Furazan hydrazone energetic compound and synthesis method thereof

Abstract

The invention discloses a furazan hydrazone energetic compound and a synthesis method thereof, the furazan hydrazone energetic compound is named as 2-bis ((3-methyl-4-furazan)-methylene hydrazino)-1-oxalyl hydrazine, and the furazan hydrazone energetic compound is expected to be used for high-energy low-sensitivity energetic materials. The invention also provides a synthesis method of the compound, which comprises the following steps: by taking trans-butenal containing an aldehyde group as a substrate, reacting with sodium nitrite under the acidic conditions of formic acid and the like, carrying out ring closing to obtain 3-methyl-4-formyl-2-furazan, and finally, carrying out ring closing to obtain the 3-methyl-4-formyl-2-furazan. The furazan hydrazone compound is constructed by carrying out condensation reaction on the aldehyde group, oxalyl hydrazine and other multi-hydrazino structure compounds. The synthesis method disclosed by the invention has the characteristics of simplicity and convenience in operation, high safety, high yield and the like.

Description

Technical Field

[0001] This invention belongs to the field of energetic materials and relates to an energetic compound of the furazolidone class and its synthesis method. Background Technology

[0002] In recent years, energetic materials have been increasingly widely used in military and civilian applications, particularly in high explosives, initiators, pyrotechnics, propellants, and gas generators. Consequently, the requirements for energetic materials are becoming increasingly stringent, demanding not only excellent detonation performance but also low sensitivity, good chemical stability, and environmental friendliness. The pursuit of a balance between high energy and low sensitivity remains a perennial theme in energetic materials research, where the presence of nitrogen-rich heterocyclic frameworks can enhance compound stability and enthalpy of formation. Furazan rings, with their high positive enthalpy of formation (219 kJ / mol), are particularly noteworthy. -1 Furazan oxide has potential applications in both propellants and explosives. Furthermore, furazan oxide, being a nitrogen-oxidized derivative of furazan, further enhances the oxygen balance and formation enthalpy (226 kJ / mol) of the furazan ring skeleton. -1 ).

[0003] Studies have shown that introducing a furazolidone ring into the molecular backbone can increase the molecular density by approximately 0.06-0.08 g cm⁻¹. -3 The detonation velocity increased by approximately 300 m / s. -1 Furthermore, the furazan oxide ring is also a large π-bond system, and its introduction helps improve the stability of energetic compounds. Therefore, linking the furazan oxide ring with other energetic groups or skeletons can yield high-nitrogen energetic derivatives with good overall performance. Meanwhile, generating energetic ionic salts is also an effective method for preparing energetic materials. The properties of ionic salts can be adjusted by changing the component ions with different properties, thereby obtaining a richer variety of higher-energy and safer energetic materials.

[0004] There are few reports on heterocyclic cationic salts based on furazan oxide, and the thermal decomposition temperature of furazan oxide-based energetic materials is low, which limits the practical application of furazan oxide-based energetic materials. Summary of the Invention

[0005] The purpose of this invention is to propose a novel oxidized furazolidone-based energetic compound and its preparation method, which uses inexpensive and readily available raw materials, has a high reaction yield and high product purity.

[0006] In a first aspect, the present invention provides an energetic compound of the furazanhydrazone class, named 2-bis((3-methyl-4-oxidofuzanyl)-methylenehydrazyl)-1-oxalylhydrazine, with the structure shown in Formula 1:

[0007]

[0008] In a second aspect, the present invention provides a method for synthesizing the oxidized furazolidone-type energetic compound described in the first aspect, comprising:

[0009] (1) The step of reacting trans-butenal with sodium nitrite to generate 3-methyl-4-formyl-2-oxofraxan intermediate 1 via a cyclization reaction.

[0010]

[0011] (2) The step of synthesizing the target product, furazolidone hydrazone-like energetic compound 2, by condensing intermediate 1 with oxalohydrazide.

[0012]

[0013] Preferably, the molar ratio of trans-butenoic acid to sodium nitrite is 1:1.5 to 3.

[0014] Preferably, the ring-closing reaction temperature is 10°C and the time is 24 hours.

[0015] Preferably, the molar ratio of intermediate 1 to oxalohydrazide is 1.77:1.

[0016] Preferably, the reflux temperature for the condensation reaction is 78°C, and the time is 20-24 hours.

[0017] Thirdly, the present invention provides a crystal prepared from the oxidized furazolidone hydrazone-like energetic compound described in the first aspect, wherein the crystal structure is triclinic, space group P-1, and cell number [missing information]. α=2.623(3)°, β=82.233(3)°, γ=81.031(3), and the unit cell volume is Each unit cell contains three molecules, and the crystal density of this compound is 1.384 g / cm³. -3 .

[0018] Fourthly, the present invention provides the use of the furazolidone-type energetic compounds described in the first aspect as explosives.

[0019] Compared with existing oxidized furazolidone synthesis techniques, the method of the present invention has the following advantages:

[0020] (1) Existing methods for synthesizing furazolidone hydrazones are lengthy and have low yields. This invention utilizes the cyclization reaction of aldehydes and sodium nitrite to directly synthesize furazolidone hydrazones in one step. The target compound is then obtained directly through a simple condensation system, which simplifies the reaction process, increases the overall reaction yield, and reduces production costs.

[0021] (2) The target compound has good detonation performance, low mechanical sensitivity, and high thermal decomposition temperature compared to the conventional explosive TNT. These combined properties make this series of compounds potential to become high-energy, low-sensitivity explosives. Attached Figure Description

[0022] Figure 1 The NMR spectrum of 2-bis((3-methyl-4-oxyfurazanyl)-methylenehydrazine)-1-oxalylhydrazine is 1H NMR.

[0023] Figure 2 The NMR spectrum of 2-bis((3-methyl-4-oxyfurazanyl)-methylenehydrazine)-1-oxalylhydrazine is shown in carbon.

[0024] Figure 3 The image shows a single crystal of 2-bis((3-methyl-4-oxyfurazanyl)-methylenehydrazine)-1-oxalylhydrazine. Detailed Implementation

[0025] The present invention will be further described below with reference to the embodiments.

[0026] This invention uses trans-butenal as a raw material, which undergoes a cyclization reaction with sodium nitrite to generate a 3-methyl-4-formyl-2-oxofurazan intermediate. The intermediate is then condensed with oxalylhydrazine to synthesize the target product 2-bis((3-methyl-4-oxofurazanyl)-methylenehydrazyl)-1-oxalylhydrazine. The specific synthesis method is as follows: Trans-butenal is added to a three-necked flask, followed by glacial acetic acid. The reaction flask is placed in a low-temperature bath at 14°C and stirred. 1.5–3 equivalents of sodium nitrite (preferably 2.3 equivalents) are dissolved in water. The sodium nitrite solution is slowly added dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 14°C. After the addition is complete, the temperature is maintained and stirring continues for 24 hours. After the reaction was complete, sodium bicarbonate solid was added to the reaction solution to adjust the pH to neutral. The mixture was extracted three times with dichloromethane. The organic phases were combined, washed twice with water, dried over anhydrous magnesium sulfate, concentrated, and separated by column chromatography to obtain 3-methyl-4-formyl-2-oxofurazan. Next, oxalohydrazine, anhydrous ethanol, and dilute hydrochloric acid were added to a three-necked flask. The prepared 3-methyl-4-formyl-2-oxofurazan was added in batches under stirring, and the mixture was then refluxed for 24 hours. Upon cooling, a white precipitate formed. This precipitate was filtered, washed with cold ethanol, and the target compound, 2-bis((3-methyl-4-oxofurazanyl)-methylenehydrazyl)-1-oxalohydrazine, was obtained.

[0027] Example 1:

[0028] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 14°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask using a constant-pressure dropping funnel, maintaining the temperature at 14°C. After the addition is complete, continue stirring at the same temperature for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry to anhydrous magnesium sulfate, and concentrate to obtain a yellow oily liquid. Separate 4.5 g of 3-methyl-4-formyl-2-oxofuranozanol by column chromatography, with a yield of 32.86%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Under stirring, 3.08 g of the intermediate 3-methyl-4-formyl-2-oxofrazanol was added in portions. The mixture was heated in a water bath at 30 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.633 g of a white solid, with a yield of 77.88%.

[0029] The proton and carbon NMR spectra are as follows: Figure 1 and Figure 2 As shown.

[0030] 1 H NMR (500MHz, DMSO-d6): δ = 8.60 (s, 2H), 8.12 (s, 2H), 2.51 (s, 6H) ppm;

[0031] 13 C NMR (125MHz, DMSO-d6): δ=164.40, 142.25, 133.32, 39.97, 10.10ppm.

[0032] Example 2:

[0033] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 10°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 10°C. After the addition is complete, maintain the temperature and continue stirring for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry to anhydrous magnesium sulfate, concentrate, and obtain a yellow oily liquid. After standing, 4.51 g of 3-methyl-4-formyl-2-oxofuranozanol precipitates, with a yield of 33.93%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Under stirring, 3.08 g of the intermediate 3-methyl-4-formyl-2-oxofrazanol was added in portions. The mixture was heated in an oil bath at 45 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.626 g of a white solid, with a yield of 77.77%.

[0034] Example 3:

[0035] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 10°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 10°C. After the addition is complete, maintain the temperature and continue stirring for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry over anhydrous magnesium sulfate, concentrate, and obtain a yellow oily liquid. After standing, 4.49 g of 3-methyl-4-formyl-2-oxofurane precipitates, with a yield of 32.78%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Then, 3.08 g of self-made 3-methyl-4-formyl-2-oxofrazanol was added in portions under stirring. The mixture was heated in an oil bath at 45 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.615 g of a white solid, with a yield of 77.58%.

[0036] Example 4:

[0037] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 10°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 10°C. After the addition is complete, continue stirring at the same temperature for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry over anhydrous magnesium sulfate, concentrate, and obtain a yellow oily liquid. Upon standing, 4.37 g of 3-methyl-4-formyl-2-oxofurane precipitates, with a yield of 31.90%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Then, 3.08 g of self-made 3-methyl-4-formyl-2-oxofrazine was added in portions under stirring. The mixture was heated in an oil bath at 45 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.606 g of a white solid, with a yield of 77.46%.

[0038] Example 5:

[0039] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 10°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 10°C. After the addition is complete, maintain the temperature and continue stirring for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry over anhydrous magnesium sulfate, concentrate, and obtain a yellow oily liquid. After standing, 4.35 g of 3-methyl-4-formyl-2-oxofuranozanol precipitates, with a yield of 31.76%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Then, 3.08 g of self-made 3-methyl-4-formyl-2-oxofrazine was added in portions under stirring. The mixture was heated in an oil bath at 55 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.613 g of a white solid, with a yield of 77.55%.

[0040] Example 6:

[0041] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 10°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 10°C. After the addition is complete, continue stirring at the same temperature for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry over anhydrous magnesium sulfate, concentrate, and obtain a yellow oily liquid. Upon standing, 4.43 g of 3-methyl-4-formyl-2-oxofuranozanol precipitates, with a yield of 32.34%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Then, 3.08 g of self-made 3-methyl-4-formyl-2-oxofrazine was added in portions under stirring. The mixture was heated in an oil bath at 65 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.605 g of a white solid, with a yield of 77.41%.

[0042] Example 7:

[0043] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 10°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 10°C. After the addition is complete, continue stirring at the same temperature for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry over anhydrous magnesium sulfate, concentrate, and obtain a yellow oily liquid. Upon standing, 4.41 g of 3-methyl-4-formyl-2-oxofuranozanol precipitates, with a yield of 32.20%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Then, 3.08 g of self-made 3-methyl-4-formyl-2-oxofrazine was added in portions under stirring. The mixture was heated in an oil bath at 75 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.615 g of a white solid, with a yield of 77.58%.

[0044] Example 8:

[0045] Add 6 mL of trans-butenal to a 250 mL three-necked flask, then add 20 mL of glacial acetic acid. Place the reaction flask in a 10°C low-temperature bath and stir. Dissolve 17.2 g of sodium nitrite in 100 mL of water. Slowly add the sodium nitrite solution dropwise to the three-necked flask through a constant-pressure dropping funnel, maintaining the temperature at 10°C. After the addition is complete, continue stirring at the same temperature for 24 h. After the reaction is complete, add solid sodium bicarbonate to the reaction solution to adjust the pH to neutral. Extract repeatedly with 3 × 100 mL of dichloromethane. Combine the organic phases, wash twice with water, dry over anhydrous magnesium sulfate, concentrate, and obtain a yellow oily liquid. Upon standing, 4.42 g of 3-methyl-4-formyl-2-oxofuranozanol precipitates, with a yield of 32.27%. 2.36 g of oxalohydrazide, 50 mL of anhydrous ethanol, and 2 mL of dilute hydrochloric acid were added to a 250 mL three-necked flask. Then, 3.08 g of self-made 3-methyl-4-formyl-2-oxofrazine was added in portions under stirring. The mixture was heated in an oil bath at 78 °C for 24 h. After cooling, a white precipitate formed. The precipitate was filtered and washed with cold ethanol to give 4.615 g of a white solid, with a yield of 77.58%.

[0046] A small amount of the synthesized compound was taken and dissolved in methanol:DMF at a ratio of 1:1 (volume ratio). The filtered solution was then injected via syringe and evaporated in an oven to obtain single crystals, the structure of which is shown below. Figure 3 As shown.

[0047] The compound prepared in this invention exhibits good detonation performance, Dc = 7150.145 ms. -1 With a Pd value of 18.798 GPa, lower mechanical sensitivity, and higher thermal decomposition temperature (Tonset = 249 °C), it is superior to traditional explosives like TNT (Dc = 6881 m / s). -1 (Pd = 19.5 GPa). These combined properties give this series of compounds the potential to become high-energy, low-sensitivity explosives. The compounds of this invention have a decomposition temperature of 249 °C and a heat of formation of 442.766535 kJ / mol. Compared with other furazan-type energetic compounds, the target compounds have higher thermal stability.

Claims

1. An energetic compound of the furazolidone class, characterized in that, Its name is 2-bis((3-methyl-4-oxozanyl)-methylenehydrazyl)-1-oxalylhydrazine, and its structure is shown in Formula 1:

2. A method for synthesizing an energetic compound of the furazolidone class, characterized in that, include: (1) The step of reacting trans-butenal with sodium nitrite to generate 3-methyl-4-formyl-2-oxofraxan intermediate 1 via a cyclization reaction. (2) The step of synthesizing the target product, furazolidone hydrazone-like energetic compound 2, by condensing intermediate 1 with oxalohydrazide.

3. The synthesis method as described in claim 2, characterized in that, The molar ratio of trans-butenoic acid to sodium nitrite is 1:1.5 to 3.

4. The synthesis method according to claim 2, characterized in that, The ring-closure reaction was carried out at a temperature of 10°C for 24 hours.

5. The synthesis method as described in claim 2, characterized in that, The molar ratio of intermediate 1 to oxalohydrazide is 1.77:

1.

6. The synthesis method according to claim 2, characterized in that, The reflux temperature for the condensation reaction is 78°C, and the reaction time is 20-24 hours.

7. A crystal prepared from an energetic compound of the furazolidone class as described in claim 1, characterized in that, The crystal structure is triclinic, space group P-1, and cell number [missing information]. α=2.623(3)°, β=82.233(3)°, γ=81.031(3), and the unit cell volume is Each unit cell contains three molecules, and the crystal density of this compound is 1.384 g / cm³. -3 .

8. The use of a furazolidone-based energetic compound as described in claim 1 as an explosive.

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