Binaphthalene skeleton-based copper-based metal organic framework material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of metal organic framework materials, and discloses a binaphthalene skeleton-based copper-based metal organic framework material and a preparation method and application thereof.The preparation method comprises the following steps: by taking cupric nitrate and other bivalent copper salts as raw materials, a pyridine functionalized binaphthalene compound as a ligand and triethylamine or ammonia water as a regulator, regulating and controlling the macroscopic size of a crystal, and preparing the binaphthalene skeleton-based copper-based metal organic framework material. In combination with coordination of pyridine groups and metal ions, rapid reaction is carried out, and MOFs material crystals with high crystallinity and large size are obtained. The MOFs metal frame material is novel in structure and stable in skeleton, rich nitrogen-containing ligands and unsaturated metal sites are contained in crystals, and carbon dioxide gas molecules can be directly captured from air. Based on the specific adsorption effect of carbon dioxide, high carbon dioxide / nitrogen adsorption selectivity is shown.

Description

Technical Field

[0001] The present invention relates to the technical field of metal-organic framework materials, and specifically to a copper-based metal-organic framework material based on a binaphthyl skeleton, and its preparation method and application. Background Art

[0002] Metal-organic framework (MOFs) materials are porous framework crystalline materials formed by the coordination bond interaction between metal ions and organic ligands. It inherits the characteristics of crystalline functional materials such as the certainty of structure, the designability of structure, the tunability of pore channels, good stability, and easy modification of functional groups, as well as the presence of a variety of unsaturated coordination sites inside the structure, making it show a high selective effect on specific molecules and having broad application prospects in gas adsorption, separation, and storage. For carbon dioxide and nitrogen gases with similar molecular sizes, the key to selective adsorption and separation using MOFs materials lies in the preferential interaction between the active sites inside the material cavity and the target gas molecules. In addition, the stable structure, regular pore channels, and high specific surface area of MOFs crystal functional materials can further ensure the efficient and highly selective adsorption and separation of gas molecules by MOFs materials during multiple adsorption / desorption cycles. However, to apply the excellent gas adsorption performance of MOFs materials to actual production, the following limitations should be overcome: 1. Get rid of the limitations of traditional high-energy-consuming solvothermal synthesis, and synthesize the corresponding MOFs materials under mild conditions in a short time with relatively simple operations; 2. Design and synthesize MOFs materials with specific capture ability for carbon dioxide molecules at low concentrations, especially in air. According to the principle of framework chemistry, the structure of organic ligands and the coordination form of coordinating atoms not only play a decisive role in the topological structure and crystallinity of MOFs materials, but also have an important impact on the performance and activity of unsaturated coordination of MOFs materials. Therefore, selecting appropriate ligands selectively is an important breakthrough point for simplifying crystal synthesis conditions and regulating material adsorption selectivity. Chinese Patent with Publication No. CN106279213B discloses a highly stable copper-based metal-organic framework material and its preparation method and application. Using 4,4-bipyridine and disodium 1,2-ethanedisulfonate as ligands, the prepared copper-based metal-organic framework material has the characteristics of good stability and excellent selectivity for guest molecules. However, this patent requires the additional addition of sulfonic acid ligands and does not show good carbon dioxide / nitrogen adsorption selectivity. Summary of the Invention

[0003] The present invention solves the problem of poor gas adsorption and separation performance of existing metal framework materials for carbon dioxide and nitrogen.

[0004] The technical solution of the present invention includes a preparation method of a copper-based metal-organic framework material based on a binaphthyl skeleton, comprising the following steps:

[0005] S1: Add metal copper salt to distilled water, stir to dissolve, and obtain solution A.

[0006] S2: Add pyridyl binaphthyl ligand to N,N-dimethylformamide, stir to dissolve, and obtain solution B.

[0007] S3: Drop solution A into solution B, stir and mix evenly, then add a regulator, keep the temperature at 35 - 50 °C for 12 - 24 h for reaction, filter, wash, dry, and activate in vacuum at 120 - 130 °C for 4 - 6 h to obtain a copper-based metal-organic framework material based on the binaphthyl skeleton.

[0008] Among them, the structural formula of the pyridyl binaphthyl ligand is .

[0009] Preferably, the ratio of the metal copper salt, pyridyl binaphthyl ligand, and regulator is (3 - 3.3) mol: 1 mol: (0.2 - 0.5) L.

[0010] Preferably, the metal copper salt is any one of copper nitrate, copper chloride, copper acetate, and copper sulfate.

[0011] Preferably, the regulator is triethylamine or ammonia water.

[0012] Preferably, the structural formula of the copper-based metal-organic framework material based on the binaphthyl skeleton includes [CuL 4 (H 2 O) 2 (NO 3 ) 6 、[CuL 4 (H 2 O) 2 (Cl) 6 、[CuL 4 (H 2 O) 2 (CH3COO) 6 Any one of them, and L in the structural formula is the pyridyl binaphthyl ligand.

[0013] Preferably, the copper-based metal-organic framework material based on the binaphthyl skeleton is applied to the gas adsorption and separation of carbon dioxide and nitrogen.

[0014] Preferably, the preparation method of the pyridyl binaphthyl ligand is:

[0015] (1)Add binaphthol, potassium carbonate, and bromoethane to acetone, stir and react under an argon atmosphere, cool, distill under reduced pressure, add distilled water, stir and then filter, wash with distilled water, and dry to obtain intermediate 1. The reaction formula is:

[0016] .

[0017] (2) Add intermediate 1 to dichloromethane. After stirring, add liquid bromine dropwise under an ice-water bath condition. After stirring and reacting, add an aqueous solution of sodium thiosulfate to quench the excessive bromine. Add dichloromethane for extraction. The dichloromethane organic phase is dried with anhydrous sodium sulfate, filtered, and the filtrate is evaporated under reduced pressure. The crude product is separated by column chromatography to obtain intermediate 2. The reaction formula is:

[0018] .

[0019] (3) Add intermediate 2, 4-pyridylboronic acid pinacol ester, potassium phosphate, and tetrakis(triphenylphosphine)palladium to N,N-dimethylformamide. Under an argon gas atmosphere, carry out the reaction, distill under reduced pressure, and the crude product is separated by column chromatography to obtain the pyridyl binaphthyl ligand. The reaction formula is:

[0020] .

[0021] Preferably, the molar ratio of binaphthol, potassium carbonate, and bromoethane in (1) is 1:(3.4 - 3.6):(3.429 - 3.7) of binaphthol, potassium carbonate, and bromoethane.

[0022] Preferably, the reaction temperature in (1) is 55 - 60 °C, and the reaction time is 6 - 8 h.

[0023] Preferably, the reaction temperature in (2) is 20 - 25 °C, and the reaction time is 10 - 12 h.

[0024] Preferably, in (2), the molar ratio of intermediate 1 to liquid bromine is 1:(5 - 6).

[0025] Preferably, the reaction temperature in (3) is 100 - 110 °C, and the reaction time is 60 - 72 h.

[0026] Preferably, in (3), the molar ratio of intermediate 2, 4-pyridylboronic acid pinacol ester, potassium phosphate, and tetrakis(triphenylphosphine)palladium is 1:(6 - 7):(6 - 8):(0.16 - 0.2).

[0027] Advantageous technical effects of the present invention: The present invention uses binaphthol, bromoethane, liquid bromine, 4-pyridylboronic acid pinacol ester, etc. as reactants to prepare a pyridyl binaphthyl ligand. Using divalent copper salts such as copper nitrate as raw materials, the pyridine-functionalized binaphthyl compound as a ligand, and triethylamine or ammonia water as a regulator to control the macroscopic size of the crystal, and combining the coordination of the pyridine group with metal ions, and then reacting quickly to obtain a MOFs material crystal with high crystallinity and large size. The preparation method of this MOFs material has a simple process, mild conditions, is easy to scale up the synthesis, and does not require the addition of sulfonic acid and carboxylic acid ligands. Only by adding pyridine ligands, a coordination polymerization reaction can be carried out to obtain a pyridine copper-based MOFs material. This method has high reference and research value for the rapid, effective and large-scale preparation of MOFs materials.

[0028] The copper-based metal-organic framework material prepared by the present invention has a novel structure, a stable framework, and rich nitrogen-containing ligands and unsaturated metal sites inside the crystal. Single crystal structure analysis shows that the unsaturated sites of this MOFs crystal material can directly capture carbon dioxide gas molecules from the air, indicating that this metal-organic framework material has a specific adsorption effect on carbon dioxide. This provides a new strategy for the design and synthesis of MOFs materials for direct air capture of carbon dioxide. Based on this specific adsorption effect of carbon dioxide, this MOFs material has obtained a high carbon dioxide / nitrogen adsorption selectivity. Description of the Drawings

[0029] Figure 1 It is the asymmetric unit structure diagram of the copper-based metal-organic framework material based on the binaphthyl skeleton in Example 3.

[0030] Figure 2 It is the in-situ adsorption diagram of carbon dioxide of the copper-based metal-organic framework material based on the binaphthyl skeleton in Example 3.

[0031] Figure 3 It is the three-dimensional structure diagram of the copper-based metal-organic framework material based on the binaphthyl skeleton in Example 3.

[0032] Figure 4 It is the thermogravimetric curve of the copper-based metal-organic framework material based on the binaphthyl skeleton in Example 3.

[0033] Figure 5 It is the gas adsorption and desorption curve of the copper-based metal-organic framework material based on the binaphthyl skeleton in Example 3 at 273K.

[0034] Figure 6 It is the gas adsorption and desorption curve of the copper-based metal-organic framework material based on the binaphthyl skeleton in Example 3 at 298K.

[0035] Figure 7Gas IAST selectivity of the copper-based metal-organic framework material based on a binaphthyl skeleton in Example 3 at 273 K.

[0036] Figure 8 Gas IAST selectivity of the copper-based metal-organic framework material based on a binaphthyl skeleton in Example 3 at 298 K. Detailed implementation manners

[0037] The present invention will be further clarified below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, those skilled in the art's various equivalent modifications of the present invention all fall within the scope defined by the appended claims of this application.

[0038] Example 1:

[0039] (1) Add 70 mmol of binaphthol (CAS registry number: 18531-99-2), 238 mmol of potassium carbonate, and 240 mmol of bromoethane to 300 mL of acetone. Under an argon atmosphere, stir and reflux at 55 °C for 8 h. Distill under reduced pressure, add 2 L of distilled water, stir for 6 h, filter, wash, and dry to obtain Intermediate 1 with a yield of 98.6%. The structural formula is .

[0040] (2) Add 20 mmol of Intermediate 1 to 100 mL of dichloromethane. After stirring, add 100 mmol of liquid bromine dropwise under an ice-water bath condition. Stir and react at 25 °C for 10 h. Add an aqueous solution of sodium thiosulfate to quench the excess bromine, extract, and perform column chromatography separation on the crude product. Elute with a mixed solution of petroleum ether and ethyl acetate to obtain Intermediate 2 with a yield of 59.5%. The structural formula is .

[0041] (3) Add 10 mmol of Intermediate 2, 60 mmol of 4-pyridylboronic acid pinacol ester, 60 mmol of potassium phosphate, and 2 mmol of tetrakis(triphenylphosphine)palladium to 100 mL of N,N-dimethylformamide. Under an argon gas atmosphere, stir and react at 100 °C for 72 h. Distill under reduced pressure, and perform column chromatography separation on the crude product. Elute with a mixed solution of dichloromethane and methanol to obtain the pyridyl binaphthyl ligand with a yield of 75.3%. The structural formula is .

[0042] Example 2:

[0043] (1) 70 mmol of binaphthol (CAS Registry Number: 18531-99-2), 252 mmol of potassium carbonate, and 259 mmol of bromoethane were added to 300 mL of acetone. Under an argon atmosphere, the mixture was stirred and refluxed at 60 °C for 6 h. Then, it was distilled under reduced pressure. 2 L of distilled water was added, and the mixture was stirred for 6 h, filtered, washed, and dried to obtain Intermediate 1 with a yield of 95.2%.

[0044] (2) 20 mmol of Intermediate 1 was added to 100 mL of dichloromethane. After stirring, 120 mmol of liquid bromine was added dropwise under an ice-water bath condition. The mixture was stirred at 20 °C for 12 h. An aqueous solution of sodium thiosulfate was added to quench the excess bromine. After extraction, the crude product was separated by column chromatography and eluted with a mixed solution of petroleum ether and ethyl acetate to obtain Intermediate 2 with a yield of 66.9%.

[0045] (3) 10 mmol of Intermediate 2, 70 mmol of 4-pyridylboronic acid pinacol ester, 80 mmol of potassium phosphate, and 1.6 mmol of tetrakis(triphenylphosphine)palladium were added to 100 mL of N,N-dimethylformamide. Under an argon atmosphere, the mixture was stirred at 110 °C for 60 h. Then, it was distilled under reduced pressure. The crude product was separated by column chromatography and eluted with a mixed solution of dichloromethane and methanol to obtain the pyridyl binaphthyl ligand with a yield of 71.7%.

[0046] Example 3:

[0047] (1) 3 mmol of copper nitrate was added to 1.5 mL of distilled water and stirred until dissolved to obtain Solution A.

[0048] (2) 1 mmol of pyridyl binaphthyl ligand (prepared in Example 1) was added to 10 mL of N,N-dimethylformamide and stirred until dissolved to obtain Solution B.

[0049] (3) Solution A was added dropwise to Solution B. After stirring and mixing evenly, 0.2 mL of the regulator ammonia water (mass fraction 20%) was added. The mixture was kept at 35 °C for reaction for 24 h, filtered, washed with an acetone aqueous solution with a volume ratio of 1:1, and dried. Finally, under vacuum conditions, it was activated at 120 °C for 6 h to obtain a copper-based metal-organic framework material based on the binaphthyl skeleton. The structural formula is [CuL 4 (H 2 O) 2 (NO 3 ) 6 , where L is the pyridyl binaphthyl ligand.

[0050] Figure 1 is the structural diagram of the asymmetric unit of the copper-based metal-organic framework material based on the binaphthyl skeleton; Figure 3It is a three-dimensional structure diagram of a metal framework material; it is proved that copper nitrate and pyridyl binaphthyl ligand react to generate a copper-based metal-organic framework material based on the binaphthyl skeleton. Figure 2 It is an in-situ adsorption diagram of carbon dioxide by the metal framework material, which contains rich nitrogen-containing ligands and unsaturated metal sites and can directly capture carbon dioxide gas molecules from the air, indicating that the metal framework material has specific adsorption for carbon dioxide. Figure 4 It is the thermogravimetric curve of the copper-based metal-organic framework material based on the binaphthyl skeleton, indicating that the metal framework material has good thermal stability.

[0051] Example 4:

[0052] (1) Add 3.3 mmol of copper acetate to 1.5 mL of distilled water and stir to dissolve to obtain solution A.

[0053] (2) Add 1 mmol of pyridyl binaphthyl ligand (prepared in Example 1) to 10 mL of N,N-dimethylformamide and stir to dissolve to obtain solution B.

[0054] (3) Drop solution A into solution B, stir and mix well, then add 0.5 mL of the regulator triethylamine and keep the temperature at 50 °C for 12 h. Filter, wash with an acetone aqueous solution with a volume ratio of 1:1, dry, and finally activate at 120 °C for 6 h under vacuum conditions to obtain a copper-based metal-organic framework material based on the binaphthyl skeleton. The structural formula is [CuL 4 (H 2 O) 2 (CH3COO) 6 , where L is the pyridyl binaphthyl ligand.

[0055] Example 5:

[0056] (1) Add 3 mmol of copper chloride to 1.5 mL of distilled water and stir to dissolve to obtain solution A.

[0057] (2) Add 1 mmol of pyridyl binaphthyl ligand (prepared in Example 1) to 10 mL of N,N-dimethylformamide and stir to dissolve to obtain solution B.

[0058] (3) Drop solution A into solution B, stir and mix well, then add 0.2 mL of the regulator ammonia water (mass fraction 20%) and keep the temperature at 45 °C for 24 h. Filter, wash with an acetone aqueous solution with a volume ratio of 1:1, dry, and finally activate at 130 °C for 4 h under vacuum conditions to obtain a copper-based metal-organic framework material based on the binaphthyl skeleton. The structural formula is [CuL 4 (H 2 O) 2 (Cl) 6 , where L is the pyridyl binaphthyl ligand.

[0059] Comparative Example 1:

[0060] (1) Add 3 mmol of copper nitrate to 1.5 mL of distilled water, stir to dissolve, and obtain Solution A.

[0061] (2) Add 1 mmol of pyridyl binaphthyl ligand (prepared in Example 1) to 10 mL of N,N-dimethylformamide, stir to dissolve, and obtain Solution B.

[0062] (3) Drop Solution A into Solution B, stir and mix evenly, then keep the reaction at 35 °C for 24 h, filter, wash with an aqueous acetone solution with a volume ratio of 1:1, dry, and finally activate at 120 °C for 6 h under vacuum conditions to obtain a copper-based metal-organic framework material based on the binaphthyl skeleton.

[0063] Comparative Example 2: In this comparative example, MOF materials were prepared using conventional trimesic acid and 4,4'-bipyridine as ligands.

[0064] Add 0.4 g of copper nitrate trihydrate, 0.095 g of trimesic acid, and 4,4'-bipyridine to 9 mL of N,N-dimethylformamide and 9 mL of ethanol, stir and pour into a reaction kettle, react at 120 °C for 12 h, filter, wash with an aqueous acetone solution with a volume ratio of 1:1, dry, and finally activate at 120 °C for 6 h under vacuum conditions to obtain MOF materials.

[0065] Comparative Example 3: In this comparative example, MOF materials were prepared using conventional 2,2'-bipyridine-4,4'-dicarboxylic acid as a ligand.

[0066] Add 0.14 mmol of copper nitrate and 0.1 mol of 2,2'-bipyridine-4,4'-dicarboxylic acid to a mixed solvent of 1 mL of N,N-dimethylacetamide, 1 mL of acetonitrile, and 1 mL of water, stir and pour into a reaction kettle, react at 125 °C for 36 h, cool, filter, wash with ethanol, dry, and finally activate at 120 °C for 6 h under vacuum conditions to obtain MOF materials.

[0067] Use a gas sorption analyzer to measure the nitrogen adsorption / desorption curve and carbon dioxide adsorption / desorption curve of the MOF materials at temperatures of 273 K and 298 K. The test results are shown in the following table and Figures 5 - 8 .

[0068] Table 1 Gas adsorption capacity test at a temperature of 273 K and a relative pressure P / P 0 of 1

[0069] Carbon dioxide adsorption capacity (mL / g) Nitrogen adsorption capacity (mL / g) Example 3 25.95 17.04 Example 4 25.33 17.08 Example 5 24.27 16.92 Comparative Example 1 21.16 14.56 Comparative Example 2 16.30 12.21 Comparative Example 3 13.19 9.65

[0070] Table 2 Gas adsorption capacity test at a temperature of 298 K and a relative pressure P / P 0Gas adsorption capacity test at 1

[0071] Carbon dioxide adsorption capacity (mL / g) Nitrogen adsorption capacity (mL / g) Example 3 11.58 0.80 Example 4 11.45 0.88 Example 5 10.67 0.73 Comparative Example 1 9.86 0.69 Comparative Example 2 7.04 0.62 Comparative Example 3 5.62 0.49

[0072] As can be seen from Table 1, Table 2 and Figures 5 - 6 it can be seen that for the copper-based metal-organic framework materials based on binaphthyl skeletons in Examples 3-5, at 273K and a relative pressure of 1, the adsorption capacity for carbon dioxide reaches 24.27 - 25.95 mL / g. At 298K and a relative pressure of 1, the adsorption capacity for carbon dioxide reaches 10.67 - 11.58 mL / g, which is significantly higher than that of Comparative Examples 1 - 3.

[0073] From Figure 7 and Figure 8 it can be seen that for the metal-organic framework material prepared in Example 3, at temperatures of 273K and 298K, in a mixed gas with a volume ratio of carbon dioxide to nitrogen of 1:9 or 2:8, the metal-organic framework material exhibits good gas IAST selectivity.

[0074] Inspired by the above ideal embodiments according to the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing a copper-based metal organic framework material based on a binaphthyl skeleton, characterized in that: The preparation method comprises: S1: Add copper salt to distilled water and stir to dissolve to obtain solution A; S2: Add pyridylbinaphthyl ligand to N,N-dimethylformamide, stir and dissolve, and obtain solution B; S3: adding solution A dropwise to solution B, stirring and mixing, adding a regulator, keeping the mixture warm for reaction, filtering, washing, drying, and vacuum activating to obtain a copper-based metal organic framework material based on a binaphthyl skeleton; The structural formula of the pyridylbinaphthyl ligand is .

2. The method for preparing a copper-based metal organic framework material based on a binaphthyl skeleton according to claim 1, characterized in that: The ratio of the metal copper salt, the pyridyl binaphthyl ligand and the regulator is (3-3.3) mol:1 mol:(0.2-0.5) L; the metal copper salt is any one of copper nitrate, copper chloride, copper acetate and copper sulfate.

3. The method for preparing a copper-based metal organic framework material based on a binaphthyl skeleton according to claim 2, characterized in that: The regulator is triethylamine or ammonia water.

4. The method for preparing a copper-based metal organic framework material based on a binaphthyl skeleton according to claim 1, characterized in that: The temperature of the heat preservation reaction in S3 is 35-50°C, and the time is 12-24h; the temperature of the vacuum activation is 120-130°C, and the time is 4-6h.

5. A copper-based metal organic framework material based on a binaphthyl skeleton obtained by the preparation method according to any one of claims 1 to 4, characterized in that: The structural formula of the copper-based metal organic framework material based on the binaphthyl skeleton includes any one of [CuL4(H2O)2](NO3)6, [CuL4(H2O)2](Cl)6, and [CuL4(H2O)2](CH3COO)6, wherein L is a pyridyl binaphthyl ligand.

6. Use of the copper-based metal organic framework material based on the binaphthyl skeleton according to claim 5 in the gas adsorption separation of carbon dioxide and nitrogen.

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