A high-energy oxidant of dinitrophenyl azofurazan and a preparation method thereof

Abstract

This invention discloses a high-energy oxidant, dinitroformyl azofuran, and its preparation method, the molecular formula of which is C6N. 12 O 14 Its density is 1.865 g∙cm³. ‑3 The carbon dioxide-oxygen balance is 6.894%, and the oxygen content is 48.26%. The steps are as follows: oxime formation: 4-(hydroxyimino)-3-oxobutyric acid is prepared from 3-oxoglutaric acid; cyclization: 4-(hydroxyimino)-3-oxobutyric acid reacts with hydroxylamine hydrochloride to cyclize into aminofurazanine; oxidative coupling: two molecules of aminofurazanine are oxidatively coupled to azofurazanine diacetic acid; nitration: azofurazanine diacetic acid is nitrated to dinitroformin azofurazan. The dinitroformin azofurazan oxidant of this invention has advantages such as high density, high oxygen content, good thermal stability, high energy performance, and low characteristic signal, and can be used as a high-energy oxidant in composite solid propellants.

Description

Technical Field

[0001] This invention relates to a high-energy oxidant, dinitroformyl azofuran, and its preparation method, belonging to the field of energetic materials technology. Background Technology

[0002] Modern warfare places higher demands on the flight speed of various missiles and rockets. Therefore, as the power source for missile and rocket engines, the performance of propellants directly affects the combat and survivability of related weapons. Propellant development prioritizes high-energy components. Employing high-energy oxidizers is the most direct and effective technical approach to increasing propellant energy. The development of high-energy oxidizers for next-generation solid propellants is an urgent requirement for promoting the continuous progress of solid propellant technology and facilitating the upgrading of weaponry.

[0003] Nitroform hydrazine, developed in the 1950s, has had its applications limited due to poor stability, high sensitivity, and irregular grain morphology. In the mid-1970s, literature reported the synthesis of ammonium dinitramide (AND) molecules, but AND cannot meet the requirements for solid propellant processing and storage in terms of hygroscopicity, safety, and compatibility, and therefore remains unused. Currently, ammonium perchlorate (AP) is still widely used as a propellant. Its advantages include high effective oxygen and hydrogen content, but its disadvantages include low enthalpy of formation, halogen content, and significant pollution. Therefore, an ideal high-energy oxidant should be a compound with high oxygen-nitrogen content, high oxygen-to-carbon ratio, high enthalpy of formation, high density, low characteristic signal, and clean, green combustion products. Summary of the Invention

[0004] The purpose of this invention is to provide a high-energy oxidant and its preparation method.

[0005] Technical solution to achieve the purpose of this invention:

[0006] A high-energy oxidant with the chemical formula C6N 12 O 14 The structural formula is:

[0007]

[0008] The crystal structure of this energetic compound has the following characteristics:

[0009] Crystal system: Orthorhombic;

[0010] Group: Pbca;

[0011] Unit cell parameters: α = β = γ = 90°;

[0012] Unit cell volume:

[0013] Z = 4;

[0014] Density: 1.865 g·cm³ -3 (296K).

[0015] This invention provides a method for preparing a high-energy oxidant, comprising:

[0016] (1) The step of preparing 4-(hydroxyimino)-3-oxobutyric acid by reacting 3-oxoglutaric acid in concentrated hydrochloric acid and sodium nitrite.

[0017]

[0018] (2) The step of preparing aminofurazanol by placing 4-(hydroxyimino)-3-oxobutyric acid in a mixture of sodium hydroxide solution and hydroxylamine hydrochloride solution and stirring for a period of time, and then adding urea to react.

[0019]

[0020] (3) The step of preparing azofuran diacetic acid by reacting aminofuranacetic acid in dilute hydrochloric acid and potassium permanganate solution;

[0021]

[0022] (4) The step of preparing dinitroformin azofuran by reacting azofuran diacetic acid in a nitric acid-sulfuric acid system;

[0023]

[0024] Preferably, in step (1), the reaction temperature is -5℃ to reflux temperature; the molar ratio of 3-oxoglutaric acid, concentrated hydrochloric acid and sodium nitrite is 1:2.1:1.

[0025] Preferably, in step (2), the reaction temperature is 80-100℃; the molar ratio of 4-(hydroxyimino)-3-oxobutyric acid, sodium hydroxide, hydroxylamine hydrochloride and urea is 1:4.8:3.5:2.5.

[0026] Preferably, in step (3), the concentration of dilute hydrochloric acid is 20 wt%; the reaction temperature is 20-60℃; and the molar ratio of aminofuran acetic acid, hydrochloric acid, and potassium permanganate is 1:1.2:1.1.

[0027] Preferably, in step (4), the nitric acid-sulfur mixture is a mixture of concentrated sulfuric acid and fuming nitric acid with a volume ratio of 1.2 to 2.0; the reaction temperature is 20 to 45°C.

[0028] Compared with the prior art, the beneficial effects of this invention are:

[0029] (1) The high-energy oxidant of the present invention has a covalent structure in which the nitro group and the azofuran ring are directly linked, which is superior to the ionic structure of traditional oxidants such as ammonium perchlorate or ammonium dinitramide in terms of hygroscopicity and stability.

[0030] (2) The high-energy oxidant of the present invention has good thermal stability and a decomposition temperature of 155℃ (heating rate 5℃·min). -1 Before thermal decomposition, there is a significant melting and endothermic process, with a total heat release of (1048 g). -1 It has a large heat capacity and exhibits significant exothermic characteristics of energetic compounds.

[0031] (3) The carbon dioxide oxygen balance of the high-energy oxidant of the present invention is 6.894%, and the oxygen content is 48.26%.

[0032] (4) The density of the high-energy oxidant of the present invention is 1.865 g·cm³. -3 It exhibits excellent detonation performance, with a calculated detonation pressure of 35.1 GPa and a detonation velocity of 9012 m / s using EXPLO5. -1 .

[0033] (5) The high-energy oxidant of the present invention is chlorine-free and is an excellent low-signature solid propellant component. Attached Figure Description

[0034] Figure 1 This is a crystal structure diagram of the dinitroformyl azofuran of the present invention (viewing perpendicular to the plane of the furazan ring).

[0035] Figure 2 This is a crystal structure diagram of the dinitroformyl azofuran of the present invention (viewing from a plane parallel to the furazan ring).

[0036] Figure 3 This is a unit cell packing diagram of the dinitroform azofuran of the present invention.

[0037] Figure 4 Differential scanning calorimetry (DSC) of dinitroform-azofuran in this invention (heating rate 5°C / min) -1 ).

[0038] Figure 5 This is the carbon NMR spectrum of the dinitroformyl azofuran of the present invention (the solvent is deuterated dimethyl sulfoxide).

[0039] Figure 6 This is the infrared spectrum of the dinitroform azofuran of the present invention. Detailed Implementation

[0040] The following embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0041] The present invention provides a method for preparing a high-energy oxidant, the reaction equation of which is as follows:

[0042]

[0043] The specific steps are as follows:

[0044] Step 1: Add sodium nitrite and 3-oxoglutaric acid to concentrated hydrochloric acid. Stir the reaction mixture at a certain temperature for 3-10 hours. After the reaction is complete, pour the reaction solution into cold water while stirring. Continue stirring for 0.5-3 hours. Filter, wash with dilute hydrochloric acid, and dry to obtain 4-(hydroxyimino)-3-oxobutyric acid.

[0045] Step 2: Control the temperature at 10-15℃, add sodium hydroxide solution to hydroxylamine hydrochloride solution, then add 4-(hydroxyimino)-3-oxobutyric acid, stir for 0.5-2 hours, continue to add urea, after the addition is complete, heat the reaction system to a certain temperature and maintain it for 3-5 hours. When the reaction is complete, cool the reaction system to room temperature, extract with diethyl ether, combine the organic phases, dry with anhydrous magnesium sulfate, and remove the solvent by vacuum rotary evaporation to obtain aminofurazanol acetic acid;

[0046] Step 3: Add aminofurazanine to 20wt% hydrochloric acid, add potassium permanganate solution dropwise, stir the reaction at a certain temperature for 0.5-6 hours, treat with oxalic acid solution until the reaction solution decolorizes, collect the precipitate by filtration, wash with water, dry, and obtain azofurazanine diacetic acid.

[0047] Step 4: Add fuming nitric acid dropwise to 98wt% concentrated sulfuric acid at -10 to 5℃. After the addition is complete, stir for 0.5h. Add azofuran diacetic acid in batches below 5℃. Gradually restore the reaction system to room temperature. Then stir the reaction at a certain temperature for 10 to 15h. After the reaction is complete, pour the reaction solution into ice water, filter, wash, and dry to obtain dinitroformazofuran.

[0048] Example 1: 24g of sodium nitrite and 50g of 3-oxoglutaric acid were added to 60mL of concentrated hydrochloric acid. The reaction mixture was stirred at 0℃ for 8h. After the reaction was complete, the reaction solution was poured into cold water while stirring, and stirring was continued for 3h. The mixture was then filtered, and the solution was 1mol·L⁻¹. -1 Washed with dilute hydrochloric acid and dried, 35 g of 4-(hydroxyimino)-3-oxobutyric acid was obtained, with a yield of 61.9%.

[0049] 278 g of hydroxylamine hydrochloride was dissolved in 140 mL of deionized water to prepare solution A; 223 g of sodium hydroxide was dissolved in 233 mL of deionized water to prepare solution B; the temperature was controlled at 10–15 °C, and solution B was added to solution A. After the addition was complete, 150 g of 4-(hydroxyimino)-3-oxobutyric acid was added to the reaction solution, and the mixture was stirred for 0.5 h. Then, 170 g of urea was added, and the reaction system was heated to 95 °C and maintained for 5 h. After the reaction was complete, the reaction system was cooled to room temperature, extracted three times with 3 × 150 mL of diethyl ether, the organic phases were combined, dried over anhydrous magnesium sulfate, and the solvent was removed by vacuum rotary evaporation to obtain 130 g of aminofurazanol acetic acid, with a yield of 79.4%.

[0050] 7.2 g of aminofurazanine was added to 100 mL of 20% hydrochloric acid, and 8.5 g of potassium permanganate aqueous solution was added dropwise to 100 mL. The mixture was stirred at 20 °C for 0.5 h, and then treated with oxalic acid solution until the reaction solution decolorized. The precipitate was collected by filtration, washed with water, and dried to obtain 6.2 g of azofurazanine diacetic acid, with a yield of 89.9%.

[0051] 4 mL of fuming nitric acid was added dropwise to 5 mL of 98% concentrated sulfuric acid at -10 to 5 °C. After the addition was complete, the mixture was stirred for 0.5 h. 1 g of azofuran diacetic acid was added in portions below 5 °C. The reaction system was gradually brought back to room temperature, and then stirred at 20 °C for 10 h. After the reaction was completed, the reaction solution was poured into ice water, filtered, washed, and dried to obtain 1 g of dinitroformazofuran, with a yield of 61.0%.

[0052] Example 2: 24 g of sodium nitrite and 50 g of 3-oxoglutaric acid were added to 60 mL of concentrated hydrochloric acid. The reaction mixture was heated to reflux and stirred for 10 h. After the reaction was complete, the reaction solution was poured into cold water while stirring, and stirring was continued for 0.5 h. The mixture was then filtered, and 0.5 mol·L⁻¹ was obtained. -1 Washed with dilute hydrochloric acid and dried, 41 g of 4-(hydroxyimino)-3-oxobutyric acid was obtained, with a yield of 72.6%.

[0053] 278 g of hydroxylamine hydrochloride was dissolved in 140 mL of deionized water to prepare solution A; 223 g of sodium hydroxide was dissolved in 233 mL of deionized water to prepare solution B; the temperature was controlled at 10–15 °C, and solution B was added to solution A. After the addition was complete, 150 g of 4-(hydroxyimino)-3-oxobutyric acid was added to the reaction solution, and the mixture was stirred for 1 h. Then, 170 g of urea was added, and the reaction system was heated to 100 °C and maintained for 3 h. After the reaction was complete, the reaction system was cooled to room temperature, extracted three times with 3 × 150 mL of diethyl ether, the organic phases were combined, dried over anhydrous magnesium sulfate, and the solvent was removed by vacuum rotary evaporation to obtain 139 g of aminofurazanol acetic acid, with a yield of 84.9%.

[0054] 7.2 g of aminofurazanine was added to 100 mL of 20% hydrochloric acid, and 8.5 g of potassium permanganate aqueous solution was added dropwise to 100 mL. After stirring at 40 °C for 6 h, the reaction solution was treated with oxalic acid solution until it decolorized. The precipitate was collected by filtration, washed with water, and dried to obtain 5.8 g of azofurazanine diacetic acid, with a yield of 84.1%.

[0055] 4 mL of fuming nitric acid was added dropwise to 5 mL of 98% concentrated sulfuric acid at -10 to 5 °C. After the addition was complete, the mixture was stirred for 0.5 h. 1 g of azofuran diacetic acid was added in portions below 5 °C. The reaction system was gradually brought back to room temperature, and then stirred at 20 °C for 15 h. After the reaction was completed, the reaction solution was poured into ice water, filtered, washed, and dried to obtain 1.1 g of dinitroformazofuran, with a yield of 67.1%.

[0056] Example 3: 24 g of sodium nitrite and 50 g of 3-oxoglutaric acid were added to 60 mL of concentrated hydrochloric acid. The reaction mixture was stirred at -5 °C for 3 h. After the reaction was complete, the reaction solution was poured into cold water while stirring, and stirring was continued for 1 h. The mixture was then filtered, and 0.5 mol·L⁻¹ was obtained. -1 Washed with dilute hydrochloric acid and dried, 31 g of 4-(hydroxyimino)-3-oxobutyric acid was obtained, with a yield of 54.9%.

[0057] 278 g of hydroxylamine hydrochloride was dissolved in 140 mL of deionized water to prepare solution A; 223 g of sodium hydroxide was dissolved in 233 mL of deionized water to prepare solution B; the temperature was controlled at 10–15 °C, and solution B was added to solution A. After the addition was complete, 150 g of 4-(hydroxyimino)-3-oxobutyric acid was added to the reaction solution, and the mixture was stirred for 1 h. Then, 170 g of urea was added, and the reaction system was heated to 95 °C and maintained for 4 h. After the reaction was complete, the reaction system was cooled to room temperature, extracted three times with 3 × 150 mL of diethyl ether, the organic phases were combined, dried over anhydrous magnesium sulfate, and the solvent was removed by vacuum rotary evaporation to obtain 126 g of aminofurazanol acetic acid, with a yield of 77.0%.

[0058] 7.2 g of aminofurazanine was added to 100 mL of 20% hydrochloric acid, and 8.5 g of potassium permanganate aqueous solution was added dropwise to 100 mL. After stirring at 60 °C for 1 h, the reaction solution was treated with oxalic acid solution until it decolorized. The precipitate was collected by filtration, washed with water, and dried to obtain 5 g of azofurazanine diacetic acid, with a yield of 72.5%.

[0059] 4.5 mL of fuming nitric acid was added dropwise to 9 mL of 98% concentrated sulfuric acid at -10 to 5 °C. After the addition was complete, the mixture was stirred for 0.5 h. 1 g of azofuran diacetic acid was added in portions below 5 °C. The reaction system was gradually brought back to room temperature, and then stirred at 40 °C for 15 h. After the reaction was completed, the reaction solution was poured into ice water, filtered, washed, and dried to obtain 1.3 g of dinitroformazofuran, with a yield of 79.3%.

[0060] Example 4: 24 g of sodium nitrite and 50 g of 3-oxoglutaric acid were added to 60 mL of concentrated hydrochloric acid. The reaction mixture was stirred at 15 °C for 5 h. After the reaction was complete, the reaction solution was poured into cold water while stirring, and stirring was continued for 2 h. The mixture was then filtered. (1 mol·L⁻¹) -1 Washed with dilute hydrochloric acid and dried, 39 g of 4-(hydroxyimino)-3-oxobutyric acid was obtained, with a yield of 69.0%.

[0061] 278 g of hydroxylamine hydrochloride was dissolved in 140 mL of deionized water to prepare solution A; 223 g of sodium hydroxide was dissolved in 233 mL of deionized water to prepare solution B; the temperature was controlled at 10–15 °C, and solution B was added to solution A. After the addition was complete, 150 g of 4-(hydroxyimino)-3-oxobutyric acid was added to the reaction solution, and the mixture was stirred for 0.5 h. Then, 170 g of urea was added, and after the addition was complete, the reaction system was heated to 90 °C and maintained for 5 h. After the reaction was completed, the reaction system was cooled to room temperature, extracted three times with 3 × 150 mL of diethyl ether, the organic phases were combined, dried over anhydrous magnesium sulfate, and the solvent was removed by vacuum rotary evaporation to obtain 106 g of aminofurazanol acetic acid, with a yield of 65.0%.

[0062] 7.2 g of aminofurazanine was added to 100 mL of 20% hydrochloric acid, and 8.5 g of potassium permanganate aqueous solution was added dropwise to 100 mL. After stirring at 50 °C for 5 h, the reaction solution was treated with oxalic acid solution until it decolorized. The precipitate was collected by filtration, washed with water, and dried to obtain 5.6 g of azofurazanine diacetic acid, with a yield of 81.2%.

[0063] 5 mL of fuming nitric acid was added dropwise to 10 mL of 98% concentrated sulfuric acid at -10 to 5 °C. After the addition was complete, the mixture was stirred for 0.5 h. 1 g of azofuran diacetic acid was added in portions below 5 °C. The reaction system was gradually brought back to room temperature, and then stirred at 25 °C for 12 h. After the reaction was completed, the reaction solution was poured into ice water, filtered, washed, and dried to obtain 1.4 g of dinitroformazofuran, with a yield of 85.4%.

[0064] Comparative Example 1: 1g of azofuran diacetic acid was added in portions to 5mL of fuming nitric acid at a temperature below 5℃. The reaction system was gradually restored to room temperature, and then stirred at 25℃ for 12h. After the reaction was completed, the reaction solution was poured into ice water to obtain an oily liquid, indicating that the reaction failed.

[0065] Comparative Example 2: 5 mL of fuming nitric acid was added dropwise to 10 mL of acetic anhydride at -10 to 5 °C. After the addition was complete, the mixture was stirred for 0.5 h. 1 g of azofuran diacetic acid was added in batches at below 5 °C. The reaction system was gradually restored to room temperature, and then stirred at 25 °C for 12 h. After the reaction was completed, the reaction solution was poured into ice water to obtain an oily liquid. The reaction failed.

[0066] The dinitroformyl azofurans obtained in Examples 1-4 were dissolved in ethyl acetate and slowly evaporated at room temperature to obtain pale yellow blocky single crystals. Single-crystal X-ray diffraction tests were performed, and their crystal structures are as follows. Figures 1-3 As shown, their unit cell parameters are the same, as shown in the attached table below:

[0067] Appendix

[0068]

[0069]

[0070] The dinitroform-azofuran obtained in Example 1 was characterized, and the analytical results are as follows:

[0071] like Figure 4 The differential scanning calorimetry (DSC) curve shown is at 155℃ (decomposition, heating rate 5℃·min). -1 Before thermal decomposition, there is a significant melting and endothermic process, with a total heat release of (1048 g). -1 Large, exhibiting significant exothermic characteristics of energetic compounds. For example... Figure 5 The MRI scan shown is as follows. 13 C NMR (DMSO-d6): δ 161.75, 161.20, 141.06, 136.23 ppm. (Example) Figure 6 The infrared spectrum shown is IR(ATR): 1632,1615,1592,1481,1404,1277,1064,986,914,840,796,706,685,624,599,577cm -1 Elemental analysis: C6 N12 O14 (464.136): Measured (calculated) C 15.48 (15.53), N 36.17 (36.21).

[0072] The dinitroform-azofuran obtained in Example 1 was tested and found to have an impact sensitivity of 4J and a friction sensitivity of 80N.

[0073] The carbon dioxide oxygen balance of the dinitroformyl azofuran obtained in Example 1 was calculated to be 6.894%, and the oxygen content was 48.26%.

[0074] The density of the dinitroform-azofuran obtained in Example 1 was tested to be 1.865 g·cm³. -3 It exhibits excellent detonation performance, with a calculated detonation pressure of 35.1 GPa and a detonation velocity of 9012 m / s using EXPLO5. -1 .

Claims

1. A crystalline Form I of the high-energy oxidizer dinitrophenyl azofurazan, characterized by, Crystal form I is prepared by the following method: (1) The step of preparing 4-(hydroxyimino)-3-oxobutyric acid by oximation of 3-oxoglutaric acid in concentrated hydrochloric acid and sodium nitrite; ； (2) The step of preparing aminofurazanol by placing 4-(hydroxyimino)-3-oxobutyric acid in a mixture of sodium hydroxide solution and hydroxylamine hydrochloride solution and stirring for a period of time, and then adding urea to undergo a cyclization reaction. ； (3) The step of preparing azofurandiacetic acid by oxidative coupling reaction of aminofurandiacetic acid in dilute hydrochloric acid and potassium permanganate solution; ； (4) The step of preparing dinitroformin azofuran diacetic acid by nitration reaction in a nitrate-sulfur mixed acid system; ； In step (1), the reaction temperature is -5℃ to reflux temperature; the molar ratio of 3-oxoglutaric acid, concentrated hydrochloric acid, and sodium nitrite is 1:2.1:

1. In step (2), the reaction temperature is 80-100℃; the molar ratio of 4-(hydroxyimino)-3-oxobutyric acid, sodium hydroxide, hydroxylamine hydrochloride, and urea is 1:4.8:3.5:2.

5. In step (3), the concentration of dilute hydrochloric acid is 20 wt%; the reaction temperature is 20–60 °C; and the molar ratio of aminofuran acetic acid, hydrochloric acid, and potassium permanganate is 1:1.2:1.

1. In step (4), the nitric acid-sulfuric acid mixture is a mixture of concentrated sulfuric acid and fuming nitric acid with a volume ratio of 1.2 to 2.0; the reaction temperature is 20 to 45°C. Crystal form I of this high-energy oxidant has the following characteristics: Crystal system: Orthorhombic; Point cloud: Pbca ; Cell parameters: a = 10.1788 (14) Å, b = 9.6711 (12) Å, c = 16.790 (2) Å, α = β = γ = 90°; Cell dimensions: 1652.8 (4) A 3 ; Z = 4； Density: 1.865 g·cm³ -3 (296 K).

2. The application of crystal form I of the high-energy oxidant dinitroformazofuran as described in claim 1 as a component of a solid propellant.

Images