A method for synthesizing a caged tetraacetyl hexaazaisowurtzitane (TAIW) based on an electrochemical route

Abstract

The application discloses a method for synthesizing a cage-shaped tetraacetyl hexaazaisowurtzitane (TAIW) based on an electrochemical path, wherein a Pd catalyst is in-situ grown on a carbon felt by an electrodeposition method to serve as a working electrode, a graphite rod and a saturated silver chloride solution are used as a counter electrode and a reference electrode respectively; a PdCl2 solution is configured, Na2SO4 is added to form an electroplating solution, and 50 cycles of cyclic voltammetry scanning are performed to obtain a working electrode loaded with the Pd catalyst; acetonitrile and water mixed solution are added to the cathode and anode chambers of an H-shaped electrolytic cell respectively to serve as a solvent and a supporting electrolyte; benzylamine and acetic anhydride are added to the cathode chamber, and the mixture is subjected to magnetic stirring at room temperature for 10 min, and a normal-pressure dropping funnel is used to drop a 40% glyoxal aqueous solution; argon is introduced into the cathode chamber to remove dissolved oxygen in the solution; a negative current is applied to the prepared working electrode, and after reaction, filtration is performed, the filter cake is washed twice with cold acetonitrile, and the filter cake is air-dried at room temperature to obtain the cage-shaped tetraacetyl hexaazaisowurtzitane.

Description

Technical Field

[0001] This application belongs to the field of electrochemical synthesis, and in particular relates to a method for synthesizing cage-like tetraacetylhexaazaisowoodsane (TAIW) based on an electrochemical pathway. Background Technology

[0002] Cage-like compounds, with their compact, three-dimensional cage-like carbon skeletons and each molecule composed of multiple carbon rings, have attracted considerable attention due to their high energy and high stress characteristics. Among them, hexanitrohexaazaisowulzane (HNIW or CL-20) has a significantly higher energy output than traditional energetic compounds such as octogen (HMX) and rDX, and also possesses better thermal stability and lower detonation sensitivity. Improvements and optimizations have been made to Nielsen's synthetic method and process, mainly including improvements to the synthetic route, nitrifying agent, nitrification process, and modifications to the solvent and catalyst. After improvements, the synthetic routes for CL-20 mostly employ a four-step synthesis method as follows: a. First, benzylamine and glyoxal are condensed in an acetonitrile / water azeotropic solution with formic acid as a catalyst to synthesize hexabenzylhexaazaisowoodsane (HBIW); b. Under the coexistence of hydrogen atmosphere and acetic anhydride, the six benzyl groups on HBIW are partially or completely converted to acetyl groups or other substituents (such as TAIW) through a palladium / carbon catalyst; c. TAIW is nitrated in a nitric acid-sulfur mixture or fuming nitric acid to obtain crude α-CL-20 or γ-CL-20; d. Finally, α-CL-20 or γ-CL-20 is recrystallized under specific solution conditions to obtain ε-CL-20 with the best performance.

[0003]

[0004] Based on the current process summary, we can see that the synthesis of CL-20 is quite complex and requires hydrogen gas, which carries an explosion risk, as a hydrogen source to participate in the dissociation reaction of the benzyl group on the cage-like compound. The high production cost and safety risks are also major factors restricting the large-scale practical application of CL-20. Therefore, improving the reaction pathway is of great economic and defense value.

[0005] Solar photovoltaic, wind power, hydropower, and geothermal energy technologies have developed rapidly in recent years. In the electrocatalytic process, under the condition of applying a certain negative voltage to the working electrode, protons (H+) are continuously generated in situ on the surface of the catalyst in the electrolyte. +This triggers further hydrogenation reactions. The avoidance of hydrogen use also greatly alleviates safety concerns under electrocatalytic pathway conditions. Furthermore, by adjusting different voltage levels, the selectivity or yield of hydrogenation intermediates can be effectively controlled. More importantly, the unique advantages of the electrocatalytic system avoid the need for large-scale catalyst feeding required in traditional catalytic systems, thus significantly reducing catalyst costs in the CL-20 production process. Summary of the Invention

[0006] Technical problem solved: This application provides a method for synthesizing cage-like tetraacetylhexaazaisowizane (TAIW) based on an electrochemical pathway, which solves the technical problems of high production cost and high safety risk in the prior art.

[0007] Technical solution:

[0008] A method for synthesizing cage-like tetraacetylhexaazaisowulzane (TAIW) based on an electrochemical pathway includes the following steps: S1 Electrode preparation: Pd catalyst is grown in situ on carbon felt by electrodeposition as the working electrode, and graphite rod and saturated silver chloride solution electrode are used as the counter electrode and reference electrode, respectively.

[0009] S2 Preparation of electroplating solution: Prepare a 20 mmol / L PdCl2 solution and add it to a glass bottle. Then add Na2SO4 as a supporting electrolyte and maintain the Na2SO4 concentration in the solution at 0.5 mol / L without stirring.

[0010] S3 is used to prepare the working electrode: with 0.1 V·S -1 The electroplating solution prepared in step S1 was subjected to 50 cyclic voltammetric scans at a potential range of -0.5 to 1.7 V to obtain a working electrode supported on the Pd catalyst.

[0011] S4 Preparation of H-type electrolytic cell: First, add a mixture of acetonitrile and water as solvent to the cathode and anode chambers of the H-type electrolytic cell, respectively, and add two equal amounts of supporting electrolyte to each chamber; then add 5g of benzylamine and 2.2g of acetic anhydride to the cathode chamber, stir magnetically at room temperature for 10 minutes, and then add 3.05g of 40% glyoxal aqueous solution dropwise using a normal pressure dropping funnel. The glyoxal aqueous solution is added over a period of about five minutes, and the temperature of the reaction solution during the addition process does not exceed 25°C.

[0012] After the addition is complete, argon gas is passed through the electrolytic solution in the cathode chamber for 30 minutes to remove dissolved oxygen from the solution;

[0013] S5 was used for electrocatalytic reaction: a certain negative current was applied to the working electrode prepared in S1. After the reaction was carried out for 1 hour, the product solution was collected and filtered. The filter cake was washed twice with 50 mL of cold acetonitrile. The product was air-dried at room temperature to obtain the product cage-like tetraacetyl hexaazaisowoodsane TAIW.

[0014] Furthermore, the working electrode and reference electrode mentioned in step S1 are placed in the cathode reaction tank, and the counter electrode is placed in the anode reaction tank, with the two separated by a Nafion-117 diaphragm; the graphite rod is 10cm long and 1cm in diameter.

[0015] Furthermore, the filtration in step S3 is performed using a sand core funnel decompression filtration method.

[0016] Furthermore, the supporting electrolyte in step S4 is sodium chloride granules, with each serving being 1.6g.

[0017] Further, in step S4, the volume ratio of the acetonitrile and water mixture is 10:1; the magnetic stirring speed at room temperature is 1000 r / min; and in step S5, the negative current density is maintained at -50 mA / cm². 2 .

[0018] Beneficial effects:

[0019] 1. This invention discloses a novel strategy for the electrocatalytic synthesis of cage-like tetraacetylhexaazaisowurtzite (TAIW). Compared to traditional catalytic preparation routes, the electrochemical method utilizes protons (H... + The continuous in-situ generation of ) directly participates in the second step of benzyl dissociation reaction, thus simultaneously satisfying the objectives of safety, reliability, and process simplification.

[0020] 2. The purity and yield of the product were verified by high performance liquid chromatography and mass spectrometry. The feasibility of large-scale preparation of cage-like compounds under electrochemical processes was further demonstrated by flow cell testing. This application provides a promising new approach for the controllable and safe preparation of high-energy cage-like compounds of CL-20 in the future. Attached Figure Description

[0021] Figure 1 The structure and composition characterization of the palladium catalyst supported on carbon felt in this application are shown in the following images: a: X-ray diffraction (XRD) pattern of the electroplated palladium sample; b: X-ray photoelectron spectroscopy of the catalyst sample; cd: SEM images of the catalyst sample at low and high magnification; eg: EDS-mapping image of the catalyst sample; h: high-resolution image of the catalyst sample.

[0022] Figure 2 This is a high-performance liquid chromatogram of TAIW.

[0023] Figure 3 This is the mass spectrum of TAIW;

[0024] Figure 4 This is a schematic diagram of a scaled-up experiment of a full-phase flow cell. Detailed Implementation

[0025] The following embodiments are intended to enable those skilled in the art to more fully understand this application, but do not limit this application in any way.

[0026] To further illustrate the technical path and effects of this invention in achieving its intended purpose, the following detailed description, in conjunction with the accompanying drawings and specific embodiments, describes an electrochemical strategy for synthesizing cage-like tetraacetylhexaazaisowulzane (TAIW) according to this invention.

[0027] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0028] Example 1

[0029] A method for synthesizing cage-like tetraacetylhexaazaisowoodsane (TAIW) via an electrochemical pathway includes the following steps:

[0030] S1 Electrode preparation: Pd catalyst was grown in situ on carbon felt by electrodeposition as working electrode, and graphite rod and saturated silver chloride solution electrode were used as counter electrode and reference electrode, respectively.

[0031] S2 Preparation of electroplating solution: Prepare a 20 mmol / L PdCl2 solution and add it to a glass bottle. Then add Na2SO4 as a supporting electrolyte and maintain the Na2SO4 concentration in the solution at 0.5 mol / L without stirring.

[0032] S3 Preparation of working electrode: The electroplating solution prepared in step S1 was subjected to 50 cyclic voltammetric scans at a scan rate of 0.1 V·S⁻¹ in a potential range of -0.5 to 1.7 V to obtain a working electrode supported on Pd catalyst.

[0033] S4 Preparation of H-type electrolytic cell: First, add a mixture of acetonitrile and water as solvent to the cathode and anode chambers of the H-type electrolytic cell, respectively, and add two equal amounts of supporting electrolyte to each chamber; then add 5g of benzylamine and 2.2g of acetic anhydride to the cathode chamber, stir magnetically at room temperature for 10 minutes, and then add 3.05g of 40% glyoxal aqueous solution dropwise using a normal pressure dropping funnel. The glyoxal aqueous solution is added over a period of about five minutes, and the temperature of the reaction solution during the addition process does not exceed 25°C.

[0034] After the addition is complete, argon gas is passed through the electrolytic solution in the cathode chamber for 30 minutes to remove dissolved oxygen from the solution;

[0035] S5 performs the electrocatalytic reaction: A certain negative current is applied to the working electrode prepared by S1 (current density maintained at -50 mA / cm²). 2 After reacting for 1 hour, the product solution was collected, filtered, and the filter cake was washed twice with 50 mL of cold acetonitrile. The product was then air-dried at room temperature to obtain the product, cage-like tetraacetyl hexaazaisowurtzite (TAIW).

[0036] Furthermore, the working electrode and reference electrode mentioned in step S1 are placed in the cathode reaction tank, and the counter electrode is placed in the anode reaction tank, with the two separated by a Nafion-117 diaphragm; the graphite rod is 10cm long and 1cm in diameter.

[0037] Furthermore, the filtration in step S3 is performed using a sand core funnel decompression filtration method.

[0038] Furthermore, the supporting electrolyte in step S4 is sodium chloride granules, with each serving being 1.6g.

[0039] Further, in step S4, the volume ratio of the acetonitrile and water mixture is 10:1; and the magnetic stirring speed at room temperature is 1000 r / min.

[0040] The product TAIW obtained by the above method was weighed, and the sample was characterized by high performance liquid chromatography (HPLC) and mass spectrometry (MS) to verify the purity of the product.

[0041] The solution was prepared according to the above proportions and scaled up proportionally, then transferred to a 1000mL glass bottle as the electrolyte tank. A full-phase circulating flow cell scale-up experiment was conducted using palladium-loaded carbon felt as the working electrode, a custom-designed miniature saturated silver chloride electrode as the reference electrode, and nickel foam as the counter electrode. A schematic diagram is shown below. Figure 4 As shown.

Claims

1. A method for synthesizing cage-like tetraacetylhexaazaisowulzane (TAIW) via an electrochemical pathway, characterized in that, Includes the following steps: S1 Electrode preparation: Pd catalyst was grown in situ on carbon felt by electrodeposition as working electrode, and graphite rod and saturated silver chloride solution electrode were used as counter electrode and reference electrode, respectively. S2 Preparation of electroplating solution: Prepare a 20 mmol / L PdCl2 solution and add it to a glass bottle. Then add Na2SO4 as a supporting electrolyte and maintain the Na2SO4 concentration in the solution at 0.5 mol / L without stirring. S3 is used to prepare the working electrode: with 0.1 V·S -1 The electroplating solution prepared in step S1 was subjected to 50 cyclic voltammetric scans at a potential range of -0.5 to 1.7 V to obtain a working electrode supported on the Pd catalyst. S4 Preparation of H-type electrolytic cell: First, add a mixture of acetonitrile and water as solvent to the cathode and anode chambers of the H-type electrolytic cell, respectively, and add two equal amounts of supporting electrolyte to each chamber; then add 5g of benzylamine and 2.2g of acetic anhydride to the cathode chamber, stir magnetically at room temperature for 10 minutes, and then add 3.05g of 40% glyoxal aqueous solution dropwise using a normal pressure dropping funnel. The glyoxal aqueous solution is added over a period of about five minutes, and the temperature of the reaction solution does not exceed 25°C during the addition process. After the addition is complete, argon gas is passed through the electrolytic solution in the cathode chamber for 30 minutes to remove dissolved oxygen from the solution; S5 was used for electrocatalytic reaction: a certain negative current was applied to the working electrode prepared in S1. After the reaction was carried out for 1 hour, the product solution was collected and filtered. The filter cake was washed twice with 50 mL of cold acetonitrile. The product was air-dried at room temperature to obtain the product cage-like tetraacetyl hexaazaisowoodsane TAIW.

2. The method for synthesizing cage-like tetraacetylhexaazaisowulzane (TAIW) based on an electrochemical pathway as described in claim 1, characterized in that: The working electrode and reference electrode mentioned in step S1 are placed in the cathode reaction tank, and the counter electrode is placed in the anode reaction tank, with the two separated by a Nafion-117 diaphragm; the graphite rod is 10cm long and 1cm in diameter.

3. The method for synthesizing cage-like tetraacetylhexaazaisowitzane (TAIW) based on an electrochemical pathway as described in claim 1, characterized in that: The filtration described in step S3 is performed using a sand core funnel pressure reduction filtration method.

4. The method for synthesizing cage-like tetraacetylhexaazaisowitzane (TAIW) based on an electrochemical pathway as described in claim 1, characterized in that: The supporting electrolyte in step S4 is sodium chloride granules, with a dosage of 1.6g per serving.

5. The method for synthesizing cage-like tetraacetylhexaazaisowitzane (TAIW) based on an electrochemical pathway as described in claim 1, characterized in that: The volume ratio of acetonitrile and water in step S4 is 10:1; the magnetic stirring speed at room temperature is 1000 r / min; and the negative current density in step S5 is maintained at -50 mA / cm². 2 .

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