Novel diamine ternary self-assembly energetic material and preparation method thereof

Abstract

The invention belongs to the technical field of energetic materials, and discloses a novel diamine ternary self-assembly energetic material and a preparation method thereof. The chemical structural unit of the energetic material is composed of a double-protonated ethylenediamine cation, a double-protonated propane diamine cation and four perchlorate anions, the crystal of the energetic material belongs to a monoclinic system, and the space group of the energetic material is P21 / c. The material shows excellent comprehensive performance, including positive oxygen balance, positive enthalpy of formation, high theoretical specific impulse and good thermal stability and moisture absorption resistance. The preparation method comprises the following steps: dissolving ethylenediamine and propane diamine in water to form a mixed solution, then adding a perchloric acid aqueous solution, magnetically stirring to separate out a white solid, and filtering to obtain a target product. The method takes water as a solvent, is simple in process, environment-friendly, low in cost and suitable for large-scale production, and provides a novel component which is high in performance and green in preparation for the field of energetic materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energetic materials, and particularly relates to a novel diamine-based ternary self-assembled energetic material and a preparation method thereof. BACKGROUND

[0002] Energetic materials, such as CL-20, RDX and HMX, are mostly single-molecule compounds, and the energy density, detonation performance and stability of the single-molecule compounds are mainly determined by the chemical bond characteristics and molecular structure in the single-molecule compounds. In order to pursue higher energy levels, the traditional technical route is usually committed to introducing more energetic groups (such as nitro groups) or constructing higher tension ring structure in a single-molecule skeleton. However, this "intramolecular design" strategy is often accompanied by long and complex synthesis steps, harsh reaction conditions and high manufacturing cost, thereby limiting the further development and application thereof.

[0003] In order to overcome the above inherent limitations, the research paradigm is gradually shifted from "intramolecular design" to "intermolecular design". Among them, the energetic polyionic crystal as a typical representative of this idea, through the method of crystal engineering, different energetic ions or neutral molecules are self-assembled into a new crystal material by means of intermolecular forces such as ionic bond and hydrogen bond. This "molecular building block" type of assembly method theoretically provides a convenient way to flexibly control the performance of the material. However, many self-assembled energetic materials reported in the prior art often have difficulty in achieving the desired balance in performance. Specifically, how to simultaneously achieve high energy density (such as high oxygen balance and positive enthalpy of formation) and excellent stability (such as high thermal decomposition temperature and low hygroscopicity) at the intermolecular level is still a core technical problem to be solved. For example, some materials may perform well in energy parameters, but their thermal stability or moisture resistance is insufficient, which seriously affects their reliability and storage life in actual working conditions; on the contrary, some stable materials may be deficient in energy output.

[0004] Therefore, there is an urgent need in the art to develop a novel energetic material that can fundamentally balance and take into account high energy characteristics and high stability, thereby providing a more superior high-energy component for the propellant field. SUMMARY

[0005] The purpose of the present application is to provide a novel diamine-based ternary self-assembled energetic material and a preparation method thereof, so as to solve the core technical problem in the prior art that high energy characteristics and high stability cannot be simultaneously achieved through intermolecular design.

[0006] In order to achieve the above technical purpose, the following technical solutions are specifically adopted in the present application: In one aspect of this application, a novel diamine-based ternary self-assembled energetic material is provided, wherein the chemical structural unit of the diamine-based ternary self-assembled energetic material is composed of one diprotonated ethylenediamine cation, one diprotonated propylenediamine cation, and four perchlorate anions: ; The diamine-based ternary self-assembled energetic material belongs to the monoclinic crystal system. P2 1 / c Space group, cell parameters: a = 7.8549 Å, b = 24.742 Å, c = 9.9887 Å, α = 90°. β =97.606° gamma =90°, Z =1.

[0007] In one embodiment, the diamine-based ternary self-assembled energetic material exhibits a diffraction angle of 2° in Cu-Kα radiation X-ray powder diffraction. theta Characteristic diffraction peaks are observed at 7.108°, 11.379°, 14.256°, 15.587°, 18.200°, 13.397°, 21.163°, 21.447°, 22.593°, 23.024°, 24.515°, 24.880°, 25.187°, 27.823°, 31.462°, and 31.094°, with an error of ±0.2° for each diffraction angle.

[0008] In one embodiment, the diamine-based ternary self-assembled energetic material, when tested using differential scanning calorimetry, has a peak decomposition temperature of 302°C and an initial decomposition temperature of 272°C.

[0009] In another aspect of this application, a method for preparing the novel diamine-based ternary self-assembled energetic material is provided, comprising the following steps: Step 1: Dissolve ethylenediamine and propylenediamine in an aqueous solution and stir magnetically to obtain a homogeneous mixed solution; Step 2: Add perchloric acid aqueous solution to the obtained mixed solution, stir magnetically and a white solid precipitates out. Filter out the mother liquor to obtain the diamine-based ternary self-assembled energetic material.

[0010] In one embodiment, the molar ratio of ethylenediamine, propylenediamine, and perchloric acid is 2~1:1:4~10.

[0011] In one embodiment, the molar ratio of ethylenediamine and propylenediamine in step one includes, but is not limited to, 1:1.

[0012] In one embodiment, the perchloric acid aqueous solution in step two is a 70% perchloric acid aqueous solution.

[0013] The application has the beneficial effects of: The diamine-based ternary self-assembled energetic material described in the application exhibits excellent comprehensive performance in energy characteristics and stability. Through the synergistic effect between +5.97% oxygen balance, 35 kJ / mol positive enthalpy of formation, and 4.73% hydrogen content, the theoretical specific impulse of the material reaches 286.6 N·s / kg, exhibiting excellent energy release potential. At the same time, the material has extremely low moisture absorption rate in a 60% relative humidity environment, and the initial thermal decomposition temperature is as high as 272℃, which reflects good physical and thermal stability.

[0014] In terms of preparation process, the material adopts a water phase crystallization route, completely avoiding the use of organic solvents, not only significantly reducing production cost and environmental load, but also having mild process conditions and safe operation, and having the potential for industrialized scale production.

[0015] In summary, the application provides a new green component with excellent energy performance and practical stability for the field of energetic materials, which has important application value in the fields of military and aerospace such as solid propellants. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Figure 1 is a polarizing microscope image of the ternary self-assembled energetic material of Example 3 of the application; Figure 2 Figure 2 is a PXRD graph of the ternary self-assembled energetic material of Example 3 of the application; Figure 3 Figure 3 is a TGA / DSC graph of the ternary self-assembled energetic material of Example 3 of the application; Figure 4 Figure 4 is a single crystal structure graph of the ternary self-assembled energetic material of Example 3 of the application; Figure 5 Figure 5 is a dynamic vapor adsorption result graph of the ternary self-assembled energetic material of Example 3 of the application. DETAILED DESCRIPTION

[0017] The technical solutions of the application will be described below in conjunction with specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the application, not all embodiments, and are only used to illustrate the application, and should not be regarded as limiting the scope of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the application.

[0018] This application utilizes an intermolecular design approach to construct a ternary self-assembled crystal structure based on diamine cations and perchlorate ions, addressing the key challenge of synergistically improving energy density and stability in energetic materials. The design employs ethylenediamine and propylenediamine as structural units, which, after protonation, form dications. These dications then self-assemble with four perchlorate anions in a specific stoichiometric ratio within the crystal space through electrostatic interactions and a hydrogen bond network. This structure fully leverages the high oxygen balance provided by perchlorate ions, combined with the positive enthalpy of formation and hydrogen content contributed by the amine cations, achieving energy performance optimization at the molecular assembly level. Simultaneously, the dense ion packing and strong hydrogen bond network endow the crystal with excellent thermal stability and moisture resistance. This concept is realized through an aqueous crystallization process, avoiding the use of organic solvents and forming a technical path that combines high performance with green preparation characteristics.

[0019] This self-assembled energetic material exhibits excellent comprehensive performance: it possesses a positive oxygen balance (+5.97%, based on CO), a positive enthalpy of formation (35 kJ / mol) beneficial for increasing specific impulse, and a high hydrogen content (4.73%). Furthermore, the material also exhibits good hygroscopic resistance, a high initial thermal decomposition temperature of 272℃, and good stability. Moreover, the reaction precursors and reagents of this self-assembled energetic material are all inexpensive and readily available bulk chemicals, which can be obtained through crystallization in an environmentally friendly aqueous system, demonstrating potential for green and low-cost preparation. In summary, this novel energetic material not only provides an effective way to solve the problem of low enthalpy of formation in traditional multi-component oxidants, but also shows great promise as a high-performance component in fields such as advanced solid propellant formulations.

[0020] In one specific embodiment, a novel diamine-based ternary self-assembled energetic material is provided, wherein the crystal of the energetic material is formed by a self-assembly process of ions in a specific stoichiometric ratio. Its basic structural unit comprises a diprotonated ethylenediamine cation, a diprotonated propylenediamine cation, and four perchlorate anions: ; These components, through intermolecular forces such as ionic bonds and hydrogen bonds, together construct a ternary crystal structure in a defined stoichiometric ratio.

[0021] The energetic material possesses definite crystallographic characteristics. Its crystal belongs to the monoclinic crystal system, with space group [space group number missing]. P2 1 / c Single-crystal X-ray diffraction analysis revealed the following unit cell parameters: unit cell axis lengths a = 7.8549 Å, b = 24.742 Å, c = 9.9887 Å; unit cell axis angles α = 90°. β =97.606° gamma =90°, number of molecules in unit cell Z=1. Single-crystal structure analysis confirms that each asymmetric unit of the energetic material consists of a diprotonated ethylenediamine cation, a diprotonated propylenediamine cation, and four perchlorate anions. These ions are arranged in an ordered manner in three-dimensional space through electrostatic interactions and hydrogen bond networks, forming a ternary self-assembled crystal structure.

[0022] In some embodiments, experimental data for single-crystal structure determination were acquired using an X-ray single-crystal diffractometer manufactured by Rigaku Corporation, Japan, model: Rigaku R-AXIS Rapid II. Specifically, a molybdenum target (Mo-Kα) was used as the X-ray source during the testing process, emitting X-rays with a wavelength λ of 0.71073 Å. The instrument's operating voltage was set to 50 kV, and the operating current was set to 90 mA. All measurements were performed at a constant temperature of 298 K (approximately 25 °C).

[0023] The crystal structure and phase purity of the novel diamine-based ternary self-assembled energetic material were characterized by X-ray powder diffraction.

[0024] Tests showed that the obtained X-ray powder diffraction pattern was at a specific diffraction angle of 2. theta The location shows a series of characteristic diffraction peaks. These characteristic peaks are located at 2... theta The angle values ​​include: 7.108°, 11.379°, 14.256°, 15.587°, 18.200°, 21.163°, 21.447°, 22.593°, 23.024°, 24.515°, 24.880°, 25.187°, 27.823°, 31.094°, and 31.462°. It should be noted that a reasonable error range of ±0.2° is allowed for the measurement of each of the above diffraction angles.

[0025] In some embodiments, the X-ray powder diffraction method is performed using a D / MAX2500 powder diffractometer manufactured by Rigaku Corporation, Japan. Specifically, the test conditions are set as follows: a copper target is used as the X-ray source to generate Cu-Kα radiation with a wavelength λ of 1.5418 Å. The instrument operating voltage is 40 kV and the operating current is 100 mA. Data acquisition is performed in continuous scanning mode at a scanning speed of 8° / min.

[0026] In one specific embodiment of the present invention, the thermal decomposition characteristics of the novel diamine-based ternary self-assembled energetic material are determined by differential scanning calorimetry.

[0027] Test results show that the diamine-based ternary self-assembled energetic material exhibits clear thermal decomposition behavior. Its initial decomposition temperature, i.e., the temperature at which the thermal decomposition process begins, is 272℃. Simultaneously, a sharp exothermic peak was observed on the DSC curve, corresponding to a peak decomposition temperature of 302℃. This indicates that the diamine-based ternary self-assembled energetic material possesses high thermal stability.

[0028] In some embodiments, the differential scanning calorimetry (DSC) is performed using a Mettler Toledo DSC instrument. During testing, 0.2–0.5 mg of sample is accurately weighed and placed in a dedicated crucible, which is then placed inside the instrument's heating furnace. High-purity argon gas is continuously introduced into the furnace as both a protective and reactive gas, with the protective gas flow rate controlled at 50.0 ml / min and the reactive gas flow rate controlled at 200.0 ml / min. The temperature control program is set to start at 30.0 °C and increase at a constant rate of 10.0 °C per minute until the final temperature reaches 400.0 °C. Throughout the heating process, the instrument automatically records the heat flux signal generated by the sample as the temperature changes. Data acquisition, program control, and subsequent analysis are all performed using the STARe Software 18.0 system developed by Mettler Toledo.

[0029] In another specific embodiment, a method for preparing the novel diamine-based ternary self-assembled energetic material is provided, comprising the following steps: Step 1: Prepare the raw material solution Both ethylenediamine and propylenediamine were dissolved together in deionized water. The mixture was then placed on a magnetic stirrer and stirred at room temperature until a homogeneous and transparent solution was formed.

[0030] Step 2: Perform the crystallization reaction. Under continuous stirring, a 70% aqueous solution of perchloric acid was slowly added to the mixed solution obtained in step one. After the addition was complete, the solution was magnetically stirred for another 10 minutes at room temperature. During this process, a white solid was observed to gradually precipitate out of the solution.

[0031] Step 3: Product separation. After the reaction is complete, the solid product and mother liquor are separated by filtration. The collected white solid is the novel diamine-based ternary self-assembled energetic material.

[0032] In some embodiments, the molar ratio of ethylenediamine, propylenediamine, and perchloric acid is 2 to 1:1:4 to 10. Specifically, it can be 1:1:4, 1:1:5, 1:1:6, 1:1:7, 1:1:8, 1:1:9, 1:1:10, 2:1:4, 2:1:5, 2:1:6, 2:1:7, 2:1:8, 2:1:9, or 2:1:10.

[0033] This method uses water as the sole solvent, avoiding the use of organic solvents. It is simple to operate, environmentally friendly, and low-cost, making it suitable for industrial-scale production. By controlling the raw material ratio and crystallization conditions, the target product with the desired composition and crystal structure can be stably obtained.

[0034] The technical solution of this application will be further described below with reference to specific embodiments.

[0035] Example 1 Weigh 0.061 g of ethylenediamine (1 mmol) and 0.074 g of propylenediamine (1 mmol) and place them in a reaction vessel. Add 5 ml of deionized water to the vessel, start a magnetic stirrer, and stir at room temperature until the solids are completely dissolved, forming a homogeneous and transparent mixed solution.

[0036] While maintaining continuous stirring, 0.4 ml of a 70% perchloric acid aqueous solution (4 mmol) was slowly added dropwise to the above mixed solution using a pipette. After the addition was complete, the reaction mixture was continued to be magnetically stirred at room temperature. After a period of time, solid substances gradually precipitated from the reaction system.

[0037] After the reaction was complete, the solid product and mother liquor were separated by filtration. Observation of the resulting white solid using a polarizing microscope confirmed that its morphology was transparent, blocky crystals, such as... Figure 1 As shown, this crystal is the target product, a novel diamine-based ternary self-assembled energetic material.

[0038] Example 2 Weigh 0.122 g of ethylenediamine (2 mmol) and 0.074 g of propylenediamine (1 mmol) and place them in a reaction vessel. Add 5 ml of deionized water to the vessel, start the magnetic stirrer, and stir at room temperature to form a homogeneous and transparent mixed solution.

[0039] While maintaining continuous stirring, 0.4 ml of a 70% perchloric acid aqueous solution (4 mmol) was slowly added dropwise to the above mixed solution using a pipette. After the addition was complete, the reaction mixture was continued to be magnetically stirred at room temperature. After a period of time, blocky crystals gradually precipitated in the reaction system.

[0040] After the reaction is complete, the solid product and mother liquor are separated by filtration. The collected block crystals are the target product, a novel diamine-based ternary self-assembled energetic material.

[0041] Example 3 Weigh 0.061 g of ethylenediamine (1 mmol) and 0.074 g of propylenediamine (1 mmol) and place them in a reaction vessel. Add 5 ml of deionized water to the vessel, start the magnetic stirrer, and stir at room temperature to form a homogeneous and transparent mixed solution.

[0042] While maintaining continuous stirring, 1.0 ml of a 70% perchloric acid aqueous solution (10 mmol) was slowly added dropwise to the above mixed solution using a pipette. After the addition was complete, the reaction mixture was continued to be magnetically stirred at room temperature. After a period of time, blocky crystals gradually precipitated in the reaction system.

[0043] After the reaction is complete, the solid product and mother liquor are separated by filtration. The collected block crystals are the target product, a novel diamine-based ternary self-assembled energetic material.

[0044] Experimental Example 1. X-ray powder diffraction (PXRD): The powder diffractometer used was a Rigaku D / MAX2500 manufactured by Rigaku Corporation, Japan. The testing conditions were as follows: CuKα target, voltage 40 kV, current 100 mA, scanning wavelength λ = 1.5418 Å, continuous scanning, and a scanning speed of 8° / min. Data analysis was performed using Jade 7.0 software after collection.

[0045] The diamine-based ternary self-assembled energetic material prepared in Example 1 was tested, and its X-ray diffraction pattern is shown below. Figure 2 As shown, Examples 1-3 exhibit consistent PXRD test results.

[0046] 2. Differential Scanning Calorimeter (DSC): The tests were performed using a Mettler Toledo DSC instrument. 0.2–0.5 mg of sample was added to a crucible and placed in the furnace. High-purity argon was used as a protective gas (gas rate of 50.0 mL / min) and a reaction gas (gas rate of 200.0 mL / min) within the furnace. The measurement temperature range was 30.0–400.0 °C, with a heating rate of 10.0 °C / min. The temperature and heat changes of the sample during heating were measured. Program control, data recording, and analysis were all performed using STAReSoftware 18.0 software developed by Mettler Toledo.

[0047] The diamine-based ternary self-assembled energetic material prepared in Example 1 was subjected to DSC testing, and the results are as follows: Figure 3 As shown, within the test temperature range, the peak decomposition temperature of the diamine-based ternary self-assembled energetic material is 302 ℃, and the initial decomposition temperature is 272 ℃, indicating good thermal stability.

[0048] 3. X-ray single-crystal diffraction (SXRD): This invention utilizes an X-ray single-crystal diffractometer (RigakuR_AXISRapidII) manufactured by Rigaku Corporation of Japan. X-rays are generated using a MoKα target with a wavelength of λ = 0.71073 Å. The test voltage is 50 kV and the current is 90 mA. Single-crystal analysis and refinement are performed using SHELXS-2013 software. Detailed single-crystal measurement data are shown in Table 1. Figure 4 It has the crystal structure of a diamine-based ternary self-assembled energetic material with unit cell parameters a = 7.8549 Å, b = 24.742 Å, c = 9.9887 Å, α = 90°, β = 97.606°, γ = 90°, and Z = 1, belonging to the monoclinic crystal system. P2 1 / c Space group.

[0049] Table 1. Single-crystal structure determination data of novel diamine-based ternary self-assembled energetic materials

[0050] 4. Hygroscopicity test Dynamic vapor adsorption (DVS) experiments were performed using a Q5000 SA dynamic vapor adsorption analyzer. Sample mass was monitored at relative humidity of 5-90%, with a step size of 2% and an initial mass of 3-10 mg. Equilibrium time was maintained until sample mass stabilized (a change of <0.01% occurred within 2 minutes), with a maximum equilibration time of 120 minutes per step. Figure 5 As shown, the diamine-based ternary self-assembled energetic material is essentially non-hygroscopic at 60% humidity, indicating that this novel diamine-based ternary self-assembled energetic material has good moisture resistance.

[0051] Although the embodiments of this application have been described above in conjunction with the accompanying drawings, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of this application, and these are all within the scope of protection of this application.

Claims

1. A novel diamino-triamine based self-assembling energetic material, characterized in that, The chemical structural unit of the diamine-based ternary self-assembled energetic material is composed of a doubly protonated ethylenediamine cation, a doubly protonated propylenediamine cation and four perchlorate anions. ； The diamine-based ternary self-assembled energetic material belongs to a monoclinic system, P2 1 / c Space group, cell parameters: a = 7.8549 Å, b = 24.742 Å, c = 9.9887 Å, α = 90°, β = 97.606°, Gamma = 90°, Z = 1.

2. The novel diamino-triamine based self-assembling energetic material of claim 1, wherein, The diamine-based ternary self-assembled energetic material has characteristic diffraction peaks at 7.108°, 11.379°, 14.256°, 15.587°, 18.200°, 13.397°, 21.163°, 21.447°, 22.593°, 23.024°, 24.515°, 24.880°, 25.187°, 27.823°, 31.462°, 31.094° in the Cu-Kα radiation X-ray powder diffraction spectrum, wherein the error of each diffraction angle is ±0.2°. Theta The diamine-based ternary self-assembled energetic material has characteristic diffraction peaks at 7.108°, 11.379°, 14.256°, 15.587°, 18.200°, 13.397°, 21.163°, 21.447°, 22.593°, 23.024°, 24.515°, 24.880°, 25.187°, 27.823°, 31.462°, 31.094° in the Cu-Kα radiation X-ray powder diffraction spectrum, wherein the error of each diffraction angle is ±0.2°.

3. The novel diamino-triamine based self-assembling energetic material of claim 1, wherein, The diamine-based ternary self-assembled energetic material has a peak decomposition temperature of 302 DEG C and an initial decomposition temperature of 272 DEG C when tested by using differential scanning calorimetry.

4. The process for the preparation of the novel diamino-triamine based self-assembly energetic material according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: Step one, dissolving ethylenediamine and propylenediamine in an aqueous solution to obtain a uniform mixed solution by magnetic stirring; Step two, adding an aqueous perchloric acid solution to the obtained mixed solution, and then precipitating white solids after magnetic stirring, filtering the mother liquor to obtain the diamine-based ternary self-assembled energetic material.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the ethylenediamine, propylenediamine and perchloric acid is 2-1:1:4-10.

6. The preparation method according to claim 4, characterized in that, The aqueous perchloric acid solution in step two is a 70% aqueous perchloric acid solution.

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