Method for the preparation of a methanamide polynitro energetic compound and the compound thus obtained

Abstract

The application provides a methylnitramide polynitro nitrogen-rich energetic compound, characterized by comprising a methylnitramide polynitro pyrazole energetic compound substituted by a nitroform functional group and an azo bridged methylnitramide polynitro pyrazole energetic compound; the structural formula of the methylnitramide polynitro pyrazole energetic compound substituted by the nitroform functional group is formula I or formula II, and the structural formula of the azo bridged methylnitramide polynitro pyrazole energetic compound is formula III or formula IV. The application also provides an application and a preparation method of the methylnitramide polynitro nitrogen-rich energetic compound. The methylnitramide group is combined with traditional nitroform substituted polynitro pyrazole compounds and azo bridged polynitro pyrazole compounds, and the application is green and high-energy.

Description

Technical Field

[0001] This invention belongs to the field of energetic materials synthesis technology, specifically relating to formnitramide polynitro nitrogen-rich energetic compounds and their preparation methods. Background Technology

[0002] In recent decades, the development of novel energetic materials has received considerable attention due to their widespread use in military and civilian applications. Simultaneously, higher requirements have been placed on these novel energetic materials, including high energy, good safety, and environmental friendliness. The energy of nitroazole energetic compounds mainly originates from high-energy chemical bonds and ring strain in their ring structures, such as N-N, CN, and NO bonds. They possess high nitrogen and low carbon-hydrogen content, high density, easier oxygen balance, and combustion products that are predominantly environmentally friendly N2, making them a new class of high-energy compounds.

[0003] Amide groups, a common functional group in medicinal chemistry, have been rarely studied in energetic materials. The presence of large-molecule O atoms and NH₂ hydrogen bonds in amides can often modulate the density and sensitivity of energetic materials. Furthermore, amide groups can be further nitrated to form nitramide groups. The classic energetic material dinitrourea (DNU) is derived from urea nitration and possesses advantages such as high density and high detonation performance. This demonstrates that nitramides are an energetic group with great potential for energetic derivatization. The focus of this study is to combine nitramide groups with nitrogen-rich heterocyclic pyrazoles to construct novel nitrogen-rich energetic materials with high density and high detonation performance. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a formamide polynitro nitrogen-rich energetic compound and its preparation method, which combines the nitramide group with traditional nitropyrazole compounds substituted with nitroform or azo-bridged polynitropyrazole compounds, resulting in a green and high-energy compound.

[0005] The technical problem solved by this invention is achieved by the following technical solution:

[0006] The first objective of this invention is to provide a metronidamide polynitro-rich nitrogen-enriched energetic compound, characterized in that it comprises a metronidamide polynitropyrazole energetic compound substituted with a nitroform functional group and an azo-bridged metronidamide polynitropyrazole energetic compound; wherein the nitroform-substituted metronidamide polynitropyrazole energetic compound has the structural formula of Formula I or Formula II, and the azo-bridged metronidamide polynitropyrazole energetic compound has the structural formula of Formula III or Formula IV.

[0007]

[0008] The second objective of this invention is to provide the application of the above-mentioned metronidamide polynitro nitrogen-rich energetic compound as an energetic material.

[0009] Furthermore, the nitroform-functionalized substituted metronidazole polynitropyrazole energetic compound is used as an oxidizing agent in the preparation of propellants or explosives.

[0010] Furthermore, the azo-bridged metronidazole polynitropyrazole energetic compound is used as a high explosive.

[0011] The third objective of this invention is to provide a method for preparing the above-mentioned formamide polynitro nitrogen-rich energetic compound, wherein the formamide polynitro nitrogen-rich energetic compound is a nitroform functionalized formamide polynitropyrazole energetic compound, and the preparation method includes the following steps:

[0012] 1) Dissolve the formamide polynitro compound in an organic solvent, then add an aqueous solution of NaOH to the solution, stir for 20-60 min, add bromoacetone dropwise, and react at room temperature for 20-30 h. After the reaction is complete, collect the solid to obtain the intermediate product.

[0013] 2) The intermediate product is subjected to a nitration reaction with a nitrate-sulfur mixture to obtain a nitramide polynitropyrazole energetic compound with a nitraldehyde functional group substituted.

[0014] Furthermore, the formamide polynitro compound is selected from 5-formamide-3,4-dinitro-1H-pyrazole or 4-formamide-3,5-dinitro-1H-pyrazole.

[0015] Furthermore, the organic solvent mentioned in step 1) is methanol or acetonitrile.

[0016] Furthermore, the molar ratio of NaOH to formamide polynitro compound is 1.2:1.

[0017] Furthermore, the molar ratio of bromoacetone to formamide polynitro compound is 1.5:1.

[0018] Furthermore, the nitration reaction involves slowly adding the intermediate product to a nitrate-sulfur mixture at 0–10°C, then slowly heating it to room temperature for 40–60 hours. After the reaction is complete, the mixture is filtered, washed, and dried in solid form.

[0019] Furthermore, the ratio of the intermediate product to the nitric acid-sulfur mixture is 1g:11-15ml, and the nitric acid-sulfur mixture is an acid obtained by mixing 100% nitric acid and 98% sulfuric acid in a volume ratio of 1:1.5.

[0020] A method for preparing the above-mentioned metronidazole polynitro nitrogen-rich energetic compound, wherein the metronidazole polynitro nitrogen-rich energetic compound is an azo-bridged metronidazole polynitropyrazole energetic compound, and the preparation method includes the following steps:

[0021] 1) After reacting the formamide polynitro compound with THA, an N-NH2 intermediate compound is obtained;

[0022] 2) Dissolve the N-NH2 intermediate in acetonitrile. After it is completely dissolved, add tert-butyl hypochlorite. After the reaction is complete, add saturated sodium carbonate solution to adjust the pH to neutral. Collect the solid to obtain the azo-bridged formamide polynitropyrazole energetic compound.

[0023] 3) The azo-bridged formamide polynitropyrazole energetic compound is subjected to a nitration reaction with a nitrate-sulfur mixture to obtain the azo-bridged formamide polynitropyrazole energetic compound.

[0024] Furthermore, the formamide polynitro compound is selected from 5-formamide-3,4-dinitro-1H-pyrazole or 4-formamide-3,5-dinitro-1H-pyrazole.

[0025] Furthermore, during the amination reaction, an equivalent amount of DBU to the formamide polynitro compound is added first, followed by the addition of THA.

[0026] Furthermore, in step 2), the ratio of the N-NH2 intermediate compound to tert-butyl hypochlorite is 1 mmol: 1.5 mmol.

[0027] Furthermore, in step 2), the temperature conditions for the reaction between the N-NH2 intermediate compound and tert-butyl hypochlorite are -20 to -5°C.

[0028] Furthermore, the nitration reaction involves adding an azo-bridged formamide polynitropyrazole energetic compound to a nitric-sulfur mixed acid at 0–10°C, reacting at room temperature for 0.5–1.5 h, and then filtering, washing, and drying in a solid state after the reaction is complete.

[0029] Furthermore, the ratio of the azo-bridged formamide polynitropyrazole energetic compound to the nitric-sulfur mixed acid is 0.1g:1.1-1.5ml, and the nitric-sulfur mixed acid is an acid obtained by mixing 100% nitric acid and 98% sulfuric acid in a volume ratio of 1:1.5.

[0030] Furthermore, the obtained azo-bridged metronidazole polynitropyrazole energetic compound was washed with trichloroacetic acid.

[0031] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0032] This invention uses 5-formamide-3,4-dinitro-1H-pyrazole or 4-formamide-3,5-dinitro-1H-pyrazole as raw materials to obtain formamide polynitro nitrogen-rich energetic compounds. The resulting nitroformamide polynitropyrazole energetic compounds with substituted nitroform functional groups have a density of 1.89 g / cm³. 3Above, the oxygen balance is greater than 10%; the density of the obtained azo-bridged metronidazole polynitropyrazole energetic compound is 1.93 g / cm³. 3 The detonation velocity is greater than 9400 m / s. Through further control of the nitration reaction conditions, the preparation process is safe and reliable.

[0033] The nitroform-functionalized formamide polynitropyrazole energetic compound of the present invention is used as an oxidant. It has high density, high oxygen balance, and does not contain halogens or other atoms that would produce characteristic signals. It is green and high-energy, and is a good type of energetic oxidant.

[0034] The azo-bridged metronidazole polynitropyrazole energetic compound of this invention, when used as a high explosive, has high density and high detonation performance, and is expected to replace RDX.

[0035] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0036] Figure 1 This is a single-crystal X-ray diffraction structure of the nitroform-functionalized substituted formamide polynitropyrazole energetic compound obtained in Example 1 of the present invention, which is a formamide polynitro-rich nitrogen-enriched energetic compound and its preparation method.

[0037] Figure 2 This is a single-crystal X-ray diffraction structure of the nitroform-functionalized substituted formamide polynitropyrazole energetic compound obtained in Example 3 of the present invention, which is a formamide polynitro-rich nitrogen-enriched energetic compound and its preparation method.

[0038] Figure 3 This is an X-ray diffraction structure diagram of the azo-bridged formamide polynitro pyrazole energetic compound 6 obtained in Example 3 of the present invention, which is a formamide polynitro nitrogen-rich energetic compound and its preparation method.

[0039] Figure 4 This is the nuclear magnetic resonance spectrum of the azo-bridged metronidazole-based energetic compound 7 in Example 3 of the present invention, which describes a metronidazole polynitro-rich nitrogen-enriched energetic compound and its preparation method.

[0040] Figure 5 This is an X-ray diffraction structure diagram of the azo-bridged metronidazole polynitro-rich energetic compound 7 in Example 3 of the present invention, which describes a metronidazole polynitro-rich nitrogen-rich energetic compound and its preparation method.

[0041] Figure 6The X-ray diffraction structure of the azo-bridged formamide polynitro pyrazole energetic compound 9 obtained in Example 4 of the present invention, which is a formamide polynitro nitrogen-rich energetic compound and its preparation method, is shown.

[0042] Figure 7 This is the nuclear magnetic resonance spectrum of the azo-bridged metronidazole-based energetic compound 10 in Example 4 of the present invention, which describes a metronidazole polynitro-rich nitrogen-enriched energetic compound and its preparation method.

[0043] Figure 8 This is an X-ray diffraction structure diagram of the azo-bridged metronidazole polynitro-rich energetic compound 10 in Example 4 of the present invention, which describes a metronidazole polynitro-rich nitrogen-rich energetic compound and its preparation method. Detailed Implementation

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0045] In addition, unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing from the market or prepared by existing methods.

[0046] Example 1: A method for preparing a nitroform-functionalized formamide polynitropyrazole energetic compound. The steps of the method for preparing a nitroform-functionalized formamide polynitropyrazole energetic compound are as follows:

[0047] 1) Dissolve 2 mmol (402 mg) of 5-carboxamide-3,4-dinitro-1H-pyrazole in 5 ml of acetonitrile. Then add 96 mg of NaOH in 6 ml of H2O aqueous solution. Stir at room temperature for 30 min. Finally, add 3 mmol of bromoacetone and react at room temperature for 24 h. After the reaction is complete, collect the solid by vacuum filtration, wash with 10 ml of deionized water, and dry to obtain intermediate product 1 with a yield of 70%.

[0048] 2) At 0–10 °C, 1 g of intermediate product 1 was slowly added to 11–15 mL of a nitric acid mixture with a mass ratio of 100% nitric acid and 98% sulfuric acid of 1:1.2. The mixture was then slowly heated to 25 °C and reacted at this temperature for 48 h. After the reaction was completed, the mixture was filtered, the solid was washed with 2 mL of trifluoroacetic acid, and dried to obtain nitroform-functionalized metronidazole polynitropyrazole energetic compound 2 with a yield of 63%.

[0049] The reaction route is as follows:

[0050]

[0051] The 1H NMR spectrum of intermediate product 1 is as follows:

[0052] 1 H NMR(d6-DMSO): δ8.307, δ8.082(br,2H), δ5.684(s,2H), δ2.336(s,3H).

[0053] The structure of the nitroform-functionalized formamide polynitropyrazole energetic compound 2 was verified by single-crystal X-ray diffraction, as shown in Figure 2. Figure 1 As shown.

[0054] The results above confirm the structure of the compound as shown in the reaction route.

[0055] The thermal decomposition temperature, density, detonation performance, impact sensitivity, and friction sensitivity of the nitroform-functionalized formamide polynitropyrazole energetic compound 2 are shown in Table 1.

[0056] Calculations show that the enthalpy of formation of the nitroform-substituted metronidazole polynitropyrazole energetic compound 2 is 247.92 kJ / mol, the detonation velocity is 8757 m / s, and the detonation pressure is 33.1 GPa.

[0057] In summary, the nitroform-functionalized metronidazole polynitropyrazole energetic compounds have high density, high oxygen balance and good detonation performance, making them suitable for use as oxidants in the preparation of propellants or explosives.

[0058] Example 2: A method for preparing a nitroform-functionalized formamide polynitropyrazole energetic compound

[0059] The preparation method of a nitroform-functionalized formamide polynitropyrazole energetic compound includes the following steps:

[0060] 1) Dissolve 2 mmol (402 mg) of 4-carboxamide-3,5-dinitro-1H-pyrazole in 5 ml of acetonitrile, then add 96 mg of NaOH in 6 ml of H2O aqueous solution, stir at room temperature for 30 min, and finally add 3 mmol of bromoacetone. React at room temperature for 24 h. After the reaction is complete, collect the solid by vacuum filtration, wash with 10 ml of deionized water, and dry to obtain intermediate product 3 with a yield of 72%.

[0061] 2) At 0–10 °C, 1 g of intermediate product 3 was slowly added to 11–15 mL of a nitric acid mixture with a mass ratio of 100% nitric acid and 98% sulfuric acid of 1:1.2. The mixture was then slowly heated to 25 °C and reacted at this temperature for 48 h. After the reaction was completed, the mixture was filtered, the solid was washed with 2 mL of trifluoroacetic acid, and dried to obtain 4, a nitroform-functionalized metronidazole polynitropyrazole energetic compound, with a yield of 68%.

[0062] The reaction route is as follows:

[0063]

[0064] The 1H NMR spectrum of intermediate product 3 is as follows:

[0065] 1H NMR (d6-DMSO): δ7.063, δ6.730(br,2H), δ5.658(s,2H), δ2.234(s,3H).

[0066] The structure of compound 4, a nitroform-functionalized formamide polynitropyrazole energetic compound, was verified by single-crystal X-ray diffraction, as shown in Figure 4. Figure 2 As shown.

[0067] The results above confirm the structure of the compound as shown in the reaction route.

[0068] The thermal decomposition temperature, density, detonation performance, impact sensitivity, and friction sensitivity of the nitraldehyde-substituted formamide polynitropyrazole energetic compound 4 are shown in Table 1.

[0069] Calculations show that the enthalpy of formation of the nitroform-substituted metronidazole polynitropyrazole energetic compound 4 is 228.4 kJ / mol, the detonation velocity is 8817 m / s, and the detonation pressure is 33.7 GPa.

[0070] In summary, the nitroform-functionalized metronidazole polynitropyrazole energetic compounds have high density, high oxygen balance and good detonation performance, making them suitable for use as oxidants in the preparation of propellants or explosives.

[0071] Example 3: A method for preparing an azo-bridged metronidazole polynitropyrazole energetic compound

[0072] The preparation method of an azo-bridged metronidazole polynitropyrazole energetic compound includes the following steps:

[0073] 1) 2 mmol of 402 mg 5-carboxamide-3,4-dinitro-1H-pyrazole was added to 5 ml of acetonitrile and completely dissolved. Then an equivalent amount of DBU was added and the mixture was stirred at room temperature for 3 h. Finally, freshly prepared THA was added and the mixture was stirred for another 3 h. The mixture was then dried under vacuum by rotary evaporation to obtain N-NH2 intermediate compound 5, with a yield of 65%.

[0074] 2) Dissolve 216 mg of 1 mmol N-NH2 intermediate compound 5 in 5 ml acetonitrile, stir until completely dissolved, then add 162 mg of 1.5 mmol tert-butyl hypochlorite, and react at -10 °C for 3 h. After the reaction is complete, add saturated sodium carbonate solution to adjust the pH to neutral, collect the solid by filtration, wash and dry to obtain azo-bridged formamide polynitropyrazole energetic compound 6, with a yield of 60%.

[0075] 3) At 0–10 °C, 0.1 g of the azo-bridged formamide polynitropyrazole energetic compound 6 was slowly added to 1.1–1.5 mL of a nitric acid mixture with a mass ratio of 100% nitric acid and 98% sulfuric acid of 1:1.2. The mixture was then slowly heated to 25 °C and reacted at this temperature for 1 h. After the reaction was completed, the mixture was filtered, the solid was washed with 2 mL of trifluoroacetic acid, and dried to obtain the azo-bridged formamide polynitropyrazole energetic compound 7 with a yield of 90%.

[0076] The reaction route is as follows:

[0077]

[0078] The NMR spectrum of N-NH2 intermediate 5 is as follows:

[0079] 1H NMR(d6-DMSO): δ8.450(br,2H), δ7.362(s,2H).

[0080] 13C NMR (d6-DMSO): δ156.2, 142.3, 135.4, 123.3ppm.

[0081] The NMR spectrum of the azo-bridged formamide polynitropyrazole energetic compound 6 is as follows:

[0082] 1H NMR(d6-DMSO): δ8.841(s,2H), δ8.660(s,2H).

[0083] 13C NMR (d6-DMSO): δ156.2, 142.3, 135.4, 123.3ppm.

[0084] The structure of the azo-bridged formamide polynitropyrazole energetic compound 6 was verified by single-crystal X-ray diffraction, and the structure is shown in Figure 6. Figure 3 As shown.

[0085] The carbon NMR spectra of compound 7, an azo-bridged metronidazole-polynitropyrazole energetic compound, are shown below. Figure 4 As shown:

[0086] 13C NMR (d3-CD3CN): δ154.9, 150.5, 139.5, 134.6ppm.

[0087] The structure of the azo-bridged metronidazole polynitropyrazole energetic compound 7 was verified by single-crystal X-ray diffraction, and the structure is shown in Figure 7. Figure 5 As shown.

[0088] The results above confirm the structure of the compound as shown in the reaction route.

[0089] The thermal decomposition temperature, density, detonation properties, impact sensitivity, and friction sensitivity of compounds 6 and 7 are shown in Table 1.

[0090] Calculations show that the enthalpy of formation of the azo-bridged metronidamide polynitropyrazole energetic compound 7 is 670.65 KJ / mol, the detonation velocity is 9405 m / s, and the detonation pressure is 39.3 Gpa.

[0091] In summary, the azo-bridged metronidazole polynitropyrazole energetic compound 7 has high density, high oxygen balance and high detonation performance, and is expected to replace RDX as a new generation of high explosive.

[0092] Example 4: A method for preparing an azo-bridged metronidazole polynitropyrazole energetic compound

[0093] The preparation method of an azo-bridged metronidazole polynitropyrazole energetic compound includes the following steps:

[0094] 1) 2 mmol of 402 mg of 4-carboxamide-3,5-dinitro-1H-pyrazole was added to 5 ml of acetonitrile and completely dissolved. Then an equivalent amount of DBU was added and the mixture was stirred at room temperature for 3 h. Finally, freshly prepared THA was added and the mixture was stirred for another 3 h. The mixture was then dried under vacuum by rotary evaporation to obtain N-NH2 intermediate compound 8, with a yield of 68%.

[0095] 2) Dissolve 216 mg of 1 mmol N-NH2 intermediate compound 8 in 5 ml acetonitrile, stir until completely dissolved, then add 162 mg of 1.5 mmol tert-butyl hypochlorite, and react at -10 °C for 3 h. After the reaction is complete, add saturated sodium carbonate solution to adjust the pH to neutral, collect the solid by filtration, wash and dry to obtain azo-bridged formamide polynitropyrazole energetic compound 9, with a yield of 65%.

[0096] 3) At 0–10 °C, 0.1 g of azo-bridged formamide polynitropyrazole energetic compound 9 was slowly added to 1.1–1.5 mL of a nitric acid mixture with a mass ratio of 100% nitric acid and 98% sulfuric acid of 1:1.2. The mixture was then slowly heated to 25 °C and reacted at this temperature for 1 h. After the reaction was completed, the mixture was filtered, the solid was washed with 2 mL of trifluoroacetic acid, and dried to obtain azo-bridged formamide polynitropyrazole energetic compound 10, with a yield of 88%.

[0097] The reaction route is as follows:

[0098]

[0099] The NMR spectrum of N-NH2 intermediate compound 8 is as follows:

[0100] 1H NMR(d6-DMSO): δ7.876(br,2H), δ7.589(s,2H).

[0101] 13C NMR (d6-DMSO): δ157.2, 147.2, 137.4, 124.6ppm.

[0102] The NMR spectrum of the azo-bridged formamide polynitropyrazole energetic compound 9 is as follows:

[0103] 1H NMR(d6-DMSO): δ7.804(s,2H), δ7.500(s,2H).

[0104] 13C NMR (d6-DMSO): δ156.5, 143.4, 135.2, 123.8ppm.

[0105] The structure of the azo-bridged metronidazole polynitropyrazole energetic compound 9 was verified by single-crystal X-ray diffraction, and the structure is shown in Figure 9. Figure 6 As shown.

[0106] The carbon NMR spectra of azo-bridged metronidazole polynitropyrazole energetic compound 10 are shown below. Figure 7 As shown:

[0107] 13C NMR (d3-CD3CN): δ155.7, 149.7, 138.5, 131.2ppm.

[0108] The structure of azo-bridged metronidamide polynitropyrazole energetic compound 10 was verified by single-crystal X-ray diffraction, and the structure is shown in Figure 10. Figure 8 As shown.

[0109] The results above confirm the structure of the compound as shown in the reaction route.

[0110] The thermal decomposition temperature, density, detonation properties, impact sensitivity, and friction sensitivity of compounds 9 and 10 are shown in Table 1.

[0111] Calculations show that the enthalpy of formation of the azo-bridged metronidazole polynitropyrazole energetic compound 10 is 676.83 KJ / mol, the detonation velocity is 9440 m / s, and the detonation pressure is 39.6 Gpa.

[0112] In summary, the azo-bridged metronidazole polynitropyrazole energetic compound 10 has high density, high oxygen balance and high detonation performance, and is expected to replace RDX as a new generation of high explosive.

[0113] Table 1 shows the properties of the compounds in each example.

[0114] Table 1 Properties of the compounds in each example

[0115]

[0116] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0117] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A formnitramide polynitro nitrogen-rich energetic compound, characterized in that: The metronidamide polynitro nitrogen-rich energetic compound is a metronidamide polynitropyrazole energetic compound with nitraldehyde functional group substitution or an azo-bridged metronidamide polynitropyrazole energetic compound; the structural formula of the nitraldehyde functional group-substituted metronidamide polynitropyrazole energetic compound is Formula I or Formula II, and the structural formula of the azo-bridged metronidamide polynitropyrazole energetic compound is Formula III or Formula IV. (Formula I) (Formula II) (Formula III) (Formula IV).

2. The application of the metronidamide polynitro nitrogen-rich energetic compound according to claim 1 as an energetic material.

3. The application as described in claim 2, characterized in that: The application of the nitroform-functionalized substituted metronidazole polynitropyrazole energetic compound as an oxidizing agent in the preparation of propellants or explosives.

4. The application as described in claim 2, characterized in that: The application of the azo-bridged metronidazole polynitropyrazole energetic compound as a high explosive.

5. A method for preparing the formamide polynitro nitrogen-rich energetic compound according to claim 1, characterized in that, The formamide polynitro nitrogen-rich energetic compound is a formamide polynitropyrazole energetic compound with nitraldehyde functional group substitution, and its preparation method includes the following steps: 1) Dissolve the formamide polynitro compound in an organic solvent, then add an aqueous solution of NaOH to the solution, stir for 20-60 min, add bromoacetone dropwise, and react at room temperature for 20-30 h. After the reaction is complete, collect the solid to obtain the intermediate product; the formamide polynitro compound is selected from 5-formamide-3,4-dinitro-1H-pyrazole or 4-formamide-3,5-dinitro-1H-pyrazole; 2) The intermediate product is subjected to a nitration reaction with a nitrate-sulfur mixture. The nitration reaction is carried out by slowly adding the intermediate product to the nitrate-sulfur mixture at 0~10℃, and then slowly heating to room temperature for 40~60h to obtain a nitraldehyde-functionalized metronidazole polynitropyrazole energetic compound.

6. The method for preparing a formnitramide polynitro nitrogen-rich energetic compound as described in claim 5, characterized in that: The molar ratio of NaOH to formamide polynitro compound is 1.2:1, and the molar ratio of bromoacetone to formamide polynitro compound is 1.5:

1.

7. A method for preparing the formnitramide polynitro nitrogen-rich energetic compound according to claim 1, characterized in that: The metronidamide polynitro nitrogen-rich energetic compound is an azo-bridged metronidamide polynitropyrazole energetic compound, and its preparation method includes the following steps: 1) After reacting the formamide polynitro compound with THA, an N-NH2 intermediate compound is obtained, wherein the formamide polynitro compound is selected from 5-formamide-3,4-dinitro-1H-pyrazole or 4-formamide-3,5-dinitro-1H-pyrazole; 2) The N-NH2 intermediate compound was dissolved in acetonitrile. After it was completely dissolved, tert-butyl hypochlorite was added. After the reaction was completed, saturated sodium carbonate solution was added to adjust the pH to neutral. The solid was collected to obtain the azo-bridged formamide polynitropyrazole energetic compound. 3) The azo-bridged formamide polynitropyrazole energetic compound is subjected to a nitration reaction with a nitrate-sulfur mixed acid. The nitration reaction is carried out by adding the azo-bridged formamide polynitropyrazole energetic compound to the nitrate-sulfur mixed acid at 0~10℃ and then reacting at room temperature for 0.5~1.5h to obtain the azo-bridged formamide polynitropyrazole energetic compound.

8. The method for preparing a formnitramide polynitro nitrogen-rich energetic compound as described in claim 7, characterized in that: In step 2), the ratio of the N-NH2 intermediate compound to tert-butyl hypochlorite is 1 mmol: 1.5 mmol.

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