Composite including metal organic structure and method for producing same

Abstract

Provided are: a composite that includes a metal organic structure and is prepared by solid phase synthesis in the presence of a trace amount of an aqueous solvent or without any solvents; and a method for producing the same. This composite includes: a water-insoluble metal salt or metal chloride; and a metal organic structure. The composite is characterized in that: the metal organic structure is formed of a metal component of the water-insoluble metal salt or metal chloride, and an organic ligand to which the metal component can be coordinated; and the metal organic structure has a zeolite-like imidazolate structure or a terephthalate structure.

Description

Composite containing metal organic framework and method for producing same

[0001] The present invention relates to a composite containing a metal organic framework and a method for producing the same, and more particularly to a composite containing a metal organic framework prepared by mechanochemical synthesis and a method for producing the same.

[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 of metal organic frameworks having this regular pore size and high specific surface area has been promoted.

[0003] Conventionally, metal organic frameworks have been 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 zeolite-like imidazolate framework (ZIF) is obtained by mixing a hydrated nitrate with an imidazole-type organic compound in N,N-diethylformamide, and then heating the resulting solution at 85 to 150°C for 48 to 96 hours. In addition, Patent Document 2 listed below describes a metal organic framework having a UiO-66 structure as a basic skeleton, ６ O ４ (OH) ４ The document describes a metal organic framework represented by the formula (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.

[0004] The metal-organic frameworks described in Patent Documents 1 and 2 are synthesized by heating a metal compound and an organic ligand in an organic solvent under high-temperature conditions for a long period of time, and are expected to be highly productive and environmentally friendly production methods. In addition to liquid-phase synthesis using a solvent as described in Patent Documents 1 and 2, solid-phase synthesis is also known as a method for synthesizing metal-organic frameworks. Solid-phase synthesis has the advantage that it can use metal salts and organic ligands that are insoluble in the solvent, and that the by-product generated after synthesis is water, resulting in less impact on the environment and the human body. Furthermore, direct mixing of raw materials provides excellent productivity, and the absence of the use of solvents also reduces costs.

[0005] As an example of a metal organic framework produced by solid phase synthesis, Patent Document 3 below describes a composite comprising composite particles containing a metal oxide particle in the center of the composite particle and a polycrystalline particle of a zeolite-like imidazolate structure in the outer shell of the metal oxide particle, wherein the imidazolate ligand is an imidazolate ligand derived from imidazole or a derivative thereof which may have a substituent. It also describes that such a composite is produced by grinding and mixing or heating and leaving to stand a reaction mixture obtained by mixing a metal oxide and imidazole or a derivative thereof.

[0006] US Patent Application Publication No. 2007 / 202038 JP 2017-88542 A JP 2014-156434 A

[0007] The adsorption performance of porous materials is represented by adsorption / desorption isotherms and is classified by IUPAC into types I to VI. Among these, types IV and V indicate the possibility of the presence of mesopores (pores of 2 to 50 nm) and are known to exhibit characteristic hysteresis, in which the adsorption and desorption processes do not coincide. It is expected that the metal-organic framework contained in the composite described above will also have such hysteresis capability. Therefore, an object of the present invention is to provide a composite containing a metal-organic framework, prepared by mechanochemical synthesis (solid-phase synthesis) in the absence of a solvent or in the presence of a trace amount of aqueous solvent, and a method for producing the same. Another object of the present invention is to provide a composite containing a metal structure having hysteresis capability.

[0008] According to the present invention, there is provided a composite comprising a water-insoluble metal salt or metal chloride and a metal organic framework, wherein the metal organic framework comprises a metal component of the water-insoluble metal salt or metal chloride and an organic ligand capable of coordinating with the metal component, and is a metal organic framework having a zeolite-like imidazolate structure or a terephthalate structure.

[0009] In the composite of the present invention, it is preferable that: (1) the metal of the water-insoluble metal salt or metal chloride is zinc or zirconium, and the organic ligand is imidazole or terephthalic acid, or a derivative thereof; and (2) the composite has hysteresis capability in gas adsorption / desorption.

[0010] The present invention also provides a method for producing the above-mentioned composite, comprising: a mixing step of mixing a water-soluble metal salt with an organic ligand; and a grinding and mixing step of grinding and mixing the mixture obtained in the mixing step.

[0011] In the method for producing a composite of the present invention, it is preferable that: (1) both the mixing step and the pulverization-mixing step are carried out under conditions of room temperature and normal pressure; (2) in the pulverization-mixing step, pulverization-mixing is carried out in the presence of water or an alcohol in an amount equal to or less than the total amount of the water-soluble metal salt and the organic ligand; and (3) after the pulverization-mixing step, a washing step is carried out to wash the composite obtained in the pulverization-mixing step.

[0012] The composite of the present invention provides a novel composite comprising a water-insoluble metal salt or metal chloride and a metal-organic framework having a zeolite-like imidazolate structure or a terephthalate structure. The method for producing the composite of the present invention enables solid-phase synthesis at low temperatures without a solvent or in the presence of a trace amount of aqueous solvent, and has the advantages of low environmental impact and excellent productivity. Furthermore, the composite of the present invention has the hysteresis ability of a metal-organic framework, which allows it to increase the maximum adsorption amount of an adsorbate (gas) and is capable of supporting the adsorbate (gas) for a long period of time compared to composites without hysteresis ability.

[0013] FIG. 1 shows the classification of hysteresis patterns according to IUPAC.

[0014] (Complex) The composite of the present invention is a composite comprising a water-insoluble metal salt or metal chloride and a metal-organic framework. An important feature of the composite is that the metal-organic framework comprises a metal component of the water-insoluble metal salt or metal chloride and an organic ligand capable of coordinating with the metal component, and has a zeolite-like imidazolate structure or a terephthalate structure. As described below, the composite of the present invention is a novel composite produced by grinding and mixing a water-soluble metal salt, a metal component generated from the water-soluble metal salt, and an organic ligand capable of coordinating with the metal component of the water-insoluble metal salt or metal chloride generated from the water-soluble metal salt, in a solventless or trace amount of aqueous solvent. The metal-organic framework having a zeolite-like imidazolate structure contained in the composite is a metal-organic framework having a zeolite-like topology obtained from the metal component and the imidazolate ligand. The metal-organic framework having a zeolite-like terephthalate structure is a metal-organic framework obtained from the metal component and a terephthalic acid-based ligand consisting of terephthalic acid, a terephthalic acid derivative, or an anion thereof.

[0015] In the complex of the present invention, the water-soluble metal salt is basic zinc carbonate (ZnCO ３ ) ２ (Zn(OH) ２ ) ３), zirconium(IV) carbonate hydrate (Zr(CO ３ ) ２ ・xH ２ In particular, basic zinc carbonate can be suitably used in a metal organic framework having a zeolite-like imidazolate structure, and zirconium chloride oxide octahydrate can be suitably used in a metal organic framework having a zeolite-like terephthalate structure. In addition, zinc carbonate (ZnCO ３ ) ２ ), zinc oxide (ZnO), zirconium chloride, zirconium chloride oxide, sodium chloride, zinc chloride, etc. may also be used as raw materials, and zinc carbonate and zirconium chloride oxide are particularly suitable.

[0016] Furthermore, as an organic ligand capable of coordinating with a metal component generated from a water-soluble metal salt, or a metal component of a water-insoluble metal salt or metal chloride generated from the water-soluble metal salt, in the case of a metal organic framework having a zeolite-like imidazolate structure, an imidazole compound can be used as the organic ligand. Specific examples include 2-methylimidazole, imidazole-2-carbaldehyde, 5-azabenzimidazole, and 4-azabenzimidazole, and 2-methylimidazole can be particularly preferably used. Furthermore, in the case of a metal organic framework having a zeolite-like terephthalate structure, examples of suitable dicarboxylic acids 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; and derivatives or anions thereof. In particular, at least one of terephthalic acid, a terephthalic acid derivative, and anions thereof is preferred, and among these, an alkali metal salt of terephthalic acid such as disodium terephthalate can be preferably used.

[0017] From an environmental viewpoint, it is particularly preferable that the terephthalic acid is derived from recycled polyethylene terephthalate. Such recycled materials include, for example, polyesters recycled by mechanical recycling, and generally 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.

[0018] In the composite of the present invention, the content of the metal organic framework in the composite is desirably as large as possible, and is suitably 10% by mass or more, preferably 25% by mass or more, particularly 40% by mass or more. If the content of the metal organic framework is lower than the above range, it may be difficult for the composite to fully exhibit the excellent gas adsorption and desorption capabilities, etc., of the metal organic framework.

[0019] As mentioned above, in the IUPAC classification of adsorption / desorption isotherms (Types I to VI), a phenomenon in which the adsorption and desorption processes do not coincide (hysteresis) occurs, particularly in Type IV and Type V isotherms. This hysteresis is said to be primarily related to capillary condensation in the mesopore region. Furthermore, the hysteresis observed in Type IV and Type V is classified by IUPAC into Types H1 to H4, as shown in Figure 1. Generally, Type H1 refers to the aggregates or masses of spherical particles. Type H2 refers to cases that cannot be classified into H1, H3, or H4. Type H3 refers to the presence of slit-type pores or pores with sufficiently narrow openings and wide depths. Type H4 refers to the presence of slit-type pores and the presence of both mesopores and micropores. The dashed line in Figure 1 indicates low-pressure hysteresis. In the composite of the present invention, the contained metal organic framework has hysteresis capability in gas adsorption / desorption, and therefore the composite itself can also exhibit hysteresis capability. In particular, the hysteresis capability possessed by the composite of the present invention is preferably one of H1, H2, and H4 hysteresis capabilities that are exhibited in a relative pressure range of 0.4 to 1.0 and that are derived from mesopores and / or micropores, or low-pressure hysteresis capabilities. Composites having such hysteresis capability have a larger maximum adsorption amount and are capable of supporting the adsorbed gas in the pores compared to composites that do not have hysteresis capability.

[0020] The types of pores that the metal organic framework has in this specification are N ２ The adsorption rate was determined from a theoretical adsorption isotherm for the pore diameter obtained by using the gas as an adsorbed molecule. Specifically, the measurement was carried out using a BELSORP-MAX II model manufactured by Microtrackbell, as shown in the examples described later.

[0021] (Method for producing the composite) The method for producing the composite of the present invention is characterized by comprising a mixing step of mixing a water-soluble metal salt and an organic ligand, and a grinding and mixing step of grinding and mixing the mixture obtained in the mixing step. The water-soluble metal salt and the organic ligand are as described above.

[0022] [Mixing Step] In the mixing step, a water-soluble metal salt is mixed with an organic ligand capable of coordinating with the metal component of a water-insoluble metal salt or metal chloride produced from the water-soluble metal salt. The blending ratio of the water-soluble metal salt to the organic ligand cannot be generally determined depending on the type of metal component and organic ligand used, but it is desirable that the organic ligand be in the range of 0.1 to 1.0 parts by mass per 1 part by mass of the water-soluble metal salt. Specifically, when basic zinc carbonate is used as the aqueous metal salt and 2-methylimidazole is used as the organic ligand, it is preferable that 0.1 to 1.0 parts by mass, particularly 0.3 to 0.7 parts by mass, of 2-methylimidazole be blended per 1 part by mass of basic zinc carbonate. When zirconium chloride oxide hydrate is used as the water-soluble metal salt and disodium terephthalate is used as the organic ligand, it is suitable to blend 0.1 to 1.0 parts by mass, preferably 0.3 to 0.7 parts by mass, of disodium terephthalate per 1 part by mass of zirconium chloride oxide hydrate.

[0023] In the mixing step, mixing is preferably carried out for 1 to 10 minutes under normal temperature and pressure conditions. In this specification, "under normal temperature (15 to 25°C) and normal pressure conditions" means a state in which no intentional heating or pressure is applied, and has the same meaning as room temperature and atmospheric pressure. In the mixing step, mixing can be carried out using a conventionally known mixing device such as a mortar, a ball mill, or various mixers.

[0024] [Crushing and Mixing Step] In the crushing and mixing step, the mixture obtained in the mixing step is crushed and mixed. In the crushing and mixing step, a metal-organic framework is produced by reacting a water-soluble metal salt with an organic ligand, thereby forming a composite. In this reaction step, the only by-product produced is water, and the composite contains the metal-organic framework and a water-insoluble metal salt or metal chloride produced from the water-soluble metal salt. In the crushing and mixing step, the mixture can be crushed and mixed in a solvent-free state without adding a solvent. However, crushing and mixing may also be performed in the presence of a small amount of water or alcohol. This has the advantage of promoting the solid-phase reaction. The amount of water or alcohol added is equal to or less than the total amount of the water-soluble metal salt and organic ligand used, and is particularly preferably added in an amount of 0.65 mass% or less of the total amount. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, etc., with methanol being particularly preferred.

[0025] In the grinding and mixing step, grinding and mixing are preferably carried out at room temperature and normal pressure for 10 minutes to 24 hours. In the grinding and mixing step, grinding and mixing can be carried out using a conventional grinding and mixing device such as a mortar, a ball mill, a vibration mill, a stamp mill, a jet mill, a wet jet mill, or a biaxial kneader. When the grinding and mixing step is carried out without using a solvent and the device used in the mixing step also has a grinding function, the grinding and mixing step can be carried out continuously with the mixing step without being separated.

[0026] [Washing Step] In the method for producing a composite of the present invention, it is preferable to have a washing step of washing the composite obtained in the grinding and mixing step after the grinding and mixing step, as necessary. That is, by washing the composite obtained in the grinding and mixing step, it is possible to adjust the content of components other than the metal organic framework in the composite and also to obtain a composite having hysteresis ability. The washing is performed using a good solvent that can dissolve the compound to be removed by washing, among the water-insoluble metal salt or metal chloride and the organic ligand.

[0027] [Drying Step] The composite obtained in the pulverization and mixing step contains water, which is a reaction by-product, or, if a trace amount of water or alcohol is added as a solvent, also contains such solvent. Therefore, it is preferable to dry the composite to remove the contained water and alcohol. In addition, the composite that has been subjected to the above-mentioned washing step as needed also contains washing water and the like, so it is preferable to dry it. The drying conditions are not limited thereto, but drying at 30 to 120°C for 1 to 48 hours is preferable. By drying, a composite containing a powdery metal-organic framework can be obtained.

[0028] In order to explain the present invention in more detail, examples carried out by the present inventors will be described below.

[0029] [Gas adsorption / desorption behavior / pore structure evaluation] The pore volumes and pore volume ratios of the composites containing the metal organic frameworks (MOFs) having a zeolite-like imidazolate structure or terephthalate structure of the examples, and the MOFs of the comparative examples, were measured by multipoint nitrogen gas adsorption isotherms at liquid nitrogen temperature using a BELSORP MAX II type manufactured by Microtrackbell, Inc., and the gas adsorption / desorption behavior was evaluated. The pore structures were also evaluated by the t method, MP method, and BJH method. [Crystal structure evaluation] The crystal structures of the composites of the examples and the MOFs of the comparative examples were evaluated by powder X-ray diffraction (PXRD) using a SmartLab manufactured by Rigaku Corporation. [Thermogravimetric analysis evaluation] Using a thermogravimetric analyzer (TG / DTA7220 manufactured by Hitachi High-Tech Science Corporation), measurements were performed in a nitrogen atmosphere at a temperature increase rate of 5°C / min at temperatures ranging from 100°C to 850°C to evaluate the presence or absence of a zeolite-like imidazolate structure or a terephthalate structure. The abundance ratio (weight ratio) of the substance forming the zeolite-like imidazolate structure or terephthalate structure to the other substance containing a water-insoluble metal salt or metal chloride in the composites of the examples and comparative examples was evaluated based on the amount of change in the TG curve accompanying thermal decomposition in a specific temperature range.

[0030] Preparation of Composite Example 1 200 YTZ balls (φ10 mm, 95% ZrO ２ +HfO ２ , 5%Y ２ O ３) was placed in a 250 ml container (polypropylene container) filled with basic zinc carbonate ([ZnCO ３ ] ２ [Zn(OH) ２ ] ３ ) and 2-methylimidazole were added, and the mixture was rotated at 250 rpm on a small ball mill rotating stand (AV-2, manufactured by Asahi Rika Seisakusho Co., Ltd.) for 3 hours to grind and mix. Thereafter, the ground mixture was removed from the polypropylene container and dried at 50°C for 18 hours to obtain Composite A according to Example 1. The mass ratio of the components was basic zinc carbonate:2-methylimidazole = 1.00:0.33. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite A showed a type I adsorption isotherm and was a material having micropores. PXRD measurement revealed that the obtained Composite A had a zeolite-like imidazolate structure and zinc carbonate (ZnCO ３ ) was confirmed to be a composite containing zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance that forms the zeolite-like imidazolate structure to the other substances in the obtained composite A was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 58:42.

[0031] Example 2 Composite B was obtained in the same manner as in Example 1, except that the mass ratio of the components was basic zinc carbonate:2-methylimidazole = 1.00:0.65. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite B showed a type I adsorption isotherm and was a material having micropores. PXRD measurement confirmed that the obtained Composite B was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from the zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite B was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 48:52 (substance forming the zeolite-like imidazolate structure:other substances).

[0032] Example 3 Composite C was obtained in the same manner as in Example 1, except that the mass ratio of the components (basic zinc carbonate:2-methylimidazole) was 1.00:0.33 and the rotation speed was 100 rpm. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite C showed a type I adsorption isotherm and was a material with micropores. PXRD measurement confirmed that the obtained Composite C was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from the zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite C was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 49:51 (substance forming the zeolite-like imidazolate structure:other substances).

[0033] Example 4 Composite D was obtained in the same manner as in Example 1, except that the mass ratio of the components (basic zinc carbonate:2-methylimidazole) was 1.00:0.65 and the rotation speed was 100 rpm. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite D showed a type I adsorption isotherm and was a material having micropores. PXRD measurement confirmed that the obtained Composite D was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from the zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite D was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 47:53 (substance forming the zeolite-like imidazolate structure:other substances).

[0034] Example 5 Composite E was obtained in the same manner as in Example 1, except that the mass ratio of the components (basic zinc carbonate:2-methylimidazole) was 1.00:0.33, the rotation speed was 100 rpm, and the grinding and mixing time was 6 hours. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite E showed a type I adsorption isotherm and was a material with micropores. PXRD measurement confirmed that the obtained Composite E was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from the zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite E was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 40:60 (substance forming the zeolite-like imidazolate structure:other substances).

[0035] Example 6 Composite F was obtained in the same manner as in Example 1, except that the mass ratio of the components (basic zinc carbonate:2-methylimidazole) was 1.00:0.65, the rotation speed was 100 rpm, and the grinding and mixing time was 6 hours. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite F showed a type I adsorption isotherm and was a material with micropores. PXRD measurement confirmed that the obtained Composite F was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from the zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite F was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 51:49 (substance forming the zeolite-like imidazolate structure:other substances).

[0036] Example 7: 2.00 g of Composite E prepared in Example 5, 20 ml of purified water, and a stir bar were added to a 70 ml container (mayonnaise jar) and stirred for 5 minutes to obtain a suspension containing a solid product. The solid product was filtered from the resulting suspension and dried at 50°C for 18 hours to obtain Composite G. Gas adsorption / desorption behavior and pore structure evaluation of the resulting Composite G demonstrated that it possessed H4-type hysteresis in the relative pressure range of 0.4 to 1.0 and possessed micropores. PXRD analysis confirmed that the resulting Composite G was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite G was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 56:44 (substance forming the zeolite-like imidazolate structure:other substances).

[0037] Example 8 Composite H was obtained in the same manner as in Example 7, except that 20 mL of 0.05 M hydrochloric acid aqueous solution was used instead of pure water. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite H showed that it had H4-type hysteresis in the relative pressure range of 0.4 to 1.0 and was a material with micropores. PXRD measurement confirmed that the obtained Composite H was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from the zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite H was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 48:52 (substance forming the zeolite-like imidazolate structure:other substances).

[0038] Example 9 Composite I was obtained in the same manner as in Example 7, except that a 0.05 M aqueous solution of sodium carbonate was used instead of pure water. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite I indicated that it had H4-type hysteresis in the relative pressure range of 0.4 to 1.0 and was a material with micropores. PXRD measurement confirmed that the obtained Composite I was a composite containing a zeolite-like imidazolate structure and zinc carbonate. Thermogravimetric analysis confirmed the thermal decomposition behavior derived from zinc carbonate at 200°C to 300°C, and the thermal decomposition behavior derived from the zeolite-like imidazolate structure at 550°C to 800°C. Furthermore, the ratio of the substance forming the zeolite-like imidazolate structure to the other substances in the obtained composite I was calculated from the rate of change of the TG curve from 550°C to 800°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 57:43 (substance forming the zeolite-like imidazolate structure:other substances).

[0039] Comparative Example 1: The gas adsorption / desorption behavior and pore structure of ZIF-8, a reagent sold by Sigma-Aldrich, were evaluated. The material exhibited a type I adsorption isotherm and had micropores without hysteresis. PXRD measurements confirmed that ZIF-8 contained only a zeolite-like imidazolate structure. Thermogravimetric analysis confirmed that the thermal decomposition behavior was solely attributable to the zeolite-like imidazolate structure at temperatures between 550°C and 800°C. The reduction rate was 39%.

[0040] Example 10: Composite J was obtained in the same manner as in Example 1, except that zirconium chloride oxide octahydrate and disodium terephthalate were used, and the mass ratio of the components was zirconium chloride oxide octahydrate:disodium terephthalate = 1.00:0.65. The gas adsorption / desorption behavior and pore structure evaluation of the obtained composite J indicated that it was a material having micropores and mesopores. PXRD measurement confirmed that the obtained composite J was a composite containing a zeolite-like terephthalate structure, zirconium chloride oxide, and sodium chloride. Thermogravimetric analysis confirmed thermal decomposition behavior derived from metal chlorides at 800°C to 850°C, and thermal decomposition behavior derived from the zeolite-like terephthalate structure at 450°C to 600°C. Furthermore, the ratio of the substance forming the zeolite-like terephthalate structure to the other substances in the obtained composite J was calculated from the rate of change of the TG curve from 450°C to 600°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 17:83 (substance forming the zeolite-like terephthalate structure:other substances).

[0041] Example 11 Composite K was obtained in the same manner as in Example 1, except that zirconium chloride oxide octahydrate and disodium terephthalate were used, and methanol was added as a solvent, resulting in a mass ratio of zirconium chloride oxide octahydrate:disodium terephthalate:methanol = 1.00:0.65:1.00. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite K revealed that it was a material having micropores and mesopores. PXRD measurement confirmed that the obtained Composite K was a composite containing a zeolite-like terephthalate structure, zirconium chloride oxide, and sodium chloride. Thermogravimetric analysis confirmed thermal decomposition behavior derived from metal chlorides at 800°C to 850°C, and thermal decomposition behavior derived from the zeolite-like terephthalate structure at 450°C to 600°C. Furthermore, the ratio of the substance forming the zeolite-like terephthalate structure to the other substances in the obtained composite K was calculated from the rate of change of the TG curve from 450°C to 600°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 26:74 (substance forming the zeolite-like terephthalate structure:other substances).

[0042] Example 12 Composite L was obtained in the same manner as in Example 1, except that zirconium chloride oxide octahydrate and disodium terephthalate were used, and pure water was added as a solvent, resulting in a mass ratio of zirconium chloride oxide octahydrate:disodium terephthalate:pure water = 1.00:0.65:1.00. The gas adsorption / desorption behavior and pore structure evaluation of the obtained Composite L revealed that it was a material having micropores and mesopores. PXRD measurement confirmed that the obtained Composite L was a composite containing a zeolite-like terephthalate structure, zirconium chloride oxide, and sodium chloride. Thermogravimetric analysis confirmed thermal decomposition behavior derived from metal chlorides at 800°C to 850°C, and thermal decomposition behavior derived from the zeolite-like terephthalate structure at 450°C to 600°C. Furthermore, the ratio of the substance forming the zeolite-like terephthalate structure to the other substances in the obtained composite L was calculated from the rate of change of the TG curve from 450°C to 600°C in the rate of change of the TG curve from 100°C to 850°C, and was found to be 24:76 (substance forming the zeolite-like terephthalate structure:other substances).

[0043] (Comparative Example 2) Gas adsorption / desorption behavior and pore structure evaluation were performed on zirconium benzenedicarboxylate MOF, a reagent sold by Strem Chemicals, Inc. The material exhibited a type I adsorption isotherm and had micropores without hysteresis. PXRD measurement confirmed that the zirconium benzenedicarboxylate MOF had only a zeolite-like terephthalate structure. Thermogravimetric analysis confirmed that the thermal decomposition behavior was solely attributable to the zeolite-like terephthalate structure at 450°C to 600°C. The reduction rate was 36%.

[0044] The composite of the present invention has a zeolite-like imidazolate structure or terephthalate structure as a constituent element, and therefore can provide the inherent functions of these structures, such as adsorbents. Examples include use as adsorbents for inorganic gas components, organic gas components, and organic components, such as nitrogen gas, hydrogen, carbon monoxide, carbon dioxide, helium, and argon. Furthermore, since the composite contains a water-insoluble metal salt or metal chloride as a constituent element, it is expected to simultaneously and comprehensively exhibit the inherent functions of the water-insoluble metal salt or metal chloride in addition to the functions of the zeolite-like imidazolate structure or terephthalate structure. Based on the above functions, the composite of the present invention can be used as a functional material for a variety of applications. Examples include gas storage and gas separation, reaction catalysts, and gas sensors.

Claims

1. A complex comprising a water-insoluble metal salt or metal chloride, and a metal organic framework, wherein the metal organic framework comprises a metal component of the water-insoluble metal salt or metal chloride, and an organic ligand capable of coordinating with the metal component, and is a metal organic framework having a zeolite-like imidazolate structure or terephthalate structure.

2. The complex of claim 1, wherein the metal of said water-insoluble metal salt or metal chloride is zinc or zirconium, and said organic ligand is imidazole or terephthalic acid, or a derivative thereof.

3. The composite according to claim 1 or 2, which has hysteresis in gas adsorption and desorption.

4. A method for producing the complex according to claim 1, comprising a mixing step of mixing a water-soluble metal salt with an organic ligand, and a grinding and mixing step of grinding and mixing the mixture obtained in the mixing step.

5. The method for producing a composite according to claim 4, wherein the mixing step and the pulverizing and mixing step are both carried out under normal temperature and pressure conditions.

6. The method for producing a complex according to claim 4 or 5, wherein the grinding and mixing step is carried out in the presence of water or an alcohol in an amount equal to or less than the total amount of the water-soluble metal salt and the organic ligand.

7. The method for producing a complex according to claim 4 or 5, further comprising a washing step of washing the complex obtained in the grinding and mixing step, after the grinding and mixing step.

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