Method for capturing and transferring pentazolate anions based on cationic covalent organic frameworks

Abstract

The application discloses a method for capturing and transferring pentaazol anions based on cationic covalent organic frameworks. The method adds hydrogen-bond cationic COFs into a pentaazol anion salt solution system, filters after adsorption for a certain time, and adds the collected cationic COFs adsorbed with the pentaazol anion salt into methanol to release the pentaazol anions. The method is simple, safe, does not cause metal pollution, and is beneficial to the stability of the pentaazol anions.

Description

Technical Field

[0001] This invention belongs to the field of high-energy energetic materials research and relates to a method for capturing and transferring pentazolium anions based on a cationic covalent organic framework. Background Technology

[0002] All-nitrogen compounds are a new type of ultra-high-energy energetic material developed in recent years. They possess advantages such as high density, high energy, and green, pollution-free detonation products, and are expected to be applied in explosives, propellants, and other fields. As an important building block in all-nitrogen compounds, the pentazolium anion (N5)... - It has attracted widespread attention due to its excellent performance.

[0003] N5 - The ion possesses a cyclic aromatic structure, exhibits good inherent stability, and demonstrates high reactivity, enabling it to combine with energetic cations to yield energetic ionic salts with excellent detonation performance. N5 - Research on ions and their derivatives can be traced back to 1903. However, due to the instability of the N-N bond in the arylpentazole ring, which is easily broken during the reaction, it is impossible to obtain a structurally complete five-membered nitrogen ring. Therefore, the preparation of stable N5-N rings has been hampered. - No substantial progress had been made in the ionic aspect. In 2017, Hu Bingcheng's team successfully synthesized and isolated the first room-temperature stable N5 by using ferrous glycinate and m-chloroperoxybenzoic acid as auxiliary and oxidant, respectively, through oxidative cleavage. - Ionic salts [(N5)6(H3O)3(NH4)4Cl]. However, these compounds contain large amounts of H2O, Clˉ, and NH4 in their molecular structure. + Low-energy materials, such as N5, have lower density and energy, which in turn affects their final performance. Therefore, in order to fully release N5 - Ion energy, transfer and reassembly N5 - Ions are used to construct high-energy N5 - The key to ionic salts. Currently, the transfer and assembly of N5ˉ ions are mainly achieved through the exchange of cations via metathesis reactions. Firstly, the ion exchange process breaks down the N5ˉ ion... - The original stable equilibrium system of ions leads to the decomposition of some five-membered nitrogen rings, resulting in a low yield of the target product; secondly, the repeated ion exchange process is complex and cumbersome, and also causes a large amount of metal waste and environmental pollution; thirdly, ion exchange requires the formation of precipitates or gases, lacks universality, and is difficult to achieve various N5 solutions. - Preparation of ionic salts. Therefore, new methods, techniques, or material systems are needed to solve the above-mentioned N5... - Key issues in the ion transfer assembly process.

[0004] Covalent organic frameworks (COFs) are a novel class of crystalline porous organic framework materials composed of small organic molecules linked by covalent bonds. They possess characteristics such as good chemical stability and directional controllability of pore structure and function. Ionic COFs (ICOFs), as a special type, not only maintain the atomic periodicity and skeletal porosity of the COF structure, but also allow electrostatic interactions to be introduced into the framework through charged groups on the framework or its sides. This results in superior performance and application potential compared to traditional neutral COFs in ion adsorption and separation, ion conduction, and other applications. Summary of the Invention

[0005] This invention provides a method for capturing and transferring pentazolium anions based on a cationic covalent organic framework.

[0006] The technical solution of this invention is:

[0007] The method for capturing and transferring pentazolium anions based on a cationic covalent organic framework is as follows:

[0008] (1) Capture: The pentaazole anionic salt is dissolved in a solvent, and then hydrogen-bonded cationic COFs are added for adsorption. The solvent is a 0%–100% methanol aqueous solution, and the hydrogen-bonded cationic COFs are:

[0009]

[0010] (2) Transfer: Filter the mixed solution that has been completely adsorbed in step (1), collect the hydrogen-bonded cationic COFs that have adsorbed pentaazole anion salt, and then add them to methanol and stir to achieve the desorption of pentaazole anion salt.

[0011] Furthermore, in step (1), the adsorption temperature is 20 to 40°C, preferably 40°C.

[0012] Furthermore, in step (1), the adsorption time is 4 to 6 hours, preferably 4 hours.

[0013] Furthermore, in step (1), the molar ratio of the pentaazole anionic salt to the hydrogen-bonded cationic COFs is 1.2:0.05-0.06.

[0014] Furthermore, in step (1), the solvent is pure water.

[0015] Furthermore, in step (2), the stirring time is 3 to 5 hours, preferably 4 hours.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] This invention selects hydrogen-bonded cationic COFs as the adsorbent for pentazolium anions, achieving the capture and transfer of pentazolium anion salts through adsorption and desorption processes. The method of this invention is simple to operate, has a high adsorption capacity, fast adsorption rate, and short adsorption time, and unlike other methods, it does not cause significant metal waste or environmental pollution. Furthermore, it avoids the N5+ contamination associated with other methods. - When ions form π-π interactions or hydrogen bonds with other groups, their stability can be greatly improved. Attached Figure Description

[0018] Figure 1 XRD patterns of multi-hydrogen bonded cationic COFs GA and GB.

[0019] Figure 2 Fourier transform infrared spectra of multi-hydrogen bonded cationic COFs GA, GB, and the raw materials.

[0020] Figure 3 This is a graph showing the adsorption curve of pentazolium anions by multi-hydrogen bonded cationic COFs in Example 5.

[0021] Figure 4 Mass spectrum of pentazolium anion released from multi-hydrogen bonded cationic COFs. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0023] The hydrogen-bonded cationic COFs described in this invention are synthesized using existing methods, as referenced in [Environ. Sci. Technol. 2019, 53, 5212-5220, J. Am. Chem. Soc. 2018, 140, 896-899.], specifically:

[0024] Triaminoguanidine hydrochloride (TG) Cl2,5-Dihydroxyterephthalaldehyde (Dha, 49.8 mg, 0.3 mmol) and 2,5-dihydroxyterephthalaldehyde (Dha, 49.8 mg, 0.3 mmol) were dissolved in a mixed solvent of 3.4 mL tetrahydrofuran and 0.6 mL water, or triaminoguanidine hydrochloride (28.0 mg, 0.2 mmol) and 1,3,5-tricarboxymethyl phloroglucinol (TP, 42.0 mg, 0.2 mmol) were dissolved in a mixed solvent of 2 mL 1,4-dioxane and 0.6 mL water. The mixture was then sonicated for 15 minutes to promote homogeneous mixing of the reactants and initial reaction. The mixture was then frozen with liquid nitrogen and subjected to three cycles of vacuum-nitrogen purging. Finally, the tube was sealed under vacuum and heated in an oven at 120 °C for 3 days. After the reaction was complete, the tube was cooled to room temperature, filtered, and the solid product was collected and washed sequentially with tetrahydrofuran, N,N-dimethylformamide, and anhydrous ethanol. The washed product was dried overnight in a vacuum oven at 80°C to completely remove residual moisture and solvent, yielding yellow solid GA and GB samples.

[0025] To ensure that the obtained materials are hydrogen-bonded cationic COFs (GA and GB), characterization was performed. Powder X-ray diffraction patterns of GA and GB were measured at room temperature using a Miniflex 600 X-ray powder diffractometer (Japan). The test conditions were: Cu Kα radiation, 2θ range of 2.5°–40°, current of 15 mA, and voltage of 40 kV.

[0026] The results are as follows Figure 1 As shown, the peaks at 5.2° and 27.3° of GA indicate a certain degree of crystallinity, but the relatively low intensity of these peaks suggests that the crystallinity of GA is not very high. This may be due to the weak intermolecular interactions of GA or the presence of a significant amount of disordered structure. Similarly, the small peaks at 9.7° and 27.3° of GB also indicate a certain degree of crystallinity. The peak positions of GB differ from those of GA, reflecting the differences in their crystal structures.

[0027] To verify the formation of imine bonds in COFs, GA, GB, and the synthesized starting materials were characterized by Fourier transform infrared spectroscopy. The results are as follows: Figure 2 As shown. Triaminoguanidine hydrochloride at 3320 and 3210 cm⁻¹ -1 The characteristic peak of the stretching vibration of amino (NH) appears at 1674 cm⁻¹, and both 2,5-dihydroxyterephthalaldehyde and 1,3,5-tricarboxymethylphloroglucinol show a peak at 1674 cm⁻¹. -1 The characteristic peak of the aldehyde group (C=O) is observed at 1624 cm⁻¹. In the infrared spectra of GA and GB, this peak is also present at 1624 cm⁻¹. -1 A new tensile vibration band appeared at this point, and this peak is similar to the characteristic peak of the aldehyde group in the raw material (1674 cm⁻¹). -1The shift in the value indicates that a reaction occurred between the aldehyde group and the amino group, forming an imine bond (C=N).

[0028] Example 1

[0029] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of water as a solvent to the flask and mix well. Take 50 mL of each flask and pour it into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 20°C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA was 178 mg / g, and the highest adsorption capacity of GB was 185 mg / g.

[0030] Example 2

[0031] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of water as a solvent to the flask and mix well. Take 50 mL of each flask and pour it into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 25°C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA was 183 mg / g, and the highest adsorption capacity of GB was 197 mg / g.

[0032] Example 3

[0033] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of water as a solvent to the flask and mix well. Take 50 mL of each flask and pour it into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 30°C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA was 191 mg / g, and the highest adsorption capacity of GB was 212 mg / g.

[0034] Example 4

[0035] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of water as a solvent. Shake well. Take 50 mL of each flask and pour it into two narrow-mouthed test bottles. Add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively and stir. Take 0.1 mL of each sample at regular intervals, and then dilute 10-fold with chromatographic methanol. Place the test bottles at 35℃ and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively and stir. Take 0.1 mL of each sample at regular intervals, and then dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA is 210 mg / g, and the highest adsorption capacity of GB is 231 mg / g.

[0036] Example 5

[0037] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of water as a solvent to the flask. Mix well, and pour 50 mL of each flask into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 40°C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. At regular intervals, take 0.1 mL of each sample and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The results are as follows: Figure 3 As shown, the highest adsorption capacity of GA was 230 mg / g, and the highest adsorption capacity of GB was 269 mg / g.

[0038] Example 6

[0039] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of 20% methanol aqueous solution as a solvent to the flask. Shake well, and pour 50 mL of each solution into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 40 °C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA is 212 mg / g, and the highest adsorption capacity of GB is 253 mg / g.

[0040] Example 7

[0041] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of 40% methanol aqueous solution as a solvent to the flask. Shake well, and pour 50 mL of each solution into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 40 °C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA was 191 mg / g, and the highest adsorption capacity of GB was 231 mg / g.

[0042] Example 8

[0043] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of 60% methanol aqueous solution as a solvent to the flask. Shake well, and pour 50 mL of each solution into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 40 °C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA is 170 mg / g, and the highest adsorption capacity of GB is 212 mg / g.

[0044] Example 9

[0045] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of 80% methanol aqueous solution as a solvent to the flask. Shake well, and pour 50 mL of each solution into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 40 °C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA was 152 mg / g, and the highest adsorption capacity of GB was 193 mg / g.

[0046] Example 10

[0047] Add 250 mg (2.4 mmol) of pentazocine salt to a 250 mL volumetric flask, then add 250 mL of 100% methanol aqueous solution as a solvent to the flask. Shake well, and pour 50 mL of each solution into two narrow-mouthed reagent bottles. Take 0.1 mL of each sample and dilute 10-fold with chromatographic methanol. Place the reagent bottles at 40 °C and add GA (20 mg, 0.05 mmol) and GB (20 mg, 0.06 mmol) respectively, stirring. Take 0.1 mL of each sample at regular intervals and dilute with chromatographic methanol. Determine the sample concentration using high-performance liquid chromatography (HPLC). The highest adsorption capacity of GA is 125 mg / g, and the highest adsorption capacity of GB is 168 mg / g.

[0048] Example 11

[0049] The hydrogen-bonded cationic COFs that adsorbed pentazocine salt were separated from the other remaining mixture by filtration.

[0050] A filter membrane with a pore size of 5 μm was selected. The mixed system after adsorption in Example 5 was slowly poured into the filtration device and filtered to ensure that the hydrogen-bonded cationic COFs were effectively retained on the filter medium, while the unadsorbed impurities and excess solution were successfully separated out through the filter medium, thereby obtaining a pure cationic COFs sample adsorbed with pentazolium hydrazine salt.

[0051] After obtaining the hydrogen-bonded cationic COFs adsorbed with pentazocine hydrazine salt through filtration, 20 mg was carefully transferred to a clean and dry reaction vessel. Then, 50 mL of chromatographic methanol solvent was accurately measured and added to the reaction vessel. The methanol solvent and the hydrogen-bonded cationic COFs were thoroughly mixed with stirring for 3-5 h, preferably 4 h. Then, 1 mL of sample solution was aspirated and transferred to pre-labeled, clean, and well-sealed sample tubes, ready for subsequent mass spectrometry analysis.

[0052] Mass spectrometry was performed on a TSQ Quantum ultra AM mass spectrometer using an spray ionization (ESI) source. The sample was injected via a syringe pump at a flow rate of 5 μL / min. The instrument was operated in negative ion mode with a capillary voltage set to -3000 V and a dissociation potential set to -20 V. After mass spectrometry analysis, the following results were obtained: Figure 4 The results clearly show the presence of characteristic peaks corresponding to the pentazolium anion. The appearance of these characteristic peaks indicates that after adding the hydrogen-bonded cationic COFs containing the adsorbed pentazolium anion salt to the methanol solvent and allowing for a period of interaction, the pentazolium anion is successfully released from the hydrogen-bonded cationic COFs and can be detected in mass spectrometry analysis.

[0053] Comparative Example 1

[0054] This comparative example is basically the same as Example 5, except that GA is replaced with anionic resin. 900(OH) was used to determine the sample concentration using high-performance liquid chromatography, revealing anionic resin. 900(OH) did not adsorb pentazocine salt.

[0055] Comparative Example 2

[0056] This comparative example is basically the same as Example 5, except that GA was replaced with 732 hydrogen-type strong acid cation exchange resin. The sample concentration was determined by high performance liquid chromatography, and it was found that the 732 hydrogen-type strong acid cation exchange resin did not adsorb pentazocine salt.

[0057] Comparative Example 3

[0058] This comparative example is basically the same as Example 5, except that GA was replaced with cationic resin nonionic TPB-TMPD-COF (RSC Adv,2024,14,1665-1669). The sample concentration was determined by high performance liquid chromatography, and it was found that nonionic TPB-TMPD-COF did not adsorb pentazocine salt.

Claims

1. A method for the capture and transfer of pentazolate anions based on cationic covalent organic frameworks, characterized in that, Specifically: (1) Capture: Pentazolium anionic salt is dissolved in a solvent, and then hydrogen-bonded cationic COFs are added for adsorption. The solvent is a 0%~100% methanol aqueous solution, and the hydrogen-bonded cationic COFs are: or ; (2) Transfer: Filter the mixed solution that has been completely adsorbed in step (1), collect the hydrogen-bonded cationic COFs that have adsorbed pentaazole anion salt, and then add them to methanol to achieve the desorption of pentaazole anion salt.

2. The method of claim 1, wherein, In step (1), the adsorption temperature is 20~40 ℃.

3. The method of claim 1, wherein, In step (1), the adsorption time is 4 to 6 hours.

4. The method of claim 1, wherein, In step (1), the molar ratio of pentaazole anionic salt to hydrogen-bonded cationic COFs is 1:0.05~0.

06.

5. The method of claim 1, wherein, In step (1), the solvent is pure water.

6. The method of claim 1, wherein, In step (2), the stirring time is 3~5 hours.

7. The method of claim 1, wherein, In step (2), the stirring time is 4 hours.

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