1.3-trifluoromethyl-6-nitro-amino- [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound,

the structure is shown as formula (I):

2. the process for preparing 3-trifluoromethyl-6-nitroamino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazines according to claim 1, which comprises the steps of: 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine and ammonia are used as raw materials, a polar solvent is added into the raw materials, the mixture is fully stirred, and after the reaction reaches the end point, the 3-trifluoromethyl-6-amino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine compound is obtained through separation and purification; nitrifying the 3-trifluoromethyl-6-amino- [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound by adopting a nitration system to obtain the 3-trifluoromethyl-6-nitro-amino- [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound, wherein the compound is also a tetrazine energetic compound.

3. A process for the preparation of tetrazines according to claim 2, wherein: the source of the ammonia raw material refers to ammonia gas or ammonia water; the mass ratio of 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine to ammonia is 1: 5-10; the reaction temperature is 0-100 ℃.

4. A process for the preparation of tetrazines according to claim 2, wherein: detecting the complete conversion of the 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine raw material in the reaction solution by using a thin-layer chromatography to judge the reaction end point, wherein the thin-layer chromatography silica gel is silica gel GF254, and a thin-layer chromatography developing agent is a petroleum ether and ethyl acetate solution with the volume ratio of 1-50: 1; the color development mode is iodine color development or ultraviolet color development.

5. The method for preparing tetrazine compounds as claimed in claim 2, wherein the specific steps of separation and purification are as follows: after the reaction is finished, cooling the reaction bottle to room temperature, adding a proper amount of water to quench the reaction, adding ethyl acetate to extract the aqueous phase, combining the organic phases, washing the organic phase by using NaCl aqueous solution in sequence, drying by using anhydrous sodium sulfate, filtering, recovering the solvent by rotary evaporation, and separating the residue by recrystallization or silica gel column chromatography to obtain the 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound.

6. A process for preparing a tetrazine energetic compound as claimed in claim 2 wherein: the nitration system is a reaction in which nitration liquid is adopted for nitration reaction; the nitrifying liquid is dilute nitric acid, concentrated nitric acid, fuming nitric acid, mixed nitric acid and sulfuric acid, nitric acid-trifluoroacetic anhydride or nitric acid-acetic anhydride.

7. A process for preparing a tetrazine energetic compound as claimed in claim 2 wherein: in the nitration reaction, the proportion relation of the mass g of the 3-trifluoromethyl-6-amino- [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound to the volume mL of the nitration liquid is 1: 5-20.

8. A method for the further preparation of an energetic ionic salt using the tetrazine energetic compound obtained by the method of claim 2, characterized in that it comprises the steps of: the tetrazine energetic compound is subjected to acid-base neutralization reaction by adopting nitrogenous micromolecules, and a solid product, namely energetic ionic salt, is obtained by filtering.

9. A method of preparing an energetic ionic salt according to claim 8 wherein: the nitrogen-containing small molecule refers to ammonia water, hydroxylamine aqueous solution, hydrazine hydrate, guanidine or triaminoguanidine.

10. A method of preparing an energetic ionic salt according to claim 8 wherein: in the acid-base neutralization reaction, the amount ratio of the tetrazine energetic compound to the nitrogen-containing micromolecule substance is 1: 1 to 5.

Background

Energetic materials (commonly called explosives) are substances which can generate violent oxidation-reduction reaction under certain external stimulation to release a large amount of energy. In military affairs, energetic materials are the energy source of weapon ammunition, and the energy determines the destruction effect of the weapon. In the civil industry, energetic materials are widely applied to the fields of fireworks, automobile airbags, deep sea drilling and the like. Based on this, the research of energetic materials has attracted attention from countries around the world. The history of the research of energetic materials dates back to black powder in ancient China and nitroglycerin invented by Sobolite in Italian in 19 th century. After the 20 th century, scientists at home and abroad have devoted themselves to the study of energetic material energy enhancement, representative of which are trinitrotoluene (TNT), hexogen (RDX), octogen (HMX), hexanitrohexaazaisowurtzitane (CL-20), etc., where the detonation velocity of CL-20 reaches surprisingly 9706 meters per second. However, with the increase of energy, the strength of chemical bonds in the compound is gradually weakened, and the explosive is more sensitive to external stimuli such as heat, friction, impact, static electricity and the like, so that the safety performance of the explosive is greatly reduced. At present, accidents caused by self-explosion, sympathetic explosion and the like of ammunition all over the world cause immeasurable loss to military and economy of some countries. Therefore, the use of high-energy and low-sensitivity explosives to replace existing explosives is an important means for improving the safety of ammunition usage and storage.

The safety performance of a representative elementary explosive decreases with increasing energy

The energy sources for rocket propellants are also primarily explosives and metal fuels. The aluminum powder has high density, low oxygen consumption, high combustion enthalpy, rich raw materials and low cost, so the aluminum powder becomes a metal fuel widely used in the propellant. But the agglomeration phenomenon generated during the combustion of the aluminum particles can lead to incomplete combustion of the aluminum, so that the combustion efficiency of the aluminum powder is reduced, in addition, the two-phase flow loss is aggravated due to the agglomeration, and the erosion effect of solid products can lead to aggravation of ablation of a heat insulating layer and a spray pipe of a combustion chamber, so that the working safety of an engine is influenced. In view of the agglomeration of aluminum powder in the propellant during combustion, which is a problem, many national scholars have conducted a great deal of research. It has now been found that fluorocarbonsThe material can generate exothermic reaction with aluminum, improve the ignition performance of the aluminum, and generate Al F₃The sublimation of (a) can both reduce the formation of solid phase products and lead to dissociation of the agglomerates. From the above studies, it can be seen that the use of fluorine-containing compounds to solve the agglomeration of aluminum during combustion is a more feasible approach. Considering that in rocket propellants, explosives can both provide energy and initiate the combustion of aluminum powder, the development of energetic materials containing fluorine would be an important approach to solve the above-mentioned problems of rocket propellants.

At present, the research and development of the fluorine-containing group substituted energetic single-substance explosive is still in the primary stage. According to the category of the fluorine-containing group, the preparation of difluoroamino energetic elementary explosives can be mainly divided; preparing a pentafluorosulfur energetic elementary explosive; preparing a fluorine gem-dinitromethyl energetic elementary explosive; preparation of trifluoromethyl substituted energetic single-substance explosive and the like. Representative examples are as follows.

In 2001, Axenrod et al designed and synthesized 3,3 '-difluoroamino-7, 7' -dinitro-octahydro-1, 5-dinitro-1, 5-diazocino (TNFX), which contains two difluoroamino groups and four nitro groups and has a good oxygen balance and a calculated density of 1.96g cm^-3Unfortunately, the detonation velocity is 7.92km · s and the detonation pressure is only^-129.3GPa (Tetrahedron Letters,2001,42,2621-2623.), the structural formula of which is shown below.

TNFX structural formula

The Shreeve project group in 2007 synthesizes pentafluorosulfanylazole energetic derivatives by a click chemistry method, and results show that although the compounds have higher density, the detonation performance of the compounds is not ideal (org. Lett.2007,9, 3841-3844.). For example, 2, 4-diazido-6- (4-pentafluorosulfanyl-1H-pyrazol-3-yl) -1,3, 5-triazine has a density of 1.88 g/cm-3 and an explosion velocity of only 7.46 km/s^-1The detonation pressure was 20.41 GPa.

Representative energetic Pentafluorosulfanylazoles

Zhang Jia Rong et al synthesized 3,3' -bis (fluorodinitromethyl-ONN-azoxy) azoxyfurazan (FDNAF) type fluorogeminal dinitromethyl energetic compound (organic chemistry, 2017,37,2736-2744.), and the molecular structure is shown as follows. The theoretical density of the material is 2.02g cm^-3The detonation velocities and detonation pressures were 9735 m.s, respectively^-144.9GPa, impact falling height of 36cm (10 kg falling weight), decomposition temperature of 233.4 ℃, is an energetic compound with excellent comprehensive performance.

Representative fluoro geminal dinitromethyl energetic compound

Recently, the shreeve task group synthesizes trifluoromethyl substituted triazole energetic materials by using HFOX-7 and trifluoroacetic acid as raw materials (org. Lett.2021,23, 76-80.). Due to the fact that the compound contains gem-dinitro methyl, the compound has good detonation performance (8.7 m.s)^-133.6GPa), and the introduction of trifluoromethyl group makes the compound have excellent sensitivity (IS)>40J；FS>360N)。

Representative trifluoromethyl energetic compounds

In summary, although several single ring energy-containing compounds substituted with fluorine-containing groups have been synthesized. However, in consideration of the fact that the condensed ring compound has a larger plane than the monocyclic compound, the condensed ring compound is easier to form surface-surface stacking in the aspect of crystal stacking, and more modification sites can be used for introducing energy-containing groups, the development of the fluorine-containing group substituted condensed ring energy-containing material has important research significance, and the energy-containing material has a very wide application prospect in the military or civil fields.

Disclosure of Invention

Aiming at the technical problems, the invention provides a fluorine-containing [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine ammonium nitrate and a preparation method thereof. The preparation method is simple and easy to operate.

In order to achieve the above purpose, the invention adopts the following specific technical scheme:

the structure of the 3-trifluoromethyl-6-nitro-amino- [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound is shown as the formula (I):

as a preferred embodiment herein, the structural formula of the 3-trifluoromethyl-6-nitroamino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine compound is:

as a preferred embodiment of the present application, the process for preparing 3-trifluoromethyl-6-nitroamino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine compound comprises the following steps: 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine and ammonia are used as raw materials, a polar solvent is added into the raw materials, the mixture is fully stirred, and after the reaction reaches the end point, the 3-trifluoromethyl-6-amino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine compound is obtained through separation and purification. Nitrifying the 3-trifluoromethyl-6-amino- [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound by adopting a nitration system to obtain the 3-trifluoromethyl-6-nitro-amino- [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound, wherein the compound is also a tetrazine energetic compound.

As a preferred embodiment herein, the source of the ammonia source is ammonia gas or ammonia water; the mass ratio of 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine to ammonia is (1: 5-10); the reaction temperature is 0-100 ℃.

As a better embodiment in the application, the reaction end point is judged by detecting the complete conversion of a 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine raw material in a reaction solution through thin-layer chromatography, the thin-layer chromatography silica gel is silica gel GF254, and a thin-layer chromatography developing agent is a petroleum ether and ethyl acetate solution with the volume ratio of 1-50: 1; the color development mode is iodine color development or ultraviolet color development.

As a preferred embodiment in the present application, the specific steps of separating and purifying are as follows: after the reaction is finished, cooling the reaction bottle to room temperature, adding a proper amount of water to quench the reaction, adding ethyl acetate to extract the aqueous phase, combining the organic phases, washing the organic phase by using NaCl aqueous solution in sequence, drying by using anhydrous sodium sulfate, filtering, recovering the solvent by rotary evaporation, and separating the residue by recrystallization or silica gel column chromatography to obtain the 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazole [4,3-b ] [1,2,4,5] tetrazine compound.

As a preferred embodiment in the present application, the nitration system refers to a reaction in which a nitration liquid is used for nitration reaction; the nitrifying liquid is dilute nitric acid, concentrated nitric acid, fuming nitric acid, mixed nitric acid and sulfuric acid, nitric acid-trifluoroacetic anhydride or nitric acid-acetic anhydride. In the nitration reaction, the proportion relationship between the mass g of the tetrazine compound and the volume mL of the nitration liquid is 1: 5-20.

As a preferred embodiment of the present application, the method for preparing an energetic ionic salt from the tetrazine energetic compound obtained by the method comprises the following steps: the tetrazine energetic compound is subjected to acid-base neutralization reaction by adopting nitrogenous micromolecules, and a solid product, namely energetic ionic salt, is obtained by filtering.

As a preferred embodiment herein, the nitrogen-containing small molecule refers to ammonia, aqueous hydroxylamine, hydrazine hydrate, guanidine, or triaminoguanidine. In the acid-base neutralization reaction, the amount ratio of the tetrazine energetic compound to the nitrogen-containing micromolecule substance is 1: 1 to 5.

As a preferred embodiment of the present invention, the ammonium salt of 3-trifluoromethyl- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine-6-nitramine prepared by the above method IS an energetic material (IS >40J, FS >360N) which has a high density (p ═ 1.78), good thermal stability (thermal decomposition temperature 194 ℃) and IS not sensitive to external stimuli.

Compared with the prior art, the invention has the following beneficial effects:

the preparation method comprises the following steps of (I) taking easily prepared 3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine as a raw material, and carrying out three-step reaction to obtain the 3-trifluoromethyl-6-nitroamino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine compound and energetic material containing energetic ionic salt.

And (II) the reaction condition is mild, the operability is strong, the cost is low, the safety is high, the reaction conversion rate and the yield are high, the process flow is short, and the reaction scale is easy to expand.

And (III) the product is a high-energy low-sensitivity fluorine-containing nitrogen-rich condensed ring energetic material, is simple to separate, and has the advantage of being suitable for industrial production.

Drawings

FIG. 1, FIG. 2 and FIG. 3 show the 3-trifluoromethyl-6-nitroamino- [1,2,4] obtained in example 1]Triazole [4,3-b ]][1,2,4,5]Process for producing tetrazine compound (3)¹H NMR spectrum,¹³CNMR spectra and single crystal diffractograms;

FIGS. 4,5 and 6 are views showing the corresponding energetic ammonium salt (4) of the tetrazine compound (3) obtained in example 1¹H NMR spectrum,¹³CNMR spectra and single crystal diffractograms.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.

It should be noted that, in order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

3-trifluoromethyl-6- (3, 5-dimethylpyrazole) - [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine is a known compound and can be synthesized by the prior art.

The polar solvent is cheap and easy to obtain, is used as a reaction solvent, is beneficial to dissolving a reactant substrate, and orderly promotes the nucleophilic substitution reaction or the acid-base neutralization reaction, thereby effectively avoiding side reaction and improving the reaction yield; n, N-Dimethylformamide (DMF) and N-methylpyrrolidone (NMP) are commonly used aprotic polar solvents, so anhydrous N-methylpyrrolidone is used as the reaction solvent in all of the examples.

Example 1 preparation of the compound 3-trifluoromethyl-6-amino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine (2):

to a 250mL dry three-necked flask equipped with a magnetic stirrer was added compound 1(2.84g,10mmol), about 50mL of NMP as a solvent, and ammonia gas was bubbled through the mixture for half an hour with stirring. The reaction flask was then placed in an oil bath at 50 ℃ and stirred well for 2 h. After confirming the end of the reaction by thin layer chromatography, the reaction flask was cooled to room temperature, an appropriate amount of aqueous solution was added to quench the reaction, ethyl acetate was added to extract the aqueous phase, the organic phases were combined, the organic phase was washed with a saturated aqueous NaCl solution, dried over anhydrous sodium sulfate, filtered, the solvent was recovered by rotary evaporation, and after column chromatography of the residue, 1.7g of yellow solid (2) was obtained in 83% yield.

Td 219℃；¹H NMR(600MHz,DMSO-d6)δ8.56(s,2H).¹³C NMR(151MHz,DMSO-d6)δ157.61,151.00,135.00,117.61.IR(KBr)_max 3340,3222,2927,1630,1614,1532,1474,1378,1212,1185,1147,1020,939,756,682cm^-1；elemental analysis(％)for C₄H₂F₃N₇(205.1):calcd C,23.42；H,0.98；N,47.80.Found:C 23.62；H 1.23；N 46.33.

Example 2 preparation of the compound 3-trifluoromethyl-6-nitroamino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine (3):

30mL of concentrated sulfuric acid was added to a dry, oxygen-free nitrogen-blanketed reaction tube, the reaction flask was cooled to 0 ℃ in a cryotank, and 15mL of pure nitric acid was added dropwise thereto, followed by slow addition of Compound 2(2g,10mmol) prepared in example 1. After 3 hours of reaction, the reaction was poured into ice water and filtered to give the solid product 3 in 77% yield.

Td 113℃；1H NMR(600MHz,DMSO-d6)δ6.47(s,1H),2.60(s,3H),2.32(s,3H).¹³C NMR(151MHz,DMSO-d6)δ158.94,149.87,135.71(d,J＝41.2Hz),120.30(d,J＝289.8Hz).IR(KBr)_max 3127,2980,1636,1539,1472,1307,1243,1164,1061,1024,758,665cm^-1；elemental analysis(％)for C₄HF₃N₈O₂(250.1):calcd C,19.21；H,0.40；F,22.79；N,44.80；O,12.79.Found:C 19.27；H 0.53；N 46.02.

EXAMPLE 3 preparation of the Compound 3-trifluoromethyl- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine-6-nitramine ammonium salt (4):

to an anhydrous single neck flask was added compound 3(2.5g,10mmol), anhydrous ethanol 20mL, 25% aqueous ammonia (1.4g,20mmol) was added dropwise to the flask, stirring was continued at 50 ℃ for 2h and filtration gave 2.27g of a yellow solid, 86% yield of the product 3-trifluoromethyl- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine-6-nitramine ammonium salt (4).

The thermal decomposition temperature test of Compound 4 by Differential Scanning Calorimeter (DSC) showed that the thermal decomposition temperature of the compound was 194 ℃ and the density of the compound was (1.7832 g/cm)^-3) The impact sensitivity and the friction sensitivity of the compound are respectively measured by an impact sensitivity instrument and a friction sensitivity instrument>40J,>360N。

Td 194℃；1H NMR(600MHz,DMSO-d6)δ7.21(s,4H).13C NMR(151MHz,DMSO-d6)δ159.14,149.74,135.73,120.03.IR(KBr)_max 3331，3053，1690，1612，1507，1472，1257，1159，1019，966，921，738，671cm^-1；elemental analysis(％)for C₄H₄F₃N₉O₂(267.0):calcd C,17.99；H,1.51；N,47.19.Found:C 17.67；H 1.63；N 46.05.

Example 4 preparation of the compound 3-trifluoromethyl-6-nitroguanidino- [1,2,4] triazolo [4,3-b ] [1,2,4,5] tetrazine (5):

to a 250mL dry three-necked flask equipped with a magnetic stirrer was added compound 1(2.84g,10mmol), potassium carbonate (2.76g,20mmol), nitroguanidine (1.04g,10mmol), and acetonitrile solvent (ca. 50 mL). The reaction flask was then placed in an oil bath at 90 ℃ and stirred well for 4 h. After confirming the end of the reaction by thin layer chromatography, the reaction flask was cooled to room temperature, an appropriate amount of aqueous solution was added to quench the reaction, ethyl acetate was added to extract the aqueous phase, the organic phases were combined, the organic phase was washed with a saturated aqueous NaCl solution, dried over anhydrous sodium sulfate, filtered, the solvent was recovered by rotary evaporation, and after column chromatography of the residue, 2.4g of yellow solid (5) was obtained in 82% yield.

The thermal decomposition temperature test of Compound 5 by Differential Scanning Calorimeter (DSC) showed that the thermal decomposition temperature of the compound was 222 ℃ and the density of the compound was (1.912 g/cm) by densitometer^-3) The combination is measured by adopting an impact sensitivity meter and a friction sensitivity meterThe impact sensitivity and the friction sensitivity of the object are respectively>40J,>360N。¹H NMR(600MHz,DMSO-d6)δ13.25(s,1H),9.79(s,3H).¹³C NMR(151MHz,DMSO-d6)δ157.14,150.57,136.21,118.97.IR(KBr)max:3520.19，3445.78，3365.79，1640.28，1595.26，1572.77，1538.00，1471.06，1380.06，1279.69，1241.19，1182.61，1069.50，1026.20，756.74.elemental analysis(％)for C₅H₃F₃N₁₂O₂(267.0):calcd C,20.56；H,1.04；N,47.95.Found:C20.35；H 1.33；N 46.88.

The above examples are only preferred embodiments of the patent, but the scope of protection of the patent is not limited thereto. It should be noted that, for those skilled in the art, without departing from the principle of this patent, several improvements and modifications can be made according to the patent solution and its patent idea, and these improvements and modifications should also be regarded as the protection scope of this patent.