Metal organic framework material based on dodecacarboxyl organic ligand, synthesis of metal organic framework material and application of metal organic framework material in natural gas purification

Abstract

The invention discloses a dodecacarboxyl organic ligand-based metal organic framework material as well as synthesis and application thereof. The preparation method comprises the following steps: firstly, carrying out multi-step organic synthesis to obtain a dodecacarboxyl organic ligand H12HDTB, and then respectively reacting the H12HDTB with metal ions such as copper, indium, zirconium, iron and the like by a solvothermal method to obtain the metal organic framework material. The material disclosed by the invention shows relatively low adsorption capacity to methane, has relatively high adsorption capacity to ethane, propane and n-butane, and shows a selective adsorption separation effect to the gases. Meanwhile, due to the small pore diameter, isobutane cannot enter the material, and the isobutane is screened. Therefore, the material provided by the invention also has the potential of screening n-butane and iso-butane.

Description

Technical Field

[0001] The present invention relates to the technical field of synthesis of metal organic framework materials and gas adsorption separation, and in particular to the synthesis of metal organic framework materials based on dodecacarboxyl organic ligands and the application of the materials in natural gas upgrading. Background Art

[0002] Metal-organic frameworks (MOFs) are a type of crystalline porous materials formed by coordination between organic ligands and metal ions or metal clusters. Metal-organic frameworks with adjustable pore size and specific surface area can be obtained by modifying organic ligands and selecting different types of metal ions or metal clusters. At the same time, through network chemistry, the topological structure of the metal-organic framework is pre-designed and synthesized to obtain a porous material with adjustable structure. Due to its porous nature and good chemical and physical stability, metal-organic framework materials are usually used for gas storage and separation. Improving the adsorption capacity and selectivity of metal-organic framework materials through structural design is the key to its application in the field of gas adsorption and separation technology.

[0003] Organic ligands are one of the key elements in the design and synthesis of metal-organic framework materials, and highly connected organic ligands account for a minority of the metal-organic framework materials reported so far. So far, no relevant patents have reported the synthesis of twelve-carboxyl organic ligands. Moreover, high-connected ligands are one of the keys to obtaining highly connected metal-organic framework materials. The highly connected metal-organic framework materials (connection number ≥ 12) currently reported in the literature are designed and synthesized through the strategy of molecular building blocks. Highly connected ligands have positioning and network-guiding functions in the synthesis of metal-organic framework materials and have a high degree of symmetry. Different from highly connected metal clusters, such as twelve-connected zirconium clusters and eighteen-connected rare earth metal clusters, although these metal clusters have high connection sites, they cannot necessarily be fully coordinated in the synthesis of framework materials, which leads to a reduction in the number of connections. Due to the characteristics of its multi-carboxyl group, the highly connected organic ligand can fully coordinate with the metal cluster to form a dense network structure.

[0004] In terms of natural gas / methane adsorption, the applicant has done some work. For example, the patent specification with publication number CN119119499A discloses two metal organic framework materials Zr-TTB-1 and Zr-TTB-2, their preparation methods and applications in methane adsorption; the patent specification with publication number CN119331264A discloses a pyrene-based metal organic framework material Cr-TBPP-MOF suitable for low-temperature methane adsorption storage, its preparation method and application in low-temperature methane adsorption.

[0005] At present, most of the metal organic framework materials used for natural gas purification are based on the sieving mechanism of pore size. By designing small molecule organic ligands and selecting appropriate metal salts, smaller pores or holes are obtained, and smaller gas molecules are adsorbed inside the material, while larger gas molecules are separated because they cannot enter the pores. Due to their multi-branched characteristics, highly connected ligands can form a dense network structure after complete coordination, forming smaller mesh channels and holes. This has hardly been reported in previous literature, and there are no examples of using metal organic framework materials based on highly connected ligands for gas adsorption and separation. Its application in natural gas upgrading also needs to be studied. Summary of the invention

[0006] In view of the above technical problems and the shortcomings in the art, the present invention provides a dodecacarboxyl organic ligand, a metal organic framework material based on the dodecacarboxyl organic ligand, and its synthesis and application. The metal organic framework material of the present invention can be used for adsorption separation of methane / ethane, methane / propane, methane / butane, normal butane / isobutane, etc., to obtain high-purity methane gas, recover C2-C4 low-carbon alkanes, and separate normal butane and isobutane.

[0007] The present invention is based on the synthesis of a metal organic framework material of a dodecacarboxyl organic ligand. The dodecacarboxyl organic ligand can be firstly obtained by a multi-step organic synthesis method, and then the dodecacarboxyl organic ligand H 12 HDTB and Cu 2+ 、In 3+ 、Zr 4+ , Fe 3+ The corresponding metal organic framework materials are obtained by reaction and coordination of metal ions.

[0008] [1] A metal organic framework material based on a dodecacarboxyl organic ligand is obtained by reacting and coordinating raw materials comprising the following components:

[0009] The dodecacarboxyl organic ligand H having the structure shown in the following formula (I): 12 HDTB:

[0010]

[0011] Metal ion: Cu 2+ 、In 3+ 、Zr 4+ , Fe 3+ At least one of .

[0012] The metal organic framework material based on the dodecacarboxyl organic ligand of the present invention has a three-dimensional network structure, and its structure is as follows: in the framework, the six arms of the dodecacarboxyl organic ligand are uniformly deflected to the left or right, and the whole molecule is in the shape of a propeller, and each carboxyl group is coordinated with a metal cluster, wherein the copper cluster is a paddle-shaped four-connected binuclear copper cluster, the indium cluster is a tetrahedral four-connected mononuclear cluster, the zirconium ion forms a six-connected hexanuclear zirconium cluster in an anti-triangular prism configuration, and the iron ion forms a six-connected trinuclear iron cluster in a triangular prism configuration. The corresponding structure is shown in Figure 1 .

[0013] [2] The method for preparing a metal organic framework material based on a dodecacarboxyl organic ligand according to [1] comprises the steps of:

[0014] (1) Prepare an organic ligand containing dodecyl carboxyl group H 12 HDTB and N,N-dimethylformamide solution of the metal ions, with or without 1,4-dioxane and water, adding a regulator, and reacting at 75-150° C. (e.g., 120° C., 130° C., etc.) in a sealed state; the regulator comprises at least one of hydrochloric acid, formic acid, and trifluoroacetic acid;

[0015] (2) The solid product obtained by the sealing reaction in step (1) is soaked in N,N-dimethylformamide and acetone in turn, and then vacuumed, degassed and activated to obtain the metal organic framework material based on dodecyl carboxyl organic ligand.

[0016] In step (1), the source of the metal ion may be a metal salt. 12 The mass ratio of HDTB to the metal salt may be 1:2-4, such as 1:3.

[0017] In step (1), when 1,4-dioxane and water are added, the volume ratio of N,N-dimethylformamide, 1,4-dioxane and water may be 4:1:1-2.

[0018] In step (1), the sealing reaction time may be 12 to 48 hours.

[0019] Step (2) may specifically include: after the sealing reaction of step (1) is completed, the mother liquor is removed, and N,N-dimethylformamide is added to soak the solid product obtained by the reaction, and clean N,N-dimethylformamide is replaced after each soaking for 5 to 10 hours. This process is repeated 4 to 6 times, and then the solid product is placed in acetone to exchange and remove N,N-dimethylformamide. The soaking time of acetone is 3 to 6 hours each time, and the acetone is exchanged 8 to 10 times, and then vacuum degassing and activation is carried out at 100° C. for 12 to 15 hours to obtain the metal organic framework material based on dodecyl carboxyl organic ligand.

[0020] [3] Application of the metal organic framework material based on dodecacarboxyl organic ligands according to [1] for gas adsorption. The metal organic framework material based on dodecacarboxyl organic ligands can be used to adsorb gases such as nitrogen and C1-C4 alkanes.

[0021] [4] The use of the metal organic framework material based on dodecacarboxyl organic ligand according to [1] for the adsorption and separation of methane and C2-C4 alkanes, wherein the C2-C4 alkanes include at least one of ethane, propane and n-butane.

[0022] [5] Application of the metal organic framework material based on dodecacarboxyl organic ligand according to [1] for the adsorption and separation of n-butane and isobutane.

[0023] [6] A dodecacarboxyl organic ligand H having the structure shown in the following formula (I): 12 HDTB:

[0024]

[0025] [7] The dodecacarboxyl organic ligand H according to [6]. 12 The preparation method of HDTB comprises: adding 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) having a structure as shown in formula (II), dicobalt octacarbonyl and 1,4-dioxane into a high-pressure reaction container under an anhydrous and oxygen-free environment, heating at 120-130° C. for reaction, removing the solvent after the reaction is completed, and purifying the solid crude product to obtain a dodecyl ester precursor having a structure as shown in formula (III);

[0026]

[0027] The dodecyl ester precursor is hydrolyzed to obtain the dodecyl carboxyl organic ligand H 12 HDTB.

[0028] The dodecacarboxyl organic ligand H 12 In the preparation method of HDTB, the mass ratio of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) to dicobalt octacarbonyl can be 10 to 20:1.

[0029] The dodecacarboxyl organic ligand H 12 In the preparation method of HDTB, the ratio of the mass of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) to the volume of 1,4-dioxane can be 1 g:8-12 mL, for example, 1 g:10 mL.

[0030] The dodecacarboxyl organic ligand H 12 In the preparation method of HDTB, the heating reaction time at 120-130° C. can be 24-36 hours.

[0031] The dodecacarboxyl organic ligand H 12 In the preparation method of HDTB, the heating reaction at 120-130° C. may be accompanied by stirring.

[0032] The dodecacarboxyl organic ligand H 12 In the preparation method of HDTB, the solid crude product can be purified by silica gel column chromatography to obtain the dodecyl ester precursor. Further, the column chromatography solvent used is a mixed solvent of dichloromethane and ethyl acetate, and further, the volume ratio of dichloromethane to ethyl acetate can be 100:1-5.

[0033] The dodecaned ester precursor is hydrolyzed to obtain the dodecaned carboxyl organic ligand H 12 The specific operation of HDTB may include: dissolving the dodecyl ester precursor in a mixed solvent of 1,4-dioxane, ethanol and water, adding potassium hydroxide, heating for reaction, removing the solvent after the reaction stops, adding water to dissolve the solid, adding acid (such as hydrochloric acid, etc.) to the obtained aqueous solution, adjusting the pH to 1-3, collecting the precipitate, washing, and drying to obtain the dodecyl carboxyl organic ligand H 12 HDTB.

[0034] In the mixed solvent of 1,4-dioxane, ethanol and water, the volume ratio of 1,4-dioxane, ethanol and water can be 1:1:1.

[0035] The mass ratio of the lauryl ester precursor to potassium hydroxide may be 1:3-6.

[0036] After adding potassium hydroxide, the heating reaction time can be 12 to 24 hours.

[0037] The preparation method of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) may include: adding 1,2-bis(3,5-dibromophenyl)acetylene, 4-(methoxycarbonyl)phenylboric acid, potassium carbonate, tetrakis(triphenylphosphine)palladium, tetrahydrofuran and water into a reaction device under nitrogen conditions, heating the reaction at 80-90° C., washing the solid precipitate, and obtaining 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)).

[0038] In the preparation method of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)), the heating reaction time at 80-90° C. can be 12-24 hours.

[0039] In the preparation method of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)), the solvent used for washing can be one or more of tetrahydrofuran, 1,4-dioxane, water and ethanol.

[0040] In the preparation method of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)), the molar ratio of 1,2-bis(3,5-dibromophenyl)acetylene, 4-(methoxycarbonyl)phenylboric acid, potassium carbonate and tetrakis(triphenylphosphine)palladium can be 1:4-8:8-16:0.1-0.2.

[0041] In the preparation method of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)), the volume ratio of tetrahydrofuran to water can be 4 to 5:1.

[0042] The present invention first obtains the dodecacarboxyl organic ligand H by multi-step organic synthesis. 12 HDTB, and then H 12 HDTB reacts with metal ions such as copper, indium, zirconium, and iron to obtain metal organic framework materials.

[0043] The metal organic framework material based on the dodecacarboxyl organic ligand has a very small amount of adsorption of methane and a very weak adsorption capacity, but has a strong adsorption capacity and a high adsorption capacity for ethane, propane, and normal butane. In addition, due to the suitable pore size and size, the material of the present invention has a certain separation ability for normal butane and isobutane. After testing, the material of the present invention can be used for adsorption separation of methane / ethane, methane / propane, methane / butane, normal butane / isobutane, etc., to obtain high-purity methane gas and recover C2-C4 low-carbon alkanes and separate normal butane and isobutane. Therefore, the material of the present invention can be used for selective adsorption and separation of industrial mixed gases containing a large amount of methane, such as natural gas, biogas, and cracking gas.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. The present invention designs and synthesizes a never-before-reported dodecacarboxyl organic ligand, expands the ligand structure of metal-organic frameworks, and contributes to the exploration of highly connected metal-organic frameworks.

[0046] 2. The present invention designs and synthesizes metal organic framework materials based on dodecacarboxyl organic ligands. These materials have complex pore and hole structures and good thermal stability, laying a foundation for the application of gas adsorption separation.

[0047] 3. The metal organic framework material based on dodecacarboxyl organic ligand designed and synthesized by the present invention has a small amount of adsorption of methane and a weak adsorption capacity, but has a strong adsorption capacity and a high adsorption capacity for ethane, propane, and n-butane. Therefore, it can be used to selectively purify methane, specifically manifested as highly selective adsorption separation of methane / ethane, methane / propane, and methane / butane, and can be used for selective adsorption separation of industrial mixed gases containing a large amount of methane such as natural gas, biogas, and cracking gas. In addition, due to its suitable pore size, it also has a good separation effect for n-butane and isobutane. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the structure of copper clusters, indium clusters, zirconium clusters and iron clusters coordinated with the carboxyl groups in the dodecacarboxyl organic ligands in the metal organic framework material structure based on the dodecacarboxyl organic ligands of the present invention.

[0049] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) prepared in Example 1.

[0050] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the dodecyl ester precursor prepared in Example 2.

[0051] Figure 4 H prepared in Example 3 12 H NMR spectrum of HDTB.

[0052] Figure 5 This is the crystal structure diagram of Cu-HDTB-shp prepared in Example 4.

[0053] Figure 6 This is the crystal structure diagram of In-HDTB-shp prepared in Example 5.

[0054] Figure 7 This is the crystal structure diagram of Zr-HDTB-alb prepared in Example 6.

[0055] Figure 8 This is the crystal structure diagram of Fe-HDTB-alb prepared in Example 7.

[0056] Fig. 9 This is a nitrogen adsorption desorption diagram of Cu-HDTB-shp prepared in Example 4.

[0057] Fig.10 This is a nitrogen adsorption desorption diagram of In-HDTB-shp prepared in Example 5.

[0058] Fig.11 This is a nitrogen adsorption desorption diagram of Zr-HDTB-alb prepared in Example 6.

[0059] Fig.12 This is a nitrogen adsorption desorption diagram of Fe-HDTB-alb prepared in Example 7.

[0060] Fig.13 This is the X-ray powder diffraction (PXRD) pattern of Cu-HDTB-shp prepared in Example 4.

[0061] Fig.14 This is the PXRD pattern of In-HDTB-shp prepared in Example 5.

[0062] Fig.15 This is the PXRD pattern of Zr-HDTB-alb prepared in Example 6.

[0063] Fig.16 This is the PXRD pattern of Fe-HDTB-alb prepared in Example 7.

[0064] Fig.17 This is a diagram showing the adsorption and desorption of methane, ethane, propane and n-butane of Zr-HDTB-alb prepared in Example 6.

[0065] Fig.18 This is a diagram showing the adsorption and desorption of n-butane and isobutane of Zr-HDTB-alb prepared in Example 6.

[0066] Fig.19 This is a diagram showing the adsorption and desorption of methane, ethane, propane and n-butane of Fe-HDTB-alb prepared in Example 7.

[0067] Fig. 20 This is a diagram showing the adsorption and desorption of n-butane and isobutane of Fe-HDTB-alb prepared in Example 7. DETAILED DESCRIPTION

[0068] The present invention will be further described below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. The operating methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0069] Embodiment 1:

[0070] 5',5""-(Ethylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)):

[0071]

[0072] 1,2-bis(3,5-dibromophenyl)acetylene (1 mmol) and 4-(methoxycarbonyl)phenylboronic acid (4.4 mmol), potassium carbonate (8 mmol), tetrakis(triphenylphosphine)palladium (0.1 mmol), tetrahydrofuran and water (volume ratio of 4:1) were added to a round-bottom flask under nitrogen. The whole reaction was heated and stirred at 80-90°C for 12 h. The solid precipitate was filtered and washed to obtain the intermediate 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)). The hydrogen nuclear magnetic resonance spectrum was as follows: Figure 2 shown.

[0073] Embodiment 2:

[0074] Dodecyl precursor:

[0075]

[0076] The intermediate 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) and octacarbonyl dicobalt (mass ratio of 10:1), and ultra-dry 1,4-dioxane are added to a high-pressure reaction bottle in an anhydrous and oxygen-free environment, and the entire reaction is heated and stirred at 120-130°C for 36 hours. Among them, the amount of ultra-dry 1,4-dioxane used is 10mL per gram of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)). After the reaction is completed, the solvent is dried and the crude product is purified by silica gel column chromatography to obtain a dodecyl ester product. The hydrogen nuclear magnetic resonance spectrum is as follows Figure 3 The column chromatography solvent used was a mixed solvent of dichloromethane and ethyl acetate, with a ratio of 100:3.

[0077] Embodiment 3:

[0078] H 12 HDTB:

[0079]

[0080] The dodecyl ester precursor is dissolved in a mixed solvent of 1,4-dioxane, ethanol and water (volume ratio of 1:1:1), and an appropriate amount of potassium hydroxide is added. The reaction is stirred, heated and refluxed for 12 hours. Among them, the mass ratio of dodecyl ester precursor and potassium hydroxide is 1:6. After the reaction stops, all solvents are dried and an appropriate amount of water is added to dissolve the solid. An appropriate amount of concentrated hydrochloric acid is added to the aqueous solution, and the pH is adjusted to 1-3, and a precipitate appears. The precipitate is filtered, washed with water, and dried to obtain a dodecyl carboxyl organic ligand H 12 HDTB, H NMR spectrum Figure 4 shown.

[0081] Embodiment 4:

[0082] Synthesis of copper MOF based on dodecacarboxyl organic ligand (Cu-HDTB-shp):

[0083] H 12 HDTB (30 mg) and Cu(NO3)2·3H2O (60 mg) were dissolved in N,N-dimethylformamide (2 mL), and 1,4-dioxane (0.5 mL) and water (1 mL) were added. Then, 6 drops of concentrated hydrochloric acid were dripped into the mixed solution. After mixing evenly, the container was sealed and placed in an oven at 75°C. After 12 hours, a blue solid precipitated. The mother liquor in the container was removed, and N,N-dimethylformamide was added to soak the product. Clean N,N-dimethylformamide was replaced after each soaking for 5 to 10 hours. This process was repeated 4 to 6 times, and the product was placed in acetone to exchange and remove N,N-dimethylformamide. Each soaking time in acetone is 3 to 6 hours, and 8 to 10 exchanges of acetone are required. Then, vacuum degassing and activation were carried out at 100°C for 12 to 15 hours to obtain Cu-HDTB-shp, and the crystal structure is as follows Figure 5 The Cu-HDTB-shp activated in this example was subjected to a 77K nitrogen adsorption-desorption experiment under liquid nitrogen conditions. The results are shown in Fig. 9 shown. Fig.13 The PXRD test results of Cu-HDTB-shp prepared in this example are shown, which are basically consistent with the peak position of the simulated PXRD curve, indicating that the designed MOF is successfully prepared with high phase purity.

[0084] The single crystal structure data of the copper MOF based on dodecacarboxyl organic ligand (Cu-HDTB-shp) is shown in Table 1.

[0085] Table 1

[0086]

[0087] Embodiment 5:

[0088] Synthesis of indium MOF based on dodecacarboxyl organic ligand (In-HDTB-shp):

[0089] H 12 HDTB (30 mg), In(NO3)3·5H2O (90 mg) were dissolved in N,N-dimethylformamide (2 mL), and 1,4-dioxane (0.5 mL) and water (0.5 mL) were added. Subsequently, 0.3 mL of concentrated hydrochloric acid was added to the mixed solution. After mixing evenly, the container was sealed and placed in an oven at 120°C. After 24 hours, a white solid precipitated. The mother liquor in the container was removed, and N,N-dimethylformamide was added to soak the product. Clean N,N-dimethylformamide was replaced after each soaking for 5 to 10 hours. This process was repeated 4 to 6 times, and the product was placed in acetone to exchange and remove N,N-dimethylformamide. Each soaking time in acetone is 3 to 6 hours, and 8 to 10 exchanges of acetone are required. Then, vacuum degassing and activation were performed at 100°C for 12 to 15 hours to obtain In-HDTB-shp, and the crystal structure is as follows Figure 6 The activated In-HDTB-shp in this example was subjected to a 77K nitrogen adsorption-desorption experiment under liquid nitrogen conditions. The results are shown in Fig.10 shown. Fig.14 The PXRD test results of In-HDTB-shp prepared in this example are shown, which are basically consistent with the peak position of the PXRD curve obtained by simulation, indicating that the designed MOF is successfully prepared with high phase purity.

[0090] The single crystal structure data of indium MOF based on dodecacarboxyl organic ligand (In-HDTB-shp) is shown in Table 2.

[0091] Table 2

[0092]

[0093] Embodiment 6:

[0094] Synthesis of zirconium MOF based on dodecacarboxyl organic ligand (Zr-HDTB-alb):

[0095] H 12HDTB (30 mg) and ZrCl4 (60 mg) were dissolved in N,N-dimethylformamide (2 mL), and then formic acid (2 mL) was added. After mixing evenly, the container was sealed and placed in an oven at 130°C. After 24 hours, a white solid precipitated. The mother liquor in the container was removed, and N,N-dimethylformamide was added to soak the product. Clean N,N-dimethylformamide was replaced after each soaking for 5 to 10 hours. This process was repeated 4 to 6 times, and the product was placed in acetone to exchange and remove N,N-dimethylformamide. Each soaking time in acetone is 3 to 6 hours, and 8 to 10 exchanges of acetone are required. Then, vacuum degassing and activation were performed at 100°C for 12 to 15 hours to obtain Zr-HDTB-alb, and the crystal structure is as follows Figure 7 The activated Zr-HDTB-alb in this example was subjected to a 77K nitrogen adsorption-desorption experiment under liquid nitrogen conditions. The results are shown in Fig.11 shown. Fig.15 The PXRD test results of Zr-HDTB-alb prepared in this example are shown, which are basically consistent with the peak position of the PXRD curve obtained by simulation, indicating that the designed MOF is successfully prepared with high phase purity.

[0096] The single crystal structure data of the zirconium MOF based on dodecacarboxyl organic ligand (Zr-HDTB-alb) is shown in Table 3.

[0097] Table 3

[0098]

[0099] The Zr-HDTB-alb framework is relatively stable, and adsorption-desorption experiments of methane, ethane, propane, n-butane, and isobutane were carried out at 298K. Fig.17 As shown in the figure, the material has a low adsorption capacity for methane, but a high adsorption capacity for ethane, propane, and n-butane, and has the potential to selectively adsorb and separate the mixed gas. At the same time, n-butane and isobutane also show significantly different adsorption capacities, and an obvious screening effect is shown for isobutane. The results are shown in Fig.18 shown.

[0100] Embodiment 7:

[0101] Synthesis of iron MOF based on dodecacarboxyl organic ligand (Fe-HDTB-alb):

[0102] H 12HDTB (30 mg) and FeCl3·6H2O (60 mg) were dissolved in N,N-dimethylformamide (3 mL), and trifluoroacetic acid (1 mL) was added. After mixing evenly, the container was sealed and placed in an oven at 150°C. After 24 hours, a yellow solid precipitated. The mother liquor in the container was removed, and N,N-dimethylformamide was added to soak the product. Clean N,N-dimethylformamide was replaced after each soaking for 5 to 10 hours. This process was repeated 4 to 6 times, and the product was placed in acetone to exchange and remove N,N-dimethylformamide. Each soaking time in acetone is 3 to 6 hours, and 8 to 10 exchanges of acetone are required. Then, vacuum degassing and activation were performed at 100°C for 12 to 15 hours to obtain Fe-HDTB-alb, and the crystal structure is as follows Figure 8 The Fe-HDTB-alb activated in this example was subjected to a 77K nitrogen adsorption-desorption experiment under liquid nitrogen conditions. The results are shown in Fig.12 shown. Fig.16 The PXRD test results of Fe-HDTB-alb prepared in this example are shown, which are basically consistent with the peak position of the PXRD curve obtained by simulation, indicating that the designed MOF is successfully prepared with high phase purity.

[0103] The single crystal structure data of the iron MOF based on dodecacarboxyl organic ligand (Fe-HDTB-alb) is shown in Table 4.

[0104] Table 4

[0105]

[0106] The Fe-HDTB-alb framework is relatively stable, and adsorption-desorption experiments of methane, ethane, propane, n-butane, and isobutane were carried out at 298K. Fig.19 As shown in the figure, the material has a low adsorption capacity for methane, but a high adsorption capacity for ethane, propane, and n-butane, and has the potential to selectively adsorb and separate the mixed gas. At the same time, n-butane and isobutane also show significantly different adsorption capacities, and an obvious screening effect is shown for isobutane. The results are shown in Fig. 20 shown.

[0107] It can be seen that the material of the present invention exhibits a lower adsorption capacity for methane, and has a higher adsorption capacity for ethane, propane, and n-butane, showing a selective adsorption and separation effect for these gases. At the same time, due to its smaller pore size, isobutane cannot enter the interior of the material, and it exhibits a screening effect on isobutane. Therefore, the material of the present invention also has the potential to screen n-butane and isobutane.

[0108] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A metal organic framework material based on dodecacarboxyl organic ligands, characterized in that: It is obtained by reacting and coordinating the raw materials comprising the following composition: The dodecacarboxyl organic ligand H having the structure shown in the following formula (I): 12 HDTB: Metal ion: Cu 2+ 、In 3+ 、Zr 4+ , Fe 3+ At least one of .

2. The metal organic framework material based on dodecacarboxyl organic ligand according to claim 1, characterized in that: The metal organic framework material based on dodecacarboxyl organic ligands has a three-dimensional network structure, and its structure is as follows: in the framework, the six arms of the dodecacarboxyl organic ligands are uniformly deflected to the left or right, and the entire molecule is in the shape of a propeller, and each carboxyl group is coordinated with a metal cluster, wherein the copper cluster is a paddle-shaped four-connected binuclear copper cluster, the indium cluster is a tetrahedral four-connected mononuclear cluster, the zirconium ions form a six-connected hexanuclear zirconium cluster in an anti-triangular prism configuration, and the iron ions form a six-connected trinuclear iron cluster in a triangular prism configuration.

3. The method for preparing a metal organic framework material based on a dodecacarboxyl organic ligand according to claim 1 or 2, characterized in that: Includes steps: (1) Prepare an organic ligand containing dodecyl carboxyl group H 12 HDTB and N,N-dimethylformamide solution of the metal ions, with or without 1,4-dioxane and water, adding a regulator, and reacting at 75-150° C. in a sealed state; the regulator includes at least one of hydrochloric acid, formic acid, and trifluoroacetic acid; (2) The solid product obtained by the sealing reaction in step (1) is soaked in N,N-dimethylformamide and acetone in turn, and then vacuumed, degassed and activated to obtain the metal organic framework material based on dodecyl carboxyl organic ligand.

4. The preparation method according to claim 3, characterized in that: In step (1): The source of the metal ion is a metal salt, and the dodecacarboxyl organic ligand H 12 The mass ratio of HDTB to the metal salt is 1:2-4; The sealing reaction time is 12 to 48 hours.

5. Use of the metal organic framework material based on dodecacarboxyl organic ligand according to claim 1 or 2 for adsorbing gas.

6. The use of the metal organic framework material based on dodecacarboxyl organic ligand according to claim 1 or 2 for adsorption and separation of methane and C2-C4 alkanes, characterized in that: The C2-C4 alkane includes at least one of ethane, propane and n-butane.

7. Use of the metal organic framework material based on dodecacarboxyl organic ligand according to claim 1 or 2 for adsorption and separation of n-butane and isobutane.

8. A dodecacarboxyl organic ligand H having a structure as shown in the following formula (I): 12 HDTB:

9. The dodecacarboxyl organic ligand H according to claim 8 12 The method for preparing HDTB is characterized in that: include: 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) having a structure as shown in formula (II), dicobalt octacarbonyl, and 1,4-dioxane are added to a high-pressure reaction vessel in an anhydrous and oxygen-free environment, and heated at 120-130° C. for reaction. After the reaction is completed, the solvent is removed, and the solid crude product is purified to obtain a dodecyl ester precursor having a structure as shown in formula (III); The dodecyl ester precursor is hydrolyzed to obtain the dodecyl carboxyl organic ligand H 12 HDTB.

10. The preparation method according to claim 9, characterized in that: The preparation method of 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)) comprises: adding 1,2-bis(3,5-dibromophenyl)acetylene, 4-(methoxycarbonyl)phenylboric acid, potassium carbonate, tetrakis(triphenylphosphine)palladium, tetrahydrofuran and water into a reaction device under nitrogen conditions, heating the reaction at 80-90° C., washing the solid precipitate, and obtaining 5',5""-(acetylene-1,2-diyl)bis(([1,1':3',1"-terphenyl]-4,4"-dimethoxycarbonyl)).

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