Process for the preparation of trinitromethyl tricyclic series energetic compounds

Abstract

This invention relates to a method for preparing trinitromethyl tricyclic compounds containing nitrogen-rich groups, belonging to the field of energetic materials technology. The specific preparation steps are as follows: Scheme 1 uses 2,3-diaminomaleonitrile to obtain the corresponding methyl ester-substituted intermediate through multiple steps of cyclization, acidification, and esterification. Then, through multiple steps of hydrazine substitution, cyclization with ethyl 3-ethoxy-3-iminopropionate hydrochloride, ester hydrolysis, and nitration, the target compound trinitromethyl tricyclic compound 2 is successfully synthesized. Scheme 2 uses ethyl diazonium acetate to obtain the corresponding methyl ester-substituted intermediate through multiple steps of cyclization, acidification, and esterification. Then, through multiple steps of hydrazine substitution, cyclization with ethyl 3-ethoxy-3-iminopropionate hydrochloride, nitration, salt formation, and renitration, the target compounds trinitromethyl tricyclic compounds 1, 3, and 4 are synthesized. The target compound has advantages such as high nitrogen content, high density, good thermal stability and excellent detonation performance, and can be used as a component of energetic materials, showing potential application value.

Description

Technical Field

[0001] This invention relates to a method for preparing trinitromethyltricyclic energetic compounds, belonging to the field of energetic materials technology. Background Technology

[0002] In energetic materials research, introducing high-energy groups through framework functionalization is a common method to improve detonation performance. However, a long-standing core challenge in this field is how to balance molecular thermal stability and mechanical sensitivity while increasing energy. High-energy-density materials generally exhibit a contradiction between energy properties (such as detonation velocity and detonation pressure) and safety properties. For example, typical high-energy explosives, such as HMX and CL-20, have much higher mechanical sensitivity than insensitive systems like TATB, ICM-102, and FOX-7, and their thermal decomposition temperatures are usually lower. This phenomenon profoundly reveals the intrinsic connection between the integrity of intramolecular conjugated structures, crystal stacking patterns, and energy release behavior. Therefore, precisely controlling molecular configuration, hydrogen bond networks, and the degree of electron delocalization to break the inherent balance between energy and stability has become key to overcoming the performance bottlenecks of existing energetic materials.

[0003] Against this backdrop, trinitromethyl polycyclic compounds have been rapidly developed. Trinitromethyl (−C(NO2)3), as a high-energy explosive group with an oxygen content as high as 64.0%, can introduce multiple nitro groups at a single substitution site, significantly improving the oxygen balance and heat of formation of the compound. Simultaneously, the large conjugated planar system and ring strain effect of the polycyclic structure not only endow the molecule with a high heat of formation and good thermal stability, but also enhance π-π stacking interactions and intramolecular / intermolecular hydrogen bond networks, effectively reducing mechanosensitivity and demonstrating the potential for synergistic optimization of energy and safety.

[0004]

[0006] Based on the above analysis, this invention designs and synthesizes four trinitromethyl energetic tricyclic compounds with different ring skeletons. These compounds use imidazole, furan, 1,2,3-triazole, and 1,2,4,5-tetraazine as basic skeletons, respectively, and are bridged by 1,2,4-triazole units. Furthermore, a trinitromethyl detonating group is introduced to enhance detonation performance, ultimately yielding a series of novel 1,2,4-triazole-based trinitromethyl tricyclic energetic compounds with advantages such as high nitrogen content, high density, good thermal stability, excellent detonation performance, and environmental friendliness. These compounds can serve as novel high-energy-density materials and have potential applications in the field of energetic materials. Summary of the Invention

[0007] The purpose of this invention is to provide a series of methods for preparing trinitromethyl tricyclic energetic compounds, resulting in a series of novel energetic materials with stable structures and excellent properties.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] The preparation method of the trinitromethyltricyclic series energetic compounds of the present invention comprises the following steps:

[0010] Acetic acid intermediate scheme 1:

[0011] Using 2,3-diaminomaleonitrile as a raw material, hydrochloric acid and sodium nitrite were added to an aqueous solution to obtain 1H-1,2,3-triazol-4,5-dicarboxynitrile. Subsequently, 1H-1,2,3-triazol-4,5-dicarboxynitrile was reacted in an aqueous sodium hydroxide solution for a period of time, followed by dropwise acidification with concentrated hydrochloric acid to obtain 1H-1,2,3-triazol-4,5-dicarboxylic acid. 1H-1,2,3-triazol-4,5-dicarboxylic acid was then esterified with concentrated sulfuric acid in a methanol solution to obtain dimethyl 1H-1,2,3-triazol-4,5-dicarboxylate. Dimethyl 1H-1,2,3-triazol-4,5-dicarboxylate was then reacted with hydrazine hydrate and heated under reflux for 12 hours. h yielded the solid product 1H-1,2,3-triazol-4,5-dicarboxyhydrazide; 1H-1,2,3-triazol-4,5-dicarboxyhydrazide was reacted with ethyl 3-ethoxy-3-iminopropionate in a solvent under reflux to give diethyl 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate; then, diethyl 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate was added to methanol and water containing sodium hydroxide. The mixed solution was reacted for a period of time, and then acidified with concentrated sulfuric acid to obtain 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyldiacetic acid; finally, 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetic acid was added to fuming nitric acid and concentrated sulfuric acid for secondary mixed acid nitration to obtain 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole (2).

[0012] Ammonium salt intermediate scheme 2:

[0013] Step (1) Using ethyl diazonate as raw material, sodium hydroxide is added to an aqueous solution and reacted for a period of time. After filtration, the precipitate is acidified with concentrated hydrochloric acid in an aqueous solution to obtain 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid. Then, 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid is esterified with concentrated sulfuric acid in a methanol solution to obtain dimethyl 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid.

[0014] Step (2) Imidazole-4,5-dicarboxylic acid dimethyl ester, furan-2,5-dicarboxylic acid dimethyl ester and 2H-1,2,4,5-tetrazine-3,6-dicarboxylic acid dimethyl ester were reacted with hydrazine hydrate and heated under reflux for 12 h to obtain solid products 1H-imidazolium-4,5-dicarbonylhydrazine, furan-2,5-dicarbonylhydrazine and 2H-1,2,4,5-tetrazine-3,6-dicarbonylhydrazine respectively.

[0015] Step (3) 1H-imidazolium-4,5-dicarboxyhydrazide, furan-2,5-dicarboxyhydrazide, and 2H-1,2,4,5-tetraazine-3,6-dicarboxyhydrazide were reacted with ethyl 3-ethoxy-3-iminopropionate in a solvent under reflux to obtain diethyl 2,2'-((1H-imidazolium-4,5-diyl)bis(1H-1,2,4-triazolium-5,3-diyl)diacetate, diethyl 2,2'-((furan-2,5-diyl)bis(1H-1,2,4-triazolium-5,3-diyl)diacetate, and diethyl 2,2'-((2H-1,2,4,5-tetraazine-3,6-diyl)bis(1H-1,2,4-triazolium-5,3-diyl)diacetate.

[0016] Step (4) Diethyl 2,2'-((1H-imidazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate, diethyl 2,2'-((furan-2,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate and diethyl 2,2'-((2H-1,2,4,5-tetraazine-3,6-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate were added to fuming nitric acid and concentrated sulfuric acid respectively to form a mixed acid mixture. Nitration yields a dinitromethyl-substituted intermediate, followed by slow dropwise addition of ammonia to give 4,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium diammonium salt, 2,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-furan diammonium salt, and 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazol-5,3-diyl)diammonium salt.

[0017] Step (5) 4,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium diammonium salt, 2,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-furan diammonium salt and 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazol-5,3-diyl)diammonium salt respectively Fuming nitric acid and concentrated sulfuric acid were added for secondary mixed acid nitration to obtain 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium (1), 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine (3) and 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan (4).

[0018] In Scheme 1, concentrated hydrochloric acid is added dropwise to acidify the solution to a pH of approximately 3-4. The ratio of 1H-1,2,3-triazol-4,5-dicarboxylic acid to methanol is 20 mmol: 40-50 mL.

[0019] In step (2) of scheme 2, the ratio of hydrazine hydrate is 1:2 or 1:4.

[0020] The molar ratio of ammonia water to reactants in step (4) of scheme 2 is 1:1 or 1:2.

[0021] The ratio of concentrated sulfuric acid to fuming nitric acid used in step (5) of scheme 2 is 1:1, 1.5:1, or 2:1.

[0022] Beneficial effects

[0023] 1. The trinitromethyl tricyclic energetic compounds of the present invention have advantages such as high nitrogen content, high density, good thermal stability, and excellent detonation performance. Their decomposition products are mainly N2, which is environmentally friendly.

[0024] 2. The raw materials for preparing the trinitromethyl tricyclic energetic compounds of the present invention are readily available, the product yield is high, the synthesis is stable, and the process is safe and reliable.

[0025] 3. The trinitromethyl tricyclic series of energetic compounds of the present invention can be used as novel high-energy-density materials and have potential applications in the field of energetic materials. Attached Figure Description

[0026] Figure 1 Involves the corresponding structural units of compounds Figure 2-5 Synthesis of Trinitromethyl Tricyclic Energetic Compounds

[0027] Figure 6Crystal structure diagram of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium

[0028] Figure 7 DSC curve of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazole

[0029] Figure 8 TG curve of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazole

[0030] Figure 9 It is a 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole 13 C NMR

[0031] Figure 10 DSC curve of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole

[0032] Figure 11 TG curve of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole

[0033] Figure 12 It is 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan 1 H NMR

[0034] Figure 13 DSC curve of 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan

[0035] Figure 14 TG curve of 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan

[0036] Figure 15 Crystal structure diagram of 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine

[0037] Figure 16 DSC curve of 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine

[0038] Figure 17TG curve of 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine Detailed Implementation

[0039] The present invention is implemented through the following embodiments, but the conditions and results described in the implementation do not constitute a limitation on the content and rights of the invention.

[0040] Example 1

[0041] 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium (1), the preparation steps of this compound are as follows:

[0042] (1) Dimethyl imidazole-4,5-dicarboxylate (0.92 g, 5 mmol) was added to a 50 mL two-necked flask and dissolved in methanol (12 mL). Hydrazine hydrate (80%, 5 mL) was slowly added dropwise to the solution. The reaction mixture was refluxed at 80 °C for 12 hours. After cooling to room temperature, a white turbid liquid was obtained. The precipitate was filtered and collected, washed three times with methanol, and dried under reduced pressure to obtain a white precipitate of 1H-imidazole-4,5-dicarboxyhydrazide.

[0043] (2) Ethyl 3-ethoxy-3-iminopropionate hydrochloride (4 g, 20.44 mmol) was dissolved in acetonitrile (30 ml) and placed in a 100 ml Erlenmeyer flask. Then, Et3N (1 ml) was added dropwise at room temperature and the mixture was stirred for 0.5 h. 1H-imidazolium-4,5-dicarboxyhydrazide (0.64 g, 3.49 mmol) was dissolved in glacial acetic acid (8 ml) and then added to the acetonitrile mixture. The reaction mixture was refluxed at 110 °C for 12 h. The reaction was then cooled to room temperature, and the solid was filtered. The solid was washed three times with acetonitrile and dried under reduced pressure to give diethyl 2,2'-((1H-imidazolium-4,5-diyl)bis(1H-1,2,4-triazolium-5,3-diyl)diacetate.

[0044] (3) Under ice-water bath conditions (0 °C), compound 2,2'-((1H-imidazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diethyl diacetate (0.605 g, 1.55 mmol) was added to a mixture of acid H2SO4 (98%, 3 ml) and HNO3 (100%, 3 ml). After stirring at room temperature for 24 h, the reaction mixture was poured into ice water and the precipitate was filtered. The mother liquor was extracted with ethyl acetate, dried with anhydrous sodium sulfate, and the solvent was rotary evaporated to obtain a yellowish-white powder of (2,2'-((1H-imidazol-4,5-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazol-5,3-diyl)diethyl diacetate).

[0045] (4) Dissolve 0.62 g (1H-imidazolium-4,5-diyl)bis(3-(gem-dinitromethyl)-1H-1,2,4-triazolium-5,3-diyl)diethyl diacetate in 20 ml of ethyl acetate and 10 ml of methanol. Gradually add ammonia water until the solution changes from yellow-green to bright yellow. After standing, a yellow precipitate precipitates. Filter to obtain (4,5-bis[3-(gem-dinitromethyl)-1H-1,2,4-triazolium-5-yl]-1H-imidazolium diammonium salt).

[0046] (5) Under ice-water bath conditions (0 °C), (4,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium diammonium salt) (0.598 g, 1.8781 mmol) was added in portions to 5 ml of concentrated sulfuric acid and 3 ml of fuming nitric acid. The reaction mixture was stirred at 0 °C for 0.5 h, and then the reaction was continued at room temperature for 12 h. The mixture was quenched in ice, and a white flocculent precipitate of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole (1) was precipitated.

[0047] 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazol(1), belonging to the monoclinic system, space group P-1, a=9.1740(3) Å, b=9.4719(3) Å, c=13.6243(4) Å, α=83.112(10)°, β=73.128(10)°, γ=64.257(10)°, Z=2, crystal volume 1020.46(6) [Å] 3 Crystal density 1.732 g·cm³ -3 Its crystal structure diagram is as follows Figure 6 As shown.

[0048] Differential scanning calorimetry (DSC) analysis was performed on 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole, and its temperature was 5 °C·min. -1 The DSC curves at the heating rate are as follows: Figure 7 As shown, the compound begins to decompose at 122.74 °C, releasing a large amount of heat.

[0049] The DSC, NMR, IR, mass spectrometry, and sensitivity test data of the target compound 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole are as follows:

[0050] DSC (5 °C min -1): 122.74 ºC (dec); 1 H NMR (DMSO-d6, 400 MHz): δ 8.3ppm; 13 C NMR (DMSO‐d6, 151 MHz): δ 150.68, 147.94, 140.40, 122.75 ppm; IR(KBr)ν: 3053(m), 2893(m), 1593(s), 1512(s), 1288(s), 1223(s), 1169(s), 1099(s),966(s), 796(s), 588(s) cm -1 ; ESI‐MS (in CH3OH): (m / z) Calcd. (found): 499.0096(499.0049) 453.0155(453.0120) for [MH / NO2] ‐ ; Impact sensitivity: 11.5 J; friction tester: 360 N.

[0051] Example 2

[0052] 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-2H-1,2,3-triazole (2), the preparation steps of this compound are as follows:

[0053] (1) 2,3-Diaminomaleitrile (2.16 g, 20.0 mmol) was dissolved in 25 ml of water, and hydrochloric acid (12 mol / L, 1.67 ml) was added. Sodium nitrite (1.38 g, 20.0 mmol) was gradually added under ice-water bath conditions, while keeping the reaction temperature below 4 °C. Then the temperature was raised to 60 °C and the reaction was stirred for 2 h. After filtration, vacuum filtration was performed to obtain a light yellowish-brown solid, 1H-1,2,3-triazol-4,5-dicarboxynitrile.

[0054] (2) 1H-1,2,3-triazol-4,5-dicarboxynitrile (1.19 g, 10.0 mmol) was dissolved in water (10 ml) and NaOH (2.00 g, 50 mmol), and refluxed at 100 °C for 5 h. After cooling to room temperature, hydrochloric acid (12 mol / L) was added until the pH was approximately 1. The reaction was then stirred at 0 °C for 0.5 h, the precipitate was filtered and washed with cold water to obtain a white solid, 1H-1,2,3-triazol-4,5-dicarboxylic acid.

[0055] (3) 1H-1,2,3-triazol-4,5-dicarboxylic acid (1.57 g, 10.0 mmol) was added to methanol (20 ml) and 98% sulfuric acid (4 ml), and refluxed at 65 °C for 5 h. After cooling to room temperature, NaHCO3 was added until the pH was neutral. The methanol was removed by rotary evaporation of the filtrate, and deionized water (15 ml) was added. After mixing well, the mixture was extracted with ethyl acetate (3 × 20 ml), and the ethyl acetate was removed by rotary evaporation to obtain a white-green solid, which was dimethyl 1H-1,2,3-triazol-4,5-dicarboxylic acid.

[0056] (4) 0.925 g (5 mmol) of compound 1H-1,2,3-triazole-4,5-dicarboxylic acid dimethyl ester was added to 25 ml of anhydrous methanol, stirred and dissolved, and then hydrazine hydrate (80%, 2.5 ml) was slowly added dropwise. The mixture was refluxed for 12 h. The precipitate was filtered and washed with methanol to obtain a white solid 1H-1,2,3-triazole-4,5-dicarboxylic acid hydrazine.

[0057] (5) Ethyl 3-ethoxy-3-iminopropionic acid hydrochloride (4 g, 20.44 mmol) was dissolved in acetonitrile (30 ml), and triethylamine (0.5 ml) was added at room temperature. The mixture was stirred for 0.5 h. Then, 1H-1,2,3-triazol-4,5-dicarboxyhydrazide (0.646 g, 3.49 mmol) was dissolved in glacial acetic acid (8 ml), and then transferred to the hydrochloride solution. The mixture was refluxed at 110 °C for 12 h. The suspension was cooled to room temperature, filtered, and washed three times with deionized water to obtain a grayish-white solid, 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diethyl diacetate.

[0058] (6) Dissolve 1.5 g NaOH in 15 ml deionized water and stir at 80 °C until dissolved. Then add 0.75 g, 2 mmol of 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetic acid diethyl ester. React for 4 h. Then transfer to an ice-water bath and stir. Add concentrated sulfuric acid dropwise until the pH is neutral. Filter and wash three times with methanol to obtain a yellowish-white solid of 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetic acid.

[0059] (7) 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetic acid (0.638 g, 2 mmol) was placed in an Erlenmeyer flask and stirred for 0.5 h under ice-salt bath conditions. Then, 5 ml of concentrated sulfuric acid and 3 ml of fuming nitric acid were added successively, and the mixture was stirred for another 0.5 h under ice-salt bath conditions. The mixture was then reacted at room temperature for 24 h. The solution was quenched with ice to precipitate the precipitate, which was then filtered and washed three times with deionized water to obtain a pale yellow precipitate of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-2H-1,2,3-triazole (2).

[0060] The structure of 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-2H-1,2,3-triazole was characterized, and its specific structure was confirmed by carbon NMR spectroscopy. Figure 9 As shown. Furthermore, differential scanning calorimetry (DSC) thermal analysis was performed on it, and its temperature was 5 °C·min. -1 The DSC curves at the heating rate are as follows: Figure 10 As shown, the compound begins to decompose at 103.1 °C, releasing a large amount of heat.

[0061] The DSC, NMR, IR, mass spectrometry, and sensitivity test data of the target compound 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-2H-1,2,3-triazole are as follows:

[0062] DSC (5 °C min -1 ): 103.1 ºC (dec); 1 H NMR (DMSO-d6, 400 MHz); 13 C NMR(DMSO-d6, 151 MHz): δ 156.64, 151.61, 149.62, 148.76, 148.47, 133.16 ppm; IR(KBr) ν: 3510(w), 1591(s), 1439(s), 1284(s), 1173(s), 1122(s), 966(s), 796(s), 631(s); ESI-MS (in CH3OH): (m / z) Calcd. (found): 499.9714 (500.0002)453.9981(454.0073) for [M‐H / NO2] ‐ ; Impact sensitivity: 1 J; friction tester:120 N.

[0063] Example 3

[0064] 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan(3), the preparation steps of this compound are as follows:

[0065] (1) Dimethyl furan-2,5-dicarboxylate (0.92 g, 5 mmol) was dissolved in methanol (12 ml), and hydrazine hydrate (80%, 5 ml) was slowly added dropwise to the solution. The reaction mixture was refluxed at 80 °C for 12 h. After cooling the reaction mixture to room temperature, a white precipitate was obtained. The precipitate was filtered, washed three times with methanol, and dried under reduced pressure to obtain a white solid furan-2,5-dicarboxyhydrazide.

[0066] (2) Ethyl 3-ethoxy-3-iminopropionic acid hydrochloride (4 g, 20.44 mmol) was dissolved in acetonitrile (30 ml), and then Et3N (1 ml) was added dropwise at room temperature with stirring for 0.5 h. Furan-4,5-dicarboxyhydrazide (0.64 g, 3.49 mmol) was dissolved in glacial acetic acid (8 ml), and then added to the hydrochloride solution. The mixture was heated under reflux at 110 °C for 12 h. The reaction was cooled to room temperature, and a solid precipitated. The solid was filtered, washed three times with acetonitrile, and dried under reduced pressure to give diethyl 2,2'-((furan-2,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate.

[0067] (3) Under ice-water bath conditions (0 °C), 2,2'-((furan-2,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diethyl diacetate (0.605 g, 1.55 mmol) was added to a mixture of acidic H2SO4 (98%, 3 ml) and HNO3 (100%, 3 ml), and stirred at room temperature for 24 h. The reaction mixture was poured into ice water and the precipitate was filtered. The mother liquor was extracted with ethyl acetate, dried with anhydrous sodium sulfate, and then evaporated to dryness to obtain a yellowish-white powder, which is 2,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-furan.

[0068] (4) Dissolve 0.613 g, 1.26 mmol of 2,5-bis[3-(gem-dinitromethyl)-1H-1,2,4-triazol-5-yl]-furan in 20 ml of ethyl acetate and 10 ml of methanol. Then, gradually add ammonia water until the solution changes from yellow-green to bright yellow. After standing, a yellow precipitate is formed. Filter to obtain 2,5-bis[3-(gem-dinitromethyl)-1H-1,2,4-triazol-5-yl]-furan diammonium salt.

[0069] (5) Under ice-water bath conditions (0 °C), 0.598 g of 2,5-bis[3-(gem-dinitromethyl)-1H-1,2,4-triazol-5-yl]-furan diammonium salt (0.8781 mmol) was added in portions to 5 ml of concentrated sulfuric acid and 3 ml of fuming nitric acid. The reaction mixture was stirred at 0 °C for 0.5 h and then continued to react at room temperature for 12 h. The mixture was quenched in ice, and a yellowish-white flocculent precipitate of 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan (3) was precipitated.

[0070] The structure of 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan was characterized, and its specific structure was confirmed by carbon NMR spectroscopy, as shown below. Figure 12 As shown. In addition, differential scanning calorimetry (DSC) thermal analysis was performed at 5℃·min. -1 The DSC curves at the heating rate are as follows: Figure 13 As shown, the compound begins to decompose at 84.17 °C, releasing a large amount of heat.

[0071] The DSC, NMR, IR, mass spectrometry, and sensitivity test data of the target 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan are as follows:

[0072] DSC (5 °C min -1 ): 84.17 ºC (dec); 1 H NMR (DMSO‐d6, 400 MHz): δ 8.30ppm; 13 C NMR (DMSO‐d6, 151 MHz): δ 157.18, 150.72, 148.37, 124.34, 66.93 ppm; IR(KBr) ν: 1725(m), 1591(s), 1281(s), 1095(s), 965(s), 842(s)cm -1 ; ESI‐MS (inCH3OH): (m / z) Calcd. (found): 499.0009(498.9937) for [M‐H] ‐ ; Impactsensitivity: 13J; friction tester: 360 N.

[0073] Example 4

[0074] 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine (4), the preparation steps of this compound are as follows:

[0075] (1) Dissolve 16 g NaOH in 30 ml of deionized water, add 10 ml of ethyl diazonate (22.6 mmol) dropwise at 60 °C, react for 1.5 h, filter, and wash three times with anhydrous diethyl ether to obtain a brown precipitate. Dissolve the precipitate in 10 ml of ice water, add 8.4 ml of concentrated hydrochloric acid dropwise while stirring, stir at 0 °C for 1 h, filter, and wash three times with anhydrous ethanol to obtain a yellow solid, 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid.

[0076] (2) Thionyl chloride (1.9 ml, 26.1 mmol) was slowly added to 20 ml of methanol solution and stirred thoroughly. After cooling to -20 °C, the reaction was allowed to proceed for 0.5 h. Then, 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid (2.0 g, 11.6 mmol) was slowly added to the above solution in portions. The reaction mixture was allowed to react at room temperature for 2 h. After filtration, the mixture was washed three times with 25 ml of anhydrous diethyl ether to obtain an orange precipitate as dimethyl 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid.

[0077] (3) Dimethyl 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid (2 g, 10 mmol) was dissolved in methanol (8 ml), and then hydrazine hydrate (80%, 2 ml) was slowly added dropwise. The mixture was refluxed at 80 °C for 12 h. The reaction solution was cooled to room temperature to precipitate the precipitate, which was washed with methanol (5 ml × 3) and then with anhydrous diethyl ether (5 ml × 3) to obtain a pale yellow solid, which was 2H-1,2,4,5-tetraazine-3,6-dicarboxyhydrazide.

[0078] (4) Ethyl 3-ethoxy-3-iminopropionic acid hydrochloride (2 g, 10.22 mmol) was dissolved in acetonitrile (20 ml), and triethylamine (0.5 ml) was added at room temperature, followed by stirring for 0.5 h. 2H-1,2,4,5-tetraazine-3,6-dicarboxylhydrazine (0.698 g, 3.49 mmol) was dissolved in glacial acetic acid (4 ml), and then transferred to the previously prepared acetonitrile hydrochloride mixture and refluxed at 80 °C for 12 h. After the reaction was completed, the reaction suspension was cooled to room temperature, and 100 ml of deionized water was added to the suspension. The resulting product precipitate was collected by filtration and dried in a fume hood for 2 h to obtain a brown solid, which is 2,2'-((2H-1,2,4,5-tetraazine-3,6-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diethyl diacetate.

[0079] (5) Under ice-water bath conditions (0 °C), compound 2,2'-((2H-1,2,4,5-tetraazine-3,6-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diethyl diacetate (0.605 g, 1.55 mmol) was added to a mixture of acidic H2SO4 (98%, 3 ml) and HNO3 (100%, 3 ml). After stirring at room temperature for 24 h, the reaction mixture was poured into ice water and the precipitate was filtered. The mother liquor was extracted with ethyl acetate, dried over anhydrous sodium sulfate, and the solvent was rotary evaporated to give a pink viscous solid as 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazol-5,3-diyl)diethyl diacetate.

[0080] (6) 0.712 g, 1.6 mmol of 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazole-5,3-diyl)diacetic acid diethyl ester was dissolved in 20 ml of ethyl acetate and 10 ml of methanol. Ammonia was added dropwise until the solution changed from yellow-green to bright yellow. After standing, a yellow precipitate was formed. The solution was filtered to obtain 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazole-5,3-diyl)diammonium salt.

[0081] (7) Under ice-water bath conditions (0 °C), 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazol-5,3-diyl)diammonium salt (0.733 g, 1.6 mmol) was added to a mixture of acid H2SO4 (98%, 3 ml) and HNO3 (100%, 3 ml). The reaction mixture was stirred at 0 °C for 0.5 h, and then the reaction was continued at room temperature for 12 h. The mixture was quenched in ice, and a pink solid precipitated as 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine (4).

[0082] 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine (4), belonging to the monoclinic system, space group P21 / c, a=9.4444 (10) Å, b=9.9933 (11) Å, c=10.0753 (12) Å, α=90°, β=112.018 (8)°, γ=90°, Z=2, crystal volume 881.56 (18) [Å] 3 Crystal density 1.937 g·cm³ -3 Its crystal structure diagram is as follows Figure 15 As shown.

[0083] Differential scanning calorimetry (DSC) analysis was performed on 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine, and its temperature was 5 °C·min. -1 The DSC curves at the heating rate are as follows: Figure 16 As shown, the compound begins to decompose at 122.74 °C, releasing a large amount of heat.

[0084] The DSC, NMR, IR, mass spectrometry, and sensitivity test data of the target compound 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine are as follows:

[0085] DSC (5 °C min -1 ): 122.74 ºC (dec); 1 H NMR (400 MHz, DMSO); 13 C NMR (125MHz, DMSO): δ 157.65, 152.89, 150.08, 123.19 ppm; IR (KBr): v = 3446(w), 1610(s), 1427(s), 1284(s), 1205(s), 789(s), 621(s)cm -1 ; ESI-MS (in CH3OH): (m / z)Calcd.(found): 512.9918(512.9954) 466.9992(467.0025) for [MH / NO2] ‐ ; Impact sensitivity: 1 J; friction tester: 120 N.

Claims

1. Trinitromethyltricyclic series energetic compounds, characterized in that, Having any one of the structures of formulas 1-4 (1: 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium; 2: 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole; 3: 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan; 4: 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine):

2. The method for synthesizing the trinitromethyl tricyclic series of energetic compounds according to claim 1, characterized in that: The following options are included: Acetic acid intermediate scheme 1: Using 2,3-diaminomaleonitrile as a raw material, hydrochloric acid and sodium nitrite were added to an aqueous solution to obtain 1H-1,2,3-triazol-4,5-dicarboxynitrile. Subsequently, 1H-1,2,3-triazol-4,5-dicarboxynitrile was reacted in an aqueous sodium hydroxide solution for a period of time, followed by dropwise acidification with concentrated hydrochloric acid to obtain 1H-1,2,3-triazol-4,5-dicarboxylic acid. 1H-1,2,3-triazol-4,5-dicarboxylic acid was then esterified with concentrated sulfuric acid in a methanol solution to obtain dimethyl 1H-1,2,3-triazol-4,5-dicarboxylate. Dimethyl 1H-1,2,3-triazol-4,5-dicarboxylate was then reacted with hydrazine hydrate and heated under reflux for 12 hours. h yielded the solid product 1H-1,2,3-triazol-4,5-dicarboxyhydrazide; 1H-1,2,3-triazol-4,5-dicarboxyhydrazide was reacted with ethyl 3-ethoxy-3-iminopropionate in a solvent under reflux to give diethyl 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate; then, diethyl 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate was added to methanol and water containing sodium hydroxide. The mixed solution was reacted for a period of time, and then acidified with concentrated sulfuric acid to obtain 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyldiacetic acid; finally, 2,2'-((1H-1,2,3-triazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetic acid was added to fuming nitric acid and concentrated sulfuric acid for secondary mixed acid nitration to obtain 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-1,2,3-triazole (2). Ammonium salt intermediate scheme 2: Step (1) Using ethyl diazonate as raw material, sodium hydroxide is added to an aqueous solution and reacted for a period of time. After filtration, the precipitate is acidified with concentrated hydrochloric acid in an aqueous solution to obtain 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid. Then, 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid is esterified with concentrated sulfuric acid in a methanol solution to obtain dimethyl 2H-1,2,4,5-tetraazine-3,6-dicarboxylic acid. Step (2) Imidazole-4,5-dicarboxylic acid dimethyl ester, furan-2,5-dicarboxylic acid dimethyl ester and 2H-1,2,4,5-tetrazine-3,6-dicarboxylic acid dimethyl ester were reacted with hydrazine hydrate and heated under reflux for 12 h to obtain solid products 1H-imidazolium-4,5-dicarbonylhydrazine, furan-2,5-dicarbonylhydrazine and 2H-1,2,4,5-tetrazine-3,6-dicarbonylhydrazine respectively. Step (3) 1H-imidazolium-4,5-dicarboxyhydrazide, furan-2,5-dicarboxyhydrazide, and 2H-1,2,4,5-tetraazine-3,6-dicarboxyhydrazide were reacted with ethyl 3-ethoxy-3-iminopropionate in a solvent under reflux to obtain diethyl 2,2'-((1H-imidazolium-4,5-diyl)bis(1H-1,2,4-triazolium-5,3-diyl)diacetate, diethyl 2,2'-((furan-2,5-diyl)bis(1H-1,2,4-triazolium-5,3-diyl)diacetate, and diethyl 2,2'-((2H-1,2,4,5-tetraazine-3,6-diyl)bis(1H-1,2,4-triazolium-5,3-diyl)diacetate. Step (4) Diethyl 2,2'-((1H-imidazol-4,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate, diethyl 2,2'-((furan-2,5-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate and diethyl 2,2'-((2H-1,2,4,5-tetraazine-3,6-diyl)bis(1H-1,2,4-triazol-5,3-diyl)diacetate were added to fuming nitric acid and concentrated sulfuric acid respectively to form a mixed acid mixture. Nitration yields a dinitromethyl-substituted intermediate, followed by slow dropwise addition of ammonia to give 4,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium diammonium salt, 2,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-furan diammonium salt, and 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazol-5,3-diyl)diammonium salt. Step (5) 4,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium diammonium salt, 2,5-bis[3-(genomicdinitromethyl)-1H-1,2,4-triazol-5-yl]-furan diammonium salt and 2,2'-((1,2,4,5-tetraazine-3,6-diyl)bis(3-(genomicdinitromethyl)-1H-1,2,4-triazol-5,3-diyl)diammonium salt respectively Fuming nitric acid and concentrated sulfuric acid were added for secondary mixed acid nitration to obtain 4,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1H-imidazolium (1), 3,6-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-1,2,4,5-tetraazine (3) and 2,5-bis[3-(trinitromethyl)-1H-1,2,4-triazol-5-yl]-furan (4).

3. In Scheme 1, concentrated hydrochloric acid is added dropwise to acidify the solution to a pH of approximately 3-4. The ratio of 1H-1,2,3-triazol-4,5-dicarboxylic acid to methanol is 20 mmol: 40-50 mL.

4. In step (2) of scheme 2, the ratio of hydrazine hydrate is 1:2 or 1:

4.

5. The molar ratio of ammonia water to reactants in step (4) of scheme 2 is 1:1 or 1:

2.

6. The ratio of concentrated sulfuric acid to fuming nitric acid used in step (5) of scheme 2 is 1:1, 1.5:1, or 2:1.

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