Method for producing metal organic framework

Abstract

The present invention provides a method for producing a metal organic framework by having an organic compound and a metal salt react with each other in an aqueous solvent. With this production method, it is possible to obtain a metal organic framework that has good filterability. The present disclosure provides a method for producing a metal organic framework by continuously or intermittently adding a polyvalent carboxylic acid or an alkali metal salt of a polyvalent carboxylic acid A and at least one metal compound B to a reaction vessel, and mixing the polyvalent carboxylic acid or the alkali metal salt of the polyvalent carboxylic acid A and the metal compound B in a solvent D that contains water in the presence of a base C within the reaction vessel, wherein the pH of the mixture in the reaction vessel is maintained at 6 or less both until 0.3 equivalent of the metal compound B comes 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 compound B comes into contact with 0.8 equivalent of the polyvalent carboxylic acid or the alkali metal salt of the polyvalent carboxylic acid A in the reaction vessel.

Description

Method for producing metal-organic framework

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

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

[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 discloses a compound containing biphenyl-3,3',5,5'-tetracarboxylic acid, Al(NO ３ ) ３ ・9H ２ It is described that O and piperazine were mixed and dispersed in water, nitric acid was added to the obtained white slurry, and the slurry was transferred to an autoclave, sealed, and heated at 210°C for 3 days to obtain a metal-organic framework.

[0005] International Publication No. 2013 / 144628

[0006] In a method for 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, a method for producing a metal organic framework using water as the solvent does not require a step for removing the organic solvent, and is therefore advantageous in terms of improving productivity.

[0007] However, the inventors 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 method is capable of obtaining a metal organic framework with good filterability.

[0009] The present disclosure that has achieved the above-mentioned object is as follows: [1] 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 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 reaction vessel in the presence of a base C and in a solvent D containing water, wherein the pH of the mixture in the reaction vessel is adjusted to 6 or less by the time 0.3 equivalents of the metal compound B come into contact with 0.3 equivalents of the polycarboxylic acid or the alkali metal salt of a polycarboxylic acid A 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 come into contact with 0.8 equivalents of the polycarboxylic acid or the alkali metal salt of a polycarboxylic acid A. [2] The production method according to [1], wherein the difference between the maximum and minimum pH values ​​from when 0.3 equivalents of the metal compound B contacts 0.3 equivalents of the polycarboxylic acid or alkali metal salt A of a polycarboxylic acid until when 0.8 equivalents of the metal compound B contacts 0.8 equivalents of the polycarboxylic acid or alkali metal salt A of a polycarboxylic acid is 4 or less. [3] The production method according to [1] or [2], wherein an acid-base mixture obtained by mixing the polycarboxylic acid or alkali metal salt A of a polycarboxylic acid with at least a portion of the base C is added to the reaction vessel continuously or intermittently. [4] The production method according to any of [1] to [3], wherein an acid-base mixture containing the polycarboxylic acid or alkali metal salt A of a polycarboxylic acid and a portion of the base C is added to the reaction vessel continuously or intermittently through a first addition inlet, and while the addition of the acid-base mixture is continuing, a portion of the base C is added to the reaction vessel continuously or intermittently through a second addition inlet. [5] The production method according to [3] or [4], wherein the reaction vessel is charged with metal compound B, and the acid-base mixture is added to the reaction vessel. [6] The production method according to [3] or [4], wherein the metal compound B is added to the reaction vessel continuously or intermittently through a third addition port while the addition of the acid-base mixture is continuing.[7] The method according to any one of [1] to [3], wherein an acid-base mixture containing the polycarboxylic acid or 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 the metal compound B is continuously or intermittently added to the reaction vessel through a third addition port while the addition of the acid-base mixture is continuing. [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.

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

[0011] 1 is a graph showing the pH behavior in Example 1-1 (described later), and a graph showing the pH behavior in Comparative Example 1 (described later).

[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, may be 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] The polycarboxylic acid is 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), with aromatic hydrocarbon groups and / or aromatic heterocyclic hydrocarbon groups being preferred, and aromatic hydrocarbon groups being more preferred. R may have 2 to 30 carbon atoms, or 4 to 24 carbon atoms, and preferably 6 to 18 carbon atoms. n may be 2 or more and 4 or less, preferably 2 or more and 3 or less, and more preferably 2. R is an aromatic hydrocarbon group and / or aromatic heterocyclic hydrocarbon group, and preferably has 4 to 24 carbon atoms.

[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 include —OH and / or —NH ２ The compound may contain one or more functional groups X.

[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] 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 the following formulae (A-1) to (A-3) and (A-5), more preferably formula (A-1), (A-2) or (A-5), and even more preferably formula (A-1) or (A-2). In the following formulae (A-1) to (A-9), * represents a bond, and is bonded to —COOH at *.

[0020]

[0021] In the formulae (A-1) to (A-9), at least one of the hydrogen atoms bonded to the carbon atom is —OH and / or —NH ２ The hydrogen atom bonded to the carbon atom may be substituted with a substituted aryl group, or the hydrogen atom bonded to the carbon atom may not be substituted.

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

[0023] Examples of the aromatic heterocyclic hydrocarbon group 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% (i.e., more than 50% and 100% is preferred, and 80 to 100% is more preferred). 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, and in particular, R(COOH) where R is the above formula (A-1) or (A-2). ２ and R(COOH) where 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, n is 2): R(COOH) ｎ and R(COOH) where R is an aromatic heterocyclic hydrocarbon group. ｎ When the polycarboxylic acid contains one or more of the above, 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, and 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 ｎ The total amount of one or more of these may be more than 50%, may be 60% or more, or preferably 70% or more, and may be 90% or less on a molar basis (i.e., more than 50% and 90% or less is preferred, 60 to 90% is more preferred, and 70 to 90% is even more preferred).

[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 more preferably R(COOH) where R is an aromatic heterocyclic hydrocarbon group. ｎ It is more preferable that the compound 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 (i.e., does not contain an alkali metal salt of a polycarboxylic acid).

[0027] [Metal Compound B] The metal in metal compound B may be, for example, at least one selected from the group consisting of elements of 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, and more preferably Al. 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 is particularly an Al sulfate, i.e., Al. ２ (SO ４ ) ３ Preferably, it contains Al ２ (SO ４ ) ３ The metal compound B may be a hydrate. One or more kinds of 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 above-mentioned preferred embodiments. However, when the polycarboxylic acid is 2,4-pyridinedicarboxylic acid and the metal compound is CoCl２ Combinations other than the combination:

[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. When 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 types 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 organic bases 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 may be 2 to 4 moles, relative to 1 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 that are one or more of alcohol-based solvents, amide-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, and amide-based solvents are 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 comes into contact 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 comes into contact 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 satisfied, the pH before the contact of 0.3 equivalents with the metal compound B with the polycarboxylic acid or a salt thereof A and the pH after the contact of 0.8 equivalents with the metal compound B are not particularly limited.

[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 (i.e., 5.5 to 2.5 is preferred, and 5.0 to 3.0 is more preferred). Setting these pHs within such ranges is preferred from the viewpoint of improving the filterability of the metal-organic framework to be produced. Furthermore, the difference between the maximum and minimum pH values ​​from 0.3 equivalents contact to 0.8 equivalents contact (i.e., from 0.25 equivalents contact to 0.85 equivalents contact) is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less; the smaller the difference, the more preferred, but it may be 0.01 or more (i.e., 4 to 0.01 is preferred, 3 to 0.01 is more preferred, and 2 to 0.01 is even more preferred). Setting this difference between the maximum and minimum pH values ​​within such a range is preferred from the viewpoint of improving the filterability of the metal-organic framework to be 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, and the smaller the difference the more preferable, but it may be 0.01 or more (i.e., 4 to 0.01 is preferred, 3 to 0.01 is more preferred, and 2 to 0.01 is even more preferred).

[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 to the reaction vessel an acid-base mixture prepared by mixing a polycarboxylic acid or its salt A with at least a portion of a base C (aspect (x)). The acid-base mixture may contain a salt formed between the polycarboxylic acid and the base. By employing aspect (x), the polycarboxylic acid or its salt A and the base C can be uniformly added to the reaction vessel, which is preferable because it allows the reaction of the polycarboxylic acid or its salt A and the metal compound B in the solvent D to proceed uniformly.

[0042] In 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 a portion of the base C (embodiment (x2)). In both embodiments (x1) and (x2) (i.e., embodiment (x) as a whole), the metal compound B may be added continuously or intermittently to the reaction vessel through another addition port (third addition port) while the acid-base mixture is being added (first addition port), or the metal compound B may be pre-charged in the reaction vessel, and the acid-base mixture may be added to the reaction vessel. In 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 the reaction vessel.

[0043] Of Aspect (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, and which may be the entire amount or a portion of the remaining amount of the 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 addition of the acid-base mixture is continuing (Aspect (x2-1)), or 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 a polycarboxylic acid, a salt A thereof, and a portion of the base C is added continuously or intermittently 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 added continuously or intermittently to the reaction vessel through a second addition port. In addition, in the embodiment (x2), the part of the base different from the base C mixed with the polycarboxylic acid or its salt A may be the same type as or different from the base C mixed with the polycarboxylic acid or its salt.

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

[0045] In particular, in the embodiment (x2-1), it is preferable to add metal compound B (particularly, the entire 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 is continuing.

[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) during the continuation of the addition of the acid-base mixture, the period during which the addition of the acid-base mixture is continued may be the entire period or a part of the period during which the addition of the acid-base mixture is continued.

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

[0048] Furthermore, 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 charged into a reaction vessel, and a metal compound may be added to the reaction vessel (Aspect y). In this case, base C may be charged into 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 charged into 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 charged into 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 be charged with 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. The amount of polycarboxylic acid or its salt A per 1 L of solvent D may be 0.05 to 1.5 mol, or may be 0.1 to 1 mol. The amount of metal compound B per 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 per 1 L of solvent D may be 0.1 to 3 mol, or may be 0.5 to 2.5 mol. In particular, it is preferable that the amount of polycarboxylic acid or its salt A is 0.1 to 1 mol, the amount of metal compound B is 0.05 to 0.7 mol, and the amount of base C is 0.5 to 2.5 mol per 1 L of solvent D.

[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, 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, and is preferably 0 parts by mass (i.e., 3 to 0 parts by mass is preferred, 2 to 0 parts by mass is more preferred, and 1 to 0 parts by mass is even more preferred).

[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, for example, 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, 1.7 MPa or less, or normal pressure (about 0.1 MPa) (i.e., preferably 2.0 to 0.1 MPa, more preferably 1.8 to 0.1 MPa, and even more preferably 1.7 to 0.1 MPa). 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 specific 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, compared to when 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 carried out. 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 ９ (m / kg) or more (i.e., for example, 5.0 × 10 １２ ~5.0 x 10 ９ (m / kg), 1.0 × 10 １１ ~5.0 x 10 ９ (m / kg), and 7.0 × 10 １０ ~5.0 x 10 ９ (m / kg) is more preferable, and 5.0 × 10 １０~5.0 x 10 ９ (m / kg) is more preferred.

[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, and 600m ２ / g~850m ２ / g is preferred, and 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 coefficient is 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.

[0056] This application claims the benefit of priority based on Japanese Patent Application No. 2024-012717 filed on January 31, 2024, and Japanese Patent Application No. 2024-187585 filed on October 24, 2024. The entire contents of the specifications of Japanese Patent Application No. 2024-012717 filed on January 31, 2024, and Japanese Patent Application No. 2024-187585 filed on October 24, 2024 are incorporated herein by reference.

[0057] 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, all of which are encompassed within the technical scope of the present disclosure.

[0058] The examples and comparative examples described below were evaluated by the following methods.

[0059] (1) Calculation of filtration resistance Using a metal filter capable of applying internal pressure 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 Ruth's equation. ｍ [m / kg] was calculated.

[0060] (2) BET specific surface area: Since the adsorption area occupied by 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 the water contained in the sample, the sample was heated overnight under reduced pressure at 10 Pa or less and 200°C. Apparatus: BELSORP-mini manufactured by Microtrac BEL Co., Ltd. Pretreatment conditions: (a-i) A glass rod for reducing the volume (for standard sample tubes) was placed in the standard sample tube and plugged with a quick seal. This sample tube set was prepared with the samples to be measured (up to three samples per measurement), connected to the pretreatment device (BELPREP VAC II), and after evacuating the air from the sample tube, N ２Gas (purity 99.999% or higher) is introduced up to atmospheric pressure. (a-ii) The sample tube is then removed from the pretreatment device, and its weight is measured three times using a precision balance (displaying four or more decimal places), and the average (W1) is obtained. When using a precision balance, an ionizer is used to eliminate the effects of static electricity. (a-iii) Approximately 50 mg of the sample to be measured is weighed onto a piece of wrapping paper, and the sample is placed directly into the spherical part at the bottom of the standard sample tube using a long-legged funnel. (a-iv) The glass rod is returned to the sample tube, and after sealing it with a quick seal, the total weight is measured once to provisionally confirm the amount of sample added. (a-v) The sample tube containing the sample is connected to the pretreatment device, and 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 kept under reduced pressure, and after it reaches room temperature, N ２ The gas is introduced up to atmospheric pressure and then removed from the device. (b-ii) The weight of the sample tube containing the pre-treated sample is measured three times using a precision balance, and the average (W2) is obtained. The weight of the sample is obtained by calculating W2 - W1. (b-iii) The sample weight and N at liquid nitrogen temperature are entered into the measurement software. ２ Enter the gas information (such as the second virial coefficient), enter the relative pressure you want to measure, and press the measurement start button. Then, follow the software's instructions to set up a Dewar vessel filled with liquid nitrogen and a sample tube, and then perform the measurement.

[0061] (3) Measurement of pH A portion of the liquid in the reaction vessel was sampled at several times during the dropping of the solution, and the pH was measured using a pH meter (personal pH meter PH71-11JAA, manufactured by Yokogawa Electric Corporation).

[0062] (4) Identification of Metal-Organic Framework 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 to confirm the peak pattern derived from the metal-organic framework. Radiation source: Cu Measurement range: 2θ = 3 to 40° Step size: 0.01° Scan rate: 3° / min Measurement temperature: room temperature (25°C)

[0063] Example 1-1 65.0 mmol of isophthalic acid, 143 mmol of triethylamine, and 238 mL of water were mixed to prepare a solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 33.8 mmol of O (n = 14 to 18) and 31.5 mL of water. Solution A, Solution B, and 52 mmol of triethylamine were simultaneously added dropwise to a reactor at 20 to 30°C, and each addition was completed over 30 minutes. Thereafter, the mixture in the reactor was heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. 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] Example 1-2 65.0 mmol of isophthalic acid, 195 mmol of triethylamine, and 238 mL of water were mixed to prepare a solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 33.8 mmol of O (n = 14 to 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 to 30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0065] Example 1-3 Solution A was prepared by dissolving 91 mmol of isophthalic acid and 200 mmol of triethylamine in 152 ml of water. ２ (SO ４ ) ３ ・nH ２Solution B was prepared by dissolving 47.3 mmol of O (n is 14 to 18) in 43.8 ml of water. At 20 to 30°C, solutions A and B were added dropwise over 90 minutes to a mixed solution 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 filtered under pressure, and the filtration resistivity was determined. 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.

[0066] Comparative Example 1 Solution A was prepared by mixing 65.0 mmol of isophthalic acid, 195 mmol of triethylamine, and 238 mL of water. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 33.8 mmol of O (n = 14 to 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 to 30°C. The mixture in the reactor 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 determined. 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] Example 2 65.0 mmol of isophthalic acid, 129 mmol of triethylamine, 121 mL of water, and 32 mL of N,N-dimethylformamide were mixed to prepare a solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 37.05 mmol of O (n = 14 to 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 to 30°C, and each addition was completed over 30 minutes. Thereafter, the mixture in the reactor was heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. 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] Comparative Example 2 65.0 mmol of isophthalic acid, 184 mmol of triethylamine, 121 mL of water, and 32 mL of N,N-dimethylformamide were mixed to prepare a solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 37.05 mmol of O (n = 14 to 18) and 34.5 mL of water. Solution A was added to a reactor, and solution B was added dropwise to the reactor over 30 minutes at 20 to 30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. 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] 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. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 67.6 mmol of O (n = 14 to 18) and 62.5 mL of water. Solution A, Solution B, and 104 mmol of triethylamine were simultaneously added dropwise to a reactor at 20 to 30°C, and each addition was completed over 30 minutes. Thereafter, the mixture in the reactor was heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. 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] 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. ２ (SO ４ ) ３ ・nH ２Solution B was prepared by mixing 67.6 mmol of O (n = 14 to 18) and 62.5 mL of water. Solution A was added to a reactor, and solution B was added dropwise to the reactor over 30 minutes at 20 to 30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. 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] Example 4 72.8 mmol of isophthalic acid, 18.2 mmol of 2,5-pyrroledicarboxylic acid, 32 g of a 25% by mass aqueous solution of sodium hydroxide, and 105 mL of water were mixed to prepare a solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 47.3 mmol of O (n = 14 to 18) and 43.8 mL of water. 70 g of water was added to a reactor, and at 20 to 30°C, Solution A, Solution B, and 11.7 g of a 25 mass% aqueous sodium hydroxide solution 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 obtained suspension was pressure filtered, and the filtration resistivity was determined. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0072] Comparative Example 4 72.8 mmol of isophthalic acid, 18.2 mmol of 2,5-pyrroledicarboxylic acid, 43.7 g of a 25% by mass aqueous solution of sodium hydroxide, and 175 mL of water were mixed to prepare a solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 47.3 mmol of O (n = 14 to 18) with 43.8 mL of water. Solution A was added to a reactor, and solution B was added dropwise to the reactor over 30 minutes at 20 to 30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was pressure filtered to determine the filtration resistivity. 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.

[0073] Example 5 Solution A was prepared by mixing 84.5 mmol of terephthalic acid, 186 mmol of triethylamine, and 148 mL of water. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 43.9 mmol of O (n = 14 to 18) and 40.6 mL of water. 55.7 g of water was added to a reactor, and at 20 to 30°C, Solution A, Solution B, and 67.6 mmol of triethylamine were simultaneously added dropwise to the reactor, each over 30 minutes. Thereafter, the mixture in the reactor was heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. 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] Comparative Example 5 84.5 mmol of terephthalic acid, 253.6 mmol of triethylamine, and 203.7 mL of water were mixed to prepare a solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 43.9 mmol of O (n = 14 to 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 to 30°C. The mixture in the reactor was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was filtered under pressure, and the filtration resistivity was determined. The remaining suspension was filtered, washed with water, and then vacuum-dried at 80°C for 12 hours to obtain a metal-organic framework.

[0075] Example 6 91 mmol of isophthalic acid and 200 mmol of triethylamine were dissolved in 152 ml of water to prepare a solution A. ２ (SO ４ ) ３ ・nH ２Solution B was prepared by dissolving 47.3 mmol of O (n is 14 to 18) in 43.8 ml of water. At 20 to 30°C, solutions A and B were added dropwise over 90 minutes to a mixed solution C consisting of 70 ml of water and 9.2 ml of 25 wt % aqueous sodium hydroxide solution. This was then heated at 90°C for 12 hours to obtain a suspension. A portion of the obtained suspension was pressure filtered to determine the filtration resistivity. 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.

[0076] The results of the filtration resistance and BET specific surface area of ​​the metal organic frameworks obtained in the examples and comparative examples, together with the production conditions of the metal organic frameworks, are shown in Table 1. In Table 1, the ratios shown in the examples using two types of polycarboxylic acid A represent molar ratios, and the ratios shown in the examples using two types of solvents represent mass ratios. ３ represents triethylamine, and DMF in solvent D represents N,N-dimethylformamide. Furthermore, the numerical value in parentheses after the base C used represents the molar ratio of base C to polycarboxylic acid A.

[0077]

[0078] The maximum pH values ​​at 0.3 to 0.8 equivalent contact (i.e., 0.25 to 0.85 equivalent 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, and Comparative Example 5: 9.60. The difference between the maximum and minimum pH values ​​at 0.3 equivalent contact to 0.8 equivalent contact (i.e., from 0.25 equivalent contact to 0.85 equivalent 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, and 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.

[0079] Furthermore, in Example 1-1 and Comparative Example 1, the metal compound B, Al ２ (SO ４ ) ３ ・nH ２ Graphs showing the relationship between the amount of O (n = 14 to 18) and pH 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 able to be 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 by 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, wherein the pH of the mixture in the reaction vessel is adjusted to 6 or less by the time 0.3 equivalents of the metal compound B comes into contact with 0.3 equivalents of the polycarboxylic acid or the alkali metal salt of a polycarboxylic acid A 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 of a polycarboxylic acid A.

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 of a polycarboxylic acid A until 0.8 equivalents of the metal compound B contacts with 0.8 equivalents of the polycarboxylic acid or the alkali metal salt of a polycarboxylic acid A is 4 or less.

3. The method according to claim 1, wherein an acid-base mixture prepared 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 added to the reaction vessel continuously or intermittently.

4. The production method according to claim 1, wherein an acid-base mixture containing the polycarboxylic acid or alkali metal salt of the polycarboxylic acid A 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 claim 3 or 4, wherein the metal compound B is charged in the reaction vessel and the acid-base mixture is added to the reaction vessel.

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

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

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