Iodine-containing energetic compounds based on pyrazole ring, preparation methods and applications thereof

Abstract

The present invention discloses an iodine-containing energetic compound based on a pyrazole ring, which is a mono-pyrazole ring compound with multiple iodine and multiple nitro groups or a bicyclic energetic compound connected by a C-N bond, having a high iodine content, high detonation performance and excellent mechanical sensitivity. The present invention also discloses a method for preparing an iodine-containing energetic compound based on a pyrazole ring, which uses a nitro- or iodine-substituted pyrazole ring as a raw material, and synthesizes an iodine-containing monocyclic energetic compound based on a pyrazole ring through iodination and nitration reactions respectively; then modifies the N position of the monocyclic energetic compound to introduce different polynitro heterocycles to obtain several iodine-containing energetic compounds based on a pyrazole ring that exhibit excellent mechanical sensitivity and detonation performance, providing a new idea for the design and synthesis of iodine-rich energetic bactericidal materials.

Description

Technical Field

[0001] The present invention relates to the technical field of energetic materials, and specifically relates to an iodine-containing energetic compound based on a pyrazole ring, and a preparation method and application thereof. Background Art

[0002] Since the advent of energetic materials, over the decades, through the unremitting efforts of energetic materials scientists, many kinds of nitrogen heterocyclic energetic compounds have been designed and synthesized. Five-membered nitrogen heterocycles exhibit excellent detonation performance. Iodine is one of the effective bactericides, with high bactericidal efficiency and great universality. However, it is unstable and volatile. Stabilizing it in the form of a covalent C-I bond can effectively improve its volatility, but the energy released during its release is small, resulting in a limited bactericidal range. The nitro group (NO2-) is one of the important detonation groups, which can significantly improve the detonation performance of molecules such as detonation velocity and detonation pressure. Secondly, due to the presence of molecular oxygen in it, introducing a nitro group into the molecular skeleton can significantly improve its oxygen balance. The present invention synthesizes a multi-iodo multi-nitro energetic compound through a simple preparation method, providing a reference for the development of new iodine-rich energetic materials. Summary of the Invention

[0003] An object of the present invention is to solve at least the above problems and / or defects, and provide at least the advantages described hereinafter.

[0004] Another object of the present invention is to provide an iodine-containing energetic compound based on a pyrazole ring, which realizes the coexistence of iodine and nitro groups on a nitrogen-rich heterocyclic single ring, and further improves the energy through the C-N bridging method while ensuring that the content of single-molecule iodine remains unchanged, significantly improving the oxygen balance and detonation performance of the iodine-rich compound, and providing a reference for the development of new iodine-rich energetic materials.

[0005] Another object of the present invention is to provide a method for preparing an iodine-containing energetic compound based on a pyrazole ring. Using a substituted pyrazole ring as a raw material, an iodine-containing monocyclic energetic compound based on a pyrazole ring is synthesized through iodination and nitration reactions; then the N-position of the monocyclic energetic compound is modified to introduce different nitrogen heterocycles to obtain several iodine-containing energetic compounds based on a pyrazole ring that exhibit excellent mechanical sensitivity and detonation performance, providing a new idea for the design and synthesis of iodine-rich energetic bactericidal materials.

[0006] In order to achieve these objects and other advantages according to the present invention, there is provided an iodine-containing energetic compound based on a pyrazole ring, which has the structure of the following formula (I):

[0007]

[0008] Wherein, R1 is independently hydrogen or a five-membered fully C-nitrated nitrogen heterocycle, R2 is independently iodine or nitro, and R3 is independently iodine or nitro.

[0009] Preferably, among them, R1 is hydrogen,

[0010] Preferably, among them, the iodine-containing energetic compound based on the pyrazole ring is the following compound:

[0011]

[0012] The object of the present invention can also be further realized by a preparation method of an iodine-containing energetic compound based on a pyrazole ring, which uses a substituted pyrazole ring as a raw material and synthesizes a monocyclic iodine-containing energetic compound based on a pyrazole ring through iodination and nitration reactions; then modifies the N position of the monocyclic energetic compound to introduce different nitrogen heterocycles to obtain a bicyclic iodine-containing energetic compound based on a pyrazole ring.

[0013] Preferably, among them, the substituted pyrazole ring is 3-nitro-1H-pyrazole or 4,5-triiodo-1H-pyrazole.

[0014] Preferably, among them, 1,3-dinitro-1H–1,2,4-triazole and 1,3,4-trinitro-1H-pyrazole are used to modify the N position of the monocyclic energetic compound.

[0015] Preferably, among them, when 1,3-dinitro-1H–1,2,4-triazole is used to modify the N position of the monocyclic energetic compound, the molar ratio of 1,3-dinitro-1H–1,2,4-triazole to the monocyclic energetic compound is 1:1.

[0016] Preferably, among them, when 1,3,4-trinitro-1H-pyrazole is used to modify the N position of the monocyclic energetic compound, the molar ratio of 1,3,4-trinitro-1H-pyrazole to the monocyclic energetic compound is 1:1.

[0017] The object of the present invention can also be further realized by the application of the iodine-containing energetic compound based on a pyrazole ring in the preparation of energetic materials.

[0018] The present invention at least includes the following beneficial effects:

[0019] 1. The iodine-containing energetic compound based on a pyrazole ring of the present invention is a mono-pyrazole ring compound with multiple iodine and multiple nitro groups or a bicyclic energetic compound connected by a C-N bond. Especially, the bicyclic energetic compound connected by a C-N bond significantly improves the oxygen balance of the iodine-rich compound, helps the iodine-rich compound achieve better bactericidal applications, has high detonation performance and excellent mechanical sensitivity, and provides new ideas for the development of new iodine-rich energetic materials.

[0020] 2. The preparation method of the iodine-containing energetic compound based on pyrazole ring of the present invention synthesizes the iodine-containing monocyclic energetic compound based on pyrazole ring through iodination and nitration reactions using substituted pyrazole ring as the raw material; then modifies the N position of the monocyclic energetic compound to introduce different nitrogen heterocycles to obtain several iodine-containing energetic compounds based on pyrazole ring with excellent mechanical sensitivity and detonation performance, providing a new idea for the design and synthesis of iodine-rich energetic bactericidal materials.

[0021] Other advantages, objectives and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the single crystal structure diagram of Compound 1 in Example 1 of the present invention;

[0023] Figure 2 It is the nuclear magnetic resonance carbon spectrum diagram of Compound 1 in Example 1 of the present invention;

[0024] Figure 3 It is the DSC diagram of Compound 1 in Example 1 of the present invention;

[0025] Figure 4 It is the single crystal structure diagram of Compound 2 in Example 2 of the present invention;

[0026] Figure 5 It is the nuclear magnetic resonance carbon spectrum diagram of Compound 2 in Example 2 of the present invention;

[0027] Figure 6 It is the DSC diagram of Compound 2 in Example 2 of the present invention;

[0028] Figure 7 It is the nuclear magnetic resonance carbon spectrum diagram of Compound 3 in Example 3 of the present invention;

[0029] Figure 8 It is the HRMS diagram of Compound 3 in Example 3 of the present invention;

[0030] Figure 9 It is the DSC diagram of Compound 3 in Example 3 of the present invention;

[0031] Figure 10 It is the nuclear magnetic resonance carbon spectrum diagram of Compound 4 in Example 4 of the present invention;

[0032] Figure 11 It is the HRMS diagram of Compound 4 in Example 4 of the present invention;

[0033] Figure 12 It is the DSC diagram of Compound 4 in Example 4 of the present invention;

[0034] Figure 13Single crystal structure diagram of compound 5 in Example 5 of the present invention;

[0035] Figure 14 Carbon-13 nuclear magnetic resonance spectrum of compound 5 in Example 5 of the present invention;

[0036] Figure 15 High-resolution mass spectrum (HRMS) of compound 5 in Example 5 of the present invention;

[0037] Figure 16 Differential scanning calorimetry (DSC) diagram of compound 5 in Example 5 of the present invention;

[0038] Figure 17 Carbon-13 nuclear magnetic resonance spectrum of compound 6 in Example 6 of the present invention;

[0039] Figure 18 High-resolution mass spectrum (HRMS) of compound 6 in Example 6 of the present invention;

[0040] Figure 19 Differential scanning calorimetry (DSC) diagram of compound 6 in Example 6 of the present invention. Detailed implementation manners

[0041] The present invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it according to the description in the specification.

[0042] It should be understood that the terms such as "having", "comprising" and "including" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0043] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial sources unless otherwise specified.

[0044] <Example 1>

[0045] Iodine-containing energetic compound 1 based on pyrazole ring, and its structural formula is as follows:

[0046]

[0047] The specific synthesis route is as follows:

[0048]

[0049] The specific synthesis steps are as follows:

[0050] Dissolve 339 mg of 3-nitro-1H-pyrazole (3 mmol), 845 mg of iodine (3.33 mmol) and 811 mg of potassium persulfate (3.33 mmol) in 1,2-dichloroethane (5 mL). Dropwise add trifluoroacetic acid (4 mL) and 98% sulfuric acid (0.19 mL) at 0 °C, and slowly transfer to room temperature and stir for 15 minutes. Then, heat the reaction mixture under reflux at 70 - 80 °C for 8 - 12 hours. Cool the mixture to room temperature, and blow air on the solution to evaporate the solvent to dryness. Dissolve the residue in cold water, filter to obtain the filter residue. Dissolve the crude product of the filter residue in ethanol (15 mL) by heating, filter while hot again. Add an aqueous solution of anhydrous sodium thiosulfate to the filtrate to remove the unreacted iodine. Then add crushed ice (100 g), filter, and wash with cold water to obtain 911.24 mg of pure 4,5-diiodo-3-nitro-1H-pyrazole, with a yield of 83.26%.

[0051] Compound 1 is a yellow solid; the characterization data of the hydrogen spectrum obtained by nuclear magnetic resonance are as follows: 1 1H NMR (d6-DMSO): δ 14.80 (s, 1H) ppm. The characterization data of the carbon spectrum obtained by nuclear magnetic resonance are as follows: 13 13C NMR (d6-DMSO): δ 156.71, 100.33, 70.59 ppm. The infrared spectrum data measured by an infrared spectrometer are as follows: IR (KBr): 3326.65 1536.73 1477.38 1436.44 1378.54 1350.26 1311.70 1218.18 1184.24 1030.33 960.84 825.67 756.04 686.25 630.92 613.51 584.57 485.65 cm -1 。

[0052] The single crystal structure diagram of Compound 1 is shown in Figure 1 , the nuclear magnetic resonance carbon spectrum diagram is shown in Figure 2 , the DSC diagram is shown in Figure 3 。

[0053] <Example 2>

[0054] The iodine-containing energetic compound 2 based on the pyrazole ring has the following structural formula:

[0055]

[0056] The specific synthesis route is as follows:

[0057]

[0058] The specific synthesis steps are as follows:

[0059] At 0 °C, 1 g of 3,4,5-triiodo-1H-pyrazole (2.24 mmol) was slowly added to 100% fuming nitric acid (4 mL). The temperature was slowly raised to room temperature and the reaction was maintained for 30 min until completion. The mixture was poured into crushed ice (50 mg), filtered and washed to obtain 781.24 mg of a white filter residue with a yield of 95.60%. Compound 2 is a white solid; the characterization data of the hydrogen spectrum obtained by nuclear magnetic resonance are as follows: 1 H NMR (d6-DMSO): δ There are no obvious characteristic peaks. The characterization data of the carbon spectrum obtained by nuclear magnetic resonance are as follows: 13 C NMR (d6-DMSO): δ 138.89, 94.81, 85.41 ppm. The infrared spectrum data measured by an infrared spectrometer are: IR (KBr): 2794.33 1501.10 1404.55 1291.25 1096.85 1071.40 988.03 967.08 817.77 754.32 616.92 484.01 442.55 cm -1 。

[0060] The single crystal structure diagram of Compound 2 is shown in Figure 4 , and the nuclear magnetic resonance carbon spectrum diagram is shown in Figure 5 , and the DSC diagram is shown in Figure 6 。

[0061] <Example 3>

[0062] The iodine-containing energetic compound 3 based on the pyrazole ring has the following structural formula:

[0063]

[0064] The specific synthesis route is as follows:

[0065]

[0066] The specific synthesis steps are as follows:

[0067] (1) Synthesis of the sodium salt of Compound 1:

[0068] 4,5-Diiodo-3-nitro-1H-pyrazole (1) (364 mg, 1 mmol) was dissolved in a mixed solution of methanol (3 mL) and sodium methoxide (54 mg, 1 mmol). After stirring for 5 minutes, the solution was evaporated to dryness to obtain 385 mg of orange-yellow 4,5-diiodo-3-nitro-1H-pyrazole sodium salt with a yield of 99.53%.

[0069] (2) Synthesis of Compound 3:

[0070] At room temperature, the prepared sodium salt of Compound 1 (386.8 mg, 1 mmol) was dissolved in 5 mL of methanol. A methanol solution (3 mL) of 159 mg of 1,3-dinitro-1H–1,2,4-triazole (1 mmol) was slowly added dropwise, and then 106 mg of sodium carbonate (1 mmol) was slowly added. Stir at room temperature for 6 h until the reaction was complete, and the solvent was evaporated under reduced pressure. The residue was dissolved in water (10 mL) and acidified to pH = 1 with 10% dilute HCl (1.5 mL). The white precipitate was collected by filtration and washed with water to obtain 420.13 mg of Compound 3 with a yield of 88.11%. Among them, the synthesis of 1,3-dinitro-1H–1,2,4-triazole (1,3-DNT) refers to the literature: P. Yin and J. M. Shreeve, Angew. Chem. Int. Ed., 2015, 54, 14513; Angew. Chem., 2015, 127, 14721.

[0071] Compound 3 is a white solid; the characterization data of the hydrogen spectrum obtained by nuclear magnetic resonance are as follows: 1 1H NMR (d6-DMSO): δ 8.06 (s, 1H) ppm. The characterization data of the carbon spectrum obtained by nuclear magnetic resonance are as follows: 13 13C NMR (d6-DMSO): δ 163.90, 157.70, 155.85, 106.65, 73.29 ppm. The infrared spectrum data measured by an infrared spectrometer are as follows: IR (KBr): 3626.19 3526.22 2552.42 1692.63 1588.13 1541.53 1500.85 1463.26 1412.86 1359.71 1311.51 1240.07 1217.12 1168.18 1062.09 1024.79 1014.15 950.07 837.73 827.92 756.35 730.42 707.98 643.82 620.06 556.60 461.30 cm -1 , and by high-resolution mass spectrometry cation mode analysis, the following was obtained: theoretical value of molecular weight 475.80978; 475.81066 (C5O4N7I2).

[0072] The nuclear magnetic resonance carbon spectrum of Compound 3 is shown in Figure 7 , the HRMS spectrum is shown in Figure 8 , and the DSC spectrum is shown in Figure 9 .

[0073] <Example 4>

[0074] Iodine-containing energetic compound 4 based on a pyrazole ring, and its structural formula is as follows:

[0075]

[0076] The specific synthesis route is as follows:

[0077]

[0078] The specific synthesis steps are as follows:

[0079] (1) Synthesis of the sodium salt of compound 2:

[0080] Dissolve compound 2 (364 mg, 1 mmol) in a mixed solution of methanol (3 mL) and sodium methoxide (54 mg, 1 mmol). After stirring for 5 minutes, dry the solution to obtain 380 mg of the black solid sodium salt of compound 2, with a yield of 98.24%.

[0081] (2) Synthesis of compound 4:

[0082] The specific synthesis steps are the same as those of compound 3, except that the sodium salt of compound 1 is changed to the sodium salt of compound 2. Finally, 372.97 mg of compound 4 is obtained, with a yield of 78.22%.

[0083] Compound 4 is a white solid; the characterization data of the hydrogen spectrum obtained by nuclear magnetic resonance are as follows: 1 H NMR (d6-DMSO): δ has no obvious characteristic peaks. The characterization data of the carbon spectrum obtained by nuclear magnetic resonance are as follows: 13 C NMR (d6-DMSO): δ 163.76, 155.41, 140.19, 129.73, 99.44 ppm. The infrared spectrum data measured by an infrared spectrometer are: IR (KBr): 3584.79 3243.50 1665.36 1507.63 1466.96 1440.99 1403.59 1392.42 1354.14 1327.89 1301.29 1152.68 1096.35 1068.93 1046.14 965.25 840.76 827.35 758.44 738.13 660.56 468.95 418.92 cm -1 . The molecular weight obtained by high-resolution mass spectrometry cation mode analysis is: Molecular weight: 475.81055 Theoretical value: 475.810 (C5O4N7I2).

[0084] The nuclear magnetic resonance carbon spectrum of compound 4 is shown in Figure 10 , the HRMS spectrum is shown in Figure 11 , the DSC spectrum is shown in Figure 12 .

[0085] <Example 5>

[0086] The iodine-containing energetic compound 5 based on pyrazole ring has the following structural formula:

[0087]

[0088] The specific synthesis route is as follows:

[0089]

[0090] The specific synthesis steps are as follows:

[0091] At room temperature, dissolve 386.8 mg of the sodium salt of compound 1 (1 mmol) prepared in methanol (3 mL), slowly add dropwise a methanol solution (3 mL) of 1,3,4-trinitro-1H-pyrazole (1,3,4-TNP, 203 mg, 1 mmol), and then slowly add 106 mg of anhydrous sodium carbonate (1 mmol). Stir at room temperature for 6 h until the reaction is complete. Distill off the solvent under reduced pressure, dissolve the residue in water (20 mL), and acidify it to pH = 1 with 10% dilute HCl (1.5 mL). Filter, wash with water, and collect the white precipitate to obtain 432.06 mg of solid powder compound 5, with a yield of 82.96%. Among them, the synthesis of 1,3,4-TNP refers to the reference: Shreeve, Jean′ne, M, et al. C-N bonded energetic biheterocyclic compounds with good detonation performance and high thermal stability[J]. Journal of Materials Chemistry, A. Materials for energy and sustainability, 2016.

[0092] Compound 5 is a white solid; the characterization data of the hydrogen spectrum obtained by nuclear magnetic resonance are as follows: 1 H NMR (d6-DMSO): δ 9.61 ppm. The characterization data of the carbon spectrum obtained by nuclear magnetic resonance are as follows: 13 C NMR (d6-DMSO): δ 158.07, 150.41, 141.97, 119.54, 108.78, 72.89 ppm. The infrared spectrum data measured by an infrared spectrometer are: IR (KBr): 1907.911570.59 1548.56 1522.41 1508.78 1477.39 1396.47 1363.50 1321.281168.45 1131.60 1058.861024.06 955.18 831.87 804.85 771.05 750.31 718.31682.96 629.60 599.81 542.05 441.85cm -1 Analysis by high-resolution mass spectrometry in positive ion mode gave: theoretical value of molecular weight 519.79956; 519.80049 (C6O6N7I2).

[0093] The single crystal structure diagram of Compound 5 is shown in Figure 13 , and the 13C NMR spectrum is shown in Figure 14 , and the HRMS spectrum is shown in Figure 15 , and the DSC spectrum is shown in Figure 16 .

[0094] <Example 6>

[0095] Iodine-containing energetic compound 6 based on pyrazole ring, and its structural formula is as follows:

[0096]

[0097] The specific synthesis route is as follows:

[0098]

[0099] The specific synthesis steps are as follows:

[0100] The synthesis steps of Compound 6 are the same as those of Compound 5, except that the sodium salt of Compound 1 is replaced with the sodium salt of Compound 2, and the final product is 401.28 mg with a yield of 77.05%.

[0101] Compound 6 is a white solid; the characterization data of the 1H NMR spectrum obtained by nuclear magnetic resonance are: 1 1H NMR (d6-DMSO): δ has no obvious characteristic peaks. The characterization data of the 13C NMR spectrum obtained by nuclear magnetic resonance are: 13 13C NMR (d6-DMSO): δ 150.67, 141.75, 140.33, 119.14, 99.32, 98.30 ppm. The infrared spectrum data measured by an infrared spectrometer are: IR (KBr): 3609.71 2924.82 1651.09 1510.64 1451.47 1383.08 1358.63 1322.55 1300.32 1135.36 1068.71 950.23 849.43 828.16 813.28 758.30 620.65 441.17 cm -1 Analysis by high-resolution mass spectrometry in positive ion mode shows that: the molecular weight is 519.80035, and the theoretical value is 519.80049 (C6O6N7I2).

[0102] The 13C NMR spectrum of Compound 6 is shown in Figure 17 , and the HRMS spectrum is shown in Figure 18 , and the DSC spectrum is shown in Figure 19 .

[0103] <Example 7>

[0104] Performance comparison between the pyrazole ring-based iodine-containing energetic compounds 1-6 synthesized in the examples of the present invention and the existing polyiodine compound 3,4,5-triiodo-1H-pyrazole (TIP): as shown in Table 1 below.

[0105] Table 1 Test and calculated properties of Compounds 1-6 and 3,4,5-triiodo-1H-pyrazole (TIP)

[0106]

[0107] a Decomposition temperature (onset), b Density measured by the gas pycnometer method (25 °C), d Detonation velocity calculated by EXPLO5 V6.02, e Detonation pressure calculated by EXPLO5 V6.02, f Oxygen balance based on CO2 for CaHbOcNdIe, OB = 1600(c - b / 2 - 2a) / MW, g Impact sensitivity measured by the BAM method, h Friction sensitivity.

[0108] As can be seen from the above table, the pyrazole ring-based iodine-containing energetic compounds 1 and 2 exhibit excellent thermal stability (T d : 1: 270.29 °C, 2: 304.45 °C) and excellent detonation performance (D: 1: 4514 m s -1 , 2: 4689 m s -1)(P: 1: 15.1 GPa, 2: 17.2 GPa), significantly higher than TIP. Iodine-containing energetic compounds 3-6 based on pyrazole ring exhibit higher detonation performance and excellent mechanical sensitivity, especially compound 5 (D: 5: 5903 m s -1 , P: 5: 22.3 GPa). It provides a new idea for the design and synthesis of iodine-rich energetic bactericidal materials.

[0109] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. Iodine-containing energetic compounds based on pyrazole ring, which are the following compounds: , or .

2. A method for preparing the iodine-containing energetic compounds based on pyrazole ring according to claim 1, which comprises the following steps: 1) Using 4,5-diiodo-3-nitro-1H-pyrazole or 3,5-diiodo-4-nitro-1H-pyrazole as raw materials, dissolve them in a mixed solution of methanol and sodium methoxide to prepare the sodium salt of 4,5-diiodo-3-nitro-1H-pyrazole or the sodium salt of 3,5-diiodo-4-nitro-1H-pyrazole; among them, The mixing ratio of 4,5-diiodo-3-nitro-1H-pyrazole or 3,5-diiodo-4-nitro-1H-pyrazole, methanol and sodium methoxide is 1 mmol: 3 mL: 1 mmol; 2) Dissolve the sodium salt of 4,5-diiodo-3-nitro-1H-pyrazole or the sodium salt of 3,5-diiodo-4-nitro-1H-pyrazole prepared in step 1) in methanol, slowly dropwise add a methanol solution of 1,3-dinitro-1H-1,2,4-triazole or 1,3,4-trinitro-1H-pyrazole, and then slowly add sodium carbonate, and stir and react at room temperature for 6 h; 3) After the reaction, distill off the solvent under reduced pressure, dissolve the residue in water, acidify to pH = 1 with 10% HCl, filter, wash with water and collect the white precipitate to obtain the iodine-containing energetic compounds based on pyrazole ring.

3. The method according to claim 2, wherein, When using 1,3-dinitro-1H-1,2,4-triazole to modify the N position of the monocyclic energetic compound, the molar ratio of the sodium salt of 4,5-diiodo-3-nitro-1H-pyrazole or the sodium salt of 3,5-diiodo-4-nitro-1H-pyrazole to 1,3-dinitro-1H-1,2,4-triazole or 1,3,4-trinitro-1H-pyrazole is 1:

1.

4. Use of the iodine-containing energetic compounds based on pyrazole ring according to claim 1 in the preparation of energetic materials.

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