combinations of metals and ligands. Polynitromethyl groups, as high-performance energetic groups, possess advantages such as high energy density, low occupancy of modification sites, and high oxygen content, making them suitable for synthesizing high-energy-density materials. Furthermore, the pyrazole-triazole backbone and the tetrazine fused-ring backbone, due to their large conjugated area and high heat of formation, have been considered advantageous platforms for the design and synthesis of novel energetic materials. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a novel green energetic polynitromethyl compound and its preparation method. This invention assembles a polynitromethyl group with high oxygen content, a pyrazole-triazole skeleton, and a tetrazine fused ring skeleton, and rationally combines the advantages of each to prepare a novel green nitrogen-rich energetic compound.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a novel polynitromethyl green energetic compound, wherein the compound is 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt, and its structural formula is shown in Formula 1:

[0009]

[0010] Furthermore, the compound may also be 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetrazine, with the structural formula shown in Formula 1:

[0011]

[0012] Furthermore, the method also includes a method for preparing a novel polynitromethyl green energetic compound, wherein the preparation of the 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt includes the following steps:

[0013] S1. Synthesize ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester;

[0014] S2. Synthesis of (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid;

[0015] S3. Synthesis of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole;

[0016] S4. Synthesize 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt.

[0017] Furthermore, the method also includes a method for preparing a novel polynitromethyl green energetic compound, wherein the preparation of 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetrazine comprises the following steps:

[0018] S1. Synthesize ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester;

[0019] S2. Synthesis of (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid;

[0020] S3. Synthesis of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole;

[0021] S4. Synthesize 5-(1-amino-3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazol-1-amino;

[0022] S5. Synthesize 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine.

[0023] Further, the preparation method of step S1 is as follows: at -10℃, triethylamine is added dropwise to an anhydrous acetonitrile suspension containing ethyl 3-ethoxy-3-iminopropionic acid hydrochloride, then the mixture is heated to room temperature and stirred for 30 minutes, and then 3-nitro-1H-pyrazole-5-hydrazide and acetic acid are added to obtain a first mixed solution. The first mixed solution is refluxed at 85℃ for 12 hours and then cooled to room temperature. After evaporating acetonitrile and acetic acid, deionized water is added to the residue and ultrasonically mixed. The solid is then filtered and dried to obtain ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester;

[0024] The preparation method of step S2 is as follows: Ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester is added to a deionized aqueous solution containing sodium hydroxide at room temperature to obtain a second mixed solution. The second mixed solution is refluxed at 100°C for 2 hours and then cooled to room temperature. Then, concentrated hydrochloric acid is added to adjust the pH of the second mixed solution to 1. After precipitation, filtration and drying are performed to obtain (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid.

[0025] The preparation method of step S3 is as follows: At -5℃, fuming nitric acid is added to a concentrated sulfuric acid solution containing (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid. After reacting at the first reaction temperature for 2-48 hours, the solid is filtered and dried to obtain 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole.

[0026] Further, the preparation method in step S4 is as follows: at -5°C, potassium iodide and the first base are added to the first solvent, and then 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(tinitromethyl)-1H-1,2,4-triazole is added and reacted at the second reaction temperature for 0.5-24 hours. The solid is then filtered and dried to obtain 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt.

[0027] Further, the preparation method in step S4 is as follows: at room temperature, 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is mixed with an aqueous solution containing a second base and reacted for 2-12 hours. Then, the solvent is removed and dried, and the solution is placed in a second solvent. Then, a dichloromethane solution containing an amination reagent is added, and the temperature is maintained for 2-48 hours. Then, the solvent is removed, extracted, dried, and 5-(1-amino-3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is obtained by column chromatography.

[0028] The preparation method in step S5 is as follows: 5-(1-amino-3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is added to a third solvent, an oxidant is added and the reaction is carried out for 0.5-24 hours. After the reaction is completed, the solvent is dried and column chromatography is used to obtain 9,10-dinitro-2-(trinitromethyl)-pyrazol[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine, which is the second polynitromethyl green energetic compound.

[0029] Furthermore, the first reaction temperature in step S3 is 0-130℃.

[0030] Further, the first alkali used in step S4 is any one of potassium hydroxide, potassium carbonate, potassium bicarbonate, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, tetraethylamine hydroxide, triethylamine, potassium tert-butoxide, potassium methoxide, and pyridine. The molar ratio of the amount of the alkali to the amount of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 1:1 to 5:1.

[0031] The first solvent in step S4 is any one of N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, ethyl acetate, dichloromethane, chloroform, methanol, ethanol, water, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, glycerol, acetone, pyridine, benzene, toluene, and xylene. The volume ratio of the solvent used to the mass ratio of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 3-30 mL / g.

[0032] The second reaction temperature in step S4 is 0-130℃.

[0033] Further, the second alkali used in step S4 is any one of potassium hydroxide, potassium carbonate, potassium bicarbonate, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, tetraethylamine hydroxide, triethylamine, potassium tert-butoxide, potassium methoxide, and pyridine. The molar ratio of the amount of the alkali to the amount of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 1:1 to 5:1.

[0034] The amination reagent used in step S5 is any one of hydroxylamine sulfonate, 4-methylbenzenesulfonyloxyamine, mestrimethylbenzenesulfonyloxyamine, and triisopropylbenzenesulfonyloxyamine. The molar ratio of the amination reagent to 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 1:1 to 6:1.

[0035] The oxidant used in step S5 is any one of potassium permanganate, potassium dichromate, sodium dichromate, potassium bromate, potassium chlorate, sodium chlorate, manganese dioxide, sodium hypochlorite, tert-butyl hypochlorite, sodium dichloroisocyanurate, dibromoisocyanuric acid, trichloroisocyanuric acid, hydrogen peroxide, oxygen, bromine, ammonium persulfate, and sodium tungstate. The molar ratio of the oxidant to 5-(1-amino-3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is 1:1 to 5:1.

[0036] The second and third solvents used in steps S4 and S5 are any one of N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, ethyl acetate, dichloromethane, chloroform, methanol, ethanol, water, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, glycerol, acetone, pyridine, benzene, toluene, and xylene. The volume ratio of the second solvent to the mass ratio of 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 2-20 mL / g; the volume ratio of the third solvent to the mass ratio of 5-(1-amino-3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is 2-20 mL / g.

[0037] Both steps S4 and S5 are performed at temperatures ranging from -15 to 130°C.

[0038] The beneficial effects of this invention are as follows:

[0039] 1. This invention introduces polynitromethyl groups as energy groups into the pyrazole-triazole skeleton and the tetrazine fused ring skeleton, thereby improving the oxygen balance of the molecule and enhancing the detonation performance of the energetic material.

[0040] 2. The 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt prepared in this invention has an oxygen balance of 5.9% based on carbon monoxide, and the 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine prepared in this invention has an oxygen balance of 16% based on carbon monoxide, which can improve energy release efficiency and reduce the generation of toxic gases.

[0041] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0042] To make the purpose, technical solution, and beneficial effects of the invention clearer, the following figures are provided for illustration:

[0043] Figure 1 The diagram shows an asymmetric unit with a thermal vibration ellipsoid for 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole prepared in Example 1 of this invention.

[0044] Figure 2The diagram shows the asymmetric unit with thermal vibration ellipsoids of the 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt prepared in Example 1 of the present invention.

[0045] Figure 3 The 1H NMR spectrum of the 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole dipotassium salt prepared in Example 1 of this invention;

[0046] Figure 4 Fourier transform infrared spectrum of 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole dipotassium salt prepared in Example 1 of this invention.

[0047] Figure 5 The thermal decomposition curve of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole dipotassium salt prepared in Example 1 of this invention is shown.

[0048] Figure 6 This is an asymmetric unit diagram of 5-(1-amino-3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino with thermal vibration ellipsoids obtained in Example 4 of the present invention.

[0049] Figure 7 The diagram shows an asymmetric unit with a thermal vibration ellipsoid for 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine prepared in Example 4 of this invention. Detailed Implementation

[0050] like Figure 1-7 As shown, the present invention provides novel polynitromethyl green energetic compounds, the first novel polynitromethyl green energetic compound being 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt; and the second novel polynitromethyl green energetic compound being 9,10-dinitro-2-(trinitromethyl)-pyrazol[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine.

[0051] The structural formula of 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt is shown in Formula 1:

[0052]

[0053] The structural formula of 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine is shown in Formula 2:

[0054]

[0055] Since 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt and 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine both use (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazole-3-yl)acetic acid as the starting material, the preparation steps for (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazole-3-yl)acetic acid are as follows:

[0056] (1) At -10℃, triethylamine (3.25 mL) was added dropwise to an anhydrous acetonitrile (45.0 mL) suspension containing ethyl 3-ethoxy-3-iminopropionic acid hydrochloride (5.75 g, 29.39 mmol), and then the mixture was stirred at room temperature for 30 minutes. Then 3-nitro-1H-pyrazole-5-acylhydrazide (1.71 g, 10 mmol) and acetic acid (10.0 mL) were added to obtain a first mixed solution. The first mixed solution was refluxed at 85℃ for 12 hours and then cooled to room temperature. After evaporating the acetonitrile and acetic acid, deionized water was added to the residue and ultrasonically mixed. The solid was then filtered and dried to obtain ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester.

[0057] (2) Ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester (2.66 g, 10 mmol) was added to a deionized aqueous solution containing sodium hydroxide (0.8 g, 20 mmol) at room temperature to obtain a second mixed solution. The second mixed solution was refluxed at 100 °C for 2 hours and then cooled to room temperature. Concentrated hydrochloric acid was added to adjust the pH of the second mixed solution to 1. After precipitation, the solution was filtered and dried to obtain (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid.

[0058] I. Examples 1-3 provide methods for preparing 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt.

[0059] Example 1:

[0060] S1. At -5°C, fuming nitric acid (1.5 mL) was added dropwise to a concentrated sulfuric acid (3 mL) solution containing (5-(3-nitro-1H-pyrazol-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid (0.24 g, 1 mmol) and stirred for 30 minutes. The mixture was then raised to room temperature and reacted for 48 hours. The solid was washed with trifluoroacetic acid, filtered, and dried to obtain a white solid compound, namely 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole, with a yield of 55%.

[0061] S2. At -5°C, potassium iodide (0.498 g, 3 mmol) and potassium bicarbonate (0.2 g, 2 mmol) were added to acetonitrile (10 mL) and stirred until completely dissolved. Then, 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole (0.374 g, 1 mmol) was slowly added and stirred for 15 minutes. The mixture was then stirred at 25°C for 24 hours. The precipitate was filtered, washed with anhydrous acetonitrile and methanol, and dried to obtain a yellow solid compound, which is the dipotassium salt of 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole, the first polynitromethyl green energetic compound, with a yield of 83%.

[0062] Example 2:

[0063] S1. At -5°C, fuming nitric acid (1.5 mL) was added dropwise to a concentrated sulfuric acid (3 mL) solution containing (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid (0.24 g, 1 mmol) and stirred for 30 minutes. The reaction was carried out at the first reaction temperature (28°C) for 24 hours. The solid was washed with trifluoroacetic acid, filtered, and dried to give a white solid compound, namely 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole, with a yield of 51%.

[0064] S2. At -5°C, potassium iodide (0.498 g, 3 mmol) and potassium carbonate (0.2 g, 1 mmol) were added to acetonitrile (10 mL) and stirred until completely dissolved. Then, 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole (0.374 g, 1 mmol) was slowly added and stirred for 15 minutes. The mixture was then raised to the second reaction temperature (28°C) and stirred for 4 hours. The precipitate was filtered, washed with anhydrous acetonitrile and methanol, and dried to obtain a yellow solid compound, namely 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt, which is the first polynitromethyl green energetic compound, with a yield of 81%.

[0065] Example 3:

[0066] S1. At -5°C, fuming nitric acid (1.5 mL) was added dropwise to a concentrated sulfuric acid (3 mL) solution containing (5-(3-nitro-1H-pyrazol-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid (0.24 g, 1 mmol) and stirred for 30 minutes. The mixture was then reacted at room temperature for 48 hours. The solid was washed with trifluoroacetic acid, filtered, and dried to give a white solid compound, namely 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole, with a yield of 55%.

[0067] S2. At -5°C, potassium iodide (0.498 g, 3 mmol) and potassium hydroxide (0.112 g, 2 mmol) were added to methanol (10 mL) and stirred until completely dissolved. Then, 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole (0.374 g, 1 mmol) was slowly added and stirred for 15 minutes. The mixture was then stirred at room temperature for 24 hours. The precipitate was filtered, washed with anhydrous acetonitrile and methanol, and dried to obtain a yellow solid compound, namely 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt, which is the first polynitromethyl green energetic compound, with a yield of 86%.

[0068] II. Example 4 provides a method for preparing 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetrazine.

[0069] S1. 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole (1 mmol, 0.374 g) was gradually added to an aqueous solution containing tetraethylammonium hydroxide (2 eq, 0.8415 g). The solution was stirred at room temperature for one hour until completely dissolved. After drying, 7 mL of acetonitrile was added to dissolve the solution, and THA (2.4 eq) dichloromethane solution was added dropwise at room temperature. The solution was then sealed with a glass stopper. The reaction progress was monitored by TLC. After reacting for 3 hours, the solution was dried and ice water was added. The solution was extracted with EA and dried. The crude product was further separated and purified by silica gel rapid column chromatography using a mixture of dichloromethane and petroleum ether as the eluent. After drying the eluent, a white solid product 5-(1-amino-3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino was obtained.

[0070] S2. Dissolve 5-(1-amino-3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazol-1-amino (1 mmol, 0.404 g) in 5 mL of acetonitrile. Add tert-butyl hypochlorite (t-BuOCl) (2.2 mmol, 238 mg) dropwise under ice bath conditions. After the addition is complete, stir the reaction mixture at room temperature for 30 minutes. Monitor the reaction progress using TLC. When the substrate is completely consumed and the reaction system no longer changes, add 50 mL of acetonitrile. The solution was quenched with a 2% sodium bicarbonate aqueous solution, extracted with ethyl acetate (EtOAc) (15 mL × 3), the organic phases were combined and dried with anhydrous sodium sulfate, then concentrated by vacuum distillation. The crude product was further separated and purified by silica gel rapid column chromatography using a mixture of dichloromethane and petroleum ether as eluent. After drying the eluent, a white solid product 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine was obtained, which is the novel polynitromethyl green energetic compound of the present invention.

[0071] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A novel polynitromethyl green energetic compound, characterized in that: The compound is 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt, and its structural formula is shown in Formula 1:

2. The novel polynitromethyl green energetic compound according to claim 1, characterized in that: The compound can also be 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine, with the structural formula shown in Formula 1:

3. The novel polynitromethyl green energetic compound according to claim 1 further includes a method for preparing the novel polynitromethyl green energetic compound, characterized in that: The preparation of the 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt includes the following steps: S1. Synthesize ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester; S2. Synthesis of (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid; S3. Synthesize 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole; S4. Synthesize 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt.

4. The novel polynitromethyl green energetic compound according to claim 2 further includes a method for preparing the novel polynitromethyl green energetic compound, characterized in that: The preparation of the 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetrazine comprises the following steps: S1. Synthesize ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester; S2. Synthesis of (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid; S3. Synthesize 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole; S4. Synthesize 5-(1-amino-3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazol-1-amino; S5. Synthesize 9,10-dinitro-2-(trinitromethyl)-pyrazole[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine.

5. The method for preparing the novel polynitromethyl green energetic compound according to claim 3 or 4, characterized in that: The preparation method of step S1 is as follows: at -10℃, triethylamine is added dropwise to an anhydrous acetonitrile suspension containing ethyl 3-ethoxy-3-iminopropionic acid hydrochloride, then the mixture is heated to room temperature and stirred for 30 minutes, and then 3-nitro-1H-pyrazole-5-acylhydrazide and acetic acid are added to obtain a first mixed solution. The first mixed solution is refluxed at 85℃ for 12 hours and then cooled to room temperature. After evaporating acetonitrile and acetic acid, deionized water is added to the residue and ultrasonically mixed. The solid is then filtered and dried to obtain ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester. The preparation method of step S2 is as follows: Ethyl 2-(5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)ethyl ester is added to a deionized aqueous solution containing sodium hydroxide at room temperature to obtain a second mixed solution. The second mixed solution is refluxed at 100°C for 2 hours and then cooled to room temperature. Then, concentrated hydrochloric acid is added to adjust the pH of the second mixed solution to 1. After precipitation, filtration and drying are performed to obtain (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid. The preparation method of step S3 is as follows: At -5℃, fuming nitric acid is added to a concentrated sulfuric acid solution containing (5-(3-nitro-1H-pyrazole-5-yl)-1H-1,2,4-triazol-3-yl)acetic acid. After reacting at the first reaction temperature for 2-48 hours, the solid is filtered and dried to obtain 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole.

6. The method for preparing the novel polynitromethyl green energetic compound according to claim 3, characterized in that: The preparation method in step S4 is as follows: at -5°C, potassium iodide and the first base are added to the first solvent, and then 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(tinitromethyl)-1H-1,2,4-triazole is added and reacted at the second reaction temperature for 0.5-24 hours. The solid is then filtered and dried to obtain 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(dinitromethyl)-1H-1,2,4-triazole dipotassium salt.

7. The method for preparing the novel polynitromethyl green energetic compound according to claim 4, characterized in that: The preparation method in step S4 is as follows: at room temperature, 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is mixed with an aqueous solution containing a second base and reacted for 2-12 hours. Then, the solvent is removed and the mixture is dried. The solution is placed in a second solvent, and a dichloromethane solution containing an amination reagent is added. The temperature is maintained and the reaction is carried out for 2-48 hours. Then, the solvent is removed, the mixture is extracted, dried, and 5-(1-amino-3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is obtained by column chromatography. The preparation method in step S5 is as follows: 5-(1-amino-3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is added to a third solvent, an oxidant is added and the reaction is carried out for 0.5-24 hours. After the reaction is completed, the solvent is dried and column chromatography is used to obtain 9,10-dinitro-2-(trinitromethyl)-pyrazol[1,5-d][1,2,4]triazole[5,1-f][1,2,3,4]tetraazine, which is the second polynitromethyl green energetic compound.

8. The method for preparing the novel polynitromethyl green energetic compound according to claim 5, characterized in that: The first reaction temperature in step S3 is 0-130℃.

9. The method for preparing the novel polynitromethyl green energetic compound according to claim 6, characterized in that: The first alkali used in step S4 is any one of potassium hydroxide, potassium carbonate, potassium bicarbonate, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, tetraethylamine hydroxide, triethylamine, potassium tert-butoxide, potassium methoxide, and pyridine. The molar ratio of the amount of the alkali to the amount of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 1:1 to 5:

1. The first solvent in step S4 is any one of N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, ethyl acetate, dichloromethane, chloroform, methanol, ethanol, water, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, glycerol, acetone, pyridine, benzene, toluene, and xylene. The volume ratio of the solvent used to the mass ratio of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 3-30 mL / g. The second reaction temperature in step S4 is 0-130℃.

10. The method for preparing the novel polynitromethyl green energetic compound according to claim 7, characterized in that: The second alkali used in step S4 is any one of potassium hydroxide, potassium carbonate, potassium bicarbonate, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, tetraethylamine hydroxide, triethylamine, potassium tert-butoxide, potassium methoxide, and pyridine. The molar ratio of the amount of the alkali to the amount of 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 1:1 to 5:

1. The amination reagent used in step S5 is any one of hydroxylamine sulfonate, 4-methylbenzenesulfonyloxyamine, mestrimethylbenzenesulfonyloxyamine, and triisopropylbenzenesulfonyloxyamine. The molar ratio of the amination reagent to 5-(3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 1:1 to 6:

1. The oxidant used in step S5 is any one of potassium permanganate, potassium dichromate, sodium dichromate, potassium bromate, potassium chlorate, sodium chlorate, manganese dioxide, sodium hypochlorite, tert-butyl hypochlorite, sodium dichloroisocyanurate, dibromoisocyanuric acid, trichloroisocyanuric acid, hydrogen peroxide, oxygen, bromine, ammonium persulfate, and sodium tungstate. The molar ratio of the oxidant to 5-(1-amino-3,4-dinitro-1H-pyrazol-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is 1:1 to 5:

1. The second and third solvents used in steps S4 and S5 are any one of N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, ethyl acetate, dichloromethane, chloroform, methanol, ethanol, water, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, glycerol, acetone, pyridine, benzene, toluene, and xylene. The volume ratio of the second solvent to the mass ratio of 5-(3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole is 2-20 mL / g; the volume ratio of the third solvent to the mass ratio of 5-(1-amino-3,4-dinitro-1H-pyrazole-5-yl)-3-(trinitromethyl)-1H-1,2,4-triazole-1-amino is 2-20 mL / g. Both steps S4 and S5 are performed at temperatures ranging from -15 to 130°C.

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