Production method of metal organic structure

Abstract

To provide a production method for obtaining a metal organic structure by reacting an organic compound with a metal salt(s) in an aqueous solvent, which enables obtaining a metal organic structure having good filterability.SOLUTION: A method for producing a metal organic structure includes: continuously or intermittently adding a polyvalent carboxylic acid or an alkali metal salt of the polyvalent carboxylic acid, A, and one or more metal compounds, B to a reaction vessel; and mixing in the reaction vessel the polyvalent carboxylic acid or the alkali metal salt of the polyvalent carboxylic acid, A, with the metal compounds, B, in a water-containing solvent, D, in the presence of a base, C, wherein the pH of the mixture in the reaction vessel is maintained to 6 or less until 0.3 equivalent of the metal compounds, B, in the reaction vessel come into contact with 0.3 equivalent of the polyvalent carboxylic acid or the alkali metal salt of the polyvalent carboxylic acid, A, and until 0.8 equivalent of the metal compounds, B, come into contact with 0.8 equivalent of the polyvalent carboxylic acid or the alkali metal salt of the polyvalent carboxylic acid, A.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a metal-organic framework. [Background technology]

[0002] Metal organic frameworks, also known as porous coordination polymers, are a type of material that forms a porous structure through coordination bonds between metal ions and organic ligands, and are expected to be used for gas adsorption / desorption and as catalysts.

[0003] The metal organic framework can be produced by reacting a polycarboxylic acid, which serves as an organic ligand, with a metal compound in a solvent, and then, if necessary, performing a heat treatment for a predetermined period of time.

[0004] For example, Patent Document 1 describes a method in which biphenyl-3,3',5,5'-tetracarboxylic acid, Al(NO3)3·9H2O, and piperazine are mixed and dispersed in water, nitric acid is added to the resulting white slurry, the slurry is transferred to an autoclave, sealed, and heated at 210°C for 3 days to obtain a metal organic framework. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2013 / 144628 Summary of the Invention [Problem to be solved by the invention]

[0006] In the method of obtaining a metal organic framework by reacting a polycarboxylic acid with a metal compound in a solvent, there is a method using an organic solvent such as N,N-dimethylformamide as the solvent. However, as disclosed in Patent Document 1, the method of producing a metal organic framework using water as the solvent does not require a step of removing the organic solvent, and is therefore advantageous in terms of improving productivity.

[0007] However, the inventors of the present invention have conducted studies and found that the method disclosed in Patent Document 1, in which a polycarboxylic acid and a metal compound are reacted in an aqueous solvent to obtain a metal organic framework, may result in poor filterability when the metal organic framework is extracted from the reaction solution by filtration.

[0008] Therefore, an object of the present disclosure is to provide a production method for obtaining a metal organic framework by reacting a polycarboxylic acid with a metal compound in an aqueous solvent, which can obtain a metal organic framework with good filterability. [Means for solving the problem]

[0009] The present disclosure that achieves the above object is as follows. [1] A method for producing a metal organic framework, comprising continuously or intermittently adding one or more of a polycarboxylic acid or an alkali metal salt of a polycarboxylic acid A and a metal compound B to a reaction vessel, and mixing the polycarboxylic acid or the alkali metal salt of a polycarboxylic acid A and the metal compound B in the presence of a base C in a solvent D containing water within the reaction vessel, a method for producing a metal organic framework, wherein the pH of the mixture in the reaction vessel is adjusted to 6 or less until 0.3 equivalents of the metal compound B comes into contact with 0.3 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid in the reaction vessel, and the pH of the mixture in the reaction vessel is maintained at 6 or less until 0.8 equivalents of the metal compound B comes into contact with 0.8 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid. [2] The method according to [1], wherein the difference between the maximum and minimum pH values from the time when 0.3 equivalents of the metal compound B contacts with 0.3 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid until 0.8 equivalents of the metal compound B contacts with 0.8 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid is 4 or less. [3] The method according to [1] or [2], wherein an acid-base mixture obtained by mixing the polycarboxylic acid or the alkali metal salt of the polycarboxylic acid A with at least a part of the base C is continuously or intermittently added to the reaction vessel. [4] The production method according to any one of [1] to [3], wherein an acid-base mixture containing the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid and a portion of the base C is continuously or intermittently added to the reaction vessel through a first addition port, and while the addition of the acid-base mixture is continuing, a portion of the base C is continuously or intermittently added to the reaction vessel through a second addition port. [5] The method according to [3] or [4], wherein the metal compound B is placed in the reaction vessel, and the acid-base mixture is added to the reaction vessel. [6] The method according to [3] or [4], wherein the metal compound B is added continuously or intermittently to the reaction vessel through a third addition port while the addition of the acid-base mixture is continuing. [7] The production method according to [1] or [2], wherein an acid-base mixture containing the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid and at least a part of the base C is continuously or intermittently added to the reaction vessel through a first addition port, and while the addition of the acid-base mixture is continuing, the metal compound B is continuously or intermittently added to the reaction vessel through a third addition port. [8] The method according to any one of [1] to [7], wherein the content of water in 100% by mass of the solvent D is 70% by mass or more. [Effects of the Invention]

[0010] According to the production method of the present disclosure, a metal organic framework with excellent filterability can be obtained. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a graph showing pH behavior in Example 1-1 described below. [Figure 2] 1 is a graph showing pH behavior in Comparative Example 1 described below. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure relates to a method for producing a metal organic framework by continuously or intermittently adding one or more of a polycarboxylic acid or an alkali metal salt of a polycarboxylic acid A (hereinafter, sometimes referred to as "polycarboxylic acid or its salt A") and a metal compound B to a reaction vessel, and mixing the polycarboxylic acid or its salt A and the metal compound B in the reaction vessel in a solvent D containing water in the presence of a base C. First, the polycarboxylic acid or its salt A, metal compound B, base C, and water-containing solvent D used in the present disclosure will each be described.

[0013] [Polycarboxylic acid or alkali metal salt of polycarboxylic acid A] Polycarboxylic acids are R(COOH) n (R is an n-valent group, n is an integer of 2 or more), and one or more types may be used. R may be an aliphatic chain hydrocarbon group, an aliphatic cyclic hydrocarbon group, an aliphatic heterocyclic hydrocarbon group (a group in which one or more carbon atoms of an aliphatic cyclic hydrocarbon group are replaced with heteroatoms), an aromatic hydrocarbon group, or an aromatic heterocyclic hydrocarbon group (a group in which one or more carbon atoms of an aromatic hydrocarbon group are replaced with heteroatoms), preferably an aromatic hydrocarbon group and / or an aromatic heterocyclic hydrocarbon group, more preferably an aromatic hydrocarbon group. The number of carbon atoms in R may be 2 to 30, or 4 to 24, and preferably 6 to 18. n may be 2 or more and 4 or less, preferably 2 or more and 3 or less, and more preferably 2.

[0014] The above-mentioned aliphatic chain hydrocarbon group, aliphatic cyclic hydrocarbon group, aliphatic heterocyclic hydrocarbon group, aromatic hydrocarbon group, and aromatic heterocyclic hydrocarbon group may further contain one or more functional groups X which are -OH and / or -NH.

[0015] The aliphatic chain hydrocarbon group may be linear or branched, and may be a saturated or unsaturated hydrocarbon group. Examples of the aliphatic chain hydrocarbon group include groups obtained by removing n hydrogen atoms from ethane, ethylene, acetylene, butane, butene, or hexane.

[0016] Examples of the aliphatic cyclic hydrocarbon group include groups in which n hydrogen atoms have been removed from cyclopropane, cyclobutane, cyclohexane, cyclooctane, norbornene, or adamantane.

[0017] Examples of the aliphatic heterocyclic hydrocarbon group include groups in which n hydrogen atoms have been removed from pyrrolidine, piperidine, piperazine, or morpholine.

[0018] The preferred ranges for the number of carbon atoms in the aromatic hydrocarbon group are, in order, 6 or more and 30 or less, 6 or more and 24 or less, 6 or more and 18 or less, 6 or more and 12 or less, and 6 or more and 10 or less. Specifically, groups in which n (preferably 2 or 3) hydrogen atoms have been removed from benzene or biphenyl are preferred, and groups in which n (preferably 2 or 3) hydrogen atoms have been removed from benzene are particularly preferred.

[0019] The aromatic hydrocarbon group may be any of the following formulae (A-1) to (A-9), preferably any of (A-1) to (A-3) and (A-5), more preferably (A-1), (A-2) or (A-5), and even more preferably (A-1) or (A-2). In the following formulae (A-1) to (A-9), * denotes a bond, and is bonded to —COOH at *.

[0020] [ka]

[0021] In the above (A-1) to (A-9), at least one of the hydrogen atoms bonded to the carbon atoms may be substituted with -OH and / or -NH2, or the hydrogen atoms bonded to the carbon atoms may not be substituted.

[0022] When polycarboxylic acid A contains one or two R(COOH)2 where R is (A-1) or (A-2), the total content of R(COOH)2 where R is (A-1) or (A-2) in 100% by mass of polycarboxylic acid A is preferably 80% by mass or more, more preferably 90% by mass or more, and most preferably 100% by mass.

[0023] Examples of aromatic heterocyclic hydrocarbon groups include groups in which n (e.g., 2 or 3) hydrogen atoms have been removed from pyrrole, pyrazole, imidazole, thiazole, oxazole, pyridine, pyrimidine, pyridazine, pyrazine, or triazine, and groups in which n (e.g., 2 or 3) hydrogen atoms have been removed from pyrrole or pyrazine are preferred.

[0024] Polycarboxylic acids are R(COOH) where R is an aromatic hydrocarbon group. n It is preferable that R in 100% by mass of the polycarboxylic acid contains one or more of the following: R(COOH) n The total amount of one or more of these may be more than 50% on a molar basis, preferably 80% or more, and more preferably 100%. n and R(COOH) where R is an aromatic heterocyclic hydrocarbon group. n It is also preferable that the compound contains one or more of the following, particularly one or two of R(COOH)2 in which R is the above formula (A-1) or (A-2), and R(COOH)2 in which R is a group obtained by removing n hydrogen atoms from pyrrole or pyrazine. n It is preferable that the polycarboxylic acid contains one or more of the following (particularly when n is 2): R(COOH) where R is an aromatic hydrocarbon group. n and R(COOH) where R is an aromatic heterocyclic hydrocarbon group. nWhen one or more of the above are contained, the ratio of R(COOH) where R is an aromatic hydrocarbon group to the total amount of polycarboxylic acids is n and R(COOH) where R is an aromatic heterocyclic hydrocarbon group. n The total amount of one or more of the above may be 80% or more, preferably 100%, on a molar basis. n and R(COOH) where R is an aromatic heterocyclic hydrocarbon group. n When R is an aromatic hydrocarbon group, R(COOH) n and R(COOH) where R is an aromatic heterocyclic hydrocarbon group. n R(COOH) where R is an aromatic hydrocarbon group relative to the total amount of one or more of the above. n The total amount of one or more of these may be more than 50%, or may be 60% or more, or preferably 70% or more, and may be 90% or less on a molar basis.

[0025] The alkali metal salt of the polycarboxylic acid is preferably a Li salt, a Na salt, a K salt or a Rb salt of the above-mentioned polycarboxylic acid, more preferably a Na salt, and is preferably R(COOH) where R is an aromatic heterocyclic hydrocarbon group. n It is more preferable that it is a Na salt of the group obtained by removing n (particularly 2) hydrogen atoms from pyrazine.

[0026] The polycarboxylic acid or salt thereof A is preferably polycarboxylic acid A (that is, does not contain an alkali metal salt of a polycarboxylic acid).

[0027] [Metal compound B] The metal in metal compound B may be at least one selected from the group consisting of elements in periods 4 to 6 and groups 3 to 12 of the periodic table, Al, Ga, and In. It may also be at least one selected from the group consisting of Al, Ga, In, Ti, Zr, Hf, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, preferably at least one selected from the group consisting of Al, In, Cu, and Zn, with Al being more preferred. Metal compound B may also be a metal sulfate, nitrate, acetate, perchlorate, chloride, bromide, or alkoxide, preferably a sulfate or perchlorate, more preferably a sulfate, and any of the metal compounds may be a hydrate. The metal compound preferably contains Al sulfate, i.e., Al2(SO4)3, and Al2(SO4)3 may be a hydrate. One or more metal compounds B may be used.

[0028] The molar amount of metal in metal compound B is R(COOH) n or a salt thereof.

[0029] The polycarboxylic acid or its salt A and the metal compound B can be combined in any of the preferred embodiments described above, but combinations other than the combination in which the polycarboxylic acid is 2,4-pyridinedicarboxylic acid and the metal compound is CoCl2 are preferred.

[0030] [Base C] In the present disclosure, in order to obtain a metal organic framework by reacting a polycarboxylic acid or its salt A with a metal compound B in a solvent D containing water, it is important to carry out the reaction in the presence of a base C. If the reaction is carried out without using the base C, the metal organic framework may not be obtained or the amount of impurities other than the metal organic framework may increase.

[0031] The base C may be an inorganic base or an organic base, and one or more kinds of bases may be used. Examples of inorganic bases include hydroxides, carbonates, hydrogencarbonates, phosphates, carboxylates, and alkoxides of alkali metals or alkaline earth metals, with alkali metal hydroxides being preferred, and NaOH being more preferred. Examples of the organic base include triethylamine, N,N-diisopropylethylamine, piperidine, pyridine, 4-(N,N-dimethylamino)pyridine, and pyrazine, with triethylamine or pyrazine being preferred, and triethylamine being more preferred.

[0032] The amount of base C (total amount when multiple types are used) may be 1.5 to 5 moles or 2 to 4 moles per mole of polycarboxylic acid or salt thereof A (total amount when multiple types are used).

[0033] [Solvent D] Solvent D contains water. The content of water in 100% by mass of solvent D may be 70% by mass or more and 100% by mass or less, or 80% by mass or more and 100% by mass or less, or even 100% by mass. Examples of solvents other than water that may be contained in solvent D include organic solvents such as one or more alcohol-based solvents, amide-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, with amide-based solvents being preferred. Examples of amide-based solvents include N,N-dimethylformamide and N,N-dimethylacetamide.

[0034] Next, the adjustment of pH in the production method of the present disclosure and specific procedures in a preferred embodiment will be described in detail. In the production method of the present disclosure, it is important to adjust the pH of the mixture in the reaction vessel to 6 or less before 0.3 equivalents of metal compound B contacts with 0.3 equivalents of polycarboxylic acid or a salt thereof A in the reaction vessel, and to maintain the pH of the mixture in the reaction vessel at 6 or less until 0.8 equivalents of metal compound B contacts with 0.8 equivalents of polycarboxylic acid or a salt thereof A.

[0035] The aforementioned 0.3 equivalents of the metal compound B and the polycarboxylic acid or its salt A means 0.25 equivalents or more and less than 0.35 equivalents, the aforementioned 0.8 equivalents of the metal compound B and the polycarboxylic acid or its salt A means 0.75 equivalents or more and less than 0.85 equivalents, and the aforementioned pH of 6 or less means a pH of less than 6.5.

[0036] In the production method of the present disclosure, the pH of the mixture in the reaction vessel is kept below 6.5 until 0.35 equivalents of the metal compound B contacts with 0.35 equivalents of the polycarboxylic acid or the alkali metal salt of the polycarboxylic acid A, and the pH of the mixture in the reaction vessel is kept below 6.5 until 0.85 equivalents of the metal compound B contacts with 0.85 equivalents of the polycarboxylic acid or the alkali metal salt of the polycarboxylic acid A.

[0037] One equivalent of the metal compound B and one equivalent of the polycarboxylic acid or its salt A refer to the molar amounts of the metal compound B and the polycarboxylic acid or its salt A that theoretically allow the maximum amount of metal organic framework to be formed from the metal compound B and the polycarboxylic acid or its salt A used, respectively.

[0038] The pH of the mixture in the reaction vessel is adjusted to 6 or less until 0.3 equivalents of the metal compound B contacts with 0.3 equivalents of the polycarboxylic acid or its salt A (hereinafter, may be simply referred to as "0.3 equivalent contact"), and the pH of the mixture in the reaction vessel is maintained at 6 or less until 0.8 equivalents of the metal compound B contacts with 0.8 equivalents of the polycarboxylic acid or its salt A (hereinafter, may be simply referred to as "0.8 equivalent contact"), whereby the metal in the metal compound B is in the state of a metal ion (for example, in the case of Al, Al 3+ As long as this requirement is met, there are no particular limitations on the pH before 0.3 equivalents of the metal compound B and the polycarboxylic acid or its salt A are contacted, or on the pH after 0.8 equivalents of the metal compound B and the polycarboxylic acid or its salt A are contacted.

[0039] The pH adjusted until 0.3 equivalents are contacted and the pH maintained until 0.8 equivalents are contacted are both preferably 5.5 or less, more preferably 5.0 or less, and the lower limit may be, for example, 2.5 or 3.0. Setting these pHs within such ranges is preferable from the viewpoint of improving the filterability of the metal organic framework produced. Furthermore, the difference between the maximum and minimum pH values from 0.3 equivalent contact to 0.8 equivalent contact (i.e., from 0.25 equivalent contact to 0.85 equivalent contact) is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less, and the smaller the better, but it may be 0.01 or more. Setting the difference between the maximum and minimum pH values within this range is preferable from the viewpoint of improving the filterability of the metal organic framework produced. Furthermore, the difference between the maximum and minimum pH values from the time of contact with 0.35 equivalents to the time of contact with 0.85 equivalents is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. The smaller the difference, the better, but it may be 0.01 or more.

[0040] "Continuously or intermittently adding one or more of the polycarboxylic acid or its salt A and the metal compound B to the reaction vessel" means that they are added over a predetermined period of time rather than all at once. The average addition rate from the addition of the polycarboxylic acid or its salt A to the end of the addition is, for example, 1 mmol / min to 10 mmol / min. The average addition rate from the addition of the metal compound B to the end of the addition is, for example, 0.5 mmol / min to 5 mmol / min.

[0041] More specifically, in the production method of the present disclosure, it is preferable to continuously or intermittently add an acid-base mixture obtained by mixing a polycarboxylic acid or its salt A with at least a portion of a base C to the reaction vessel (mode (x)). The acid-base mixture may contain a salt formed between the polycarboxylic acid and the base. By employing mode (x), the polycarboxylic acid or its salt A and the base C can be added uniformly to the reaction vessel, which is preferable because it allows the reaction of the polycarboxylic acid or its salt A with the metal compound B in the solvent D to proceed uniformly.

[0042] In the embodiment (x), the polycarboxylic acid or its salt A may be mixed with all of the base C (embodiment (x1)), or the polycarboxylic acid or its salt A may be mixed with only a portion of the base C (embodiment (x2)). In both of the embodiments (x1) and (x2) (i.e., the entire embodiment (x)), the metal compound B may be added continuously or intermittently to the reaction vessel through another addition port (third addition port) while the addition of the acid-base mixture (first addition port) is continuing, or the metal compound B may be pre-charged in the reaction vessel, and the acid-base mixture may be added to this reaction vessel. In the embodiment (x1), it is also preferable to pre-charge the metal compound B in the reaction vessel, and then add the acid-base mixture to this reaction vessel.

[0043] Of the aspects (x), aspect (x2) is preferred. In aspect (x2), a portion of the base C (meaning a base different from the base C mixed with the polycarboxylic acid or its salt A, which may be the entire amount or a portion of the remaining base C mixed with the polycarboxylic acid or its salt A) may be added continuously or intermittently to the reaction vessel through another addition port while the acid-base mixture is being added (aspect (x2-1)). Alternatively, the base C may be pre-charged in the reaction vessel, to which the acid-base mixture is added (aspect (x2-2)). Aspect (x2-1) is more preferred. That is, in aspect (x2-1), an acid-base mixture containing the polycarboxylic acid, its salt A, and a portion of the base C is added continuously or intermittently to the reaction vessel through a first addition port, and a portion of the base C is added continuously or intermittently to the reaction vessel through a second addition port while the acid-base mixture is being added. In addition, in the embodiment (x2), the part of the base other than the base C mixed with the polycarboxylic acid or its salt A may be the same type as the base C mixed with the polycarboxylic acid or its salt, or may be a different type.

[0044] In any of the embodiments (x1), (x2-1), and (x2-2), metal compound B (partial or all) may be charged to the reaction vessel, or metal compound B (partial or all) may be added to the reaction vessel continuously or intermittently from another addition port (third addition port) while the addition of the acid-base mixture is continuing, or part of metal compound B may be charged to the reaction vessel, and the remaining metal compound B of the metal compound B charged to the reaction vessel may be added to the reaction vessel continuously or intermittently from another addition port (third addition port) while the addition of the acid-base mixture is continuing.

[0045] In particular, in embodiment (x2-1), it is preferable to add metal compound B (particularly, all of metal compound B) continuously or intermittently to the reaction vessel through another addition port (third addition port) while the addition of the acid-base mixture continues.

[0046] When the base C and / or the metal compound B are continuously or intermittently added to the reaction vessel from another addition port (second or third addition port) while the addition of the acid-base mixture is continuing, the period during which the addition of the acid-base mixture is continuing may be the entire period or a part of the period during which the addition of the acid-base mixture is continuing.

[0047] In this specification, the first to third addition ports are different addition ports, and are not the same.

[0048] In the production method of the present disclosure, a strong acid (e.g., sulfuric acid or nitric acid) or a buffer solution (e.g., phosphate buffer solution, 2-amino-2-(hydroxymethyl)propane-1,3-diol, citric acid, phosphoric acid, diethylbarbituric acid, or boric acid) and a polycarboxylic acid may be placed in a reaction vessel, and a metal compound may be added to the reaction vessel (mode y). In this case, base C may be placed in the reaction vessel together with the polycarboxylic acid or the like, or may be added to the reaction vessel together with the metal compound. Furthermore, solvent D containing water may be placed in the reaction vessel together with the polycarboxylic acid or the like, or a mixture of the metal compound and solvent D may be added to the reaction vessel. It is preferred that solvent D containing water is placed in the reaction vessel together with the polycarboxylic acid or the like, and a mixture of the metal compound and solvent D is added to the reaction vessel.

[0049] In the present disclosure, including preferred embodiments, it is preferable that the polycarboxylic acid or its salt A, the metal compound B, and the base C are each mixed with a solvent D to form a mixed solution, and then added to a reaction vessel. In this case, the reaction vessel may or may not contain the solvent D.

[0050] In the present disclosure including preferred embodiments, the amount of polycarboxylic acid or its salt A, the amount of metal compound B, and the amount of base C are preferably within the following ranges, respectively. The amount of the polycarboxylic acid or its salt A relative to 1 L of the solvent D may be 0.05 to 1.5 mol, or may be 0.1 to 1 mol. The amount of metal compound B relative to 1 L of solvent D may be 0.01 to 1 mol, or may be 0.05 to 0.7 mol. The amount of base C relative to 1 L of solvent D may be 0.1 to 3 mol, or may be 0.5 to 2.5 mol.

[0051] In the production method of the present disclosure, additives other than the polycarboxylic acid or its salt A, the metal compound B, the base C, and the solvent D may be contained, and the amount of the additive may be 3 parts by mass or less, 2 parts by mass or less, or 1 part by mass or less, or preferably 0 part by mass, relative to 100 parts by mass of the total amount of the polycarboxylic acid or its salt A, the metal compound B, the base C, and the solvent D.

[0052] In the present disclosure, the temperature when mixing the polycarboxylic acid or its salt A and the metal compound B is, for example, 15 to 45°C, and may be 20 to 30°C. After mixing the entire amount of the polycarboxylic acid or its salt A with the entire amount of the metal compound B (preferably after mixing all of the polycarboxylic acid or its salt A, the metal compound B, the base C, and the solvent D), the mixture is preferably heated at 50 to 150°C for 5 to 30 hours, and more preferably at 70 to 120°C for 8 to 20 hours. The pressure during heating may be 2.0 MPa or less, 1.8 MPa or less, or 1.7 MPa or less, or may be atmospheric pressure. After heating, a suspension is usually obtained, and the suspension is filtered, washed with water, and dried at 60 to 100°C for about 5 to 20 hours to obtain a metal-organic framework.

[0053] The filtration resistance of the metal organic framework obtained by the production method of the present disclosure, evaluated according to the method in the Examples described below, can be 80% or less, preferably 70% or less, more preferably 60% or less, and particularly preferably 30% or less, of the case where the types and amounts of polycarboxylic acid or its salt A, metal compound B, base C, and solvent D used are the same but the pH adjustment of the present disclosure is not performed. 12 (m / kg) or less, preferably 1.0 × 10 11 (m / kg) or less, and more preferably 7.0 × 10 10 (m / kg) or less, and more preferably 5.0 × 10 10 (m / kg) or less, and 5.0 × 10 9 (m / kg) or more.

[0054] The BET specific surface area of the metal organic framework obtained by the production method of the present disclosure is, for example, 130 to 850 m 2 / g, 600m 2 / g~850m 2 / g is preferred, 650m 2 / g~850m 2 / g is more preferable, and 700m 2 / g~850m 2 The BET specific surface area of the metal organic framework is particularly preferably 600 m 2 / g~700m 2 It is also preferred that the saturation be 1 / g.

[0055] The metal organic framework produced by the production method of the present disclosure is suitable for use in, for example, adsorption and removal of gases and organic molecules. Examples of gases include water (water vapor), carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbons having 1 to 4 carbon atoms, rare gases, hydrogen sulfide, ammonia, sulfur oxides, nitrogen oxides, and siloxanes. Examples of organic molecules include hydrocarbons having 5 to 8 carbon atoms, alcohols having 1 to 8 carbon atoms, aldehydes having 1 to 8 carbon atoms, carboxylic acids having 1 to 8 carbon atoms, ketones having 1 to 8 carbon atoms, amines having 1 to 8 carbon atoms, esters having 1 to 8 carbon atoms, and amides having 1 to 8 carbon atoms. The organic molecules may contain an aromatic ring. [Example]

[0056] The present disclosure will be described in more detail below with reference to examples. The present disclosure is not limited to the following examples, and can of course be implemented with appropriate modifications within the scope of the above and below-described aims, and all such modifications are within the technical scope of the present disclosure.

[0057] The examples and comparative examples described below were evaluated by the following methods.

[0058] (1) Calculation of filtration resistance Using a metal filter that can be pressurized and filter paper (Whatman qualitative filter paper, grade 2, diameter 47 mm), the suspension after the reaction was filtered under pressure at 40 kPa at a measurement temperature of 25°C, and the filtration rate v [m / s] was measured. From the results, the filtration resistance α was calculated based on the Ruth equation. m [m / kg] was calculated.

[0059] (2) BET specific surface area Since the adsorption area of nitrogen molecules is known in advance, the amount of gas molecules adsorbed only on the sample surface was measured, and the surface area of the sample was measured using the BET adsorption isotherm. Sample preparation: To remove water from the sample, the sample was heated under reduced pressure at 10 Pa or less and 200°C overnight. Equipment: Microtrac BEL Co., Ltd. BELSORP-mini Pretreatment conditions: (ai) Place a volume-reducing glass rod (for standard sample tubes) in the standard sample tube and plug it with a quick seal. Prepare this sample tube set with the samples to be measured (up to three samples per measurement), connect it to the pretreatment device (BELPREP VACII), evacuate the air from inside the sample tube, and then introduce N2 gas (purity 99.999% or higher) up to atmospheric pressure. (a-ii) Then, remove the sample tube from the pretreatment machine and measure its weight three times using a precision balance (displaying four or more decimal places) to obtain the average (W1). When using a precision balance, use an ionizer to eliminate the effects of static electricity. (a-iii) Weigh out approximately 50 mg of the sample to be measured onto a piece of medicine paper, and use a long-footed funnel to place the sample directly into the spherical part at the bottom of the standard sample tube. (a-iv) Return the glass rod to the sample tube, plug it with a quick seal, and then measure the total weight once to provisionally confirm the amount of sample added. (av) The sample tube containing the sample is connected to the pretreatment device, and the inside of the sample tube is evacuated. (a-vi) After the pressure inside the sample tube has reached a sufficiently low level, heating begins (vacuuming continues). Measurement conditions: (bi) After the pretreatment (vacuum heating) is completed, the sample tube is cooled while being kept under reduced pressure, and after it has returned to room temperature, N2 gas is introduced up to atmospheric pressure and the tube is removed from the apparatus. (b-ii) After pretreatment, measure the weight of the sample tube containing the sample three times using a precision balance and obtain the average (W2). Calculate W2 - W1 to obtain the weight of the sample. (b-iii) Enter the sample weight and information on N2 gas at liquid nitrogen temperature (such as the second virial coefficient) into the measurement software, enter the relative pressure you want to measure, and press the measurement start button. Then, following the software's instructions, the user installs a Dewar vessel filled with liquid nitrogen and a sample tube, and then performs measurements.

[0060] (3) pH measurement Portions of the liquid in the reaction vessel were sampled at various times during the dropwise addition of the solution, and the pH was measured using a pH meter (personal pH meter PH71-11JAA, manufactured by Yokogawa Electric Corporation).

[0061] (4) Identification of metal-organic frameworks The substances produced in the examples and comparative examples were measured using a powder X-ray diffraction (PXRD) device (manufactured by Rigaku Corporation) under the following conditions, and the peak patterns derived from the metal organic framework were confirmed. Source: Cu Measurement range: 2θ=3~40° Step size: 0.01° Scanning speed: 3° / min Measurement temperature: room temperature (25℃)

[0062] Example 1-1 Solution A was prepared by mixing 65.0 mmol of isophthalic acid, 143 mmol of triethylamine, and 238 mL of water. Solution B was prepared by mixing 33.8 mmol of Al2(SO4)3·nH2O (n = 14-18) and 31.5 mL of water. At 20-30°C, solutions A, B, and 52 mmol of triethylamine were simultaneously added dropwise to the reactor, each over 30 minutes. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0063] Example 1-2 Solution A was prepared by mixing 65.0 mmol of isophthalic acid, 195 mmol of triethylamine, and 238 mL of water. Solution B was prepared by mixing 33.8 mmol of Al2(SO4)3·nH2O (n = 14-18) and 31.5 mL of water. Solution B was added to a reactor, and solution A was added dropwise to the reactor over 30 minutes at 20-30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0064] Examples 1-3 Solution A was prepared by dissolving 91 mmol of isophthalic acid and 200 mmol of triethylamine in 152 ml of water. Separately, solution B was prepared by dissolving 47.3 mmol of Al2(SO4)3·nH2O (n is 14-18) in 43.8 ml of water. At 20-30°C, solutions A and B were added dropwise over 90 minutes to a mixture C of 70 ml of water and 72.8 mmol of triethylamine. The mixture was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and dried in a vacuum drying oven at 80°C for 12 hours to obtain a metal-organic framework.

[0065] Comparative Example 1 Solution A was prepared by mixing 65.0 mmol of isophthalic acid, 195 mmol of triethylamine, and 238 mL of water. Solution B was prepared by mixing 33.8 mmol of Al2(SO4)3·nH2O (n = 14-18) and 31.5 mL of water. Solution A was added to a reactor, and solution B was added dropwise to the reactor over 30 minutes at 20-30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0066] Example 2 Solution A was prepared by mixing 65.0 mmol of isophthalic acid, 129 mmol of triethylamine, 121 mL of water, and 32 mL of N,N-dimethylformamide. Solution B was prepared by mixing 37.05 mmol of Al2(SO4)3·nH2O (n = 14-18) and 34.5 mL of water. Solution A, Solution B, and 55 mmol of triethylamine were simultaneously added dropwise to a reactor at 20-30°C over 30 minutes. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0067] Comparative Example 2 Solution A was prepared by mixing 65.0 mmol of isophthalic acid, 184 mmol of triethylamine, 121 mL of water, and 32 mL of N,N-dimethylformamide. Solution B was prepared by mixing 37.05 mmol of Al2(SO4)3·nH2O (n = 14-18) and 34.5 mL of water. Solution A was added to a reactor, and solution B was added dropwise over 30 minutes at 20-30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0068] Example 3 Solution A was prepared by mixing 104 mmol of isophthalic acid, 26 mmol of 2,5-pyrroledicarboxylic acid, 286 mmol of triethylamine, and 150 mL of water. Solution B was prepared by mixing 67.6 mmol of Al2(SO4)3·nH2O (n = 14-18) and 62.5 mL of water. Solutions A, B, and 104 mmol of triethylamine were simultaneously added dropwise to a reactor at 20-30°C over 30 minutes. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0069] Comparative Example 3 Solution A was prepared by mixing 104 mmol of isophthalic acid, 26 mmol of 2,5-pyrroledicarboxylic acid, 390 mmol of triethylamine, and 150 mL of water. Solution B was prepared by mixing 67.6 mmol of Al2(SO4)3·nH2O (n = 14-18) and 62.5 mL of water. Solution A was added to a reactor, and solution B was added dropwise over 30 minutes at 20-30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0070] Example 4 Solution A was prepared by mixing 72.8 mmol of isophthalic acid, 18.2 mmol of 2,5-pyrroledicarboxylic acid, 32 g of 25% by weight sodium hydroxide solution, and 105 mL of water. Solution B was prepared by mixing 47.3 mmol of Al2(SO4)3·nH2O (n = 14-18) and 43.8 mL of water. 70 g of water was added to a reactor, and at 20-30°C, solutions A, B, and 11.7 g of 25% by weight sodium hydroxide solution were simultaneously added dropwise over 30 minutes. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0071] Comparative Example 4 Solution A was prepared by mixing 72.8 mmol of isophthalic acid, 18.2 mmol of 2,5-pyrroledicarboxylic acid, 43.7 g of 25% by weight sodium hydroxide aqueous solution, and 175 mL of water. Solution B was prepared by mixing 47.3 mmol of Al2(SO4)3·nH2O (n = 14-18) and 43.8 mL of water. Solution A was added to a reactor, and solution B was added dropwise over 30 minutes at 20-30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework. The results are shown in Table 1.

[0072] Example 5 Solution A was prepared by mixing 84.5 mmol of terephthalic acid, 186 mmol of triethylamine, and 148 mL of water. Solution B was prepared by mixing 43.9 mmol of Al2(SO4)3·nH2O (n = 14-18) and 40.6 mL of water. 55.7 g of water was added to a reactor, and at 20-30°C, solutions A, B, and 67.6 mmol of triethylamine were simultaneously added dropwise over 30 minutes. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0073] Comparative Example 5 Solution A was prepared by mixing 84.5 mmol of terephthalic acid, 253.6 mmol of triethylamine, and 203.7 mL of water. Solution B was prepared by mixing 43.9 mmol of Al2(SO4)3·nH2O (n = 14-18) and 40.6 mL of water. Solution A was added to a reactor, and solution B was added dropwise to the reactor over 30 minutes at 20-30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the resulting suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0074] Example 6 Solution A was prepared by dissolving 91 mmol of isophthalic acid and 200 mmol of triethylamine in 152 ml of water. Separately, solution B was prepared by dissolving 47.3 mmol of Al2(SO4)3·nH2O (n is 14-18) in 43.8 ml of water. At 20-30°C, solutions A and B were added dropwise over 90 minutes to a mixture C of 70 ml of water and 9.2 ml of 25 wt% aqueous sodium hydroxide solution. The mixture was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was pressure filtered, and the filtration resistivity was measured. The remaining suspension was filtered, washed with water, and dried in a vacuum drying oven at 80°C for 12 hours to obtain a metal-organic framework.

[0075] The results of the filtration resistance and BET specific surface area of the metal organic frameworks obtained in the examples and comparative examples are shown in Table 1, along with the production conditions of the metal organic frameworks. In Table 1, the ratios shown in the examples using two types of polycarboxylic acids A represent molar ratios, and the ratios shown in the examples using two types of solvents represent mass ratios. Furthermore, NEt3 in base C represents triethylamine, and DMF in solvent D represents N,N-dimethylformamide. Furthermore, the numerical value shown in parentheses after the base C used represents the molar ratio of base C to polycarboxylic acid A.

[0076] [Table 1]

[0077] Furthermore, the maximum pH values when 0.3 to 0.8 equivalents were in contact (i.e., when 0.25 to 0.85 equivalents were in contact) were: Example 1-1: 4.00, Example 1-2: 4.00, Comparative Example 1: 9.60, Example 2: 3.74, Comparative Example 2: greater than 6, Example 3: 6 or less, Comparative Example 3: greater than 6, Example 4: 4.41, Comparative Example 4: 11.50, Example 5: 4.63, Comparative Example 5: 9.60. The difference between the maximum and minimum pH values from 0.3 equivalents of contact to 0.8 equivalents of contact (i.e., from 0.25 equivalents of contact to 0.85 equivalents of contact) was: Example 1-1: 0.14, Example 1-2: 0.79, Comparative Example 1: 5.40, Example 2: 0.08, Example 4: 0.11, Comparative Example 4: 7.50, Example 5: 0.1, Comparative Example 5: 4.70. The difference between the maximum and minimum pH values from the time of contact of 0.35 equivalents to the time of contact of 0.85 equivalents was as follows: Example 1-1: 0.11, Example 1-2: 0.63, Comparative Example 1: 4.4, Example 2: 0.08, Example 4: 0.11, Comparative Example 4: 6.6, Example 5: 0.07, Comparative Example 5: 3.2.

[0078] Furthermore, graphs showing the relationship between the amount of Al2(SO4)3·nH2O (n = 14 to 18) as metal compound B and pH for Example 1-1 and Comparative Example 1 are shown in Figures 1 and 2, respectively. As shown in Figure 1, in Example 1-1, the pH of the mixture in the reaction vessel was 6 or less by the time 0.3 equivalents of metal compound B came into contact with 0.3 equivalents of polycarboxylic acid A, and the pH of the mixture in the reaction vessel was maintained at 6 or less until 0.8 equivalents of metal compound B came into contact with 0.8 equivalents of polycarboxylic acid A. Table 1 shows that the filtration resistance of the metal-organic framework obtained in Example 1-1 was reduced. Furthermore, as shown in Figure 2, in Comparative Example 1, the pH could not be adjusted to 6 or less when 0.3 equivalents of metal compound B came into contact with 0.3 equivalents of polycarboxylic acid A, and Table 1 shows that the filtration resistance of the metal-organic framework obtained in Comparative Example 1 was high.

Claims

1. A method for producing a metal organic framework, comprising continuously or intermittently adding one or more of a polycarboxylic acid or an alkali metal salt of a polycarboxylic acid A and a metal compound B to a reaction vessel, and mixing the polycarboxylic acid or the alkali metal salt of a polycarboxylic acid A and the metal compound B in the presence of a base C in a solvent D containing water within the reaction vessel, a pH of the mixture in the reaction vessel is adjusted to 6 or less until 0.3 equivalents of the metal compound B comes into contact with 0.3 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid in the reaction vessel, and the pH of the mixture in the reaction vessel is maintained at 6 or less until 0.8 equivalents of the metal compound B comes into contact with 0.8 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid.

2. 2. The method according to claim 1, wherein the difference between the maximum and minimum pH values from the time when 0.3 equivalents of the metal compound B contacts with 0.3 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid until 0.8 equivalents of the metal compound B contacts with 0.8 equivalents of the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid is 4 or less.

3. 2. The method according to claim 1, wherein an acid-base mixture obtained by mixing the polycarboxylic acid or the alkali metal salt of the polycarboxylic acid A with at least a portion of the base C is continuously or intermittently added to the reaction vessel.

4. 2. The production method according to claim 1, wherein an acid-base mixture containing the polycarboxylic acid or the alkali metal salt A of the polycarboxylic acid and a portion of the base C is continuously or intermittently added to the reaction vessel through a first addition port, and while the addition of the acid-base mixture is continuing, a portion of the base C is continuously or intermittently added to the reaction vessel through a second addition port.

5. 5. The method according to claim 3, wherein the metal compound B is charged in the reaction vessel, and the acid-base mixture is added to the reaction vessel.

6. 5. The method according to claim 3, wherein the metal compound B is added continuously or intermittently to the reaction vessel through a third addition port while the addition of the acid-base mixture is continuing.

7. 2. The production method according to claim 1, wherein an acid-base mixture containing the polycarboxylic acid or the alkali metal salt of the polycarboxylic acid A and at least a part of the base C is continuously or intermittently added to the reaction vessel through a first addition port, and while the addition of the acid-base mixture is continuing, the metal compound B is continuously or intermittently added to the reaction vessel through a third addition port.

8. The method according to claim 1 , wherein the content of water in 100% by mass of the solvent D is 70% by mass or more.

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