Pyrazole / guanidine chimera explosive and preparation method thereof
Through the mother-born molecular structure design based on dinitropyrazole and nitroguanidine, two new chimeric explosive molecules were developed, which solved the problem of difficulty in synthesis of high-energy and low-sensitivity explosive molecules, and achieved efficient synthesis and excellent thermal stability and detonation performance significantly improves its application potential in weapon systems.
Patent Information
- Application Number
- CN202411393917.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-08
- Publication Date
- 2025-01-07
AI Technical Summary
In the field of energy-containing materials, there are complexity and difficulty in designing and synthesizing high-energy low-sensitivity explosive molecules. The existing methodology is developing slowly, making it difficult to fully utilize the potential of existing materials, resulting in a long development cycle and great difficulty.
Based on the parent molecular structure of dinitropyrazole and nitroguanidine, two new chimeric explosive molecules 3,4-dinitro-1H-5-guanidine pyrazole and 3,4-dinitro- 1H-5-nitroguanidine pyrazole and controls the reaction conditions to achieve efficient synthesis.
These new explosive molecules perform excellent in thermal stability, sensitivity and detonation performance. They have high thermal decomposition temperature and low sensitivity. The explosion speed and detonation pressure are close to or exceed traditional RDX, which significantly improve safety and performance and have important application value.
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Figure CN119263939A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of energetic materials, in particular to a pyrazole / guanidine type chimera explosive and a preparation method thereof. Background Art
[0002] Explosives are the core energy materials for achieving efficient destruction in modern weapon systems. Their energy level, safety and thermal stability have a direct impact on the overall combat effectiveness of weapons and equipment. Therefore, the performance of explosives is the key to national defense and security construction.
[0003] As a research focus in the field of energetic materials, the molecular design of furazan compounds is crucial to achieve a balance between high energy and high stability. By rationally designing the energetic molecular skeleton and selecting appropriate functional groups for arrangement, a molecular structure that meets these requirements can be constructed.
[0004] In recent years, researchers have been committed to integrating high-energy and low-sensitivity structural elements into new molecular structures, from non-cyclic to single-ring, condensed ring, linked ring, linked polycyclic, condensed polycyclic, and even condensed ring linked condensed ring, etc. The structures are becoming more and more complex and the synthesis difficulty is getting higher and higher. A simple and efficient method for designing and synthesizing high-energy and low-sensitivity energetic molecules has become a problem that needs to be solved in this field.
[0005] Despite extensive synthetic research, many energetic molecules are underutilized because their comprehensive properties do not meet application requirements. These molecules may excel in some aspects but lack in others. Using explosive molecules as building blocks to construct energetic molecules with "hybrid" or "chimera" characteristics can fully utilize the potential of these "useless" molecules.
[0006] Molecular chimeras are of great value in designing and synthesizing functional organic molecules with specific performance requirements and have been widely used in the field of biochemistry. Faced with the increasing complexity of explosive molecular skeleton design and the difficulty of synthesis, it has become particularly urgent to develop new methods suitable for the efficient synthesis of explosive molecules. The emergence of new synthetic methods is often accidental, and the establishment of methodology requires a lot of experimental accumulation and a long period of time.
[0007] Therefore, making full use of known materials and technologies to obtain new molecules that meet the target performance requirements is an important way to shorten the development cycle and reduce the difficulty of development. Summary of the invention
[0008] The purpose of the present invention is to provide a pyrazole / guanidine chimeric explosive and a preparation method thereof in order to solve the above problems. Based on the parent molecular structure of dinitropyrazole and nitroguanidine, the present invention develops two novel chimeric explosive molecules 3,4-dinitro-1H-5-guanidinopyrazole (1) and 3,4-dinitro-1H-5-nitroguanidinopyrazole (2) with excellent performance and successfully synthesizes them. The explosive has important application value in advanced weapons and equipment. These explosive molecules are designed based on the parent molecular structure of dinitropyrazole and nitroguanidine. The technical scheme of the synthesis method is summarized as follows:
[0009] Synthesis of 3,4-dinitro-1H-5-guanidinopyrazole (1):
[0010] 5-Bromo-3,4-dinitro-1H-pyrazole protected with pyrazole nitrogen is used as the starting material. This step can also be performed without using a protecting group.
[0011] The target molecule 3,4-dinitro-1H-5-guanidinopyrazole (1) was synthesized through a substitution reaction and a deprotection step, or directly through a one-step substitution reaction.
[0012] Synthesis of 3,4-dinitro-1H-5-nitroguanidine pyrazole (2):
[0013] The 3,4-dinitro-1H-5-guanidinopyrazole (1) obtained by the above synthesis was used as the starting material.
[0014] The target molecule 3,4-dinitro-1H-5-nitroguanidine pyrazole (2) was further synthesized through nitration reaction.
[0015] The design of this synthetic method makes full use of existing chemical synthesis strategies and achieves the efficient synthesis of new explosive molecules through precise chemical modification and control of reaction conditions.
[0016] The pyrazole / guanidine chimera explosive of the present invention has the following structural formula:
[0017]
[0018] The further scheme is that the synthetic route is as follows:
[0019]
[0020] The preparation method of the pyrazole / guanidine type chimera explosive of the present invention comprises the following steps:
[0021] Step 1, synthesis of 3,4-dinitro-1H-5-guanidinopyrazole (1):
[0022] Dissolve guanidine hydrochloride in excess DMSO, then add solid sodium methoxide to the solution and continue stirring at room temperature for 1-2 hours before filtering to obtain a clear solution;
[0023] Compound 7 was added to the clear solution, and the mixture was reacted at 100°C for 3-6 hours. After the reaction was completed, water was added for quenching, and ethyl acetate was used for extraction. The organic layer after extraction was dried over anhydrous sodium sulfate and filtered, and finally evaporated under vacuum to obtain a large amount of yellow solid. The yellow solid was dissolved in 30 ml of hydrochloric acid solution, stirred at 30°C for 8 hours, and then evaporated under vacuum.
[0024] The vacuum evaporation residue was dissolved in 20 ml of water, and the pH value was adjusted to 5-6 using a saturated sodium acetate solution. At this time, insoluble solids appeared in the solution. The target product 3,4-dinitro-1H-5-guanidinopyrazole (1) was obtained by filtration, washing with water and methanol, and finally drying.
[0025] Step 2, Synthesis of 3,4-dinitro-1H-5-nitroguanidine pyrazole (2):
[0026] Mix concentrated sulfuric acid and fuming nitric acid in an ice water bath, then slowly add compound 3,4-dinitro-1H-5-guanidinopyrazole (1) to the acid mixture, and after adding, stir in an ice water bath for 1-2 hours;
[0027] The reaction solution was poured into ice water for quenching, and the light yellow solid was collected by filtration, washed and dried to obtain the product 3,4-dinitro-1H-5-nitroguanidine pyrazole (2).
[0028] A further solution is that in step 1, the molar ratio of guanidine hydrochloride to solid sodium methoxide is 1:1-1.1.
[0029] A further solution is that in step 1, the structural formula of compound 7 is The molar ratio of compound 7 to guanidine hydrochloride is 0.1-0.2:1.
[0030] A further solution is that in step 1, the concentration of the hydrochloric acid solution is 1.25M-1.35M.
[0031] A further solution is that in step 2, the volume ratio of concentrated sulfuric acid to fuming nitric acid is 1:0.5-1.
[0032] Another aspect of the present invention provides the use of the above-mentioned pyrazole / guanidine chimera explosive as an energetic material.
[0033] In another aspect, the present invention provides the use of the pyrazole / guanidine chimera explosive obtained by the above-mentioned preparation method as an energetic material.
[0034] The beneficial effects of the present invention are:
[0035] The present invention successfully developed two new pyrazole / guanidine chimera energetic molecules, 3,4-dinitro-1H-5-guanidinopyrazole (1) and 3,4-dinitro-1H-5-nitroguanidinopyrazole (2), and their synthesis methods. The characterization results of these molecules in terms of thermal stability, sensitivity and detonation performance showed significant application potential.
[0036] 3,4-Dinitro-1H-5-guanidinopyrazole (1):
[0037] Thermal stability: The thermal decomposition temperature of this molecule is as high as 249°C, which exceeds that of traditional explosive RDX and shows excellent thermal stability.
[0038] Sensitivity: The impact sensitivity is 50J and the friction sensitivity is 252N. These values are much lower than RDX, indicating that molecule (1) is safer.
[0039] Detonation performance: The theoretically calculated detonation velocity is 8742m / s and the detonation pressure is 31GPa, which is comparable to RDX, proving its potential as a high-energy explosive.
[0040] 3,4-Dinitro-1H-5-nitroguanidine pyrazole (2):
[0041] Thermal stability: The thermal decomposition temperature of this molecule is 221°C, which is also higher than that of RDX, showing good thermal stability.
[0042] Sensitivity: The impact sensitivity is 7J and the friction sensitivity is 120N, which is comparable to RDX, further confirming its safety.
[0043] Detonation performance: The theoretically calculated detonation velocity is 9008m / s and the detonation pressure is 35.7GPa, which are significantly better than RDX, highlighting its potential as a high-energy explosive.
[0044] The design and synthesis of these new explosive molecules not only improve thermal stability and safety, but also maintain or enhance detonation performance, making them promising materials for future applications in weapon systems and energetic materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0046] Figure 1The hydrogen NMR spectrum of 3,4-dinitro-1H-5-guanidinopyrazole (1) of the present invention.
[0047] Figure 2 The carbon NMR spectrum of 3,4-dinitro-1H-5-guanidinopyrazole (1) of the present invention.
[0048] Figure 3 The hydrogen nuclear magnetic spectrum of 3,4-dinitro-1H-5-nitroguanidine pyrazole (2) of the present invention is shown in FIG.
[0049] Figure 4 The carbon NMR spectrum of 3,4-dinitro-1H-5-nitroguanidine pyrazole (2) of the present invention. DETAILED DESCRIPTION
[0050] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.
[0051] Example 1
[0052] Synthesis of 3,4-dinitro-1H-5-guanidinopyrazole (1):
[0053] Guanidine hydrochloride (10 equiv., 60 mmol, 5.73 g) was dissolved in DMSO ((60 mL), and then solid sodium methoxide (10 equiv., 60 mmol, 3.24 g) was added thereto. The mixture was stirred at room temperature for 1 hour and then filtered to obtain a clear solution. Next, compound 7 (1 equiv., 6 mmol, 1.92 g) was added to the solution and reacted at 100°C for 3 hours. After the reaction was completed, water was added for quenching, and ethyl acetate was used for extraction. The organic layer after extraction was dried over anhydrous water. Dry with sodium sulfate, filter, and finally evaporate under vacuum to obtain a large amount of yellow solid. Dissolve the yellow solid in 30 ml of hydrochloric acid solution (concentration of 1.25M), stir at 30°C for 8 hours, and then evaporate under vacuum. Dissolve the residue in 20 ml of water, and adjust the pH value to 5-6 with saturated sodium acetate solution. At this time, insoluble solids will appear in the solution. Filter these solids, wash with water and methanol, and finally dry to obtain the product 3,4-dinitro-1H-5-guanidinopyrazole (1) (yield of 72%). By 1H The chemical shifts δ obtained by NMR (400 MHz, DMSO-d6) and 13C NMR (100 MHz, DMSO-d6) analysis were 155.65, 151.13, 145.08, 112.68, respectively. High resolution mass spectrometry (HRMS, ESI) C4H5N7O4 [M-H+], calculated value was 214.0330, and the measured value was 214.0320. The yield was about 72%.
[0054] Example 2
[0055] Synthesis of 3,4-dinitro-1H-5-nitroguanidine pyrazole (2):
[0056] Concentrated sulfuric acid (2 ml) and fuming nitric acid (1 ml) were mixed in an ice-water bath. Then, compound 3,4-dinitro-1H-5-guanidinopyrazole (1) (1 equiv., 2 mmol, 431 mg) was slowly added to the acid mixture. After addition, the mixture was stirred in an ice-water bath for 1 hour. The reaction solution was poured into ice water for quenching. The light yellow solid was collected by filtration, washed and dried to obtain the product 3,4-dinitro-1H-5-nitroguanidinopyrazole (2) (420 mg, 81%). The chemical shifts shown by 1H NMR (400 MHz, DMSO-d6) were δ11.72-11.16 (m, 2H), 9.82 (s, 2H); the chemical shifts of 13C NMR (100 MHz, DMSO-d6) were δ156.92, 148.81, 138.32, 115.50. The molecular weight measured by high-resolution mass spectrometry (HRMS, ESI) is m / z calculated to be C4H4N8O6[M-H+]: 259.0181, and the measured value is 259.0174.
[0057] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further explain various possible combinations. In addition, the various different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.
Claims
1. A pyrazole / guanidine type chimera explosive, characterized in that: It has the following structural formula:
2. The method for preparing a pyrazole / guanidine type chimera explosive according to claim 1, characterized in that: The synthetic route is as follows:
3. The method for preparing the pyrazole / guanidine type chimera explosive according to claim 1, characterized in that: The following steps are involved: Step 1, synthesis of 3,4-dinitro-1H-5-guanidinopyrazole (1): Dissolve guanidine hydrochloride in excess DMSO, then add solid sodium methoxide to the solution and continue stirring at room temperature for 1-2 hours before filtering to obtain a clear solution; Compound 7 was added to the clear solution, and the mixture was reacted at 100°C for 3-6 hours. After the reaction was completed, water was added for quenching, and ethyl acetate was used for extraction. The organic layer after extraction was dried over anhydrous sodium sulfate and filtered, and finally evaporated under vacuum to obtain a large amount of yellow solid. The yellow solid was dissolved in 30 ml of hydrochloric acid solution, stirred at 30°C for 8 hours, and then evaporated under vacuum. The vacuum evaporation residue was dissolved in 20 ml of water, and the pH value was adjusted to 5-6 using a saturated sodium acetate solution. At this time, insoluble solids appeared in the solution. The target product 3,4-dinitro-1H-5-guanidinopyrazole (1) was obtained by filtration, washing with water and methanol, and finally drying. Step 2, Synthesis of 3,4-dinitro-1H-5-nitroguanidine pyrazole (2): Mix concentrated sulfuric acid and fuming nitric acid in an ice water bath, then slowly add compound 3,4-dinitro-1H-5-guanidinopyrazole (1) to the acid mixture, and after adding, stir in an ice water bath for 1-2 hours; The reaction solution was poured into ice water for quenching, and the light yellow solid was collected by filtration, washed and dried to obtain the product 3,4-dinitro-1H-5-nitroguanidine pyrazole (2).
4. The method for preparing a pyrazole / guanidine type chimera explosive according to claim 1, characterized in that: In the step 1, the molar ratio of guanidine hydrochloride to solid sodium methoxide is 1:1-1.
1.
5. The method for preparing the pyrazole / guanidine type chimera explosive according to claim 1, characterized in that: In the step 1, the structural formula of compound 7 is The molar ratio of compound 7 to guanidine hydrochloride is 0.1-0.2:
1.
6. The method for preparing the pyrazole / guanidine type chimera explosive according to claim 1, characterized in that: In step 1, the concentration of the hydrochloric acid solution is 1.25M-1.35M.
7. The method for preparing the pyrazole / guanidine type chimera explosive according to claim 1, characterized in that: In the step 2, the volume ratio of concentrated sulfuric acid to fuming nitric acid is 1:0.5-1.
8. Use of the pyrazole / guanidine type chimera explosive as claimed in claim 1 as an energetic material.
9. Use of the pyrazole / guanidine type chimera explosive obtained by the preparation method as claimed in claims 2 to 7 as an energetic material.