Metal organic structure and production method for same

Abstract

The present invention provides: a metal organic structure which includes an amorphous phase and has gas adsorption / desorption hysteresis ability; and a production method for preparing the metal organic structure by aqueous synthesis. This metal organic structure is composed of a metal hydrate and an organic ligand that can be bidentately coordinated with the metal hydrate, the metal organic structure being characterized in that the metal hydrate is either a zirconium hydrate, an aluminum hydrate, or a zinc hydrate, and that the metal organic structure includes an amorphous phase, and also has gas adsorption / desorption hysteresis ability.

Description

Metal organic framework and method for producing the same

[0001] The present invention relates to a metal-organic framework and a manufacturing method thereof, and more particularly to a metal-organic framework prepared by aqueous synthesis, which contains an amorphous phase and has hysteresis capability in gas adsorption / desorption, and a manufacturing method thereof.

[0002] Metal-organic frameworks (MOFs) consisting of a central metal and a multidentate organic ligand coordinated thereto are porous three-dimensional structures formed by the accumulation of metal complexes consisting of a central metal and organic ligands. Unlike other porous materials such as zeolites and activated carbons, the pores of metal-organic frameworks have pore sizes and internal pore spaces that can be designed, and many types have been reported based on the combination of metal ions and organic ligands. Metal-organic frameworks have pore sizes of approximately 0.3 nm to approximately 3 nm and specific surface areas of approximately 1,000 m. ２ / g ~ approx. 2000m ２ / g to a maximum of 5000m ２ / g or more have been reported, and development has been promoted to use them as adsorbents for various components according to the various pore sizes.

[0003] Metal-organic frameworks are generally produced by reacting metal ions with an organic compound that serves as a ligand in an organic solvent. For example, in Patent Document 1, a hydrated nitrate salt and an imidazole-type organic compound are mixed in N,N-diethylformamide, and the resulting solution is then heated at 85 to 150°C for 48 to 96 hours to obtain a zeolite-type imidazolate framework (ZIF).

[0004] In addition, Patent Document 2 below discloses a compound having a UiO-66 structure as a basic skeleton, ６ O ４ (OH) ４(L) (wherein Me is Zr or Ti, and L is a ligand (N) derived from a nitrogen-containing aromatic heterocyclic dicarboxylic acid and a ligand (C) derived from an aromatic dicarboxylic acid), in which the molar ratio of the ligand (N) to the ligand (C) is 10:90 to 60:40. Furthermore, Patent Document 3 listed below describes a Zr-MOF having open metal sites, which is obtained by mixing zirconyl chloride with a binding ligand in dimethylformamide, adding formic acid, heating the mixture at about 140°C for about 2 days, and then separating the mixture.

[0005] The metal organic framework described in Patent Document 2 requires, during its production, heat treatment of a metal compound and a nitrogen-containing aromatic heterocyclic dicarboxylic acid or the like serving as an organic ligand in an organic solvent such as dimethylformamide at a temperature of 120 to 160°C for 2 to 10 hours. The metal organic framework described in Patent Document 3 also relates to a metal organic framework based on zirconium terephthalate, but the pores and surface area of ​​the structure are adjusted by heating at high temperature in an organic solvent using a template agent. Therefore, from the perspective of environmental impact, a method for producing a new metal organic framework is desired that does not require heat treatment under high temperature conditions using an organic solvent or the use of a template agent.

[0006] As a liquid phase synthesis method for a metal organic framework, in addition to the synthesis method using an organic solvent at high temperature as described in Patent Documents 2 and 3, synthesis methods using a water / alcohol solvent at high temperature, high pressure, or normal pressure are also known. For example, Patent Document 4 listed below proposes a method for producing a porous metal complex consisting of a three-dimensional porous framework structure of a metal complex comprising a central metal and an organic ligand, which method comprises preparing a salt of the organic ligand as a first metal salt, preparing a salt of the central metal as a second metal salt, and reacting the first and second metal salts. It describes that in this method, a solvent selected from a group of solvents including N,N'-dimethylformamide, N,N'-diethylformamide, water, and alcohols can be used as the solvent.

[0007] Furthermore, Patent Document 5 listed below describes a method for preparing a metal-organic framework composition, comprising: (a) forming a reaction mixture of a metal compound whose metal is selected from Zr, V, Al, Fe, Cr, Ti, Hf, Cu, Zn, Ni, Ce, and mixtures thereof; one or more ligands selected from at least one amino-containing organic ligand or a combination of at least one amino-containing organic ligand and at least one non-amino-containing organic ligand; a solvent selected from dimethylformamide, water, ethanol, isopropanol, and mixtures thereof; and a modifier comprising at least one monocarboxylic acid; b) reacting the reaction mixture at a certain temperature and for a certain time to form a MOF; c) isolating the MOF to obtain a powder of the MOF; and d) washing the MOF powder with an acid wash containing at least one inorganic acid to obtain a MOF characterized by having activated amino groups and an average crystal size of greater than 1 μm.

[0008] US Patent Application Publication No. 2007 / 202038 JP 2017-88542 A JP 2020-532499 A JP 2006-328051 A JP 2023-519685 A

[0009] In the methods for producing metal organic frameworks described in Patent Documents 4 and 5, when alcohols or the like are used as a solvent, metal organic frameworks are obtained by heat treatment at relatively low temperatures, but the metal organic frameworks obtained by these methods have only micropores, and in Patent Document 5, the pore size is adjusted by using a regulator. The adsorption performance of porous materials is represented by adsorption / desorption isotherms, and is classified into types I to VI by IUPAC. The phenomenon in which the adsorption and desorption processes do not coincide is called hysteresis, and is known to be characteristic of porous materials having micropores or mesopores, and it is expected that metal organic frameworks will also have such hysteresis ability.

[0010] Therefore, an object of the present invention is to provide a metal-organic framework that contains an amorphous phase and has hysteresis capability in gas adsorption / desorption. Another object of the present invention is to provide a production method that can prepare a metal-organic framework having the above characteristics by aqueous synthesis, which can reduce the environmental load.

[0011] According to the present invention, there is provided a metal-organic framework comprising a metal hydrate and an organic ligand capable of bidentate coordination with the metal hydrate, wherein the metal hydrate is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate, the metal-organic framework contains an amorphous phase, and has hysteresis capability in gas adsorption and desorption.

[0012] In the metal organic framework of the present invention, it is preferable that: (1) the hysteresis ability is manifested in a relative pressure range of 0.4 to 1.0 and is any one of H1, H2, and H4 hysteresis ability derived from mesopores and / or micropores, or low-pressure hysteresis ability; and (2) the organic ligand is at least one of terephthalic acid salt, a terephthalic acid derivative salt, a terephthalic acid salt derived from a recycled polyethylene terephthalate material, and an anion derived from an organic acid.

[0013] The present invention also provides a method for producing the above-mentioned metal organic framework, comprising: step A of preparing a first solution comprising a metal hydrate and an aqueous solvent; step B of preparing a second solution comprising an organic ligand capable of coordinating to a metal ion derived from the metal hydrate and an aqueous solvent; and step C of mixing the first solution and the second solution while applying shear, wherein steps A to C are carried out under conditions of room temperature and atmospheric pressure, and the metal hydrate is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate.

[0014] In the method for producing a metal organic framework of the present invention, it is preferable that: (1) the organic ligand is at least one of a terephthalate salt, a terephthalic acid derivative salt, a terephthalate salt derived from recycled polyethylene terephthalate, and an anion derived from an organic acid; (2) the aqueous solvent of the first solution is an aqueous solvent containing water, an alcohol, and / or an alkali metal hydroxide; (3) the organic ligand includes an organic ligand having an amino group; (4) the aqueous solvent of the second solution is an aqueous solvent containing water, an alcohol, and / or an alkali metal hydroxide, or water; and (5) the content of the organic ligand in the second solution is 0.25 to 1.50 mol per 1 mol of the metal hydrate in the first solution.

[0015] The metal organic framework of the present invention has a hysteresis function in gas adsorption / desorption, and therefore has the characteristics of being able to increase the maximum adsorption amount of an adsorbate (gas) and being able to support the adsorbate (gas) for a long period of time compared to a metal organic framework that does not have a hysteresis function. Furthermore, in the method for producing a metal organic framework of the present invention, a metal organic framework having the above properties can be produced by carrying out a reaction between a metal ion and an organic compound that serves as a ligand using an aqueous solvent under conditions of room temperature and normal pressure, and this also has the advantage of imposing little burden on the environment.

[0016] FIG. 1 shows the classification of hysteresis patterns according to IUPAC.

[0017] (Metal-organic framework) The metal-organic framework of the present invention is a metal-organic framework comprising a metal hydrate and an organic ligand capable of bidentate coordination with the metal hydrate, wherein the metal hydrate is any one of zirconium hydrate, aluminum hydrate, or zinc hydrate, contains an amorphous phase, and exhibits hysteresis in gas adsorption and desorption. As described above, in the IUPAC classification of adsorption and desorption isotherms, particularly in type IV and type V isotherms, a phenomenon in which the adsorption and desorption processes do not coincide (hysteresis) occurs, and this hysteresis is said to be primarily associated with capillary condensation in the mesopore region. Furthermore, the hysteresis observed in the above-mentioned types IV and V isotherms is classified by IUPAC into patterns H1 to H4, as shown in Figure 1. Generally, type H1 refers to an aggregate or agglomerate of spherical particles, type H2 refers to a case where the aggregate cannot be classified into types H1, H3, and H4, type H3 refers to a case where the aggregate has slit-type pores or pores with sufficiently narrow entrances and wide depths, and type H4 refers to a case where the aggregate has slit-type pores and both mesopores and micropores. The dashed lines in Figure 1 indicate cases of low-pressure hysteresis. The hysteresis ability possessed by the metal organic framework of the present invention is preferably one of H1, H2, and H4 hysteresis abilities derived from mesopores and / or micropores, or low-pressure hysteresis ability, which is expressed in a relative pressure range of 0.4 to 1.0. Metal organic frameworks having such hysteresis ability have a larger maximum adsorption capacity and the ability to support adsorbed gases in the pores, compared to metal organic frameworks not having hysteresis ability.

[0018] Furthermore, an important feature of the metal organic framework of the present invention is that it contains an amorphous portion. That is, while general metal organic frameworks are crystalline porous coordination polymers, the metal organic framework of the present invention has a unique structure in which it contains an amorphous portion. In the present invention, whether the metal organic framework contains an amorphous portion can be determined by powder X-ray diffraction measurement (PXRD measurement) or thermogravimetry (TG measurement). That is, the meaning of "amorphous" in the present invention means that the diffraction peak in powder X-ray diffraction measurement (PXRD measurement) is a broad peak between 5° and 80° in 2Θ, and the position of the highest broad peak, where the half-width of the peak at half the height of the difference between the baseline of the broad peak and the peak height is 0.2° or more, is between 5° and 45° in 2Θ, or that the thermogravimetric change curve in thermogravimetry (TG measurement) exhibits a gradual decrease in temperature in the temperature range of 200°C to 500°C.

[0019] The types of pores possessed by the metal organic framework in this specification were measured by measuring the adsorption isotherm of nitrogen gas at liquid nitrogen temperature by a multipoint method using a BELSORP-max II model manufactured by Microtrackbell, as shown in the examples described later, to evaluate the gas adsorption and desorption behavior, and also by evaluating the pore structure by the t method, the MP method, or the BJH method.

[0020] The central metal of the metal organic framework of the present invention is composed of a metal hydrate, and examples of the metal of this metal hydrate include zirconium, aluminum, zinc, etc., and zirconium is particularly preferred. Examples of suitable metal hydrates include zirconium oxide chloride octahydrate, aluminum nitrate nonahydrate, and zinc nitrate hexahydrate.

[0021] On the other hand, the organic compound serving as the organic ligand is an organic compound capable of forming a coordinate bond with the metal ion, and is particularly preferably an organic compound having a ring structure. Examples of ring structures include aromatic rings, cyclorings, and heterocyclic rings, with aromatic rings being particularly preferred. The aromatic ring may be a benzene ring, a naphthalene ring, an anthracene ring, or a bonded polycyclic compound in which two or more aromatic rings are bonded, such as biphenyl or ortho-terphenyl. Suitable aromatic organic compounds include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydroisophthalic acid, and 1,2-cyclohexenedicarboxylic acid; or derivatives or anions thereof. Terephthalic acid, terephthalic acid derivatives, and at least one of these anions are particularly preferred.

[0022] In the present invention, the terephthalic acid that can be suitably used as an organic ligand is particularly preferably terephthalic acid derived from recycled polyethylene terephthalate from an environmental viewpoint. Such recycled materials include, for example, polyesters recycled by mechanical recycling, typically polyesters recycled by crushing and purifying collected polyester bottles, and these polyesters generally contain terephthalic acid and isophthalic acid. Such recycled terephthalic acid can be used alone or in combination with virgin terephthalic acid.

[0023] (Method for Producing a Metal-Organic Framework) The method for producing a metal-organic framework of the present invention comprises step A of preparing a first solution comprising a metal hydrate and an aqueous solvent, step B of preparing a second solution comprising an organic ligand capable of coordinating to a metal ion derived from the metal hydrate and an aqueous solvent, and step C of mixing the first solution and the second solution while applying shear, and an important feature is that steps A to C are carried out under conditions of room temperature and atmospheric pressure. As described above, in the metal-organic framework of the present invention, it is preferable that the metal hydrate constituting the central metal is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate, and it is preferable that the organic ligand is at least one of terephthalate, a terephthalic acid derivative salt, a terephthalate derived from a recycled polyethylene terephthalate material, and an anion derived from an organic acid.

[0024] [Step A] In the above-mentioned step A, a first solution consisting of a metal hydrate and an aqueous solvent is prepared. In step A, it is preferable to use water or a mixed solvent of water and an alcohol as the aqueous solvent. Examples of alcohols include methanol, ethanol, n-propanol, and isopropanol, with methanol being particularly preferable. When a mixed solvent of water and an alcohol is used, the water:alcohol (mass ratio) is preferably in the range of 1:0.01 to 1:2, depending on the type of alcohol used. In step A, the first solution can be prepared by mixing for, for example, 1 to 30 minutes under room temperature and atmospheric pressure conditions. In this specification, room temperature (15 to 25°C) and atmospheric pressure conditions refer to a state in which neither heating nor pressure is intentionally applied, and are equivalent to room temperature and atmospheric pressure.

[0025] The content of the metal hydrate in the first solution prepared in step A is not limited as long as it is soluble in the aqueous solvent, but is preferably in the range of 50 to 200 mg / mL. The aqueous solvent used in step A may be water or a mixed solvent of water and alcohol, and may further contain an alkali metal hydroxide, as necessary. Examples of alkali metal hydroxides that can be contained in the aqueous solvent include sodium hydroxide and potassium hydroxide, and sodium hydroxide is particularly preferred.

[0026] [Step B] In Step B, a second solution is prepared, comprising an organic ligand capable of coordinating with metal ions derived from a metal hydrate and an aqueous solvent. As described above, the organic ligand in the metal-organic framework comprises an aromatic dicarboxylic acid or the like. However, in the metal-organic framework of the present invention, from the viewpoint of forming an amorphous phase, it is preferable to improve solubility in an aqueous solvent, and an alkali metal salt of an aromatic dicarboxylic acid or the like can be suitably used. Specifically, disodium terephthalate or the like can be suitably used. Furthermore, from the viewpoint of increasing the amorphous content of the metal-organic framework, it is suitable to contain an organic ligand having an amino group and / or a nitro group together with the organic ligand. Specifically, 2-aminoterephthalic acid and nitroterephthalic acid can be suitably used. The organic ligand having an amino group and / or a nitro group is suitably contained in an amount of 0.1 to 1.2 moles per mole of the organic ligand not having an amino group and / or a nitro group.

[0027] The aqueous solvent used in step B can be water, or an aqueous solvent composed of water and alcohols and / or an alkali metal hydroxide. However, it is preferable to use an aqueous solvent obtained by adding an alkali metal hydroxide to a mixed solvent of water and alcohols as needed. When an organic ligand having an amino group is contained as the organic ligand, not only a mixed solvent containing water and alcohols but also an aqueous solvent containing water alone or water and an alkali metal hydroxide can be suitably used. It is preferable to use the same alcohol as that used in step A. When a mixed solvent of water and alcohol is used, the water:alcohol (mass ratio) is preferably in the range of 1:0.01 to 1:0.50, depending on the type of alcohol used. Examples of alkali metal hydroxides that can be contained in the aqueous solvent include sodium hydroxide and potassium hydroxide, with sodium hydroxide being particularly suitable. The addition of an alkali metal hydroxide can improve the solubility of the organic ligand and increase the amorphous content of the metal-organic framework. When a mixed solvent of water and an alkali metal hydroxide is used, the amount of alkali metal hydroxide added is preferably in the range of 0.01 to 3.00 mol per 1 mol of the organic ligand content in the second solution. In step B, the second solution can also be prepared by mixing the components at room temperature and pressure for, for example, 1 to 30 minutes.

[0028] The content of the organic ligand in the second solution prepared in step B is preferably in the range of 0.25 to 1.50 mol, particularly 0.50 to 1.25 mol, per mol of the metal hydrate in the first solution. The organic ligand is preferably contained in the second solution at a concentration of 10 to 30 mg / mL.

[0029] [Step C] In step C, the first solution or the second solution obtained in step A or B is added to one of the solutions while applying shear to the other solution, thereby preparing a mixed solution of both at room temperature and atmospheric pressure. After preparing the mixed solution, the mixed solution is further stirred and mixed for 1 to 72 hours to produce the target metal-organic framework. In step C, the shear when adding the solution may be performed by stirring while applying shear force using a known method, and is not particularly limited. Examples of the shear may include stirring using a known stirrer such as an anchor mixer, a planetary mixer, or a Henschel mixer, as well as stirring using a stirrer. The metal-organic framework produced in the mixed solution prepared in step C can be separated by filtration from the mixed solution, and if necessary, raw materials adhering to the metal-organic framework can be removed, followed by drying, thereby obtaining a powdery metal-organic framework.

[0030] In order to explain the present invention in more detail, examples carried out by the present inventors will be described below.

[0031] (Measurement Methods) [Gas Adsorption / Desorption Behavior / Pore Structure Evaluation] The pore volume and pore volume ratio of the metal-organic framework were measured using a BELSORP MAX II model manufactured by Microtrackbell Inc., with a nitrogen gas adsorption isotherm measured at liquid nitrogen temperature by a multipoint method. The gas adsorption / desorption behavior was evaluated, and the pore structure was evaluated by the t method, MP method, and BJH method. [Crystalline / Amorphous Structure Evaluation] The crystalline / amorphous (amorphous) structure of the metal-organic framework was evaluated by powder X-ray diffraction (PXRD) using a SmartLab manufactured by Rigaku Corporation. [Thermogravimetric Analysis Evaluation] The metal-organic framework was subjected to thermogravimetric analysis under a nitrogen atmosphere using a TG / DTA7220 manufactured by Hitachi High-Tech Science Corporation, at a heating rate of 5°C / min and a measurement temperature of 30°C to 900°C. The presence or absence of amorphous content in the metal-organic framework was evaluated based on the thermogravimetric change measured by thermogravimetric analysis.

[0032] Preparation of Metal-Organic Framework Example 1 As a second solution, pure water and methanol were added to a 140 ml container (mayonnaise bottle), and then disodium terephthalate was added to the container and dissolved at room temperature. As a first solution, pure water and methanol were added to a 140 ml container (mayonnaise bottle), and then zirconium oxide chloride octahydrate was added and dissolved at room temperature. Next, a stirrer was added to the second solution, and the first solution was added while stirring the second solution to prepare a mixed solution. This was further stirred for two days to obtain a suspension containing a solid product. The solid product was filtered from the obtained suspension, and the isolated solid product was washed with methanol. After washing, the solid product was vacuum dried at 60°C for 8 hours to obtain a metal-organic framework A according to Example 1. The molar ratio of each component in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.00:537.40:0:100.97. Evaluation of the gas adsorption / desorption behavior and pore structure of the obtained metal-organic framework A revealed that it had low-pressure hysteresis, with the adsorption plot and desorption plot not matching in the relative pressure range of 0.4 to 1.0, and was a material having micropores. PXRD measurement confirmed that the obtained metal-organic framework A had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 7.2° and a half-width of approximately 2.5°, indicating that it was a metal-organic framework containing an amorphous structure. Thermogravimetric analysis revealed that the obtained metal-organic framework A had a gently decreasing TG curve in the temperature range of 200°C to 500°C, indicating that it had an amorphous structure.

[0033] Example 2 A stirrer was added to the first solution, and the second solution was added while stirring the first solution to prepare a mixed solution. The molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:0.99:531.28:0:100.45. Metal-organic structure B was obtained in the same manner as in Example 1, except that the gas adsorption / desorption behavior and pore structure evaluation of the obtained metal-organic structure B showed that it had low-pressure hysteresis, in which the adsorption plot and desorption plot did not match in the relative pressure range of 0.4 to 1.0, and it was a material having micropores. PXRD measurement confirmed that the obtained metal-organic structure B had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 7.2° and a half-width of approximately 2.6°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework B had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0034] Example 3 Metal-organic structure C was obtained in the same manner as in Example 1, except that the solvent for the second solution was pure water, sodium hydroxide, and methanol, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate:disodium terephthalate:pure water:sodium hydroxide:methanol = 1.00:0.50:537.88:1.36:100.99. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal-organic structure C showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure C had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 6.1° and a half-width of approximately 2.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework C had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0035] Example 4 Metal organic structure D was obtained in the same manner as in Example 3, except that the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.00:537.09:2.69:100.77. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal organic structure D showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal organic structure D had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 30.8° and a half-width of approximately 10.0°, and was therefore a metal organic structure containing an amorphous phase. Thermogravimetric analysis evaluation showed that the obtained metal organic structure D had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, indicating that it had an amorphous structure.

[0036] Example 5 Metal-organic structure E was obtained in the same manner as in Example 3, except that the molar ratio of each component in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.25:537.86:3.28:100.95. The obtained metal-organic structure E was found to have H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and to have micropores and mesopores, based on gas adsorption / desorption behavior and pore structure evaluation. PXRD measurement confirmed that the obtained metal-organic structure E had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 30.8° and a half-width of approximately 10.0°, and was therefore a metal-organic structure containing an amorphous phase. Thermogravimetric analysis evaluation confirmed that the obtained metal-organic structure E had a gently decreasing TG curve in the temperature range of 200°C to 500°C, indicating that it had an amorphous structure.

[0037] Example 6 Metal-organic structure F was obtained in the same manner as in Example 2, except that the solvent for the second solution was pure water, sodium hydroxide, and methanol, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate:disodium terephthalate:pure water:sodium hydroxide:methanol = 1.00:1.00:533.56:2.69:100.87. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal-organic structure F showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure F had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 31.5° and a half-width of approximately 10.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework F had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0038] Example 7 Metal-organic structure G was obtained in the same manner as in Example 1, except that the solvent for the second solution was pure water and sodium hydroxide, the solvent for the first container was pure water, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:0.50:537.17:1.36:0. Based on gas adsorption / desorption behavior and pore structure evaluation, the obtained metal-organic structure G was found to have H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure G had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 6.2° and a half-width of approximately 2.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework G had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0039] Example 8 Metal-organic structure H was obtained in the same manner as in Example 7, except that the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.00:537.29:2.69:0. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal-organic structure H showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure H had a peak derived from a crystalline structure and a peak derived from an amorphous structure at a peak position of 30.9 and a half-width of approximately 10.0°, and was a metal-organic structure containing an amorphous phase. Thermogravimetric analysis evaluation showed that the obtained metal-organic structure H had a gently decreasing TG curve in the temperature range of 200°C to 500°C, indicating that it had an amorphous structure.

[0040] Example 9 Metal organic framework I was obtained in the same manner as in Example 7, except that the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.25:537.83:3.23:0. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal organic framework I showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal organic framework I had a peak derived from a crystalline structure and a peak derived from an amorphous structure at a peak position of 30.9 and a half-width of approximately 10.0°, and was a metal organic framework containing an amorphous structure. Thermogravimetric analysis evaluation showed that the obtained metal organic framework I had a gently decreasing TG curve in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0041] Example 10 Metal-organic structure J was obtained in the same manner as in Example 2, except that the solvent for the second solution was pure water and sodium hydroxide, the solvent for the first container was pure water, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.00:533.63:2.68:0. Based on gas adsorption / desorption behavior and pore structure evaluation, the obtained metal-organic structure J was found to have H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure J had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of approximately 31.5° and a half-width of approximately 10.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic structure J had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0042] Comparative Example 1 Coordination Structure K was obtained in the same manner as in Example 1, except that the solvent for the first solution and the second solution were each pure water, the mixture was stirred for four days, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.00:360.94:0:0. Evaluation of the gas adsorption / desorption behavior and pore structure of the obtained coordination structure K revealed that it was a nonporous material. Thermogravimetric analysis revealed that the obtained coordination structure K had a TG curve that did not decrease gradually but decreased sharply in the temperature range of 500°C to 600°C, and did not have an amorphous structure.

[0043] (Comparative Example 2) Gas adsorption / desorption behavior and pore structure evaluation were performed on Zirconium benzenedicarboxylate MOF (metal organic framework L), a reagent sold by Strem Chemicals, Inc. The adsorption isotherm was type I, and the material had micropores without hysteresis. Furthermore, PXRD measurement confirmed that metal organic framework L had only a crystalline structure, with no peaks due to an amorphous structure. Thermogravimetric analysis evaluation showed that the obtained metal organic framework L had a TG curve that did not decrease gradually but decreased sharply in the temperature range of 500°C to 600°C, and did not have an amorphous structure.

[0044] Example 11 Metal-organic structure M was obtained in the same manner as in Example 1, except that 2-aminoterephthalic acid was further added to the second solution as an organic ligand, and the molar ratio of the components in the mixed solution was set to zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: purified water: sodium hydroxide: methanol = 1.00:1.00:0.100:537.72:0:96.92. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal-organic structure M showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure M had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position at 7.5° and a half-width of approximately 3.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework M had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0045] Example 12 Metal-organic structure N was obtained in the same manner as in Example 11, except that the solvent for each of the first solution and the second solution was pure water, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: pure water: sodium hydroxide: methanol = 1.00:1.01:0.101:541.37:0:0. The obtained metal-organic structure N was found to have H4-type hysteresis in the relative pressure range of 0.4 to 1.0, and to have micropores, based on gas adsorption / desorption behavior and pore structure evaluation. PXRD measurement confirmed that the obtained metal-organic structure N had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position at 7.5° and a half-width of approximately 2.5°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework N had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0046] Example 13 Metal-organic structure O was obtained in the same manner as in Example 11, except that the solvent for the second solution was pure water and sodium hydroxide, the solvent for the first solution was pure water, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: pure water: sodium hydroxide: methanol = 1.00: 1.00: 0.102: 537.79: 0.27: 0. The obtained metal-organic structure O was found to have H4-type hysteresis in the relative pressure range of 0.4 to 1.0 and micropores based on gas adsorption / desorption behavior and pore structure evaluation. PXRD measurement confirmed that the obtained metal-organic structure O had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 7.4° and a half-width of approximately 1.4°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic structure O had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0047] Example 14 Metal-organic structure P was obtained in the same manner as in Example 11, except that the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: purified water: sodium hydroxide: methanol = 1.00:1.00:0.101:537.35:0.79:0. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal-organic structure P showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure P had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 7.3° and a half-width of approximately 2.5°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal-organic framework P had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0048] Example 15 Metal-organic structure Q was obtained in the same manner as in Example 11, except that the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: purified water: sodium hydroxide: methanol = 1.00:1.00:0.101:536.93:1.32:0. The gas adsorption / desorption behavior and pore structure evaluation of the obtained metal-organic structure Q showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure Q had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 7.1° and a half-width of approximately 1.8°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework Q had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0049] Example 16 Metal-organic structure R was obtained in the same manner as in Example 11, except that the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: purified water: sodium hydroxide: methanol = 1.00: 1.02: 0.103: 546.67: 2.67: 0. From the gas adsorption / desorption behavior and pore structure evaluation, the obtained metal-organic structure R was found to have H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. From the PXRD measurement, it was confirmed that the obtained metal-organic structure R had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 30.7° and a half-width of approximately 10.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework R had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0050] (Comparative Example 3) Gas adsorption / desorption behavior and pore structure evaluation were performed on Zirconium aminobenzenedicarboxylate MOF (Metal Organic Framework S), a reagent sold by Strem Chemicals, Inc. The material exhibited a type I adsorption isotherm and had micropores without hysteresis. PXRD measurement confirmed that Metal Organic Framework S had only a crystalline structure, with no peaks attributable to an amorphous structure. Thermogravimetric analysis evaluation showed that the obtained Metal Organic Framework S had a TG curve that did not decrease gradually but decreased sharply in the temperature range of 400°C to 600°C, and did not have an amorphous structure.

[0051] Example 17 Metal-organic structure T was obtained in the same manner as in Example 1, except that nitroterephthalic acid was further added to the second solution as an organic ligand, the solvent for the second solution was pure water and sodium hydroxide, the solvent for the first solution was pure water, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: nitroterephthalic acid: pure water: sodium hydroxide: methanol = 1.00:1.00:0.100:537.05:2.67:0. Evaluation of the gas adsorption / desorption behavior and pore structure of the obtained metal-organic structure T showed that it had H1-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal organic structure T had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 30.3° and a half width of approximately 8.9°, and was a metal organic structure containing an amorphous phase. Thermogravimetric analysis evaluation confirmed that the obtained metal organic structure T had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and was therefore an amorphous structure.

[0052] Example 18 A metal-organic structure U was obtained in the same manner as in Example 17, except that the solvent for the second solution was pure water, sodium hydroxide, and methanol, the solvent for the first solution was pure water and methanol, and the molar ratio of the components in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: nitroterephthalic acid: pure water: sodium hydroxide: methanol = 1.00: 1.00: 0.101: 539.97: 2.65: 101.31. The obtained metal-organic structure U was found to have an H1-type hysteresis function in the relative pressure range of 0.4 to 1.0 based on gas adsorption / desorption behavior and pore structure evaluation, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure U had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 31.1° and a half-width of approximately 10.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic structure U had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0053] Example 19 Metal-organic structure V was obtained in the same manner as in Example 1, except that aluminum nitrate nonahydrate was used in place of zirconium oxide chloride octahydrate in the first solution, and the molar ratio of the components in the mixed solution was aluminum nitrate nonahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:0.65:551.18:0:103.45. The obtained metal-organic structure V was found to have low-pressure hysteresis, in which the adsorption plot and desorption plot did not match in the relative pressure range of 0.4 to 1.0, and to have micropores, as determined by gas adsorption / desorption behavior and pore structure evaluation. PXRD measurement confirmed that the obtained metal-organic structure V had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 15.3° and a half-width of approximately 2.0°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic structure V had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0054] Example 20 Metal-organic structure W was obtained in the same manner as in Example 19, except that the solvent for the second solution was pure water, sodium hydroxide, and methanol, the solvent for the first solution was pure water and methanol, and the molar ratio of the components in the mixed solution was aluminum nitrate nonahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00: 0.65: 551.15: 2.77: 103.47. The obtained metal-organic structure W was found to have H1-type hysteresis in the relative pressure range of 0.4 to 1.0 based on gas adsorption / desorption behavior and pore structure evaluation, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure W had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 13.8° and a half-width of approximately 3.2°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic structure W had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

[0055] Example 21 Metal-organic structure X was obtained in the same manner as in Example 19, except that the solvent for the second solution was pure water and sodium hydroxide, the solvent for the first solution was pure water, and the molar ratio of the components in the mixed solution was aluminum nitrate nonahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00: 0.65: 551.03: 2.77: 0. From gas adsorption / desorption behavior and pore structure evaluation, the obtained metal-organic structure X was found to have H2-type hysteresis in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores. From PXRD measurement, it was confirmed that the obtained metal-organic structure X had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 13.7° and a half-width of approximately 3.0°, and was a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic structure X had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0056] (Comparative Example 4) The gas adsorption / desorption behavior and pore structure of Basolite A100 (MiL53) (metal-organic framework Y), a reagent sold by Sigma-Aldeich, were evaluated. The material had low-pressure hysteresis, with the adsorption plot and desorption plot not matching in the relative pressure range of 0.4 to 1.0, and also had micropores and mesopores. PXRD measurement confirmed that metal-organic framework Y had only a crystalline structure, with no peaks attributable to an amorphous structure. Thermogravimetric analysis evaluation showed that the obtained metal-organic framework Y had a TG curve that did not decrease gradually but decreased sharply in the temperature range of 500°C to 650°C, and did not have an amorphous structure.

[0057] Example 22 Metal-organic structure Z was obtained in the same manner as in Example 1, except that zinc nitrate hexahydrate was used in place of zirconium oxide chloride octahydrate in the first solution, and the molar ratio of the components in the mixed solution was zinc nitrate hexahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.00:537.50:0:100.86. The obtained metal-organic structure Z was found to have low-pressure hysteresis, in which the adsorption plot and desorption plot did not match in the relative pressure range of 0.4 to 1.0, and was a material having micropores. PXRD measurement confirmed that the obtained metal-organic structure Z had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 16.9° and a half-width of approximately 0.2°, and was therefore a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic structure Z had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0058] (Example 23) Metal-organic structure Za was obtained in the same manner as in Example 22, except that the solvent for the second solution was pure water, sodium hydroxide, and methanol, the solvent for the first solution was pure water and methanol, and the molar ratio of the components in the mixed solution was zinc nitrate hexahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00: 1.00: 537.13: 2.62: 100.81. The obtained metal-organic structure Za was found to have H1-type hysteresis in the relative pressure range of 0.4 to 1.0 based on gas adsorption / desorption behavior and pore structure evaluation, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure Za had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 36.3° and a half-width of approximately 0.6°, and was an amorphous-containing metal-organic structure. Thermogravimetric analysis showed that the obtained metal organic framework Za had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0059] (Example 24) Metal-organic structure Zb was obtained in the same manner as in Example 22, except that the solvent for the second solution was pure water and sodium hydroxide, the solvent for the first solution was pure water, and the molar ratio of the components in the mixed solution was zinc nitrate hexahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00: 1.00: 536.44: 2.62: 0. The obtained metal-organic structure Zb was found to have H1-type hysteresis in the relative pressure range of 0.4 to 1.0 based on gas adsorption / desorption behavior and pore structure evaluation, and was a material having micropores and mesopores. PXRD measurement confirmed that the obtained metal-organic structure Zb had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 36.3° and a half-width of approximately 0.6°, and was a metal-organic structure containing amorphous matter. Thermogravimetric analysis showed that the obtained metal organic framework Zb had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200°C to 500°C.

[0060] The metal-organic framework and its production method of the present invention have a reduced environmental impact and can support gases for long periods of time due to their hysteresis function, making them suitable for applications in functional materials such as gas storage, gas separation, reaction catalysts, and gas sensors.

Claims

1. A metal-organic framework comprising a metal hydrate and an organic ligand capable of bidentate coordination with the metal hydrate, wherein the metal hydrate is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate, the metal-organic framework contains an amorphous phase, and has a hysteresis capability in gas adsorption and desorption.

2. The metal organic structure according to claim 1, wherein the hysteresis function is any one of H1, H2 and H4 hysteresis functions which appear in the range of a relative pressure of 0.4 to 1.0 and which are derived from mesopores and / or micropores, or low pressure hysteresis function.

3. The metal-organic structure according to claim 1 or 2, wherein the organic ligand is at least one of a terephthalic acid salt, a terephthalic acid derivative salt, a terephthalic acid salt derived from a recycled polyethylene terephthalate material, and an anion derived from an organic acid.

4. A method for producing a metal-organic framework according to claim 1, comprising: step A of preparing a first solution comprising a metal hydrate and an aqueous solvent; step B of preparing a second solution comprising an organic ligand capable of coordinating to a metal ion derived from the metal hydrate and an aqueous solvent; and step C of mixing the first solution and the second solution while applying shear, wherein steps A to C are carried out under conditions of room temperature and normal pressure, and the metal hydrate is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate.

5. The method for producing a metal-organic framework according to claim 4, wherein the organic ligand is at least one of a terephthalic acid salt, a terephthalic acid derivative salt, a terephthalic acid salt derived from a recycled polyethylene terephthalate material, and an anion derived from an organic acid.

6. The method for producing a metal organic framework according to claim 4 or 5, wherein the aqueous solvent of the first solution is an aqueous solvent containing water, an alcohol and / or an alkali metal hydroxide.

7. The method for producing a metal organic framework according to claim 4 or 5, wherein the organic ligand comprises an organic ligand having an amino group.

8. The method for producing a metal organic framework according to claim 4 or 5, wherein the aqueous solvent of the second solution is an aqueous solvent containing water, an alcohol and / or an alkali metal hydroxide, or water.

9. The method for producing a metal organic framework according to claim 4 or 5, wherein the content of the organic ligand in the second solution is 0.25 to 1.50 mol per 1 mol of the metal hydrate in the first solution.

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