Metal organic framework and gas adsorbing material

Abstract

To provide a novel metal organic framework and a gas adsorbing material containing the metal organic framework.SOLUTION: A metal organic framework in one aspect of the embodiment contains zinc (Zn) and at least one ligand selected from 4-methylimidazole (4-MeIm), imidazole (Im), and benzimidazole (BzIm). When a mole ratio of the 4-MeIm, Im, and BzIm is x:y:z (4-MeIm:Im:BzIm), the mole ratio x:y:z falls within a polygonal region (including on a boundary line) having following vertices in a ternary composition diagram: A (1:0:0), B (0.608:0.392:0), C (0.407:0.441:0.152), D (0.278:0.496:0.226), E (0:0.613:0.387), F (0:0.388:0.612), G (0.221:0.277:0.502), H (0.455:0.117:0.428), and I (0.563:0:0.437).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to metal-organic frameworks and gas adsorbents. [Background technology]

[0002] In recent years, research on metal-organic frameworks (MOFs) has been actively conducted. Among MOFs, metal-organic frameworks containing zinc and imidazoles, called zeolite-like imidazole frameworks (ZIFs), are known to have excellent thermal and chemical stability.

[0003] For example, Non-Patent Document 1 discloses that cag-type Zn(Im)2 exhibits N2 adsorption and desorption properties. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] J. Gandara-Loe et al., “New insights into the breathing phenomenon in ZIF-4”, J. Mater. Chem. A, 2019, 7. 14552-14558. Summary of the Invention [Problem to be solved by the invention]

[0005] The cag-type Zn(Im)2 disclosed in Non-Patent Document 1 had a problem in that the gas adsorption / desorption properties at low pressure were not high.

[0006] An object of the present disclosure is to provide a novel metal-organic framework and a gas adsorbent material comprising the metal-organic framework. [Means for solving the problem]

[0007] The present inventors have conducted intensive research to solve the above problems, and have found a novel metal-organic framework having a specific composition. The present inventors have also found that the novel metal-organic framework can be used as a gas adsorbent, which has led to the present disclosure.

[0008] An example aspect of this embodiment is described as follows.

[0009] (1) A metal-organic framework comprising zinc (Zn) and at least one ligand selected from 4-methylimidazole (4-MeIm), imidazole (Im), and benzimidazole (BzIm), When the molar ratio of 4-MeIm, Im, and BzIm is x:y:z (4-MeIm:Im:BzIm), the molar ratio x:y:z in the ternary composition diagram is: A(1:0:0), B(0.608:0.392:0), C(0.407:0.441:0.152), D(0.278:0.496:0.226), E(0:0.613:0.387), F(0:0.388:0.612), G(0.221:0.277:0.502), H(0.455:0.117:0.428), I(0.563:0:0.437), A metal-organic framework that is located within a polygonal region having vertices (including the boundary line). (2) The metal-organic framework according to (1), having an ACO type topology. (3) The metal organic framework according to (1), which exhibits diffraction peaks at diffraction angles (2θ) of at least 28.4±0.4°, 30.6±0.4°, and 35.2±0.4° in powder X-ray diffraction measurement using CuKα radiation with an X-ray wavelength of 1.5418 Å. (4) A gas adsorbent comprising the metal organic framework according to any one of (1) to (3). Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a novel metal-organic framework and a gas adsorbent including the metal-organic framework. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 shows a ternary composition diagram in which the compositions of 4-MeIm, Im, and BzIm constituting the products obtained in the Examples and Comparative Examples, as determined by 1H-NMR measurement, are plotted. [Diagram 2] FIG. 1 shows X-ray diffraction patterns of the products obtained in Examples 1 to 5 (a) and X-ray diffraction patterns of the products obtained in Examples 6 to 10 (b). [Diagram 3] FIG. 1 shows X-ray diffraction patterns of the products obtained in Examples 11 to 15 (c) and X-ray diffraction patterns of the products obtained in Examples 16 to 20 (d). [Figure 4] X-ray diffraction patterns of the products obtained in Comparative Examples 1 to 3 (e) and X-ray diffraction patterns of the products obtained in Comparative Examples 4 to 7 (f) are shown. [Diagram 5] 1 shows X-ray diffraction patterns of the products obtained in Comparative Examples 8 to 12. [Figure 6] 1 shows the N2 adsorption amounts at 77K of the products obtained in Examples 1, 4, 11, 15, and 16, and Comparative Examples 7 and 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The metal organic framework and gas adsorbent of this embodiment will be described in detail below. One aspect of this embodiment is a metal organic framework containing zinc (Zn) and at least one ligand selected from 4-methylimidazole (4-MeIm), imidazole (Im) and benzimidazole (BzIm), and when the molar ratio of 4-MeIm, Im and BzIm is x:y:z (4-MeIm:Im:BzIm), the molar ratio x:y:z in a ternary composition diagram is: A(1:0:0), B(0.608:0.392:0), C(0.407:0.441:0.152), D(0.278:0.496:0.226), E(0:0.613:0.387), F(0:0.388:0.612), G(0.221:0.277:0.502), H(0.455:0.117:0.428), I(0.563:0:0.437), The metal-organic framework is within a polygonal region (including the boundary line) having vertices of the metal-organic framework. Another aspect of the present embodiment is a gas adsorbent comprising the metal-organic framework.

[0013] (Metal-organic structure) Generally, a metal organic framework, also called MOF, is a material having a porous coordination network structure with a high surface area due to the interaction between a metal and an organic ligand. The metal organic framework of this embodiment is a metal organic framework containing zinc (Zn) and at least one ligand selected from 4-methylimidazole (4-MeIm), imidazole (Im) and benzimidazole (BzIm), and the molar ratio of the 4-MeIm, Im and BzIm is within the above-mentioned specific range. A metal organic framework in which the molar ratio of 4-MeIm, Im and BzIm is within the polygonal region (including the border line) with the nine vertices A to I in the ternary composition diagram is a novel substance and has excellent gas adsorption properties. For this reason, the metal organic framework of this embodiment is The metal-organic framework can be used as a gas adsorbent.

[0014] In the metal-organic framework, zinc is usually ionized as a zinc cation, specifically a divalent cation (Zn 2+ In metal-organic frameworks, 4-methylimidazole (4-MeIm), imidazole (Im) and benzimidazole (BzIm) are usually present as monovalent anions (4-MeIm, - ,Im - , BzIm -In other words, in the present disclosure, a metal organic framework including zinc (Zn) and at least one ligand selected from 4-methylimidazole (4-MeIm), imidazole (Im), and benzimidazole (BzIm) can also be read as a metal organic framework including a cation of zinc (Zn) and a ligand of an anion of at least one imidazole selected from 4-methylimidazole (4-MeIm), imidazole (Im), and benzimidazole (BzIm).

[0015] In addition, in the metal organic framework of this embodiment, when the molar ratio of 4-MeIm, Im, and BzIm is x:y:z (4-MeIm:Im:BzIm), the molar ratio x:y:z in the ternary composition diagram is A(1:0:0), B''(0.655:0.345:0), C''(0.195:0.526:0.279), D''(0:0.535:0.465), E''(0:0.438:0.562), F''(0.161:0.321:0.518), G''(0.629:0:0.371), From the viewpoint of gas adsorption, it is more preferable that the metal organic framework is within a polygonal region having vertices (including the boundary line).

[0016] The metal organic framework of the present embodiment is one of the preferred embodiments having an ACO type topology. Having an ACO type topology is preferred from the viewpoint of gas adsorption. The metal organic framework having an ACO type topology can be confirmed, for example, by the method described in the Examples, that is, by powder X-ray diffraction measurement. In addition, when the metal organic framework of the present embodiment has an ACO type topology, it includes a case where it has only an ACO type topology and a case where it has an ACO type topology and another structure, for example, an unknown structure described later.

[0017] The metal organic framework of the present embodiment is one of the preferred embodiments in which, in powder X-ray diffraction measurement using CuKα radiation with an X-ray wavelength of 1.5418 Å, diffraction peaks appear at diffraction angles (2θ) of at least 28.4±0.4°, 30.6±0.4°, and 35.2±0.4°. Note that a metal organic framework containing zinc and at least one ligand selected from 4-methylimidazole, imidazole, and benzimidazole, in which the diffraction peaks appear, is not known, and the diffraction peaks represent an unknown structure. Powder X-ray diffraction measurement can be performed, for example, by the method described in the Examples. Note that when the metal organic framework of the present embodiment has the unknown structure, this includes a case in which it has only an unknown structure, and a case in which it has an unknown structure and another structure, for example, an ACO-type topology.

[0018] There is no particular limitation on the method for producing the metal organic framework of this embodiment. For example, a zinc oxide powder, at least one imidazole selected from 4-methylimidazole, imidazole, and benzimidazole, and hard balls such as zirconia balls are added to a ball mill container together with a solvent as necessary, and mechanically mixed using a ball mill to synthesize the metal organic framework. An example of the solvent is N,N-dimethylformamide. A specific example of the method for producing the metal organic framework of this embodiment is Examples of the method include the method described in the Examples. In this method, oxygen ions of zinc oxide and hydrogen ions of imidazoles are eliminated, and water is obtained as a by-product. After synthesis, water, solvent, etc. are removed to obtain the metal organic framework of this embodiment. The amounts of zinc oxide, imidazoles, etc. used as raw materials can be appropriately set with reference to the values ​​in the Examples described later.

[0019] (Gas adsorbent) The gas adsorbent of the present embodiment includes the metal organic framework of the present embodiment described above. The gas adsorbent of the present embodiment is one of the preferred embodiments in which the gas adsorbent is the metal organic framework of the present embodiment described above.

[0020] The gas adsorbent of this embodiment may contain other components, for example, metals such as manganese (Mn), iron (Fe), or cobalt (Co), or organic substances such as 2-methylimidazole (2-MeIm), 4-ethylimidazole (4-EtIm), 2-methylbenzimidazole (2-MeBzIm), or 5-methylbenzimidazole (5-MeBzIm), etc. In addition, the metal organic framework may be supported on another material.

[0021] The gas adsorbent of this embodiment can adsorb various gaseous substances, for example, nitrogen gas and organic substances. Examples of organic substances include methane, ethane, propane, and butane. The gas adsorbent can be used for various purposes. Examples of applications of the gas adsorbent include a gas adsorption system using the gas adsorbent, a gas separation system using the gas adsorbent, and a gas storage system using the gas adsorbent. EXAMPLES

[0022] The present embodiment will be described below with reference to examples, but the present disclosure is not limited to these examples.

[0023] [reagent] The following reagents were used in the Examples and Comparative Examples. Zinc oxide (ZnO): Fujifilm Wako Pure Chemical Industries, Ltd. 0.02μm Practical Grade 95.0+% 4-Methylimidazole (4-MeIm): Tokyo Chemical Industry Co., Ltd. >98.0% Imidazole (Im): Tokyo Chemical Industry Co., Ltd. >98.0% Benzimidazole (BzIm): Tokyo Chemical Industry Co., Ltd. >98.0% Ethanol (EtOH): Kanto Chemical Co., Ltd. Special grade 94.8%~95.8% N,N-Dimethylformamide (DMF): Fujifilm Wako Pure Chemical Industries, Ltd., ultra-dehydrated, for organic synthesis, 99.5+%

[0024] [Example 1] Into a 45 mL ball mill container were added 1.221 g (15 mmol) of zinc oxide, 2.463 g (30 mmol) of 4-methylimidazole, 3 mL of N,N-dimethylformamide, and 50 g of zirconia balls having a diameter of 5 mm.

[0025] The ball mill container was set in a planetary ball mill apparatus and rotated at 700 rpm for 3 hours. The contents were recovered from the ball mill container, and the zirconia balls were removed.

[0026] 50 mL of ethanol was added to the content, stirred, centrifuged at 16,000 rpm for 15 minutes, and the supernatant was removed. The procedure of adding the ethanol, centrifuging, and removing the supernatant was repeated a total of four times. The supernatant was removed and the recovered precipitate was dried overnight at 60° C. under reduced pressure to obtain a powder.

[0027] [Example 2] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 2.155 g (26.25 mmol) of 4-methylimidazole and 0.255 g (3.75 mmol) of imidazole.

[0028] [Example 3] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.847 g (22.5 mmol) of 4-methylimidazole, 0.255 g (3.75 mmol) of imidazole, and 0.443 g (3.75 mmol) of benzimidazole.

[0029] [Example 4] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.847 g (22.5 mmol) of 4-methylimidazole and 0.886 g (7.5 mmol) of benzimidazole.

[0030] [Example 5] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.539 g (18.75 mmol) of 4-methylimidazole, 0.511 g (7.5 mmol) of imidazole, and 0.443 g (3.75 mmol) of benzimidazole.

[0031] [Example 6] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.232 g (15 mmol) of 4-methylimidazole, 0.766 g (11.25 mmol) of imidazole, and 0.443 g (3.75 mmol) of benzimidazole.

[0032] [Example 7] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.232 g (15 mmol) of 4-methylimidazole, 0.511 g (7.5 mmol) of imidazole, and 0.886 g (7.5 mmol) of benzimidazole.

[0033] [Example 8] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.924 g (11.25 mmol) of 4-methylimidazole, 1.021 g (15 mmol) of imidazole, and 0.443 g (3.75 mmol) of benzimidazole.

[0034] [Example 9] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.924 g (11.25 mmol) of 4-methylimidazole, 0.511 g (7.5 mmol) of imidazole, and 1.329 g (11.25 mmol) of benzimidazole.

[0035] [Example 10] 2.463 g (30 mmol) of 4-methylimidazole was added to 0. A powder was obtained in the same manner as in Example 1, except that the amounts of the benzene ring and the benzene pipette were changed to 821 g (10 mmol), 0.681 g (10 mmol), imidazole, and 1.181 g (10 mmol), respectively.

[0036] [Example 11] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.616 g (7.5 mmol) of 4-methylimidazole, 1.021 g (15 mmol) of imidazole, and 0.886 g (7.5 mmol) of benzimidazole.

[0037] [Example 12] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.616 g (7.5 mmol) of 4-methylimidazole, 0.766 g (11.25 mmol) of imidazole, and 1.329 g (11.25 mmol) of benzimidazole.

[0038] [Example 13] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.308 g (3.75 mmol) of 4-methylimidazole, 0.766 g (11.25 mmol) of imidazole, and 1.772 g (15 mmol) of benzimidazole.

[0039] [Example 14] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.277 g (18.75 mmol) of imidazole and 1.329 g (11.25 mmol) of benzimidazole.

[0040] [Example 15] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.021 g (15 mmol) of imidazole and 1.772 g (15 mmol) of benzimidazole.

[0041] [Example 16] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.847 g (22.5 mmol) of 4-methylimidazole and 0.511 g (7.5 mmol) of imidazole.

[0042] [Example 17] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.539 g (18.75 mmol) of 4-methylimidazole and 0.766 g (11.25 mmol) of imidazole.

[0043] [Example 18] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.539 g (18.75 mmol) of 4-methylimidazole and 1.329 g (11.25 mmol) of benzimidazole.

[0044] [Example 19] 2.463 g (30 mmol) of 4-methylimidazole was mixed with 1.232 g (15 mmol) of 4-methylimidazole, 0.255 g (3.75 mmol) of imidazole and benzoyl A powder was obtained in the same manner as in Example 1, except that the amount of midazole was changed to 1.329 g (11.25 mmol).

[0045] [Example 20] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.308 g (3.75 mmol) of 4-methylimidazole, 1.277 g (18.75 mmol) of imidazole, and 0.886 g (7.5 mmol) of benzimidazole.

[0046] [Comparative Example 1] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.232 g (15 mmol) of 4-methylimidazole and 1.772 g (15 mmol) of benzimidazole.

[0047] [Comparative Example 2] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.616 g (7.5 mmol) of 4-methylimidazole, 0.511 g (7.5 mmol) of imidazole, and 1.7726 g (15 mmol) of benzimidazole.

[0048] [Comparative Example 3] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.766 g (11.25 mmol) of imidazole and 2.215 g (18.75 mmol) of benzimidazole.

[0049] [Comparative Example 4] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.616 g (7.5 mmol) of 4-methylimidazole, 0.255 g (3.75 mmol) of imidazole, and 2.215 g (18.75 mmol) of benzimidazole.

[0050] [Comparative Example 5] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.616 g (7.5 mmol) of 4-methylimidazole and 2.658 g (22.5 mmol) of benzimidazole.

[0051] [Comparative Example 6] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.511 g (7.5 mmol) of imidazole and 2.658 g (22.5 mmol) of benzimidazole.

[0052] [Comparative Example 7] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 3.544 g (30 mmol) of benzimidazole.

[0053] [Comparative Example 8] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.232 g (15 mmol) of 4-methylimidazole and 1.021 g (15 mmol) of imidazole.

[0054] [Comparative Example 9] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.616 g (7.5 mmol) of 4-methylimidazole and 1.532 g (22.5 mmol) of imidazole.

[0055] [Comparative Example 10] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 0.616 g (7.5 mmol) of 4-methylimidazole, 1.277 g (18.75 mmol) of imidazole, and 0.443 g (3.75 mmol) of benzimidazole.

[0056] [Comparative Example 11] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 2.042 g (30 mmol) of imidazole.

[0057] [Comparative Example 12] A powder was obtained in the same manner as in Example 1, except that 2.463 g (30 mmol) of 4-methylimidazole was changed to 1.532 g (22.5 mmol) of imidazole and 0.886 g (7.5 mmol) of benzimidazole.

[0058] [Analysis and evaluation of products] ( 1 H-NMR measurement) The powder (product, MOF) obtained in each Example and Comparative Example was decomposed and dissolved in a heavy solvent, and then the solution was 1 The H-NMR spectrum was measured, and the ratios of 4-methylimidazole (4-MeIm), imidazole (Im), and benzimidazole (BzIm) contained in the product were calculated from the integral ratio. The ratios of each component were calculated assuming that the total of 4-MeIm, Im, and BzIm was 100 mol%.

[0059] The decomposition conditions and the measuring device are shown below. Decomposition conditions: Decompose the product with a 10 wt% solution of bisulfuric acid (D2SO4) in heavy water (D2O). Measurement equipment: INOVA300 (Agilent Technologies)

[0060] (X-ray diffraction measurement) The powders (products, MOFs) obtained in each of the Examples and Comparative Examples were subjected to X-ray diffraction measurement to confirm the crystal structure.

[0061] The measurement apparatus and conditions are as follows. Measurement equipment: RINT RAPID II (Rigaku Corporation) Measurement conditions: voltage 50V, current 100mA, collimator diameter φ0.3, sample angle ω5°, CuKα radiation with X-ray wavelength of 1.5418Å

[0062] X-ray diffraction patterns were simulated for ACO-type Zn(4-MeIm)2, cag-type Zn(Im)2, and SOD-type Zn(BzIm)2, and compared with the products. Note that cag-type Zn(Im)2 is a known substance reported under the name ZIF-4, and SOD-type Zn(BzIm)2 is a known substance reported under the name ZIF-7 (or ZIF-7-I).

[0063] (N2 adsorption isotherm measurement) The products obtained in Examples 1, 4, 11, 15, and 16, and Comparative Examples 7 and 11 were pretreated under the following conditions, and then the N2 adsorption isotherms were measured. The amount of N2 adsorption at a pressure of 0.01% was calculated as the amount of N2 adsorption.

[0064] The pretreatment device, pretreatment conditions, measurement device and measurement conditions are shown below. Pretreatment device: BELPREP vacII (Microtrack BEL Co., Ltd.) Pretreatment conditions: Vacuum degree < 10 -2Pa, heated at 160°C for 6 hours Measuring device: BELSORP max (Microtrack BEL Co., Ltd.) Measurement conditions: Temperature 77K, N2 adsorption amount measured at N2 relative pressure 0-99%

[0065] When the equilibrium determination time during measurement was long and the liquid nitrogen for cooling ran out, the measurement was interrupted, and for such samples, the adsorption isotherm up to a relative N2 pressure of 100% was not measured.

[0066] The composition (amount) of 4-MeIm, Im and BzIm used in each Example and Comparative Example, and the amounts of 4-MeIm, Im and BzIm used in each product obtained 1 The compositions (analysis results) determined by H-NMR measurement and the crystal structures of the products are shown in Tables 1 and 2. FIG. 1 shows the crystal structures of 4-MeIm, Im, and BzIm constituting the products obtained in the examples and comparative examples. 1 The compositions obtained from H-NMR measurements are plotted on a ternary composition diagram. In FIG. 1, ◯ means ACO type, △ means unknown structure, ◇ means cag type, and × means SOD type. X-ray diffraction patterns obtained by X-ray diffraction measurements of the products of each Example and Comparative Example are shown in FIG. 2 to FIG. 5. In addition, FIG. 2 to FIG. 5 also show the results of simulating the X-ray diffraction patterns for ACO type Zn(4-MeIm)2, cag type Zn(Im)2, and SOD type Zn(BzIm)2. In addition, FIG. 6 shows the N2 adsorption amounts at 77K of the products obtained in Examples 1, 4, 11, 15, and 16, and Comparative Examples 7 and 11.

[0067] [Table 1]

[0068] [Table 2]

[0069] The upper and / or lower limit values ​​of the numerical ranges described in this specification can be arbitrarily combined to define a preferred range. For example, the upper and lower limit values ​​of the numerical ranges can be arbitrarily combined to define a preferred range. The upper limits of the numerical ranges can be combined in any combination to define a preferred range, and the lower limits of the numerical ranges can be combined in any combination to define a preferred range.

[0070] Although the present embodiment has been described in detail above, the specific configuration is not limited to this embodiment, and even if there are design changes within the scope that does not deviate from the gist of this disclosure, they are included in this disclosure.

Claims

1. A metal organic framework comprising zinc (Zn) and at least one ligand selected from 4-methylimidazole (4-MeIm), imidazole (Im) and benzimidazole (BzIm), When the molar ratio of 4-MeIm, Im, and BzIm is x:y:z (4-MeIm:Im:BzIm), the molar ratio x:y:z in the ternary composition diagram is: A(1:0:0), B (0.608:0.392:0), C (0.407:0.441:0.152), D (0.278:0.496:0.226), E (0:0.613:0.387), F (0:0.388:0.612), G (0.221:0.277:0.502), H (0.455:0.117:0.428), I (0.563:0:0.437), The metal-organic framework is located within a polygonal region having vertices (including the boundary line).

2. 2. The metal-organic framework of claim 1, having an ACO type topology.

3. 2. The metal organic framework according to claim 1, wherein in powder X-ray diffraction measurement using CuKα radiation having an X-ray wavelength of 1.5418 Å, diffraction peaks appear at diffraction angles (2θ) of at least 28.4±0.4°, 30.6±0.4°, and 35.2±0.4°.

4. A gas adsorbent comprising the metal organic framework according to claim 1 or 2.

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