CN114891006A - Fused ring energetic compound containing pyridazinoimidazole or energetic salt thereof and preparation method - Google Patents

Abstract

The invention discloses a pyridazinimidazole fused ring-containing energetic compound or an energetic salt thereof, which forms a series of high-energy density energetic compounds and an energetic salt thereof by introducing a nitroamine group into a pyridazinimidazole fused ring . The invention also discloses a method for preparing a pyridazinimidazole-containing condensed ring-containing energetic compound or an energetic salt thereof, which starts from known and available raw materials and synthesizes a series of pernitroamine condensed compounds with good application prospects through simple steps. Ring energetic compounds.

Description

Fused ring energetic compound containing pyridazinoimidazole or energetic salt thereof and preparation method

Technical Field

The invention relates to the technical field of energetic materials, in particular to a pyridazine imidazole fused ring energetic compound or energetic salt thereof and a preparation method.

Background

With the rapid development of modern energetic material technology, the performance requirements on novel energetic materials are higher and higher. Not only must energetic materials be developed with high energy and high density, but also the materials must have the advantages of thermal stability, low sensitivity, etc. Therefore, in recent years, High Energy Density Materials (hemms) have been receiving attention. The HEDMs have excellent comprehensive performance and are called as 'modern novel high-performance explosives', and high-energy low-sense energetic compounds gradually become hot spots for researching energetic materials.

The nitramine group has the advantage of forming a hydrogen bond network when combined with the nitramine group

When the skeletons of the atoms are connected, the nitramine can also generate hydrogen transfer and tautomerize to a nitrosamine group, thereby forming extra intramolecular hydrogen bonds and greatly promoting the formation of a plane conjugated structure. Compared with a traditional monocyclic or chain skeleton, the fused ring often has the advantages of higher heat generation, better thermal stability and the like, and is widely applied to construction of energetic materials. Therefore, the full-nitramine-substituted condensed ring energetic compound has good application prospect in the HEDMs.

Disclosure of Invention

An object of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.

It is yet another object of the present invention to provide an energetic compound of fused rings containing pyridazinoimidazole or energetic salts thereof which forms a range of energetic compounds with high energy density by combining nitroamines with fused rings.

Still another object of the present invention is to provide a method for preparing an energetic compound containing a pyridazinoimidazole fused ring or an energetic salt thereof, which synthesizes a series of full-nitramine fused ring energetic compounds with good application prospects by simple steps from known available raw materials.

To achieve these objects and other advantages in accordance with the present invention, there is provided a pyridazinoimidazole-containing fused ring energetic compound or an energetic salt thereof, wherein the energetic compound has a structure as shown in the following formula (I):

wherein A-B is C-N or C-NH, D-E is C-N or C-NH, R ₁ 、R ₂ 、R ₃ Are all nitramine groups.

It is preferred that, among others,

when A-B is C ═ N, R ₁ Is composed of

When A-B is C-NH, A-R ₁ Is C ═ N-NO ₂ 。

It is preferred that, among others,

when D-E is C ═ N, R ₃ Is composed of

When D-E is C-NH, D-R ₃ Is C ═ N-NO ₂ 。

Preferably, wherein R2 is

Preferably, the energy-containing salt is an ammonium salt, a hydroxylamine salt or a hydrazine salt.

The object of the present invention can be further achieved by a method for producing a pyridazinoimidazole-containing fused ring energetic compound or an energetic salt thereof, comprising the steps of:

step one, synthesis of intermediate compound of formula (II)

4, 5-dicyano-2-aminoimidazole is taken as a raw material, and reacts with hydrazine hydrate through ring closure reaction to obtain a compound shown in a formula (II);

step two, synthesis of compound of formula (I)

Carrying out one-step or multi-step reaction on the compound of the formula (II) obtained in the step one as an intermediate to obtain a compound of the formula (I) or an energy-containing salt thereof;

preferably, the step one specifically includes the following steps:

s1, adding 4, 5-dicyano-2-aminoimidazole into 1, 4-dioxane, dropwise adding hydrazine hydrate, and reacting for 3 hours at 80 ℃;

s2, removing 1, 4-dioxane after the S1 reaction, adding N, N-dimethylformamide and hydrazine hydrate into the reaction system, and continuing to react for 2 hours at 80 ℃;

s3, filtering, washing, drying, adding hydrochloric acid, heating to 55 deg.C, standing for 4h, cooling to separate out crystal, dissolving in water, adjusting pH to 7 to separate out solid, filtering, and washing with cold water.

Preferably, in the S1, the hydrazine hydrate is 98% hydrazine hydrate.

Preferably, in the step S3, the solvent used for washing is N, N-dimethylformamide.

Preferably, in step S3, the hydrochloric acid is 37% by mass.

The invention at least comprises the following beneficial effects:

1. the invention creatively combines the pyridazine imidazole fused ring and the nitramine group to form the energetic compound with high energy density and better stability, so that the energetic compound has more advantages in the application of energetic materials.

2. According to the preparation method of the pyridazinoimidazole fused ring energetic compound or energetic salt thereof, a series of all-nitramine fused ring energetic compounds with good application prospect can be synthesized by starting from known available raw materials and through simple steps.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

FIG. 1 shows the compound 2.2 HCl. H in example 1 of the present invention ₂ A single crystal structure diagram of O;

FIG. 2 is a structural representation of Compound 2 of example 1 of the present invention;

FIG. 3 shows the compounds 3.3H in example 1 of the present invention ₂ A single crystal structure diagram of O;

FIG. 4 is a Differential Scanning calorimetry (Difference Scanning Calorimeter DSC) profile of Compound 3 in example 1 of the present invention;

FIG. 5 is a NMR spectrum of Compound 3 in example 1 of the present invention;

FIG. 6 is a NMR spectrum of Compound 3 in example 1 of the present invention;

FIG. 7 shows Compound 4. multidot.2H in example 2 of the present invention ₂ A DSC diagram of O;

FIG. 8 shows Compound 4. multidot.2H in example 2 of the present invention ₂ Nuclear magnetic resonance hydrogen spectrum of O;

FIG. 9 shows Compound 4. multidot.2H in example 2 of the present invention ₂ Nuclear magnetic resonance carbon spectrum of O;

FIG. 10 shows Compound 5. H in example 3 of the present invention ₂ A DSC diagram of O;

FIG. 11 shows Compound 5. H in example 3 of the present invention ₂ Nuclear magnetic resonance hydrogen spectrum of O;

FIG. 12 shows Compound 5. H in example 3 of the present invention ₂ Nuclear magnetic resonance carbon spectrum of O;

FIG. 13 is a DSC of compound 6 in example 4 of the present invention;

FIG. 14 is a NMR spectrum of Compound 6 in example 4 of the present invention;

FIG. 15 is a NMR carbon spectrum of Compound 6 of example 4 of the present invention;

FIG. 16 is a DSC of compound 7 in example 5 of the present invention;

FIG. 17 is a NMR spectrum of Compound 7 in example 5 of the present invention;

FIG. 18 is a NMR carbon spectrum of Compound 7 of example 5 of the present invention;

FIG. 19 shows Compounds No. 8 and No. 3H in example 5 of the present invention ₂ A DSC diagram of O;

FIG. 20 shows Compounds No. 8 and No. 3H in example 5 of the present invention ₂ Nuclear magnetic resonance hydrogen spectrum of O;

FIG. 21 shows Compounds No. 8 and No. 3H in example 5 of the present invention ₂ Nuclear magnetic resonance carbon spectrum of O;

FIG. 22 shows Compound 9. multidot.2H in example 6 of the present invention ₂ A DSC diagram of O;

FIG. 23 shows Compound 9. 2H in example 6 of the present invention ₂ Nuclear magnetic resonance of OA hydrogen spectrum;

FIG. 24 shows Compound 9.2H in example 6 of the present invention ₂ Nuclear magnetic resonance carbon spectrum of O;

FIG. 25 shows Compound 10. CH in example 7 of the present invention ₃ DSC profile of OH;

FIG. 26 shows Compound 10. CH in example 7 of the present invention ₃ Nuclear magnetic resonance hydrogen spectrum of OH;

FIG. 27 shows Compound 10. CH in example 7 of the present invention ₃ Nuclear magnetic resonance carbon spectrum of OH;

FIG. 28 shows Compound 11.2H in example 8 of the present invention ₂ A DSC diagram of O;

FIG. 29 shows Compound 11.2H in example 8 of the present invention ₂ Nuclear magnetic resonance hydrogen spectrum of O;

FIG. 30 shows Compound 11.2H in example 8 of the present invention ₂ Nuclear magnetic resonance carbon spectrum of O.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

It is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified.

< example 1>

An energetic compound 3 having the formula:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

step one, synthesis of compound 2

4, 5-dicyano-2-aminoimidazole 1(1.33 g; 10mmol) was added to 1, 4-dioxane (10mL), dissolved dropwise with hydrazine hydrate (98%, 3mL) and then heated at 80 ℃ for 3 h. The 1, 4-dioxane was then removed and 2.5mL of N, N-Dimethylformamide (DMF) and hydrazine hydrate (98%, 5mL) were added to the system and heating continued at 80 ℃ for 2 h. The white solid was filtered, washed with DMF (3mL), dried, added with 9mL of hydrochloric acid (37%), heated to 55 deg.C for 4H, and cooled to precipitate 2.2 HCI.H ₂ O crystal, dissolving crystal in water, and using NaHCO ₃ After adjusting the solution to pH 7, a large amount of white solid precipitated, filtered, and washed with cold water (3mL), to give 2(0.58g, 35%). Compound 2.2 HCl.H ₂ The single crystal structure of O is shown in FIG. 1, and the structural characterization is shown in FIG. 2. T is a unit of _dec ：286.22℃；IR(cm ^-1 )v～＝3456，3395，3339，3104，2707，1679，1625，1560，1480，1432，1276，1242，1118，1033，829，784，752，639，583. ¹ H NMR(DMSO-d6)：5.75(s，6H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ130.4，145.4，163.2；EA(C ₅ H ₇ N ₇ ·0.2H ₂ O，165.16)：Calcd，C：35.59；H：4.42；N：58.10；Found，C：35.23；H：4.65；N：58.83.

Step two, synthesis of Compound 3

To nitric acid (100%, 6mL) was added 2(0.66g, 4mmol) at 0 deg.C and after complete addition the reaction mixture was stirred at room temperature for 2 h. After completion of the reaction, ice (10g) was added, and the mixture was allowed to stand to precipitate, filtered, and washed with cold water (3mL) to obtain yellow solid 3(0.54g, 45%). Compound 3.3H ₂ The structure of the single crystal of O is shown in figure 3, the DSC chart of compound 3 is shown in figure 4, the nuclear magnetic resonance hydrogen spectrum is shown in figure 5, and the nuclear magnetic resonance carbon spectrum is shown in figure 6. T is _dec ：115.82℃；IR(cm ^-1 )v～＝3551，3478，3199，1603，1571，1542，1479，1440，1396，1320，1295，1183，1138，965，873，820，768，653. ¹ H NMR(DMSO-d6)：δ8.36(s，1H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ128.2，140.4，154.76；EA(C ₅ H ₄ N ₁₀ O ₆ ，300.15)：Calcd，C：20.01；H：1.34；N：46.67；Found，C：19.54；H：1.68；N：46.18.

< example 2>

Fused ring energetic salt 4.2H containing pyridazinoimidazole ₂ O, the structural formula is as follows:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

adding compound 3(0.3g, 1mmol) into a mixed solution (10mL) of water and methanol (1: 1), dropwise adding an ammonia water solution (28 wt.%, 2.2mmol), reacting at normal temperature for 1H, filtering, and washing with cold water (3mL) to obtain a tan solid 4.2H ₂ O (0.28g, 76%). Compound 4.2H ₂ The DSC chart of O is shown in FIG. 7, the NMR spectrum is shown in FIG. 8, and the NMR spectrum is shown in FIG. 9. T is _dec ：192.34℃，IR(cm-1)v～＝3436，3231，1612，1571，1499，1405，1293，1203，1087，1046，1013，862，828，764，730，654，617，601. ¹ H NMR(DMSO-d6)：8.4(s，10H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ130.6，146.4，157.5；EA(C ₅ H ₁₀ N ₁₂ O ₆ ·2H ₂ O，370.24)：Calcd，C：16.22；H：3.81；N：45.4；Found，C：16.36；H：3.76；N：46.06.

< example 3>

Fused ring energetic salt 5 & H containing pyridazinoimidazole ₂ O, the structural formula is as follows:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

adding compound 3(0.3g, 1mmol) into a mixed solution (10mL) of water and methanol (1: 1), dropwise adding hydrazine hydrate solution (90%, 2.2mmol), reacting at room temperature for 1H, and filtering to obtain yellow brown solid 5. H ₂ O (0.29g, 76%). Compound 5. H ₂ The DSC chart of O is shown in figure 10, the NMR spectrum is shown in figure 11, and the NMR spectrum is shown in figure 12. T is _dec ：224.18℃，IR(cm ^-1 )v～＝3450，3342，3158，1630，1604，1577，1497，1466，1438，1337，1280，1203，1086，1046，996，863，830，765，730，666，651，615，599. ¹ H NMR(DMSO-d6)：8.4(s，10H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ130.6，146.4，157.5；EA(C ₅ H ₁₂ N ₁₄ O ₆ ·H ₂ O，382.26)：Calcd，C：15.71；H：3.69；N：51.3；Found，C：15.52；H：3.88；N：50.87.

< example 4>

The fused ring energetic salt containing the pyridazinoimidazole 6 has the following structural formula:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

compound 3(0.3g, 1mmol) was added to a mixed solution (10mL) of water and methanol (1: 1), an aqueous hydroxylamine solution (50 wt.%, 2.2mmol) was added dropwise, reacted at normal temperature for 1h, and filtered to give a tan solid 6(0.31g, 85%). The DSC chart of the compound 6 is shown in figure 13, the nuclear magnetic resonance hydrogen spectrum chart is shown in figure 14, and the nuclear magnetic resonanceThe carbon spectrum is shown in FIG. 15. T is _dec ：192.13℃，IR(cm ^-1 )v～＝3377，3231，3168，2708，1749，1613，1572，1506，1294，1202，1088，1050，1007，892，864，829，766，729，667，640，619，600. ¹ H NMR(DMSO-d6)：10.31(s，8H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ130.6，146.4，157.5；EA(C ₅ H ₁₀ N ₁₂ O ₈ ，366.21)：Calcd，C：16.4；H：2.75；N：45.9；Found，C：15.95；H：3.36；N：45.53.

< example 5>

Fused ring energetic compound 8.3H containing pyridazinoimidazole ₂ O, its structural formula is as follows:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

step one, compound 7.1.5H ₂ Synthesis of O

Compound 2(0.99g, 6mmol) was dissolved in hydrochloric acid (37%, 9mL), and KMnO was added dropwise thereto under ice-bath conditions ₄ The solution (0.65g, 4.1mmol in 4.5mL water) was reacted at 55 deg.C for 5h, filtered to give an orange-yellow solid, filtered, washed with copious amounts of water, and dried to give compound 7(0.59g, 56%). The DSC chart of the compound 7 is shown in figure 16, the nuclear magnetic resonance hydrogen spectrum chart is shown in figure 17, and the nuclear magnetic resonance carbon spectrum chart is shown in figure 18. T is _dec ：379.11℃，IR(cm ^-1 )v～＝3323，3131，1658，1542，1488，1405，1373，1307，1201，1073，1021，805，597. ¹ H NMR(DMSO-d6)：7.34(s，4H)，8.62(s，4H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ24.6，132.7，146.6，148.3，158.9；EA(C ₁₀ H ₁₀ N ₁₄ ·1.5H ₂ O，353.31)：Calcd，C：34.00；H：3.71；N：55.50；Found，C：34.18；H：4.08；N：54.71.

Step two, compound 8.3H ₂ Synthesis of O

Compound 7.1.5H ₂ Feeding O (0.35g, 1mmol) into fuming nitric acid (100%, 5mL) at-5 ℃ in batches, stirring at room temperature for 2H, pouring into ice water (10mL) to precipitate a large amount of orange yellow solid, filtering, washing with a large amount of water to obtain the compound 8.3H ₂ O (0.25g, 45%). Compound 8.3H ₂ The DSC chart of O is shown in FIG. 19, the NMR spectrum is shown in FIG. 20, and the NMR spectrum is shown in FIG. 21. T is _dec ：117.14℃，IR(cm ^- 1)v～＝3551，3400，3130，1695，1641，1600，1565，1483，1438，1383，1356，1278，1222，1192，1148，1058，973，858，772，727，670. ¹ H NMR(DMSO-d6)：5.28(s，4H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ124.5，126.5，145.6，147.4，155.0；EA(C ₁₀ H ₁₆ N ₁₈ O ₈ ·3H ₂ O，560.32)：Calcd，C：21.44；H：2.16；N：45.00；Found，C：21.67；H：2.27；N：44.77.

< example 6>

Fused ring energetic salt 9.2H containing pyridazinoimidazole ₂ O, the structural formula is as follows:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

compound 8.3H ₂ O (0.56g, 1mmol) is added into methanol solution (10mL), ammonia water solution (28 wt.%, 2.2mmol) is added dropwise, reaction is carried out for 1H at normal temperature, and filtration is carried out to obtain reddish brown solid 9.2H ₂ O (0.46g, 80%). Compound 9.2H ₂ The DSC chart of O is shown in FIG. 22, the NMR spectrum is shown in FIG. 23, and the NMR spectrum is shown in FIG. 24. T is _dec ：200.21℃，IR(cm-1)v～＝3377，3196，1603，1561，1495，1438，1353，1260，1194，1152，1069，970，850，770，725，674，553. ¹ H NMR(DMSO-d6)：7.14(s，8H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ126.7，130.6，147.0，147.9，158.4；EA(C ₁₀ H ₁₆ N ₁₈ O ₈ ·3H ₂ O，560.32)：Calcd，C：20.84；H：2.80；N：48.6；Found，C：21.45；H：3.01；N：47.16.

< example 7>

Fused ring energetic salt 10 & CH containing pyridazinoimidazole ₃ OH, the structural formula is as follows:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

compound 8.3H ₂ O (0.56g, 1mmol) is added into methanol solution (10mL), hydrazine hydrate solution (98%, 2.2mmol) is added dropwise, reaction is carried out for 1h at normal temperature, and filtration is carried out to obtain reddish brown solid 10. CH ₃ OH (0.47g, 78%). Compound 10. CH ₃ The DSC chart of OH is shown in figure 25, the NMR spectrum is shown in figure 26, and the NMR spectrum is shown in figure 27. T is _dec ：208.32℃，IR(cm-1)v～＝3379，3330，3150，1606，1459，1354，1262，1203，1064，968，861，770，674. ¹ H NMR(DMSO-d6)：6.83(s，10H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ126.5，131.1，147.1，148，158.9；EA(C ₁₀ H ₁₆ N ₁₈ O ₈ ·3H ₂ O，560.32)：Calcd，C：21.93；H：3.01；N：51.15；Found，C：21.73；H：2.84；N：51.25.

< example 8>

Fused ring energetic salt containing pyridazinoimidazole 11.2H ₂ O，The structural formula is as follows:

the specific synthetic route is as follows:

the specific synthesis steps are as follows:

compound 8.3H ₂ O (0.56g, 1mmol) was added to a methanol solution (10mL), an aqueous hydroxylamine solution (50 wt.%, 2.2mmol) was added dropwise, reacted at room temperature for 1H, and filtered to give a red-brown solid 11.2H ₂ O (0.50g, 83%). Compound 11.2H ₂ The DSC chart of O is shown in FIG. 28, the NMR spectrum is shown in FIG. 29, and the NMR spectrum is shown in FIG. 30. T is _dec ：190.49℃，IR(cm-1)v～＝3452，3163，2712，1607，1490，1447，1270，1201，1155，1074，975，855，771，675，555. ¹ H NMR(DMSO-d6)：8.05(s，8H)； ¹³ C{ ¹ H}NMR(DMSO-d6)：δ126.7，131.0，147.1，148，158.7；EA(C ₁₀ H ₁₂ N ₂₀ O ₁₀ ·2H ₂ O，608.37)：Calcd，C：19.74；H：2.65；N：46.05；Found，C：20.09；H：2.97；N：45.52.

< example 9>

The performances of the energetic compounds 3-6, 8-11 synthesized by the embodiment of the invention are compared with the performances of the existing explosives, namely hexogen (RDX) and octogen (HMX):

the performance of compounds 3-6, 8-11 was compared to that of RDX, HMX as in Table 1 below.

Table 1: test and evaluation of Compounds 3-6, 8-11, RDX and HMX

^a The content of nitrogen is controlled by the nitrogen content, ^b thermal decomposition temperature (DSC, 5 ℃ C. min.) ^-1 )， ^c The density of the anhydrous compound (25 c) measured by the pycnometer method, ^d the calculated enthalpy of formation is calculated as, ^e the calculated detonation velocity is calculated as a function of the velocity, ^g the calculated detonation pressure is calculated and used as the detonation pressure, ^h the sensitivity of the impact is higher than that of the impact, ⁱ and (4) friction sensitivity.

Neutral compounds 3 and 8.3H ₂ The properties of O and its salts, as well as the comparison with the existing high performance energetic materials RDX and HMX are as given in the table above. As can be seen from comparison of detonation velocity v and detonation pressure P, the energetic salt 6 containing the pyridazinoimidazole fused ring has the best performance and density, the detonation velocity and detonation pressure is the highest in the series, the thermal stability and the sensitivity are good, the performance of the energetic salt is superior to that of RDX and is close to that of HMX, and the energetic salt is a high-energy-density material with comprehensive performance.

The formation enthalpy and the density jointly determine the detonation velocity and the detonation pressure, the detonation velocity and the detonation pressure are the key of the performance of the energetic material, and the higher the detonation velocity and the detonation pressure, the better the detonation velocity and the detonation pressure; the impact sensitivity and the friction sensitivity are the key to use, the higher and the more insensitive, the better the stability, which means that the material is safer to prepare, use and store.

While embodiments of the invention have been disclosed above, it is not intended to be limited to the uses set forth in the specification and examples. It can be applied to all kinds of fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. It is therefore intended that the invention not be limited to the exact details and illustrations described and illustrated herein, but fall within the scope of the appended claims and equivalents thereof.

Claims (10)

1. A pyridazinimidazole fused ring-containing energetic compound or an energetic salt thereof, wherein the energetic compound has the structure of the following formula (I):

Wherein, AB is C=N or C-NH, DE is C=N or C-NH, and R ₁ , R ₂ and R ₃ are all nitroamine groups. 2. The pyridazinimidazole fused ring-containing energetic compound or its energetic salt as claimed in claim 1, wherein, When AB is C=N, R ₁ is

When AB is C-NH, AR ₁ is C=N-NO ₂ . 3. The pyridazinimidazole fused ring-containing energetic compound or its energetic salt according to claim 1, wherein, When DE is C=N, _R3 is

When DE is C-NH, DR3 is C ₌ N _- NO2. 4. The pyridazinimidazole fused ring-containing energetic compound or its energetic salt as claimed in claim 1, wherein R ₂ is

5. The pyridazinimidazole-containing fused ring-containing energetic compound or its energetic salt according to claim 1, wherein the energetic salt is an ammonium salt, a hydroxylamine salt or a hydrazine salt. 6. A method for preparing the pyridazinimidazole fused ring-containing energetic compound or its energetic salt according to any one of claims 1 to 5, comprising the steps of: Step 1. Synthesis of intermediate formula (II) compound Using 4,5-dicyano-2-aminoimidazole as a raw material, the compound of formula (II) is obtained by ring-closing reaction with hydrazine hydrate; Step 2, the synthesis of compound of formula (I) The compound of formula (II) obtained in the step 1 is used as an intermediate to carry out one or more steps of reaction to prepare the compound of formula (I) or its energetic salt;

7. The method of claim 6, wherein the step one specifically comprises the following steps: S1, 4,5-dicyano-2-aminoimidazole was added to 1,4-dioxane, hydrazine hydrate was added dropwise, and the reaction was carried out at 80 °C for 3 h; S2, remove the 1,4-dioxane in the S1 reaction, add N,N-dimethylformamide and hydrazine hydrate to the reaction system, and continue to react at 80°C for 2h; S3, filter, wash, dry, add hydrochloric acid, heat to 55°C for 4 hours, cool to precipitate crystals, add water to dissolve, adjust pH to 7 to precipitate solids, filter and wash with cold water. 8. The method of claim 7, wherein, in the S1, hydrazine hydrate is 98% hydrazine hydrate. 9. The method of claim 7, wherein, in the step S3, the solvent used for washing is N,N-dimethylformamide. 10. The method of claim 7, wherein, in the step S3, the hydrochloric acid is hydrochloric acid with a mass fraction of 37%.

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