Gem-dinitroimidazole cyclic nitrate imitation salt and preparation method thereof

Abstract

The invention discloses a gem-dinitro-imidazole ring mimic salt and a preparation method thereof, a gem-dinitro-imidazole ring cation is synthesized by taking an imidazole ring in a nitrogen-rich fused ring as a molecular skeleton and FOX-7 as a high-energy unit, and the gem-dinitro-imidazole ring cation is assembled with a mimic anion to form a high-energy ionic salt. The nitrogen-rich heterocyclic ring and the high-energy group nitryl are combined together, so that the detonation performance is improved, and the safety is also improved.

Description

Technical Field

[0001] The invention relates to a geminal dinitroimidazole nitroxyl salt and a preparation method thereof, belonging to the technical field of high-energy compounds. Background Art

[0002] Energetic materials are a type of chemical substance that can rapidly release a large amount of energy in a short period of time under external stimulation. In the application process in military and civilian fields, researchers want to obtain energetic materials with higher detonation performance to achieve the goal of efficient destruction. However, due to the inherent contradiction between the detonation performance and safety of energetic materials, high-energy groups need to be introduced to improve the detonation performance, but this usually makes the energetic materials sensitive and reduces safety. Therefore, the preparation of energetic materials that have both high energy and high stability has become a hot topic in this research field. Energetic ion salts have become the main research direction in the field of research and development of new high-energy and low-sensitivity energetic materials due to their simple and efficient reactions, strong designability and easy regulation.

[0003] Nitrogen-rich fused ring compounds are conducive to the formation of π-π stacking and conjugation effects, making the molecules have better planarity and stability, and are easy to form multiple hydrogen bonds in the preparation of energetic ion salts, which helps to improve the density and molecular stability of the compound. It is an important direction for the development of high-energy and low-sensitivity energetic materials. Shreeve et al. reacted 4-chloro-1-methyl-3,5-dinitropyrazole with hydrazine hydrate to prepare 4-methyl-6-nitropyrazolo[3,4-d][1,2,3]triazole-3-oxide, and prepared a variety of nitrogen-rich energetic ion salts. Some ion salts show insensitive characteristics, such as guanidine salts with an impact sensitivity of 40J and a friction sensitivity of 360N [J.Mater.Chem.A, 2016, 4, 1514-1519]. Therefore, using nitrogen-rich heterocycles as the skeleton of energetic materials is a feasible and effective means to balance energy and safety.

[0004] In the development of energetic materials, 1,1-diamino-2,2-dinitroethylene (FOX-7) is a new, insensitive, high energy density material (ρ: 1.88 g cm -3 , IS: 25J, FS: 350N). Shreeve et al. synthesized a series of FOX-7-like planar molecules [J.Am.Chem.Soc.2020,142,15,7153-7160] and found that the addition of tetrazole or triazole rings to the main chain of conjugated nitroenamines would produce a planar structure, which not only improved the thermal stability but also increased the sensitivity of the product. Therefore, FOX-7 can be introduced as a high-energy unit into the molecular structure of new energetic materials to achieve the effect of improving their detonation performance while balancing their safety.

[0005] At present, there is no public literature report on the preparation of geminal dinitroimidazole ring energetic ion salts. Summary of the invention

[0006] The invention overcomes the shortcomings of the prior art and provides a geminal dinitroimidazole ring nitroformic salt and a preparation method thereof.

[0007] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a geminal dinitroimidazole ring nitroformic salt having the following structure:

[0009]

[0010] In a second aspect, the present invention provides a method for preparing the gem-dinitroimidazole ring nitroformic salt described in the first aspect, comprising:

[0011] (4) a step of subjecting compound I and guanidine sulfate to a condensation reaction in a mixed solution of glacial acetic acid and concentrated sulfuric acid to prepare compound II,

[0012]

[0013] (5) a step of preparing compound III by subjecting compound II to a double decomposition reaction with barium chloride in water,

[0014]

[0015] (6) a step of preparing the target compound by subjecting compound III and silver nitroformate to a double decomposition reaction in water in the dark,

[0016]

[0017] Furthermore, in step (1), the molar ratio of compound I to guanidine sulfate is 1:1 to 1.2.

[0018] Furthermore, in step (1), the volume ratio of glacial acetic acid to concentrated sulfuric acid is 4 to 8:1.

[0019] Furthermore, in step (1), the condensation reaction temperature is 20 to 40° C., and the reaction time is 12 to 24 hours.

[0020] Furthermore, in step (2), the molar ratio of compound II to barium chloride is 1:1.

[0021] Furthermore, in step (2), the metathesis reaction temperature is 70 to 90° C., and the reaction time is 4 to 8 hours.

[0022] Furthermore, in step (3), the molar ratio of compound III to silver nitroformate is 1:1 to 1.2.

[0023] Furthermore, in step (3), the metathesis reaction temperature is 50-70° C., and the reaction time is 4-8 h.

[0024] In a third aspect, the present invention further provides a use of the gem-dinitroimidazole nitroformate salt described in the first aspect as an explosive.

[0025] Compared with the prior art, the present invention has the following advantages: (1) The nitrogen and oxygen content of the target compound of the present invention, geminal dinitroimidazole nitroformate, is as high as 78.92%, and the measured density is 1.86 g / cm 3 The detonation velocity is 8920 m / s, the detonation pressure is 35.48 Gpa, the thermal decomposition temperature is greater than 100°C, the mechanical sensitivity is 30 J for impact sensitivity, and the friction sensitivity is 252 N. It is a good high-energy insensitive explosive with good application prospects; (2) The preparation method of the present invention is simple, easy to operate, mild reaction conditions, no highly dangerous compounds participate in the reaction, and the product is also easy to separate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a process flow chart of the preparation method of the target product gem-dinitroimidazole ring nitro salt.

[0027] Figure 2 The target product of the present invention is geminal dinitroimidazole ring nitroform salt 1 H NMR (DMSO-d6) spectrum.

[0028] Figure 3 This is the TG-DSC diagram of the target product of the present invention, gem-dinitroimidazole nitroformate salt.

[0029] Figure 4 It is a crystal structure ellipsoid diagram of the target product of the present invention, geminal dinitroimidazole nitroformate salt. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described herein are only used to disclose the present invention and are not used to limit the present invention.

[0031] It should be noted that the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of this application without substantially changing the technical content.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0033] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0034] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement or value. The degree of flexibility for a particular variable can be easily determined by one skilled in the art.

[0035] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" expressly includes only A, only B, only C, and combinations of each thereof.

[0036] In order to find an energetic ion salt with better detonation performance and lower mechanical sensitivity, the present invention uses the imidazole ring in the nitrogen-rich fused ring as the molecular skeleton and FOX-7 as the high-energy unit to design and synthesize a geminal dinitroimidazolyl ring cation and assemble it with the nitroform anion to form a high-energy ion salt. Combining the nitrogen-rich heterocycle with the high-energy group nitro can improve both the detonation performance and the safety.

[0037] Combination Figure 1 The present invention provides a method for synthesizing geminal dinitroimidazole ring nitroformic salt, and the synthetic route of the synthetic method is as follows:

[0038]

[0039] In this route, solid I is synthesized with reference to the prior art, and the specific steps are: FOX-7 (10.00 mmol) and glyoxal (20 mmol) are reacted in water at 30°C for 4 hours, and then filtered and dried to obtain intermediate A; intermediate A and p-toluenesulfonic acid (1:0.05) are reacted in acetic anhydride at 40°C for 12 hours, and then filtered and dried to obtain solid I.

[0040] In this route, silver nitrate is prepared by nitrate and silver nitrate, wherein nitrate is synthesized with reference to the method reported by Ralf Haiges et al. [J.Am.Chem.Soc.2018,140,15089-15098].

[0041] Implementation Case 1:

[0042] (1) Solid Ⅰ (5 mmol) was reacted with guanidine sulfate (1:1) in a mixture of acetic acid and concentrated sulfuric acid (acetic acid: concentrated sulfuric acid = 4:1) at 20°C for 12 h, filtered and dried to obtain solid Ⅱ; (2) Solid Ⅱ was reacted with barium chloride in water at 70°C for 4 h, filtered and evaporated to obtain solid Ⅲ; (3) Solid Ⅲ was reacted with silver nitroform (1:1) in water at 50°C for 4 h, filtered and evaporated to obtain 0.9 g of solid gem-dinitroimidazole nitroform salt, with a yield of 24%.

[0043] Figure 2 It is a geminal dinitroimidazole nitro salt 1 HNMR (DMSO-d6) spectrum, the chemical shifts of hydrogen in -CH, =NH2, and -NH are 5.96 ppm, 8.16 ppm, 9.11 ppm, and 9.80 ppm, respectively.

[0044] Figure 3 This is the TG-DSC curve of gem-dinitroimidazole nitroformate. The thermal decomposition temperature of the substance is 124.5°C (heating rate: 5°C / min), and the exothermic peak temperature is 141.0°C, indicating that the substance has good thermal stability.

[0045] Figure 4 This is the X-ray single crystal diffraction pattern of geminal dinitroimidazole nitroformate salt crystals. The cation and nitroformate anion are connected by NH···O type hydrogen bonds (N6-H6B···O3; N6-H6A···O2; N5-H5···O5; N4-H4···O4; N4-H4···O6). This substance belongs to the orthorhombic system, Pbca space group; the unit cell parameters are α=90°, β=90°, γ=90°.

[0046] After testing, the measured density of geminal dinitroimidazole nitroformate is 1.86 g / cm 3 The mechanical sensitivity is 30J for impact sensitivity and 252N for friction sensitivity. It is a high-density insensitive energetic material.

[0047] According to calculation, the nitrogen and oxygen content of geminal dinitroimidazole nitroxyl salt is as high as 78.92%, the detonation velocity is 8920m / s, and the detonation pressure is 35.48Gpa, which has good application prospects.

[0048] Implementation Case 2:

[0049] The difference from Example 1 is that the molar ratio of solid I to guanidine sulfate in step (1) is 1:1.1, and the other conditions are the same. The yield of the target product is 27%.

[0050] Implementation Case 3

[0051] The difference from Example 1 is that the molar ratio of solid I to guanidine sulfate in step (1) is 1:1.2, and the other conditions are the same. The yield of the target product is 25%.

[0052] Implementation Case 4:

[0053] The difference from Implementation Case 2 is that the volume ratio of glacial acetic acid to concentrated sulfuric acid in step (1) is 6:1, and the other conditions are the same. The yield of the target product is 30%.

[0054] Implementation Case 5:

[0055] The difference from Implementation Case 2 is that the volume ratio of glacial acetic acid to concentrated sulfuric acid in step (1) is 8:1, and the other conditions are the same. The yield of the target product is 27%.

[0056] Implementation Case 6:

[0057] The difference from Example 4 is that the condensation reaction temperature in step (1) is 30° C., and the other conditions are the same. The yield of the target product is 39%.

[0058] Implementation Case 7:

[0059] Different from Implementation Case 4, the condensation reaction temperature in step (1) is 40° C., and the other conditions are the same. The yield of the target product is 34%.

[0060] Implementation Case 8:

[0061] Different from Implementation Case 6, the condensation reaction time in step (1) is 18 h, and the other conditions are the same. The yield of the target product is 45%.

[0062] Implementation Case 9:

[0063] Different from Implementation Case 6, the condensation reaction time in step (1) is 24 h, and the other conditions are the same. The yield of the target product is 44%.

[0064] Implementation Case 10:

[0065] The difference from Implementation Case 8 is that the temperature of the metathesis reaction in step (2) is 80° C., and the other conditions are the same. The yield of the target product is 49%.

[0066] Implementation Case 11:

[0067] The difference from Implementation Case 8 is that the temperature of the metathesis reaction in step (2) is 90° C., and the other conditions are the same. The yield of the target product is 53%.

[0068] Implementation Case 12:

[0069] The difference from Implementation Case 11 is that the double decomposition reaction time in step (2) is 6 h, and the other conditions are the same, and the yield of the target product is 57%.

[0070] Implementation Case 13:

[0071] The difference from Implementation Case 11 is that the double decomposition reaction time in step (2) is 8 h, and the other conditions are the same, and the yield of the target product is 60%.

[0072] Implementation Case 14:

[0073] The difference from Example 13 is that the molar ratio of solid III to silver nitroformate in step (3) is 1:1.1, and the other conditions are the same. The yield of the target product is 65%.

[0074] Implementation Case 15:

[0075] The difference from Example 13 is that the molar ratio of solid III to silver nitroformate in step (3) is 1:1.2, and the other conditions are the same. The yield of the target product is 62%.

[0076] Implementation Case 16:

[0077] The difference from Implementation Case 14 is that the temperature of the metathesis reaction in step (3) is 60° C., and the other conditions are the same. The yield of the target product is 66%.

[0078] Implementation Case 17:

[0079] The difference from Implementation Case 14 is that the temperature of the metathesis reaction in step (3) is 70° C., and the other conditions are the same. The yield of the target product is 78%.

[0080] Implementation Case 18:

[0081] The difference from Implementation Case 17 is that the double decomposition reaction time in step (3) is 6 h, and the other conditions are the same, and the yield of the target product is 74%.

[0082] Implementation Case 19:

[0083] The difference from Implementation Case 17 is that the double decomposition reaction time in step (3) is 4 h, and the other conditions are the same, and the yield of the target product is 71%.

[0084] The above-mentioned implementation cases are only preferred implementation cases in the present invention, but the implementation methods of the present invention are not limited to the above-mentioned implementation cases, such as various forms of combinations of the embodiment schemes, and any other changes, modifications, substitutions, and combinations made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are within the protection scope of the present invention.

Claims

1. A geminal dinitroimidazole nitroformate salt, characterized in that: It has the following structure:

2. A method for preparing a geminal dinitroimidazole nitroformate salt, characterized in that: include: (1) a step of subjecting compound I and guanidine sulfate to a condensation reaction in a mixed solution of glacial acetic acid and concentrated sulfuric acid to prepare compound II, (2) a step of preparing compound III by subjecting compound II to a double decomposition reaction with barium chloride in water, (3) a step of preparing the target compound by subjecting compound III and silver nitroformate to a double decomposition reaction in water in the dark, 3. The method according to claim 2, characterized in that In step (1), the molar ratio of compound I to guanidine sulfate is 1:1 to 1.

2.

4. The method according to claim 2, characterized in that In step (1), the volume ratio of glacial acetic acid to concentrated sulfuric acid is 4 to 8:

1.

5. The method according to claim 2, characterized in that In step (1), the condensation reaction temperature is 20 to 40° C., and the reaction time is 12 to 24 hours.

6. The method according to claim 2, characterized in that In step (2), the molar ratio of compound II to barium chloride is 1:

1.

7. The method according to claim 2, characterized in that In step (2), the double decomposition reaction temperature is 70-90° C., and the reaction time is 4-8 h.

8. The method according to claim 2, characterized in that In step (3), the molar ratio of compound III to silver nitroformate is 1:1 to 1.

2.

9. The method according to claim 2, characterized in that In step (3), the double decomposition reaction temperature is 50-70° C., and the reaction time is 4-8 h.

10. Use of the gem-dinitroimidazole nitroformate salt as claimed in claim 1 as an explosive.

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