High-density high-detonation-velocity multi-nitro compound and preparation method thereof

Abstract

The invention discloses a high-density high-detonation-velocity multi-nitro compound and a preparation method thereof, and the multi-nitro compound is synthesized by taking an imidazole ring in a nitrogen-rich fused ring as a molecular skeleton and taking gem-dinitromethyl and nitramine groups as high-energy units. The nitrogen-rich heterocyclic ring and the high-energy group are combined together, so that the detonation performance is improved, and the safety is also improved. The preparation method is simple, convenient to operate and mild in reaction condition, no high-risk compound participates in the reaction, and the product is easy to separate.

Description

TECHNICAL FIELD

[0001] The present application relates to a high-density high detonation velocity polynitro compound and a preparation method thereof, and belongs to the technical field of high-energy energetic compounds. BACKGROUND

[0002] Energetic materials (EMs) are a class of vital functional compounds that can rapidly release energy through chemical reactions under external stimuli. They are widely used in both military and civilian fields, including defense systems, aerospace propulsion, and industrial blasting. With the continuous advancement of technology, there is an increasing demand for high-energy density materials (HEDMs) that need to have excellent performance, enhanced safety, improved thermal stability, and less environmental impact. However, there is still a fundamental challenge in balancing high detonation performance and low mechanical sensitivity. Although historical milestone compounds such as TNT, RDX, HMX, and CL-20 have been significant, they often have limitations in stability. Therefore, designing and synthesizing compounds with excellent detonation performance while maintaining low mechanical sensitivity has become a key focus for developing the next generation of energetic materials.

[0003] The introduction of dinitromethyl groups (-CH(NO2)2) into nitrogen-containing heterocycles is considered an effective strategy to simultaneously increase the density and oxygen balance of energetic compounds. The strong oxidizing nature of nitro groups helps to increase energy content, while the introduction of dinitromethyl structures further improves energy release efficiency. In 2018, Shreeve's team prepared 4-nitramino-3-(5-dinitromethyl-1,2,4-oxadiazolyl)-furoxan by nitration of 4-amino-3-(5-acetic acid methyl ester-1,2,4-oxadiazolyl)-furoxan. Due to its excellent oxygen balance, economical synthesis using common reagents, and high overall yield, these materials are strong competitors for HMX. [J Mater Chem A., 6 (35) (2018), pp. 16833-16837]

[0004] Nitramino groups (-N-NO2) are a group of great chemical significance and have key applications in the field of energetic materials and others. This functional group endows compounds with high detonation power and moderate mechanical sensitivity. In the history of the development of energetic materials, nitramino groups have always been an indispensable component, as evidenced by widely used conventional explosives such as hexogen (RDX) and octogen (HMX). In addition, more powerful energetic compounds such as CL-20 also contain nitramino groups (-N-NO2), which highlights their fundamental role in the family of conventional chemical explosives.

[0005] Nitrogen-rich fused rings are key structural components in the design of energetic materials. These heterocyclic frameworks contain a high density of C–N, N–N, and N=N bonds, which contribute to the formation of strong positive heats of generation, thereby increasing the energy output of the resulting explosive. This framework is highly modifiable, allowing the introduction of various energetic groups such as nitro, nitramine, azide, dinitro, and trinitroethyl groups, further enhancing the detonation performance of the materials. Furthermore, most nitrogen-rich fused ring energetic compounds exhibit significant stability and safety.

[0006] Currently, there are no publicly available literature reports on the preparation of this high-density, high-explosion-velocity polynitro compound. Summary of the Invention

[0007] This invention overcomes the shortcomings of the prior art and provides a high-density, high-explosion-velocity polynitro compound and its preparation method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a high-density, high-detonation-velocity polynitro compound having the following structure:

[0010] .

[0011] In a second aspect, the present invention provides a method for preparing the high-density, high-detonation-velocity polynitro compound described in the first aspect, comprising:

[0012] The steps involved reacting compound I with a mixed solution of acetic anhydride (Ac₂O) and fuming nitric acid, followed by a substitution reaction of the resulting intermediate in acetone with a methanol solution of KI, and recrystallization of the filtrate to prepare compound II.

[0013] .

[0014] Furthermore, the molar ratio of compound 1 to fuming nitric acid is 1:15.

[0015] Furthermore, the volume ratio of acetic anhydride to fuming nitric acid is 2.5~3.5:1.

[0016] Furthermore, the nitration reaction temperature is 30~40 ℃, and the reaction time is 4~8 h.

[0017] Furthermore, the mass ratio of KI to intermediate product is 1.5 to 2:1.

[0018] Furthermore, the substitution reaction temperature is room temperature, and the reaction time is 6–18 h.

[0019] Furthermore, recrystallization is performed using acetone and water at a volume ratio of 0.5 to 1:1.

[0020] Thirdly, the present invention also provides the use of the high-density, high-detonation-velocity polynitro compound described in the first aspect as an explosive.

[0021] 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 is as high as 75.88%, and the crystal density is 1.91 g / cm³. 3 The detonation velocity is 9517 m / s, the detonation pressure is 41.55 Gpa, the thermal decomposition temperature is 274.3 ℃, the mechanical sensitivity is impact sensitivity 30 J, and the friction sensitivity is 320 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, the reaction conditions are mild, no high-risk compounds participate in the reaction, and the products are easy to separate. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the preparation method of the target product of this invention, a high-density, high-explosion-velocity polynitro compound.

[0023] Figure 2 The target product of this invention is a high-density, high-detonation-velocity polynitro compound. 1 1H NMR (DMSO-d6) spectrum.

[0024] Figure 3 This is the TG-DSC diagram of the high-density, high-detonation-velocity polynitro compound, the target product of this invention.

[0025] Figure 4 This is a crystal structure diagram of the high-density, high-explosion-velocity polynitro compound, the target product of this invention.

[0026] Figure 5 It is the solid product prepared in Example 14 of this invention. 1 1H NMR (DMSO-d6) spectrum.

[0027] Figure 6 This is a crystal structure diagram of the crystal obtained by recrystallization of the solid product prepared in Example 14 of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0029] It should be noted that terms such as "upper", "lower", "left", "right", and "middle" used in this specification are only for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0032] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.

[0033] 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” explicitly includes only A, only B, only C, and combinations thereof.

[0034] To find energetic compounds with superior detonation performance and lower mechanosensitivity, this invention uses the imidazole ring in a nitrogen-rich fused ring as the molecular backbone and geminaldinitromethyl and nitramine groups as high-energy units to design and synthesize a high-density, high-detonation-velocity polynitro compound. Combining a nitrogen-rich heterocycle with the high-energy geminaldinitromethyl and nitramine groups improves both detonation performance and safety.

[0035] Combination Figure 1 This invention provides a method for synthesizing high-density, high-detonation-velocity polynitro compounds. The synthetic route of this method is as follows:

[0036]

[0037] In this route, compound I was synthesized with reference to existing technology, and the specific steps were based on the method reported by Zhang Chong et al. [Crystal Growth & Design 2025, 25 (7), 1961-1968].

[0038] Implementation Case 1:

[0039] Compound I (5 mmol) was reacted in a mixture of 7.5 mL acetic anhydride and 3 mL fuming nitric acid (acetic anhydride:fuming nitric acid = 2.5:1) at 30 °C for 4 h, and then poured into ice water. The precipitated solid was reacted with KI (mass ratio 1.5:1) in acetone / methanol at room temperature for 6 h, and then filtered. The solution was evaporated and recrystallized in acetone / water (acetone:water = 0.5:1) to give solid II, i.e., the target product, 0.14 g, with a yield of 10%.

[0040] Figure 2 The target product is a high-density, high-detonation-velocity polynitro compound. 1 The 1H NMR (DMSO-d6) spectra show that the chemical shifts of hydrogen in -CH and -NH are 5.99 ppm, 9.43 ppm, and 9.73 ppm, respectively.

[0041] Figure 3 The image shows the TG-DSC curve of the target product, a high-density, high-explosion-velocity polynitro compound. The thermal decomposition temperature of this substance is 274.3 °C (heating rate: 5 °C / min), and the exothermic peak temperature is 301.4 °C, indicating that the substance has good thermal stability.

[0042] Figure 4 This is the X-ray single-crystal diffraction pattern of the target product, a high-density, high-explosion-velocity polynitro compound crystal. The molecule contains three hydrogen bonds: N4--H4···O2, 2.14 Å; N5--H5···O3, 2.05 Å; and N6--H6···O5, 2.00 Å. The substance belongs to the monoclinic crystal system, space group P21 / C; its unit cell parameters are a=10.9493(14) Å, b=8.3586(11) Å, c=11.783(2) Å, α= 90°, β= 117.679(4)°, and γ= 90°.

[0043] Tests showed that the crystal density of this high-density, high-detonation-velocity polynitro compound was 1.91 g / cm³. 3 It has a mechanical sensitivity of 30 J for impact and 320 N for friction, and is a high-density, blunt-sensitive, energetic material.

[0044] Calculations show that this high-density, high-detonation-velocity polynitro compound has a nitrogen and oxygen content of up to 75.88%, a detonation velocity of 9517 m / s, and a detonation pressure of 41.55 Gpa, indicating promising application prospects.

[0045] Implementation Case 2:

[0046] Unlike Implementation Case 1, the volume ratio of acetic anhydride to fuming nitric acid was 3:1, with all other conditions remaining the same, and the yield of the target product was 13%.

[0047] Implementation Case 3

[0048] Unlike Implementation Case 1, the volume ratio of acetic anhydride to fuming nitric acid was 3.5:1, with all other conditions remaining the same, and the yield of the target product was 11%.

[0049] Implementation Case 4:

[0050] Unlike Implementation Case 2, the nitration temperature was 35 °C, and all other conditions were the same, resulting in a target product yield of 17%.

[0051] Implementation Case 5:

[0052] Unlike Implementation Case 2, the nitration temperature was 40 °C, and all other conditions were the same, resulting in a target product yield of 14%.

[0053] Implementation Case 6:

[0054] Unlike Implementation Case 4, the reaction time was 6 hours, all other conditions were the same, and the yield of the target product was 20%.

[0055] Implementation Case 7:

[0056] Unlike Implementation Case 4, the reaction time was 8 hours, and all other conditions were the same, resulting in a target product yield of 18%.

[0057] Implementation Case 8:

[0058] Unlike Implementation Case 6, the mass equivalent of KI was 1.75, and all other conditions were the same, resulting in a yield of 22% for the target product.

[0059] Implementation Case 9:

[0060] Unlike Implementation Case 6, the mass equivalent of KI was 2:1, and all other conditions were the same, resulting in a yield of 21% for the target product.

[0061] Implementation Case 10:

[0062] Unlike Implementation Case 8, the subsequent reaction time was 12 hours, with all other conditions remaining the same, and the yield of the target product was 25%.

[0063] Implementation Case 11:

[0064] Unlike Implementation Case 8, the subsequent reaction time was 18 hours, with all other conditions remaining the same, and the yield of the target product was 24%.

[0065] Implementation Case 12:

[0066] Unlike Implementation Case 10, the volume ratio of acetone to water during recrystallization was 0.75:1, with all other conditions remaining the same, and the yield of the target product was 25%.

[0067] Implementation Case 13:

[0068] Unlike Implementation Case 10, the volume ratio of acetone to water during recrystallization was 1:1, with all other conditions remaining the same, and the yield of the target product was 26%.

[0069] Implementation Case 14:

[0070] Compound I (5 mmol) was reacted in a mixture of 7.5 mL acetic anhydride and 3 mL fuming nitric acid (acetic anhydride:fuming nitric acid = 2.5:1) at 30 °C for 4 h, and then poured into ice water. The resulting solid was recrystallized in acetone / water (acetone:water = 0.5:1) to give the solid product.

[0071] The solid product was characterized by NMR, and the results are as follows: Figure 5 As shown, Figure 5 of 1 In the 1H NMR (DMSO-d6) spectrum, the chemical shifts of hydrogen in -CH and -NH were 5.58 ppm, 5.60 ppm, 6.23 ppm, 6.25 ppm, 9.27 ppm, 9.67 ppm, and 9.83 ppm, respectively. The results indicate that the solid product comprises two compounds, one of which is the target product from Example 1 of this invention.

[0072] The solid product was subjected to single-crystal cultivation to obtain a crystal, which was then characterized by XRD single-crystal characterization. The results are as follows: Figure 6 As shown, Figure 6 In the X-ray single-crystal diffraction pattern, a hydrogen bond exists within the molecule, N4--H4A···O1, 2.11 Å. This substance belongs to the monoclinic crystal system, space group P21 / C; the unit cell parameters are a=16.1029(9) Å, b=8.5933(4) Å, c=12.1007(6) Å, α= 90°, β= 103.444(2)°, γ= 90°. The results indicate that this crystal is not the single-crystal structure of the target product in Example 1 of this invention, but rather a crystal of another compound (byproduct). The target product of this invention can be obtained by removing this compound (byproduct) from the solid product through a substitution reaction.

[0073] The above-described embodiments are merely preferred embodiments of the present invention, but the implementation of the present invention is not limited to the above-described embodiments. Any other changes, modifications, substitutions, or combinations made without departing from the spirit and principle of the present invention shall be considered equivalent replacements and shall be within the protection scope of the present invention.

Claims

1. A high-density, high-detonation-velocity polynitro compound, characterized in that, It has the following structure: 。 2. A method for preparing a high-density, high-detonation-velocity polynitro compound, characterized in that, include: The steps involved in preparing compound II were: nitration of compound I in a mixed solution of acetic anhydride and fuming nitric acid; substitution reaction of the resulting intermediate in acetone with a methanol solution of KI; and recrystallization of the filtrate. 。 3. The method as described in claim 2, characterized in that, The molar ratio of compound 1 to fuming nitric acid is 1:

15.

4. The method as described in claim 2, characterized in that, The volume ratio of acetic anhydride to fuming nitric acid is 2.5~3.5:

1.

5. The method as described in claim 2, characterized in that, The nitration reaction temperature is 30~40 ℃, and the reaction time is 4~8 h.

6. The method as described in claim 2, characterized in that, The mass ratio of KI to intermediate product is 1.5~2:

1.

7. The method as described in claim 2, characterized in that, The substitution reaction was carried out at room temperature for 6–18 h.

8. The method as described in claim 2, characterized in that, Recrystallization is performed using acetone and water in a volume ratio of 0.5 to 1:

1.

9. The use of the high-density, high-detonation-velocity polynitro compound as described in claim 1 as an explosive.

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