High-energy oxidant 3, 5-diamino-4-nitropyrazole perchlorate and synthesis method thereof

Abstract

The invention discloses a high-energy oxidizing agent 3, 5-diamino-4-nitropyrazole perchlorate, and the molecular formula of the high-energy oxidizing agent 3, 5-diamino-4-nitropyrazole perchlorate is C3H6O6N5Cl. The high-energy oxidant 3, 5-diamino-4-nitropyrazole perchlorate provided by the invention has the advantages of high density, high detonation performance, excellent thermal stability and low mechanical sensitivity. The 3, 5-diamino-4-nitropyrazole perchlorate is used as an oxidizing agent in the solid propellant and can replace ammonium perchlorate, so that the specific impulse of the solid propellant is greatly improved. The invention further discloses a synthesis method of the high-energy oxidant 3, 5-diamino-4-nitropyrazole perchlorate, the synthesis method is simple and efficient, reaction conditions are mild, the yield is stable, and engineering amplification is easy.

Description

Technical Field

[0001] The invention belongs to the technical field of energetic materials and relates to a high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate and a synthesis method thereof. Background Art

[0002] Oxidizers are the main components of propellants, with a content of more than 50% in solid propellants. The use of high-energy oxidizers is the most direct and effective technical approach to increase the energy of propellants. At present, ammonium perchlorate (AP), ammonium dinitramide (ADN) and hydrazine nitroformate (HNF) are common high-oxygen carriers in propellants. Due to their negative heat of formation, environmental pollution, high sensitivity, low thermal stability and hygroscopic properties, their practical application in solid rocket engine systems is limited. Therefore, the development of new oxidizers with high energy density remains a long-term goal of researchers. Summary of the invention

[0003] The purpose of the present invention is to provide a high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate and a synthesis method thereof.

[0004] The technical solution to achieve the purpose of the present invention is:

[0005] A high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate, its chemical formula is C3H6O6N5Cl, and its structural formula is:

[0006]

[0007] The crystal structure of 3,5-diamino-4-nitropyrazole perchlorate has the following characteristics:

[0008] Crystal system: orthorhombic;

[0009] Point group: -P2 ac / 2n;

[0010] Unit cell parameters: alpha=90, beta=90, gamma=90;

[0011] Unit cell volume: Z = 8;

[0012] Density: 2.013 g cm -3 (150 K).

[0013] A method for synthesizing the high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate, the reaction equation is as follows:

[0014]

[0015] include:

[0016] Step (1), suspending 3,5-diamino-4-nitropyrazole in a perchloric acid solution and stirring to react;

[0017] Step (2), mixing the reaction solution obtained in step (1) with ethyl acetate, and collecting and washing the solid;

[0018] Step (3) The solid obtained in step (2) is vacuum dried to obtain 3,5-diamino-4-nitropyrazole perchlorate.

[0019] In step (1), the molar ratio of 3,5-diamino-4-nitropyrazole to perchloric acid is 1:1 to 1:1.4.

[0020] The mass fraction of the perchloric acid solution is 70%.

[0021] The reaction temperature is 25-50°C, and the reaction time is 0.5-1h.

[0022] In step (2), preferably, the reaction solution obtained in step (1) is mixed with ethyl acetate, stirred for about 5 minutes, filtered or centrifuged, and the solid is collected and washed.

[0023] Preferably, the solid is washed with ethyl acetate.

[0024] In step (3), the drying temperature is 35 to 50°C.

[0025] Another object of the present invention is to provide the use of 3,5-diamino-4-nitropyrazole perchlorate as an oxidizer in solid propellants.

[0026] Another object of the present invention is to provide a solid propellant containing the 3,5-diamino-4-nitropyrazole perchlorate.

[0027] Preferably, the solid propellant consists of ammonium perchlorate, CL-20 (hexanitrohexaazaisowurtzitane), Al (aluminum) and 3,5-diamino-4-nitropyrazole perchlorate, or consists of CL-20, aluminum and 3,5-diamino-4-nitropyrazole perchlorate; in the solid propellant, the mass fraction of ammonium perchlorate is 57-0%, the mass fraction of CL-20 is 20%, the mass fraction of Al is 18%, and the mass fraction of 3,5-diamino-4-nitropyrazole perchlorate is 5-55%.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) 3,5-Diamino-4-nitropyrazole perchlorate has a relatively high crystal density of 2.013 g·cm -3(150K); excellent detonation performance, detonation velocity is 9001m·s -1 , explosion pressure is 38.23Gpa; excellent thermal stability; at the same time, it has low mechanical sensitivity, friction sensitivity is 12J, and impact sensitivity is 200N.

[0030] (2) 3,5-Diamino-4-nitropyrazole perchlorate can be used as an oxidant in solid propellants to replace ammonium perchlorate (AP), thereby greatly improving the specific impulse of solid propellants.

[0031] (3) The synthesis method of 3,5-diamino-4-nitropyrazole perchlorate of the present invention is simple and efficient, the reaction conditions are relatively mild, the yield is stable, and it is easy to scale up by engineering.

[0032] (4) The oxidant ammonium perchlorate currently used in solid propellants is limited due to its strong hygroscopicity. Compared with ammonium perchlorate, the 3,5-diamino-4-nitropyrazole perchlorate of the present invention has lower hygroscopicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The crystal structure diagram of 3,5-diamino-4-nitropyrazole perchlorate of the present invention.

[0034] Figure 2 This is a unit cell stacking diagram of 3,5-diamino-4-nitropyrazole perchlorate of the present invention (viewing angle β).

[0035] Figure 3 This is a unit cell stacking diagram of 3,5-diamino-4-nitropyrazole perchlorate of the present invention (viewing angle γ).

[0036] Figure 4 The carbon NMR spectrum of 3,5-diamino-4-nitropyrazole perchlorate of the present invention (the solvent is deuterated dimethyl sulfoxide).

[0037] Figure 5 The hydrogen nuclear magnetic spectrum of 3,5-diamino-4-nitropyrazole perchlorate of the present invention (the solvent is deuterated dimethyl sulfoxide).

[0038] Figure 6 The infrared spectrum of 3,5-diamino-4-nitropyrazole perchlorate of the present invention is shown in FIG.

[0039] Figure 7 This is a thermal analysis diagram of 3,5-diamino-4-nitropyrazole perchlorate of the present invention. DETAILED DESCRIPTION

[0040] The following examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0041] Example 1

[0042] 3,5-diamino-4-nitropyrazole (2.4 g, 10 mmol) was suspended in 70% perchloric acid (1.43 g, 10 mmol), heated to 50°C, and stirred for 30 min. After the reaction solution cooled to room temperature, the reaction solution was poured into ethyl acetate, stirred for about 5 min, filtered, the solid was collected, and the solid was washed with ethyl acetate, and then dried in a vacuum oven at 50°C to obtain 3,5-diamino-4-nitropyrazole perchlorate (yield: 91.3%), a white powdery solid.

[0043] Example 2

[0044] 3,5-diamino-4-nitropyrazole (2.4 g, 10 mmol) was suspended in 70% perchloric acid (1.70 g, 12 mmol), heated to 50°C, and stirred for 30 min. After the reaction cooled to room temperature, the reaction solution was poured into ethyl acetate, stirred for about 5 min, filtered, the solid was collected, and washed with ethyl acetate, and then dried in a vacuum oven at 50°C to obtain 3,5-diamino-4-nitropyrazole perchlorate (yield: 95.8%), a white powdery solid.

[0045] Example 3

[0046] 3,5-diamino-4-nitropyrazole (2.4 g, 10 mmol) was suspended in 70% perchloric acid (2.0 g, 1.4 mmol), heated to 50°C, and stirred for 30 min. After the reaction solution cooled to room temperature, the reaction solution was poured into ethyl acetate, stirred for about 5 min, filtered, the solid was collected, and the solid was washed with ethyl acetate, and then dried in a vacuum oven at 50°C to obtain 3,5-diamino-4-nitropyrazole perchlorate (yield: 95.2%), a white powdery solid.

[0047] Example 4

[0048] In order to study the possible application of 3,5-diamino-4-nitropyrazole perchlorate (replaced by A in the formula) in solid propellants, the energy properties of 3,5-diamino-4-nitropyrazole perchlorate in CL-20 propellant were estimated using EXPLO5 under the conditions of pc=70atm, pe=1atm, and T0=298K. 62％ / CL-20 20％ / Al 18％ The specific impulse calculation was performed for the basic formula, and the effect of replacing AP with 3,5-diamino-4-nitropyrazole perchlorate was investigated. The results are listed in Table 1. In Table 1, I sp is the theoretical specific impulse, C * is the characteristic velocity, T c is the combustion chamber temperature.

[0049] It can be seen from Table 1 that the theoretical specific impulse is increased from 253.0s to 285.2s by replacing ammonium perchlorate with 3,5-diamino-4-nitropyrazole perchlorate, which indicates that the 3,5-diamino-4-nitropyrazole perchlorate of the present invention is a high-energy oxidant with excellent comprehensive performance.

[0050] Table 1. Energy properties of AP / CL-20 / Al / A propellant formulations

[0051]

[0052] The perchloric acid solution of 3,5-diamino-4-nitropyrazole (Example 1) was slowly evaporated at room temperature to obtain a single crystal thereof, and an X-ray single crystal diffraction test was performed. The crystal structure thereof is as follows: Figure 1 , Figure 2 and Figure 3 Its unit cell parameters are shown in Table 2.

[0053] Table 2. Unit cell parameters of 3,5-diamino-4-nitropyrazole perchlorate

[0054]

[0055]

[0056] 3,5-diamino-4-nitropyrazole perchlorate (Example 1) was characterized, and the analysis results were as follows:

[0057] See the NMR carbon spectrum Figure 4 , 13 C NMR (DMSO-d6): δ106.57, 149.2ppm.

[0058] H NMR spectrum Figure 5 , 1 H(DMSO-d6):δ2.51,9.26ppm.

[0059] Infrared spectrum Figure 6 , IR(ATR): 3418,3304,3232,1686,1650,1524,1395,1311,1210,1045,936,774,651,629cm -1 .

[0060] Thermal analysis diagram Figure 7 The initial thermal decomposition temperature of 3,5-diamino-4-nitropyrazole perchlorate is 204.4°C.

[0061] Elemental analysis 3,5-diamino-4-nitropyrazole perchlorate C3H6O6N5Cl (243.00): found (calculated) C14.50% (14.79%), H 2.51% (2.48%), N 28.65% (28.75%).

[0062] After testing, the impact sensitivity of 3,5-diamino-4-nitropyrazole perchlorate (Example 1) is 12J, and the friction sensitivity is 200N.

[0063] The oxygen-nitrogen calorimeter test and calculation showed that 3,5-diamino-4-nitropyrazole perchlorate (Example 1) had a relatively high enthalpy of formation of 148.2 kJ·mol -1 According to the density meter test, the density of 3,5-diamino-4-nitropyrazole perchlorate solid powder (Example 1) at 298K is 1.97g·cm -3 ; Using EXPLO5V6.05.04 to calculate the detonation performance, the detonation pressure is 38.23GPa and the detonation velocity is 9001m·s -1 .

Claims

1. A high energy oxidant 3,5-diamino-4-nitropyrazole perchlorate, characterized in that: The chemical formula of 3,5-diamino-4-nitropyrazole perchlorate is C3H6O6N5Cl, and the structural formula is:

2. The high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate according to claim 1, characterized in that:

2. The crystal structure of 3,5-diamino-4-nitropyrazole perchlorate has the following characteristics: Crystal system: orthorhombic; Point group: -P2 ac / 2n; Unit cell parameters: alpha=90, beta=90, gamma=90; Unit cell volume: Z = 8; Density: 2.013 g cm -3 (150K).

3. A method for synthesizing the high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate according to claim 1, characterized in that: include: Step (1), suspending 3,5-diamino-4-nitropyrazole in a perchloric acid solution and stirring to react; Step (2), mixing the reaction solution obtained in step (1) with ethyl acetate, and collecting and washing the solid; Step (3) The solid obtained in step (2) is vacuum dried to obtain 3,5-diamino-4-nitropyrazole perchlorate.

4. The method for synthesizing the high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate according to claim 3, characterized in that: In step (1), the molar ratio of 3,5-diamino-4-nitropyrazole to perchloric acid is 1:1 to 1:1.

4.

5. The method for synthesizing the high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate according to claim 3, characterized in that: In step (1), the mass fraction of the perchloric acid solution is 70%.

6. The method for synthesizing the high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate according to claim 3, characterized in that: In step (1), the reaction temperature is 25 to 50° C. and the reaction time is 0.5 to 1 h.

7. The method for synthesizing the high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate according to claim 3, characterized in that: In step (2), the solid is washed with ethyl acetate.

8. The method for synthesizing the high-energy oxidant 3,5-diamino-4-nitropyrazole perchlorate according to claim 3, characterized in that: In step (3), the drying temperature is 35 to 50°C.

9. Use of the 3,5-diamino-4-nitropyrazole perchlorate according to claim 1 as an oxidant in a solid propellant.

10. A solid propellant, characterized in that: The invention contains the 3,5-diamino-4-nitropyrazole perchlorate as claimed in claim 1.

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