WO2025110039A1 - Metal organic structure and production method for same - Google Patents

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 same

The present invention relates to a metal-organic framework and a method for producing the same, and more specifically to a metal-organic framework prepared by aqueous synthesis, which contains amorphous matter and has hysteresis in gas adsorption/desorption, and a method for producing the same.

Metal-organic frameworks (MOFs), which are composed of a central metal and a multidentate organic ligand coordinated thereto, are porous three-dimensional structures formed by accumulating metal complexes composed of a central metal and an organic ligand. Unlike other porous materials such as zeolite and activated carbon, the pores of metal-organic frameworks are capable of designing the pore size and the space inside the pores, and many types of MOFs have been reported based on the combination of metal ions and organic ligands.
Metal-organic frameworks have been reported with pore diameters of about 0.3 nm to about 3 nm and specific surface areas of about 1000 m ² /g to about 2000 ^{m 2} /g, and even up to more than 5000 ^{m 2} /g. Development has been promoted for use as adsorbents for various components according to the various pore diameters.

Metal-organic frameworks are generally produced by reacting metal ions with organic compounds that act as ligands in an organic solvent. For example, in Patent Document 1, hydrated nitrates and imidazole-type organic compounds 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 zeolite-type imidazolate frameworks (ZIFs).

Furthermore, Patent Document 2 listed below describes a metal organic framework having a UiO-66 structure as a basic skeleton, represented by Me 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, the following Patent Document 3 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 isolating it.

The metal organic framework described in Patent Document 2 requires a heat treatment of the metal compound and the nitrogen-containing aromatic heterocyclic dicarboxylic acid serving as the 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 framework are adjusted by heating at high temperature in an organic solvent using a template agent. Therefore, from the perspective of environmental impact, a method is anticipated that can produce a new metal organic framework without using a template agent or heat treatment under high temperature conditions using an organic solvent.

As for liquid-phase synthesis methods for metal-organic frameworks, in addition to the synthesis methods using organic solvents at high temperatures as described in Patent Documents 2 and 3 above, synthesis methods using water/alcohol-based solvents at high temperatures and high pressures or at normal pressures are also known. For example, Patent Document 4 below proposes a method for producing a porous metal complex consisting of a three-dimensional porous framework structure of a metal complex having a central metal and an organic ligand, which is characterized in that a salt of the organic ligand is prepared as a first metal salt, a salt of the central metal is prepared as a second metal salt, and the first and second metal salts are reacted, and it is described 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.

Also, the following Patent Document 5 describes a method for preparing a metal organic framework composition, comprising: a. forming a reaction mixture of a metal compound in which the 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, and isopropanol, and mixtures thereof; and a modifier containing at least one monocarboxylic acid; b. reacting the reaction mixture at a certain temperature and time to form a MOF; c. isolating the MOF to provide a powder of the MOF; and d. washing the MOF powder with an acid wash containing at least one inorganic acid to provide a MOF having an activated amino group and an average crystal size greater than 1 μm.

U.S. Patent Application Publication No. 2007/202038 JP 2017-88542 A Special Publication No. 2020-532499 JP 2006-328051 A Special Publication No. 2023-519685

In the methods for producing a metal organic framework described in Patent Documents 4 and 5, when an alcohol or the like is used as a solvent, a metal organic framework is obtained by a heat treatment at a relatively low temperature. However, the metal organic framework obtained by these methods has 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 by IUPAC into types I to VI. The phenomenon in which the adsorption and desorption processes do not coincide is called hysteresis, which is known to be characteristic of porous materials having micropores or mesopores, and metal-organic frameworks are also expected to have this hysteresis ability.

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

The present invention provides a metal organic structure comprising a metal hydrate and an organic ligand capable of bidentate coordination with the metal hydrate, the metal hydrate being any one of zirconium hydrate, aluminum hydrate, and zinc hydrate, the metal organic structure containing an amorphous phase, and having a hysteresis function in gas adsorption and desorption.

In the metal organic framework of the present invention,
(1) The hysteresis ability is expressed in the range of a relative pressure of 0.4 to 1.0 and is any one of the hysteresis abilities H1, H2, and H4 derived from mesopores and/or micropores, and low pressure hysteresis ability;
(2) 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;
is preferred.

The present invention also provides a method for producing the above-mentioned metal organic framework, comprising step A of preparing a first solution consisting of a metal hydrate and an aqueous solvent, step B of preparing a second solution consisting of 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 performed under normal temperature and pressure conditions, and the metal hydrate is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate.

In the method for producing a metal organic framework of the present invention,
(1) 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;
(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 water, an aqueous solvent containing an alcohol and/or an alkali metal hydroxide, or water;
(5) The content of the organic ligand in the second solution is 0.25 to 1.50 moles per mole of the metal hydrate in the first solution;
is preferred.

The metal organic framework of the present invention has a hysteresis ability in gas adsorption and desorption, and therefore has the characteristics of being able to increase the maximum adsorption amount of the 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 ability.
Moreover, in the method for producing a metal organic framework of the present invention, the reaction between a metal ion and an organic compound serving as a ligand is carried out using an aqueous solvent under conditions of room temperature and normal pressure, whereby a metal organic framework having the above-mentioned properties can be produced, and there is also an advantage in that the environmental load is low.

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

(Metal-organic structure)
The metal organic framework of the present invention is characterized in that it comprises a metal hydrate and an organic ligand capable of bidentate coordination with the metal hydrate, the metal hydrate being any one of zirconium hydrate, aluminum hydrate, and zinc hydrate, containing an amorphous phase, and having hysteresis capability in gas adsorption/desorption.
As mentioned above, in the classification of adsorption/desorption isotherms by IUPAC, a phenomenon (hysteresis) occurs in which the adsorption and desorption processes do not coincide, especially in isotherms of types IV and V, and this hysteresis is said to be mainly related to capillary condensation in the mesopore region. In addition, hysteresis such as that seen in the above-mentioned types IV and V is classified by IUPAC into patterns of types H1 to H4 as shown in Figure 1. In general, type H1 is a case of an aggregate or a mass of spherical particles, type H2 is a case that cannot be classified into H1, H3, and H4, type H3 is a case of slit-type pores or pores with a sufficiently narrow entrance and wide depth, and type H4 indicates the presence of slit-type pores and has mesopores and micropores at the same time. In addition, the case of low-pressure hysteresis is shown by the dashed line in Figure 1.
The hysteresis ability possessed by the metal organic framework of the present invention is preferably any one of hysteresis abilities H1, H2, and H4 that is expressed in a relative pressure range of 0.4 to 1.0 and originates from mesopores and/or micropores, or low-pressure hysteresis ability. A metal organic framework having such a hysteresis ability has a larger maximum adsorption amount and is capable of supporting an adsorbed gas in the pores, as compared with a metal organic framework not having a hysteresis ability.

Moreover, an important feature of the metal organic framework of the present invention is that it contains an amorphous portion. That is, while a general metal organic framework is a crystalline porous coordination polymer, the metal organic framework of the present invention has a unique structure that contains an amorphous portion.
In the present invention, whether the metal organic framework contains an amorphous phase 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 is that the diffraction peak in powder X-ray diffraction measurement (PXRD measurement) is a broad peak between 5° and 80° at 2Θ, and the half-width, which is the width of the peak at half the height of the difference between the height of the peak and the baseline of the broad peak in the diffraction peak, is 0.2° or more, and the position of the highest broad peak is between 5° and 45° at 2Θ, or that the thermogravimetric change curve in thermogravimetric analysis (TG measurement) is a curve that gradually decreases in the temperature range of 200°C to 500°C.

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

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 suitable.
Suitable metal hydrates include zirconium oxide chloride octahydrate, aluminum nitrate nonahydrate, and zinc nitrate hexahydrate.

On the other hand, the organic compound serving as the organic ligand is an organic compound capable of forming a coordinate bond with the above-mentioned metal ion, and is particularly preferably an organic compound having a ring structure. Examples of the ring structure include an aromatic ring, a cyclo ring, and a heterocyclic ring, and is particularly preferably an aromatic ring. 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 a biphenyl or an ortho-terphenyl.
The aromatic organic compound is preferably an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, orthophthalic acid, or naphthalenedicarboxylic acid; an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydroisophthalic acid, or 1,2-cyclohexenedicarboxylic acid; or a derivative or anion thereof; and particularly preferably at least one of terephthalic acid, a terephthalic acid derivative, or anion thereof.

Terephthalic acid that can be suitably used as an organic ligand in the present invention is particularly preferably terephthalic acid derived from recycled polyethylene terephthalate from the viewpoint of environmental friendliness.
An example of such recycled materials is polyester recycled by mechanical recycling. In general, polyester is recycled by crushing and cleaning collected polyester bottles. This polyester generally contains terephthalic acid and isophthalic acid.
Such recycled terephthalic acid can be used alone or in combination with virgin terephthalic acid.

(Method for producing metal-organic structure)
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 normal pressure.
As described above, in the organometallic structure of the present invention, the metal hydrate constituting the central metal is preferably any one of zirconium hydrate, aluminum hydrate, and zinc hydrate, and the organic ligand is preferably at least one of terephthalic acid salts, terephthalic acid derivative salts, terephthalic acid salts derived from recycled polyethylene terephthalate materials, and anions derived from organic acids.

[Process A]
In the above 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 alcohol as the aqueous solvent.
Examples of alcohols include methanol, ethanol, n-propanol, and isopropanol, with methanol being particularly preferred.
When a mixed solvent of water and alcohol is used, the ratio by mass of water:alcohol is preferably in the range of 1:0.01 to 1:2, although this depends 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 normal temperature and pressure conditions.
In this specification, normal temperature (15 to 25° C.) and normal pressure conditions refer to a state in which neither heating nor pressure is intentionally applied, and have the same meaning as room temperature and atmospheric pressure.

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

[Process B]
In step B, a second solution is prepared that comprises an organic ligand capable of coordinating with the metal ions derived from the metal hydrate and an aqueous solvent.
As described above, the organic ligand in the metal organic framework is composed of an aromatic dicarboxylic acid or the like, but in the metal organic framework of the present invention, from the viewpoint of forming an amorphous structure, it is preferable to improve the solubility in an aqueous solvent, and an alkali metal salt of an aromatic dicarboxylic acid or the like can be preferably used. Specifically, disodium terephthalate or the like can be preferably used.
From the viewpoint of increasing the amorphous amount of the metal organic framework, it is preferable to contain an organic ligand having an amino group and/or a nitro group together with the above organic ligand. Specifically, 2-aminoterephthalic acid and nitroterephthalic acid can be preferably used. It is preferable to contain the organic ligand having an amino group and/or a nitro group 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.

The aqueous solvent used in step B may be water, or an aqueous solvent consisting of water and an alcohol and/or an alkali metal hydroxide, but it is preferable to use an aqueous solvent in which an alkali metal hydroxide has been added to a mixed solvent of water and an alcohol as necessary. When an organic ligand having an amino group is contained as the organic ligand, not only a mixed solvent containing water and an alcohol, but also an aqueous solvent containing only water or water and an alkali metal hydroxide can be preferably 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 ratio of water:alcohol (mass ratio) is preferably in the range of 1:0.01 to 1:0.50, although this depends 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, and sodium hydroxide is particularly preferred. By adding an alkali metal hydroxide, it is possible to improve the solubility of the organic ligand and increase the amorphous amount of the metal organic framework.
When a mixed solvent of water and an alkali metal hydroxide is used, the amount of the alkali metal hydroxide added is preferably within 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 for, for example, 1 to 30 minutes under normal temperature and pressure conditions.

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 1 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.

[Process C]
In step C, a mixed solution of the first solution or the second solution obtained in steps A and B is prepared at room temperature and pressure by adding the other solution to the first solution while applying shear to the other solution. After the mixed solution is prepared, it is further stirred and mixed for 1 to 72 hours to produce the target metal organic framework.
In step C, the shearing when the solution is added may be performed by stirring while applying a shear force by a known method, and examples of the method 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 the step C can be filtered out from the mixed solution, and then, if necessary, raw materials and the like adhering to the metal organic framework can be removed, followed by drying to obtain a powdered metal organic framework.

Below, in order to explain the present invention in more detail, we will explain examples carried out by the inventors.

(Measurement method)
[Gas adsorption/desorption behavior and pore structure evaluation]
The pore volume and pore volume ratio of the metal organic framework were measured by measuring the adsorption isotherm of nitrogen gas at liquid nitrogen temperature by a multipoint method using BELSORP MAX II type manufactured by MicrotrackBell Corporation, and the gas adsorption and desorption behavior was evaluated. At the same time, the pore structure was evaluated by the t method, the MP method, and the BJH method.
[Crystalline and amorphous structure evaluation]
The crystalline and amorphous structures of the metal-organic frameworks were 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 evaluation 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.
In addition, the presence or absence of amorphous content in the metal organic framework was evaluated based on the thermogravimetric change measured by thermogravimetric analysis.

Preparation of Metal-Organic Framework
Example 1
As the 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 the 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, which 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.
The obtained metal organic framework A was found to have low pressure hysteresis, with the adsorption plot and desorption plot not matching in the relative pressure range of 0.4 to 1.0, as a result of evaluation of the gas adsorption/desorption behavior and pore structure, and was also found to be a material having micropores.
From the PXRD measurement, it was confirmed that the obtained metal organic structure A had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of about 7.2° and a half width of about 2.5°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic framework A had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200° C. to 500° C.

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, and the molar ratio of each component 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, except that a metal organic framework B was obtained in the same manner as in Example 1. The obtained metal organic framework B was a material having low pressure hysteresis capability in which the adsorption plot and desorption plot did not match in the relative pressure range of 0.4 to 1.0, and having micropores, based on the gas adsorption/desorption behavior/pore structure evaluation.
From the PXRD measurement, it was 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 about 7.2° and a half width of about 2.6°, and was a metal organic structure containing an amorphous structure.
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.

Example 3
A metal organic structure C was obtained in the same manner as in Example 1, except that the solvent of the second solution was pure water, sodium hydroxide, and methanol, and the molar ratio of each component 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 framework C showed that it had H1 type hysteresis function 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 C had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of about 6.1° and a half width of about 2.0°, and was a metal organic structure containing an amorphous structure.
According to the thermogravimetric analysis, the obtained metal organic framework C had a TG curve that gradually decreased in the temperature range of 200° C. to 500° C., and had an amorphous structure.

Example 4
Metal organic structure D 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: 1.00: 537.09: 2.69: 100.77.
The gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework D showed that it had H1 type hysteresis function 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 D had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of about 30.8° and a half width of about 10.0°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic framework D had a TG curve that gradually decreased in the temperature range of 200° C. to 500° C., and had an amorphous structure.

Example 5
A metal organic framework 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework E showed that it had H1 type hysteresis function 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 E had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of about 30.8° and a half width of about 10.0°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal-organic framework E had a TG curve that gradually decreased in the temperature range of 200° C. to 500° C., and had an amorphous structure.

Example 6
Metal organic framework 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 each component 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 obtained metal organic framework F was found to have H1 type hysteresis capability in the relative pressure range of 0.4 to 1.0, and was a material having micropores and mesopores, based on the gas adsorption/desorption behavior and pore structure evaluation.
From the PXRD measurement, it was 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 about 31.5° and a half width of about 10.0°, and was a metal organic structure containing an amorphous structure.
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.

(Example 7)
A metal organic structure G was obtained in the same manner as in Example 1, except that the solvent of the second solution was pure water and sodium hydroxide, the solvent of the first container was pure water, and the molar ratio of each component 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.
The gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework G showed that it had H1 type hysteresis function 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 G had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of about 6.2° and a half width of about 2.0°, and was a metal organic structure containing an amorphous structure.
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.

(Example 8)
Metal organic framework H was obtained in the same manner as in Example 7, 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: 1.00: 537.29: 2.69: 0.
The gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework H showed that it had H1 type hysteresis function 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 H had a peak derived from a crystalline structure and a peak derived from an amorphous structure, which was located at a peak position of 30.9 and had a half width of about 10.0°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic framework H had a TG curve that gradually decreased in the temperature range of 200° C. to 500° C., and had an amorphous structure.

(Example 9)
Metal organic framework I was obtained in the same manner as in Example 7 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: 537.83: 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 function 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 I had a peak derived from a crystalline structure and a peak derived from an amorphous structure, which was located at a peak position of 30.9 and had a half width of about 10.0°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic framework I had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200° C. to 500° C.

(Example 10)
Metal organic structure J was obtained in the same manner as in Example 2, except that the solvent of the second solution was pure water and sodium hydroxide, the solvent of the first container was pure water, and 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: 533.63: 2.68: 0.
The gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework J showed that it had H1 type hysteresis function 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 J had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of about 31.5° and a half width of about 10.0°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic framework J had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200° C. to 500° C.

(Comparative Example 1)
The solvent for the first solution and the second solution were each pure water, and the mixture was stirred for 4 days. Coordination structure K was obtained in the same manner as in Example 1, except that the molar ratio of each component in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00:1.00:360.94:0:0.
The obtained coordination structure K was found to be a non-porous material based on the gas adsorption/desorption behavior and pore structure evaluation.
Thermogravimetric analysis showed that the resulting 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.

(Comparative Example 2)
The gas adsorption/desorption behavior and pore structure of Zirconium benzenedicarboxylate MOF (metal organic framework L), a reagent sold by Strem Chemicals, Inc., was evaluated. The adsorption isotherm was type I, and the material had micropores without hysteresis.
Furthermore, from the PXRD measurement, it was confirmed that metal organic framework L had only a crystalline structure, without any peaks derived from an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic structure 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.

Example 11
A 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 each component in the mixed solution was set to zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: pure 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 framework M showed that it had H1 type hysteresis function 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 M had a peak derived from a crystalline structure and a peak derived from an amorphous structure with a peak position of 7.5° and a half width of about 3.0°, and was a metal organic structure containing an amorphous structure.
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.

Example 12
Metal-organic framework N was obtained in the same manner as in Example 11 except that the solvents of the first solution and the second solution were each pure water, and the molar ratio of each component 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework N showed that it had H4 type hysteresis function in the relative pressure range of 0.4 to 1.0 and was a material having micropores.
From the PXRD measurement, it was 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 of 7.5° and a half width of about 2.5°, and was a metal organic structure containing an amorphous structure.
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.

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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework O showed that it had H4 type hysteresis function in the relative pressure range of 0.4 to 1.0 and was a material having micropores.
From the PXRD measurement, it was 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 about 1.4°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal-organic framework O had an amorphous structure, with a TG curve that gradually decreased in the temperature range of 200° C. to 500° C.

(Example 14)
A metal-organic framework P was obtained in the same manner as in Example 11 except that the molar ratio of each component in the mixed solution was changed to zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: pure 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 framework P showed that it had H1 type hysteresis function 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 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 about 2.5°, and was a metal organic structure containing an amorphous structure.
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.

(Example 15)
A metal-organic structure Q was obtained in the same manner as in Example 11 except that the molar ratio of each component in the mixed solution was changed to zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: pure 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 framework Q showed that it had H1 type hysteresis function 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 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 about 1.8°, and was a metal organic structure containing an amorphous structure.
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.

(Example 16)
The molar ratio of each component in the mixed solution was zirconium oxide chloride octahydrate: disodium terephthalate: 2-aminoterephthalic acid: pure water: sodium hydroxide: methanol = 1.00: 1.02: 0.103: 546.67: 2.67: 0. A metal organic structure R was obtained in the same manner as in Example 11.
The gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework R showed that it had H1 type hysteresis function 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 about 10.0°, and was a metal organic structure containing an amorphous structure.
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.

(Comparative Example 3)
The gas adsorption/desorption behavior and pore structure were evaluated for Zirconium aminobenzenedicarboxylate MOF (Metal Organic Framework S), a reagent sold by Strem Chemicals, Inc. The adsorption isotherm was type I, and the material had micropores without hysteresis.
From the PXRD measurement, it was confirmed that metal organic framework S had only a crystalline structure, without any peaks derived from an amorphous structure.
Thermogravimetric analysis 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.

(Example 17)
A 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 of the second solution was pure water and sodium hydroxide, the solvent of the first solution was pure water, and the molar ratio of each component 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.
The gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework T showed that it had H1 type hysteresis function 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 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 about 8.9°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic framework T had a TG curve that gradually decreased in the temperature range of 200° C. to 500° C., and had an amorphous structure.

(Example 18)
Metal organic structure U was obtained in the same manner as in Example 17, except that the solvent of the second solution was pure water, sodium hydroxide, and methanol, the solvent of the first solution was pure water and methanol, and the molar ratio of each component 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework U showed that it had H1 type hysteresis function 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 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 about 10.0°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic structure U had an amorphous structure, with the TG curve gradually decreasing in the temperature range of 200° C. to 500° C.

(Example 19)
Metal organic structure V was obtained in the same manner as in Example 1, except that aluminum nitrate nonahydrate was used in the first solution instead of zirconium oxide chloride octahydrate, and the molar ratio of each component 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework V showed that it had low pressure hysteresis, in which the adsorption plot and the desorption plot did not match in the relative pressure range of 0.4 to 1.0, and was a material having micropores.
From the PXRD measurement, it was 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 about 2.0°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal organic framework V had a TG curve that gradually decreased in the temperature range of 200° C. to 500° C., and had an amorphous structure.

(Example 20)
Metal organic structure W was obtained in the same manner as in Example 19 except that the solvent of the second solution was pure water, sodium hydroxide, and methanol, the solvent of the first solution was pure water and methanol, and the molar ratio of each component 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework W showed that it had H1 type hysteresis function 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 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 about 3.2°, and was a metal organic structure containing an amorphous structure.
Thermogravimetric analysis showed that the obtained metal-organic framework W had a TG curve that gradually decreased in the temperature range of 200° C. to 500° C., and had an amorphous structure.

(Example 21)
Metal organic structure X was obtained in the same manner as in Example 19, except that the solvent of the second solution was pure water and sodium hydroxide, the solvent of the first solution was pure water, and the molar ratio of each component in the mixed solution was aluminum nitrate nonahydrate: disodium terephthalate: pure water: sodium hydroxide: methanol = 1.00: 0.65: 551.03: 2.77: 0.
The gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework X revealed that it had H2 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 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 about 3.0°, and was a metal organic structure containing an amorphous structure.
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.

(Comparative Example 4)
The gas adsorption/desorption behavior and pore structure evaluation was carried out for Basolite A100 (MiL53) (metal organic framework Y) sold by Sigma-Aldeich. The material had low pressure hysteresis, in which the adsorption plot and the desorption plot did not match in the relative pressure range of 0.4 to 1.0, and also had micropores and mesopores.
From the PXRD measurement, it was confirmed that metal organic framework Y had only a crystalline structure, without any peaks derived from an amorphous structure.
Thermogravimetric analysis 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.

(Example 22)
Metal organic structure Z was obtained in the same manner as in Example 1, except that zinc nitrate hexahydrate was used in the first solution instead of zirconium oxide chloride octahydrate, and the molar ratio of each component 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework Z showed that it had low pressure hysteresis, in which the adsorption plot and the desorption plot did not match in the relative pressure range of 0.4 to 1.0, and was a material having micropores.
From the PXRD measurement, it was 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 about 0.2°, and was a metal organic structure containing an amorphous structure. From the thermogravimetric analysis evaluation, the obtained metal organic structure Z had a TG curve that gradually decreased in the temperature range of 200°C to 500°C, and had an amorphous structure.

(Example 23)
A metal organic structure Za was obtained in the same manner as in Example 22 except that the solvent of the second solution was pure water, sodium hydroxide, and methanol, the solvent of the first solution was pure water and methanol, and the molar ratio of each component 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework Za showed that it had H1 type hysteresis function 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 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 about 0.6°, and was a metal organic structure containing an amorphous 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.

(Example 24)
Metal organic structure Zb was obtained in the same manner as in Example 22 except that the solvent of the second solution was pure water and sodium hydroxide, the solvent of the first solution was pure water, and the molar ratio of each component 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 gas adsorption/desorption behavior and pore structure evaluation of the obtained metal organic framework Zb showed that it had H1 type hysteresis function 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 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 about 0.6°, and was a metal organic structure containing an amorphous structure.
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.

The metal organic framework and the method for producing the same of the present invention have a reduced environmental impact and can support gas for a long period of time due to their hysteresis function. Therefore, they can be applied to functional materials such as gas storage, gas separation, reaction catalysts, and gas sensors.

Claims (9)

A metal organic framework comprising a metal hydrate and an organic ligand capable of bidentate coordination with the metal hydrate,
The metal organic framework, wherein the metal hydrate is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate, contains an amorphous phase, and has a hysteresis capability in gas adsorption and desorption. The metal organic structure according to claim 1, wherein the hysteresis function is expressed in the range of a relative pressure of 0.4 to 1.0 and is any one of the hysteresis functions H1, H2, and H4 derived from mesopores and/or micropores, or low pressure hysteresis function. The metal-organic structure according to claim 1 or 2, wherein the organic ligand is at least one of terephthalic acid salts, terephthalic acid derivative salts, terephthalic acid salts derived from recycled polyethylene terephthalate materials, and anions derived from organic acids. 2. A method for producing a metal organic framework according to claim 1, comprising: a step A of preparing a first solution comprising a metal hydrate and an aqueous solvent; a step B of preparing a second solution comprising an organic ligand capable of coordinating with a metal ion derived from the metal hydrate and an aqueous solvent; and a step C of mixing the first solution and the second solution while applying shear,
The steps A to C are carried out under normal temperature and pressure conditions;
The method for producing a metal organic framework, wherein the metal hydrate is any one of zirconium hydrate, aluminum hydrate, and zinc hydrate. The method for producing a metal-organic framework according to claim 4, wherein the organic ligand is at least one of terephthalic acid salts, terephthalic acid derivative salts, terephthalic acid salts derived from recycled polyethylene terephthalate materials, and anions derived from organic acids. 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. The method for producing a metal organic framework according to claim 4 or 5, wherein the organic ligand includes an organic ligand having an amino group. 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. 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 moles per mole of the metal hydrate in the first solution.