Imidazole boron framework material, preparation method and application thereof
By preparing imidazole boron framework materials and utilizing the self-assembly technology of zinc ions and triimidazole borohydrides, the problem of acetylene and carbon dioxide separation was solved, achieving efficient and low-cost selective separation of acetylene/carbon dioxide.
Patent Information
- Application Number
- CN202411383244.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2044-09-30
AI Technical Summary
Existing technologies struggle to efficiently separate acetylene and carbon dioxide. Traditional methods are costly and energy-intensive, and there are few reports on the selective separation of acetylene/carbon dioxide using boron imidazoate framework materials.
Imidazole boron framework materials were prepared by coordination assembly of zinc ions and triimidazole boron hydride. The materials were synthesized at 70–90 °C through a self-assembly reaction and then activated under vacuum to prepare imidazolium boron framework materials with a CTN-type topology. The free anions were Cl- or OH-, which improved the selectivity of acetylene/carbon dioxide.
It achieves efficient separation of acetylene and carbon dioxide, with high adsorption selectivity and cost-effectiveness. It is suitable for the separation of acetylene and carbon dioxide mixtures and the preparation process is simple.
Smart Images
Figure CN119119503B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nanoporous materials technology, and in particular to an imidazole boron framework material, its preparation method, and its application. Background Technology
[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] Acetylene is a very important industrial gas, used as fuel and widely applied in the production of chemicals such as vinyl chloride, acrylic acid, and 1,4-butynediol. The main source of acetylene is petroleum fractionation and cracking processes, which inevitably produce carbon dioxide impurities, leading to a decrease in acetylene purity and hindering its subsequent use. Therefore, efficiently removing carbon dioxide and obtaining high-purity acetylene is of great significance. Both acetylene and carbon dioxide molecules are linear, with molecular sizes of [insert molecular sizes here]. and They have the same dynamic diameter Since acetylene and carbon dioxide have similar boiling points (189.3 K and 194.7 K, respectively), separation is challenging. Traditional separation methods such as solvent extraction and cryogenic distillation are costly and energy-intensive.
[0004] Metal-organic frameworks (MOFs), as an emerging type of porous material, are inorganic-organic hybrid porous solids in which inorganic metal ions / clusters self-assemble into periodic structures via coordination bonds, with organic ligands acting as connecting bridges. Due to their large specific surface area, porosity, and abundant active sites, MOFs have attracted widespread attention in fields such as gas storage and separation.
[0005] Zeolite-like MOFs with zeolite topologies have become a research hotspot in chemistry and materials science due to their periodic network structure, tunable pore size, and customizable microenvironments. Boron imidazoate frameworks (BIFs) are zeolite-like metal-organic frameworks that link ultralight elements (such as Li and B) through BN covalent bonds. Boron, as a relatively light element, can effectively reduce the density of the BIF framework, making it a promising material for gas storage and separation. While there are existing reports on the use of boron imidazoate frameworks in gas separation, these are mostly used for separating carbon dioxide from gases such as methane, ethane, and ethylene. Materials with high acetylene / carbon dioxide selectivity in boron imidazoate frameworks are rarely reported. Summary of the Invention
[0006] In view of this, the present invention provides an imidazole boron framework material, its preparation method and application. The imidazole boron framework material provided by the present invention can effectively separate carbon dioxide and acetylene mixed gas, is energy-saving and efficient, and has a simple preparation method and low cost.
[0007] In a first aspect, the present invention provides an imidazole boron framework material, which is obtained by coordination assembly of metallic zinc ions and triimidazole borohydride, wherein the free anion of the imidazole boron framework material is Cl. - or OH - .
[0008] Preferably, the triimidazole borohydride is obtained by reacting potassium borocyanide and 2-methylimidazole.
[0009] Secondly, the present invention provides a method for preparing the above-mentioned imidazole boron framework material, comprising the following steps:
[0010] Zinc chloride or zinc hydroxide, triimidazole borohydride, 2-imidazolium ketone and pyromellitic acid are dissolved in a solvent and reacted at 70-90°C to obtain a solid product. The solid product is then activated under vacuum to obtain the final product.
[0011] Preferably, the molar ratio of zinc chloride or zinc hydroxide, triimidazole borohydride, 2-imidazolium ketone and trimesic acid is 1:(0.3-0.6):(10-15):(0.3-0.6).
[0012] Preferably, the ratio of the triimidazole borohydride compound to the solvent is (0.5-0.7) g : (30-70) mL.
[0013] Preferably, the solvent is selected from a mixed solvent of N,N-dimethylformamide, 3-aminopropanol and ethanol, wherein the volume ratio of N,N-dimethylformamide, 3-aminopropanol and ethanol is (1-3):(1-3):(1-3).
[0014] Preferably, in the step of obtaining a solid product by reacting at 70–90°C, the reaction time is 20–80 h.
[0015] Preferably, after the reaction is completed, the step of washing and drying the reaction product is further included to obtain a solid product.
[0016] Preferably, in the vacuum activation step, the vacuum degree is 10. -7 Below mbar, the temperature is 120–170℃, and the time is 5–15 hours.
[0017] Preferably, the preparation method of the triimidazole borohydride is as follows: potassium borocyanide and 2-methylimidazole are mixed and subjected to a melt reaction at 200-230°C to obtain the product.
[0018] Furthermore, the molar ratio of potassium borocyanide to 2-methylimidazole is 1:(3-3.5); the reaction time of potassium borohydride and 2-methylimidazole is 3-8 h.
[0019] Thirdly, the present invention provides the application of the above-mentioned imidazole boron framework material or the imidazole boron framework material prepared by the above-mentioned preparation method in the separation of acetylene and carbon dioxide mixed gas.
[0020] Compared with the prior art, the present invention has achieved the following beneficial effects:
[0021] The imidazole boron framework material provided by this invention has a high adsorption ratio for acetylene and carbon dioxide and exhibits high adsorption selectivity. Moreover, the raw materials for synthesis are readily available, the preparation process is simple, and the cost is low, making it a promising candidate for the separation of acetylene and carbon dioxide mixed gases. Attached Figure Description
[0022] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof. Obviously, those skilled in the art can obtain other drawings based on these drawings without any inventive effort.
[0023] Figure 1 This is BIF-24(Cl) from Embodiment 1 of the present invention. - ) and BIF-24(OH) of Example 2 - Scanning electron microscope images of the following examples, where a) Example 1; b) Example 2;
[0024] Figure 2 This is BIF-24(Cl) from Embodiment 1 of the present invention. - ) and BIF-24(OH) of Example 2 - The X-ray diffraction patterns of the samples are shown, where a) is Example 1 and b) is Example 2.
[0025] Figure 3 This is BIF-24(Cl) from Embodiment 1 of the present invention. - Single-component adsorption curves of acetylene (a) and carbon dioxide (b) at different temperatures;
[0026] Figure 4 This is BIF-24(OH) from Embodiment 2 of the present invention. - Single-component adsorption curves of acetylene (a) and carbon dioxide (b) at different temperatures;
[0027] Figure 5 The imidazole boron framework material BIF-24(Cl) of Example 1 of this invention is...- (a) Imidazole boron framework material BIF-24(OH) from Example 2 - (b) and Comparative Example 1's BIF-24 (NO3) - (c) Acetylene / carbon dioxide selectivity plots calculated using the ideal adsorption solution theory at different temperatures;
[0028] Figure 6 The imidazole boron framework material BIF-24(Cl) of Example 1 of this invention is... - (a) Imidazole boron framework material BIF-24(OH) from Example 2 - (b) Graph showing the ratio of acetylene to carbon dioxide gas adsorption;
[0029] Figure 7 The imidazole boron framework material BIF-24(Cl) of Example 1 of this invention is... - (a) and the imidazole boron framework material BIF-24(OH) of Example 2 - (b) Two-component acetylene / carbon dioxide penetration plot. Detailed Implementation
[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0031] This invention provides an imidazole boron framework material, which is obtained by coordination assembly of metallic zinc ions and triimidazole borohydride, wherein the free anion of the imidazole boron framework material is Cl. - or OH - .
[0032] The imidazole boron framework material provided by this invention has a CTN-type topology and uses Cl - or OH - As free anions, free anions can affect the morphology of imidazole boron framework materials. - When the ion is free, imidazole boron framework materials often exhibit a rhombic dodecahedral structure; when OH- - When the ions are free anions, the imidazole boron framework materials mostly exhibit a spherical structure. Both have good separation performance for mixed gases of carbon dioxide and acetylene, with an acetylene / carbon dioxide selectivity of over 3.9.
[0033] In this invention, the triimidazole borohydride is obtained by reacting potassium borocyanide and 2-methylimidazole, and the organic ligand of the triimidazole borohydride obtained by the reaction is KHB(mim)3.
[0034] The present invention also provides a method for preparing the above-mentioned imidazole boron framework material, comprising the following steps:
[0035] Zinc chloride or zinc hydroxide, triimidazole borohydride, 2-imidazolium ketone and pyromellitic acid are dissolved in a solvent and reacted at 70-90°C to obtain a solid product. The solid product is then activated under vacuum to obtain the final product.
[0036] In the above-described reaction process of this invention, imidazole boron framework materials are synthesized through a solvothermal reaction of zinc chloride or zinc hydroxide with triimidazole boron hydride via self-assembly. 2-Imidazolidinone and trimellitic acid do not participate in the construction of the imidazole boron framework materials; however, they play an environmental role in the synthesis of imidazole boron framework materials. Without 2-imidazolidinone and trimellitic acid, the imidazole boron framework materials of this invention cannot be obtained.
[0037] In this invention, the molar ratio of zinc chloride or zinc hydroxide, triimidazole borohydride, 2-imidazolium ketone and trimesic acid is 1:(0.3-0.6):(10-15):(0.3-0.6).
[0038] In this invention, the ratio of the triimidazole borohydride compound to the solvent is (0.5–0.7) g : (30–70) mL. A suitable amount of solvent is beneficial for the smooth progress of the reaction.
[0039] In this invention, the solvent is selected from a mixed solvent of N,N-dimethylformamide, 3-aminopropanol and ethanol, and the volume ratio of N,N-dimethylformamide, ethanol and 3-aminopropanol is (1-3):(1-3):(1-3), for example, it can be 2:1:1, 2:1:2 or 1:3:1, etc.
[0040] In this invention, the step of obtaining a solid product by reacting at 70–90°C takes 20–80 h, more preferably 20–50 h. The reaction is preferably carried out in a reaction vessel.
[0041] In this invention, after the reaction is completed, the reaction product is further washed and dried to obtain a solid product. This invention does not impose any special limitations on the washing and drying steps; commonly used washing and drying steps in the art can be employed.
[0042] In this invention, the vacuum degree in the vacuum activation step is 10. -7 Below mbar, the temperature is 120-170℃, and the vacuum drying time is 5-15h. The vacuum activation step is to remove residual solvent molecules and gas molecules in the pores.
[0043] In this invention, the preparation method of the triimidazole borohydride compound is as follows: potassium borocyanide and 2-methylimidazole are mixed in solvent II and subjected to a melt reaction at 200-230°C to obtain the compound. The molar ratio of potassium borocyanide to 2-methylimidazole is 1:(3-3.5), more preferably 1:(3.1-3.3); the reaction time of potassium borohydride and 2-methylimidazole is 3-8 h.
[0044] This invention also provides the application of the above-mentioned imidazole boron framework material in the separation of acetylene and carbon dioxide mixed gases. The imidazole boron framework material prepared by this invention has a selectivity for acetylene / carbon dioxide of 3.9 or higher.
[0045] The technical solution of the present invention will be further described below with reference to specific embodiments. In the following embodiments, the organic ligand potassium triimidazole borohydride (KHB(mim)3) is prepared as follows: potassium borocyanide and 2-methylimidazole are mixed in a molar ratio of 1:3.1 and heated and stirred at 215°C for 4 hours to obtain the organic ligand KHB(mim)3.
[0046] Example 1
[0047] This embodiment provides an imidazole boron framework material BIF-24(Cl) - Preparation method of ).
[0048] S1. Dissolve zinc chloride, 0.6 g organic ligand KHB(mim)3, 2-imidazolidineone and pyromellitic acid in a molar ratio of 1:0.48:11.62:0.48 in a mixed solvent of 20 mL N,N-dimethylformamide, 10 mL ethanol and 10 mL 3-aminopropanol to form a mixed solution.
[0049] S2. Add the mixed solution obtained in step S1 to a 100 mL reaction vessel and heat at 80 °C for 24 h.
[0050] S3. After the reaction vessel has cooled to room temperature, wash it three times alternately with deionized water and anhydrous ethanol, and then dry it to obtain a white powder.
[0051] S4. The white powder obtained in step S3 is subjected to a vacuum of 10... -7 By maintaining the material under vacuum conditions of mbar and 150℃ for 10 hours, the imidazole boron framework material BIF-24(Cl) is obtained. - ).
[0052] Figure 1 In this example, 'a' refers to the imidazole boron framework material BIF-24(Cl) prepared in this embodiment. - Scanning electron microscope image of BIF-24 (Cl). The image shows that BIF-24 (Cl) - Imidazole boron framework materials are mainly rhombic dodecahedrons. Figure 2In this example, 'a' refers to the imidazole boron framework material BIF-24(Cl) prepared in this embodiment. - The X-ray diffraction pattern of the imidazole boron framework material BIF-24 (Cl) confirmed that... - The successful synthesis of ).
[0053] Example 2
[0054] This embodiment provides an imidazole boron framework material BIF-24(OH) - Preparation method of ).
[0055] S1. Dissolve zinc hydroxide, 0.6 g organic ligand KHB(mim)3, 2-imidazolidineone and pyromellitic acid in a molar ratio of 1:0.48:11.62:0.48 in a mixed solvent of 20 mL N,N-dimethylformamide, 10 mL ethanol and 10 mL 3-aminopropanol to form a mixed solution.
[0056] S2. Add the mixed solution obtained in step S1 to a 100 mL reaction vessel and heat at 80 °C for 24 h.
[0057] S3. After the reaction vessel has cooled to room temperature, wash it three times alternately with deionized water and anhydrous ethanol, and then dry it to obtain a white powder.
[0058] S4. The white powder obtained in step S3 is subjected to a vacuum of 10... -7 The imidazole boron framework material BIF-24(OH) was obtained by maintaining it under vacuum conditions of mbar and 150℃ for 10 hours. - ).
[0059] Figure 1 In this embodiment, 'b' refers to the imidazolium boron framework material BIF-24(Cl) prepared in this example. - Scanning electron microscope image of BIF-24(OH). The image shows that BIF-24(OH) - Imidazole boron framework materials are mainly spherical. Figure 2 In this example, 'b' represents the imidazole boron framework material BIF-24(OH) prepared in this embodiment. - The X-ray diffraction pattern of the imidazole boron framework material BIF-24(OH) confirmed that... - The successful synthesis of ).
[0060] Example 3
[0061] This embodiment provides an imidazole boron framework material BIF-24(OH) - Preparation method of ).
[0062] S1. Dissolve zinc hydroxide, 0.6 g organic ligand KHB(mim)3, 2-imidazolidineone and pyromellitic acid in a molar ratio of 1:0.48:11.62:0.48 in a mixed solvent of 20 mL N,N-dimethylformamide, 10 mL ethanol and 20 mL 3-aminopropanol to form a mixed solution.
[0063] S2. Add the mixed solution obtained in step S1 to a 100 mL reaction vessel and heat at 80 °C for 24 h.
[0064] S3. After the reaction vessel has cooled to room temperature, wash it three times alternately with deionized water and anhydrous ethanol, and then dry it to obtain a white powder.
[0065] S4. The white powder obtained in step S3 is subjected to a vacuum of 10... -7 The imidazole boron framework material BIF-24(OH) was obtained by maintaining it under vacuum conditions of mbar and 150℃ for 10 hours. - ).
[0066] Example 4
[0067] This embodiment provides an imidazole boron framework material BIF-24(OH) - Preparation method of ).
[0068] S1. Dissolve zinc hydroxide, 0.6 g organic ligand KHB(mim)3, 2-imidazolidineone and pyromellitic acid in a molar ratio of 1:0.48:11.62:0.48 in a mixed solvent of 10 mL N,N-dimethylformamide, 30 mL ethanol and 10 mL 3-aminopropanol to form a mixed solution.
[0069] S2. Add the mixed solution obtained in step S1 to a 100 mL reaction vessel and heat at 80 °C for 30 h.
[0070] S3. After the reaction vessel has cooled to room temperature, wash it three times alternately with deionized water and anhydrous ethanol, and then dry it to obtain a white powder.
[0071] S4. The white powder obtained in step S3 is subjected to a vacuum of 10... -7 The imidazole boron framework material BIF-24(OH) was obtained by maintaining it under vacuum conditions of mbar and 150℃ for 10 hours. - ).
[0072] Example 5
[0073] This embodiment provides an imidazole boron framework material BIF-24(OH) - Preparation method of ).
[0074] S1. Dissolve zinc hydroxide, 0.6 g organic ligand KHB(mim)3, 2-imidazolidineone and pyromellitic acid in a molar ratio of 1:0.4:11:0.4 in a mixed solvent of 20 mL N,N-dimethylformamide, 10 mL ethanol and 20 mL 3-aminopropanol to form a mixed solution.
[0075] S2. Add the mixed solution obtained in step S1 to a 100 mL reaction vessel and heat at 80 °C for 24 h.
[0076] S3. After the reaction vessel has cooled to room temperature, wash it three times alternately with deionized water and anhydrous ethanol, and then dry it to obtain a white powder.
[0077] S4. The white powder obtained in step S3 is subjected to a vacuum of 10... -7 The imidazole boron framework material BIF-24(OH) was obtained by maintaining it under vacuum conditions of mbar and 150℃ for 10 hours. - ).
[0078] Comparative Example 1
[0079] This embodiment provides an imidazole boron framework material BIF-24(NO3) - Preparation method of ).
[0080] S1. Dissolve zinc nitrate, 0.6 g organic ligand KHB(mim)3, 2-imidazolidineone and pyromellitic acid in a molar ratio of 1:0.48:11.62:0.48 in a mixed solvent of 20 mL N,N-dimethylformamide, 10 mL ethanol and 10 mL 3-aminopropanol to form a mixed solution.
[0081] S2. Add the mixed solution obtained in step S1 to a 100 mL reaction vessel and heat at 80 °C for 24 h.
[0082] S3. After the reaction vessel has cooled to room temperature, wash it three times alternately with deionized water and anhydrous ethanol, and then dry it to obtain a white powder.
[0083] S4. The white powder obtained in step S3 is subjected to a vacuum of 10... -7 The imidazole boron framework material BIF-24(NO3) was obtained by maintaining it under vacuum conditions of mbar and 150℃ for 10 hours. - ).
[0084] Test case
[0085] 1. Adsorption performance determination:
[0086] Figure 3 The imidazole boron framework material BIF-24(Cl) obtained in Example 1 -Single-component adsorption curves of acetylene (a) and carbon dioxide (b) at different temperatures; as shown. Figure 3 As shown, the activated BIF-24(Cl) - At room temperature and pressure (298 K, 1 bar), the adsorption capacity for acetylene is 3.17 mmol / g, which is higher than the adsorption capacity for carbon dioxide (2.11 mmol / g).
[0087] Figure 4 The imidazole boron framework material BIF-24(OH) obtained in Example 2 - Single-component adsorption curves of acetylene (a) and carbon dioxide (b) at different temperatures; as shown. Figure 4 As shown, at room temperature and pressure (298K, 1 bar), the activated BIF-24(OH) - The adsorption capacity for acetylene reached 2.14 mmol / g, while the adsorption capacity for carbon dioxide was 1.51 mmol / g. Figure 7 As shown, BIF-24(Cl - ) and BIF-24(OH - At room temperature and pressure, the gas adsorption ratios of acetylene and carbon dioxide are 1.50 and 1.41, respectively.
[0088] 2. Acetylene / Carbon Dioxide Selectivity Test:
[0089] Figure 5 The imidazole boron framework material BIF-24(Cl) of Example 1 - (a) Imidazole boron framework material BIF-24(OH) from Example 2 - (b) and Comparative Example 1's BIF-24 (NO3) - (c) Acetylene / carbon dioxide selectivity plots calculated using ideal adsorption solution theory at different temperatures; BIF-24 (Cl...) calculated using ideal adsorption solution theory. - The selectivity for acetylene / carbon dioxide at 298 K and 1 bar is 4.15, BIF-24(OH) - The selectivity for acetylene / carbon dioxide at 298 K and 1 bar is 3.92, while BIF-24 (NO3) - The selectivity for acetylene / carbon dioxide is 3.71.
[0090] Figure 6 The imidazole boron framework material BIF-24(Cl) of Example 1 of this invention is... - (a) Imidazole boron framework material BIF-24(OH) from Example 2 - (b) Chart showing the ratio of acetylene to carbon dioxide gas adsorption. At initial pressure, BIF-24(Cl...) -) and BIF-24(OH - The adsorption ratio of acetylene / carbon dioxide by BIF-24 was significantly increased at 298 K and 0.005 bar. - ) and BIF-24(OH - The adsorption ratios for acetylene and carbon dioxide were 7.02 and 7.91, respectively. These ratios decreased rapidly with increasing pressure, dropping to 1.50 and 1.41 at 1 bar.
[0091] 3. Fixed-bed penetration test:
[0092] The activated BIF-24(Cl) from Example 1 was used. - ) and BIF-24(OH) of Example 2 - The mixture of acetylene and carbon dioxide (volume ratio 50:50) was packed into an adsorption column with an inner diameter of 4 mm. A fixed-bed breakthrough experiment was conducted by introducing a acetylene:carbon dioxide mixture at a rate of 5 mL / min into the adsorption column bed under ambient pressure (298 K, 1 bar). Figure 7 As shown in (a), when the acetylene / carbon dioxide mixture enters BIF-24 (Cl - After the bed was formed, carbon dioxide broke through the bed first at 10.90 minutes, while acetylene did not break through the bed until 34.33 minutes, with a separation time of approximately 23.43 minutes. Figure 7 As shown in (b), when the acetylene / carbon dioxide mixture enters BIF-24 (OH) - After the bed was established, carbon dioxide broke through the bed first at 2.97 minutes, and acetylene began to break through the bed at 13.90 minutes, with a separation time of approximately 10.93 minutes. The fixed-bed breakthrough experiment demonstrated the effectiveness of the BIF-24(Cl) method of this invention. - ) and BIF-24(OH - It has good acetylene / carbon dioxide separation characteristics.
[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing an imidazolium boron framework material, characterized in that, Includes the following steps: Zinc chloride or zinc hydroxide, triimidazole borohydride, 2-imidazolium ketone and pyromellitic acid are dissolved in a solvent and reacted at 70-90°C to obtain a solid product. The solid product is then activated under vacuum to obtain the final product.
2. The preparation method according to claim 1, characterized in that, The molar ratio of zinc chloride or zinc hydroxide, triimidazole borohydride, 2-imidazolidine ketone and trimesic acid is 1 : (0.3~0.6) : (10~15) : (0.3~0.6); the amount ratio of triimidazole borohydride to solvent is (0.5~0.7) g : (30~70) mL.
3. The preparation method according to claim 1, characterized in that, The solvent is selected from a mixture of N,N-dimethylformamide, 3-aminopropanol and ethanol, wherein the volume ratio of N,N-dimethylformamide, 3-aminopropanol and ethanol is (1~3):(1~3):(1~3).
4. The preparation method according to claim 1, characterized in that, In the step of obtaining a solid product by reacting at 70~90℃, the reaction time is 20~80h.
5. The preparation method according to claim 1, characterized in that, After the reaction is completed, the steps of washing and drying the reaction product are further included to obtain a solid product; in the vacuum activation step, the vacuum degree is 10. -7 Below mbar, the temperature is 120~170℃, and the time is 5~15h.
6. The preparation method according to claim 1, characterized in that, The preparation method of the triimidazole borohydride is as follows: potassium borohydride is mixed with 2-methylimidazole and subjected to a melt reaction at 200~230℃ to obtain the product.
7. The preparation method according to claim 6, characterized in that, The molar ratio of potassium borohydride to 2-methylimidazole is 1:(3~3.5); the reaction time of potassium borohydride and 2-methylimidazole is 3~8h.
8. The application of the imidazole boron framework material prepared by the preparation method according to any one of claims 1 to 7 in the separation of acetylene and carbon dioxide mixed gas.