Methods for manufacturing formate, formic acid, and antifreeze.

Abstract

This invention relates to a method for manufacturing formate, which is a method for manufacturing formate, the method comprising a first step of reacting hydrogen with carbon dioxide, bicarbonate or carbonate in the presence of a solvent using a catalyst to generate formate in a reaction solution, wherein the solvent is a two-phase system existing in a state of being separated into an organic phase and an aqueous phase, and the alkali concentration in the reaction is 2.5 mol / L or higher.

Description

Technical Field

[0001] This invention relates to methods for manufacturing formate, formic acid, and antifreeze. Background Technology

[0002] There are high hopes for technologies that convert carbon dioxide into useful compounds and hydrogen energy as a next-generation energy source, as solutions to global warming and fossil fuel depletion.

[0003] Moreover, the dehydrogenation reaction of formic acid requires low energy and can be easily operated, so it is considered an excellent compound as a hydrogen storage material. Technologies for converting formate salts into formic acid and technologies for converting carbon dioxide into formic acid have attracted attention.

[0004] For example, Patent Documents 1 and 2 describe methods for efficiently separating and recovering organic acids from a mixed solution of organic acids and their metal salts using electrodialysis, and study methods for producing formic acid from formate salts.

[0005] In addition, Patent Document 3 describes a method in which an organic acid is added beforehand to decarbonate lithium hydroxide by supplying inorganic lithium acid to electrodialysis, thereby stably producing lithium hydroxide.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 7-299333

[0009] Patent Document 2: Japanese Patent Application Publication No. 10-36310

[0010] Patent Document 3: Japanese Patent No. 5367190 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] There is room for improvement in the yield of formic acid production in the existing technology, and there is a need to develop a method that can produce formic acid with higher yield and better productivity.

[0013] Therefore, the present invention provides a method for manufacturing formate, a precursor of formic acid, with high yield and excellent productivity, a method for manufacturing formic acid, and a method for manufacturing an antifreeze.

[0014] Methods for solving problems

[0015] The inventors of this application conducted repeated and in-depth research, and as a result discovered a method for manufacturing formate salts with high yield and excellent productivity, thus completing this invention.

[0016] The methods used to solve the aforementioned problems are described below.

[0017] [1]

[0018] A method for producing formate, comprising a first step of reacting hydrogen with carbon dioxide, bicarbonate, or carbonate in the presence of a solvent using a catalyst to generate formate in a reaction solution.

[0019] In the aforementioned reaction, the solvent is a two-phase system existing in a state where it is separated into an organic phase and an aqueous phase.

[0020] The concentration of alkali in the aforementioned reaction is above 2.5 mol / L.

[0021] [2]

[0022] The method for manufacturing formate as described in [1], wherein the catalyst has a catalyst turnover number (TON) of 10,000 or more, calculated by the following method.

[0023] TON calculation method:

[0024] TON = X / Y Equation 1

[0025] (In Equation 1, X represents the molar amount of potassium formate X (mol) generated in the TON-calculated reaction below, calculated by Equation 2 below, and Y represents the molar amount (mol) of the catalyst used in the reaction below.)

[0026] X=(W / M)×(Ia×Ib / R)×(A / B) Formula 2

[0027] (In Equation 2,

[0028] W represents the amount of dimethyl sulfoxide (g) used in the quantitative determination of potassium formate.

[0029] M represents the molecular weight of dimethyl sulfoxide.

[0030] R represents the ratio of the number of protons in dimethyl sulfoxide to the number of protons in potassium formate.

[0031] Ia represents the proton NMR integral value of potassium formate.

[0032] Ib represents the proton NMR integral value of dimethyl sulfoxide.

[0033] A represents the mass (g) of the lower aqueous solution obtained in the following reaction.

[0034] B represents the mass (g) of the aqueous solution used in the quantitative determination of potassium formate.

[0035] TON calculation of the reaction:

[0036] (Formate manufacturing)

[0037] In a glove box under inert gas conditions, in a glass vial equipped with a stir bar, add 10 mmol of KHCO3 to 1 mL of water, then add 0.12 μmol of catalyst and 54 μmol of methyltrioctylammonium chloride to 1 mL of toluene, dioxane, tetrahydrofuran, ethyl acetate, methylcyclohexane, or cyclopentylmethyl ether, the solvent in which the catalyst can obtain the highest TON. Then place the vial into an autoclave, seal the autoclave, and remove it from the glove box.

[0038] In an autoclave, heat to 90°C while stirring. When the target temperature is reached, pressurize the autoclave to 4.5 MPa using H2. After stirring the reaction mixture for 18 hours, cool the reaction mixture in an ice bath to release the pressure.

[0039] The upper layer of the reacted solution was removed to obtain a lower aqueous solution Ag containing potassium formate and unreacted KHCO3.

[0040] (Quantitative analysis of potassium formate)

[0041] Take the lower aqueous layer of Bg, dissolve it in 500 μL of heavy water, add Wg of dimethyl sulfoxide as an internal standard, and then proceed. 1 The NMR measurements were performed using 1H NMR, with the NMR integral value of potassium formate denoted as Ia and the NMR integral value of dimethyl sulfoxide denoted as Ib.

[0042] [3]

[0043] The method for manufacturing formate as described in [1] or [2], wherein the aforementioned catalyst is a metal complex catalyst, and a ligand of the metal complex catalyst is further added.

[0044] [4]

[0045] The method for manufacturing formate as described in [1] or [2], wherein the catalyst is at least one selected from ruthenium complexes, tautomers or stereoisomers thereof, or chlorinated compounds thereof represented by the following general formula (1).

[0046] [Chemical Formula 1]

[0047]

[0048] (In general formula (1), R0 represents a hydrogen atom or an alkyl group,

[0049] Q1 can independently represent CH2, NH, or O.

[0050] R1 independently represents either an alkyl or an aryl group (wherein, if Q1 represents NH or O, at least one of R1 represents an aryl group).

[0051] A can independently represent CH, CR5, or N, and R5 can represent alkyl, aryl, aralkyl, amino, hydroxyl, or alkoxy.

[0052] X represents a halogen atom.

[0053] n represents 0 to 3.

[0054] In the presence of multiple L ligands, each ligand can independently represent a neutral or anionic ligand.

[0055] [5]

[0056] The method for manufacturing formate as described in [4] further includes the addition of a ligand represented by the following general formula (4).

[0057] [Chemical Formula 2]

[0058]

[0059] (In general formula (4), R0 represents a hydrogen atom or an alkyl group,

[0060] Q2 can be represented independently as NH or O.

[0061] R3 represents aryl groups independently.

[0062] A can independently represent CH, CR5, or N, and R5 can represent alkyl, aryl, aralkyl, amino, hydroxyl, or alkoxy.

[0063] [6]

[0064] The method for manufacturing formate as described in any one of [1] to [5], wherein the aforementioned organic phase comprises toluene or dioxane.

[0065] [7]

[0066] The method for manufacturing formate as described in any one of [1] to [6], wherein, in the aforementioned first step, a quaternary ammonium salt is further used as a phase transfer catalyst.

[0067] [8]

[0068] A method for manufacturing formic acid includes the following steps:

[0069] The process of manufacturing formate using any one of [1] to [7]; and

[0070] The second step involves protonating at least a portion of the aforementioned formate salt via electrodialysis to generate formic acid and water.

[0071] [9]

[0072] The method for manufacturing formic acid as described in [8] involves separating the aforementioned aqueous phase, adjusting the concentration of the aforementioned formate salt in the aforementioned aqueous phase by dilution, and then using it in the second process.

[0073]

[10]

[0074] The method for manufacturing formic acid as described in [9], wherein the water generated in the aforementioned second step is used for the aforementioned dilution.

[0075]

[11]

[0076] The method for manufacturing formic acid as described in [8] involves separating the aforementioned aqueous phase, adding acid for decarbonation treatment, and then using it in the second step.

[0077]

[12]

[0078] A method for manufacturing an antifreeze, comprising a step of manufacturing a formate using any one of the formate manufacturing methods described in [1] to [7].

[0079]

[13]

[0080] The method for manufacturing the antifreeze as described in

[12] further includes a step of adding at least one acid selected from the group consisting of formic acid and acetic acid to the formate.

[0081] Invention Effects

[0082] According to the present invention, a method for manufacturing formate, a method for manufacturing formic acid, and a method for manufacturing antifreeze can be provided, which can produce formate with high yield and excellent productivity. Attached Figure Description

[0083] [ Figure 1 ] Figure 1 A schematic diagram illustrating an example of a three-chamber electrodialysis apparatus.

[0084] [ Figure 2 ] Figure 2 This is a schematic diagram illustrating an example of a formic acid manufacturing system according to an embodiment of the present invention. Detailed Implementation

[0085] [Manufacturing methods of formate and formic acid]

[0086] The embodiments of the present invention will now be described in detail.

[0087] The formate manufacturing method according to embodiments of the present invention includes a first step of reacting hydrogen with carbon dioxide, bicarbonate, or carbonate in the presence of a solvent using a catalyst to generate formate in a reaction solution.

[0088] In the aforementioned reaction, the solvent is a two-phase system existing in a state where it is separated into an organic phase and an aqueous phase.

[0089] The concentration of alkali in the aforementioned reaction is above 2.5 mol / L.

[0090] The method for manufacturing formic acid according to embodiments of the present invention includes the following steps: a step of manufacturing formate using the aforementioned method; and a second step of protonating at least a portion of the aforementioned formate by electrodialysis to generate formic acid and water.

[0091] <First Process>

[0092] In an embodiment of the present invention, the first step is a step in which hydrogen is reacted with carbon dioxide, bicarbonate or carbonate in the presence of a solvent using a catalyst to generate formate in a reaction solution.

[0093] In embodiments of the present invention, the reaction of hydrogen with carbon dioxide, bicarbonate or carbonate must be carried out in a two-phase system in which the solvent exists in a state that is separated into an organic phase and an aqueous phase.

[0094] Furthermore, the base concentration in the reaction must be above 2.5 mol / L. By maintaining a base concentration of 2.5 mol / L or higher, high-concentration formate can be produced, enabling the production of formate with a high catalyst turnover number. By increasing the catalyst turnover number of expensive catalysts, manufacturing costs can be reduced, and formate can be produced with high yield and excellent productivity.

[0095] The reaction is preferably carried out in a catalyst solution (organic phase) formed by dissolving the catalyst in an organic solvent.

[0096] The formate formed by the reaction dissolves in an aqueous solvent, thus leaching into the aqueous phase. Therefore, the formate formation reaction can be prevented from stopping at equilibrium, resulting in high-yield formate formation. Furthermore, a simple method can be used to separate the formate from the catalyst solution in the form of an aqueous solution, thus minimizing catalytic deactivation, enabling the reuse of expensive catalysts, and achieving high productivity.

[0097] According to the formate manufacturing method of the present invention, hydrogen and carbon dioxide can also be stored in the form of alkali metal formate salts. Formates have the following advantages: high hydrogen storage density, safety, stability as chemical substances, ease of operation, and long-term storage of hydrogen and carbon dioxide.

[0098] Formate has high solubility in aqueous solvents and can be separated as a high-concentration aqueous solution. If necessary, the formate concentration can be adjusted before being supplied to the second process.

[0099] The first step in the method for manufacturing formate according to embodiments of the present invention can be performed, for example, as described below.

[0100] Prepare a reaction vessel equipped with a stirrer, and introduce a solvent into the reaction vessel. If necessary, a phase transfer catalyst may also be added. Add the catalyst to the reaction vessel and dissolve it in the solvent to prepare a catalyst solution. Then, introduce hydrogen, carbon dioxide, bicarbonate, or carbonate into the reaction vessel to initiate the reaction.

[0101] (solvent)

[0102] As for the solvent involved in the embodiments of the present invention, there are no particular limitations as long as the reaction solution can form a two-phase system in which the organic phase and the aqueous phase exist in a separate state. Preferably, it includes a solvent that dissolves the catalyst and becomes homogeneous.

[0103] The organic phase is the phase that uses an organic solvent as the solvent, while the aqueous phase is the phase that uses an aqueous solvent as the solvent.

[0104] As an aqueous solvent, examples include water, methanol, ethanol, ethylene glycol, glycerol, and mixtures thereof, with water being the preferred choice from the viewpoint of low environmental impact.

[0105] Examples of organic solvents include toluene, benzene, xylene, propylene carbonate, dioxane, dimethyl sulfoxide, tetrahydrofuran, ethyl acetate, methylcyclohexane, cyclopentyl methyl ether, and mixtures thereof. From the viewpoint of separability from aqueous solvents, toluene or dioxane is more preferred. That is, the organic phase preferably contains toluene or dioxane.

[0106] (catalyst)

[0107] The catalyst involved in the embodiments of the present invention is not particularly limited, but the catalyst conversion number (TON) calculated by the following method is preferably 10,000 or more.

[0108] From the viewpoint of controlling the manufacturing cost of formate, TON is preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. In addition, the higher the TON, the better, so there is no particular upper limit, for example, it can be set to 10,000,000 or less.

[0109] TON calculation method:

[0110] TON = X / Y Equation 1

[0111] (In Equation 1, X represents the molar amount of potassium formate X (mol) generated in the TON-calculated reaction below, calculated by Equation 2 below, and Y represents the molar amount (mol) of the catalyst used in the reaction below.)

[0112] X=(W / M)×(Ia×Ib / R)×(A / B) Formula 2

[0113] (In Formula 2, W represents the amount of dimethyl sulfoxide (g) used in the quantitative determination of potassium formate.)

[0114] M represents the molecular weight of dimethyl sulfoxide.

[0115] R represents the ratio of the number of protons in dimethyl sulfoxide to the number of protons in potassium formate.

[0116] Ia represents the proton NMR integral value of potassium formate.

[0117] Ib represents the proton NMR integral value of dimethyl sulfoxide.

[0118] A represents the mass (g) of the lower aqueous solution obtained in the following reaction.

[0119] B represents the mass (g) of the aqueous solution used in the quantitative determination of potassium formate.

[0120] TON calculation of the reaction:

[0121] (Formate manufacturing)

[0122] In a glove box under inert gas conditions, in a glass vial equipped with a stir bar, add 10 mmol of KHCO3 to 1 mL of water, then add 0.12 μmol of catalyst and 54 μmol of methyltrioctylammonium chloride to 1 mL of toluene, dioxane, tetrahydrofuran, ethyl acetate, methylcyclohexane, or cyclopentylmethyl ether, the solvent in which the catalyst can obtain the highest TON. Then place the vial into an autoclave, seal the autoclave, and remove it from the glove box.

[0123] In an autoclave, heat to 90°C while stirring. When the target temperature is reached, pressurize the autoclave to 4.5 MPa using H2. After stirring the reaction mixture for 18 hours, cool the reaction mixture in an ice bath and carefully release the pressure.

[0124] The upper layer of the reacted solution was removed to obtain a lower aqueous solution Ag containing potassium formate and unreacted KHCO3.

[0125] (Quantitative analysis of potassium formate)

[0126] Take the lower aqueous layer of Bg, dissolve it in 500 μL of heavy water, add Wg of dimethyl sulfoxide as an internal standard, and then proceed. 1The NMR measurements were performed using 1H NMR, with the NMR integral value of potassium formate denoted as Ia and the NMR integral value of dimethyl sulfoxide denoted as Ib.

[0127] For example, regarding the Ru catalyst 1 and Ru catalyst 7 used in the embodiments of the present invention, in terms of the TON calculated by the above-described TON calculation method, the TON of Ru catalyst 1 is 66,000 and the TON of Ru catalyst 7 is 56,000.

[0128] In embodiments of the present invention, the catalyst used is preferably a catalyst dissolved in an organic solvent, more preferably a compound containing a metal element (metal element compound), and even more preferably a metal complex catalyst.

[0129] Examples of compounds containing metallic elements include salts formed by metallic elements, hydrides, oxides, halides (chlorides, etc.), hydroxides, carbonates, bicarbonates, sulfates, nitrates, phosphates, borates, halates, perhalates, halideates, hypohalates, and thiocyanates with inorganic acids; salts formed by alkoxides, carboxylates (acetates, (meth)acrylates, etc.) and sulfonates (trifluoromethanesulfonates, etc.) with organic acids; salts formed by amides, sulfonamides, and sulfonylimides (bis(trifluoromethanesulfonyl)imide, etc.) with organic bases; complex salts such as acetylacetone salts, hexafluoroacetylacetone salts, porphyrin salts, phthalocyanine salts, and cyclopentadiene salts; and complexes or salts containing one or more of nitrogen compounds, phosphorus compounds, compounds containing phosphorus and nitrogen, sulfur compounds, carbon monoxide, carbon dioxide, and water, including chain amines, cyclic amines, and aromatic amines. These compounds can also be hydrates and any compounds among anhydrides, without particular limitation. Among them, from the perspective of further improving the efficiency of formic acid formation, halide salts, complexes containing phosphorus compounds, complexes containing nitrogen compounds, and complexes or salts containing compounds containing both phosphorus and nitrogen are preferred.

[0130] They can be used individually or in combination with two or more.

[0131] The metal element compound can be a commercially available metal element compound or a metal element compound manufactured by known methods. Known methods include, for example, those described in Japanese Patent No. 5896539, Chem. Rev. 2017, 117, 9804-9838, and Chem. Rev. 2018, 118, 372-433.

[0132] The catalyst used in the formate manufacturing method according to the embodiments of the present invention is preferably a ruthenium complex represented by general formula (1).

[0133] The ruthenium complex represented by general formula (1) is soluble in organic solvents but insoluble in water. The formate produced by the reaction is readily soluble in water. Therefore, the separation of the catalyst from the formate is facilitated by the reaction in a two-phase system, and the separate recovery of the catalyst and formate from the reaction system is also facilitated, enabling the production of formate in high yield.

[0134] According to the method of this embodiment, the formate generated by the reaction can be separated from the catalyst using a simple operation, and the expensive catalyst can be reused.

[0135] The catalyst used in embodiments of the present invention is preferably selected from at least one of ruthenium complexes, tautomers or stereoisomers thereof, or chlorinated compounds thereof, represented by the following general formula (1).

[0136] [Chemical Formula 3]

[0137]

[0138] (In general formula (1), R0 represents a hydrogen atom or an alkyl group,

[0139] Q1 can independently represent CH2, NH, or O.

[0140] R1 independently represents either an alkyl or an aryl group (wherein, if Q1 represents NH or O, at least one of R1 represents an aryl group).

[0141] A can independently represent CH, CR5, or N, and R5 can represent alkyl, aryl, aralkyl, amino, hydroxyl, or alkoxy.

[0142] X represents a halogen atom.

[0143] n represents 0 to 3.

[0144] In the presence of multiple L ligands, each ligand can independently represent a neutral or anionic ligand.

[0145] In general formula (1), R0 represents a hydrogen atom or an alkyl group. Examples of alkyl groups represented by R0 include straight-chain, branched, cyclic, substituted or unsubstituted alkyl groups.

[0146] As the alkyl group represented by R0, alkyl groups with 1 to 30 carbon atoms are preferably included, such as methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-octyl, eicosyl, 2-ethylhexyl, etc. From the viewpoint of ease of raw material supply, alkyl groups with 6 or fewer carbon atoms are preferred, and methyl is preferred.

[0147] In general formula (1), R0 is preferably a hydrogen atom or a methyl atom.

[0148] In general formula (1), each R1 independently represents an alkyl or aryl group. Wherein, when Q1 represents NH or O, at least one of R1 represents an aryl group.

[0149] Examples of alkyl groups represented by R1 include straight-chain, branched, and cyclic substituted or unsubstituted alkyl groups. Preferably, alkyl groups with 1 to 30 carbon atoms are alkyl groups such as methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-octyl, eicosyl, and 2-ethylhexyl. From the viewpoint of catalytic activity, alkyl groups with 12 or fewer carbon atoms are preferred, and tert-butyl is particularly preferred.

[0150] Examples of aryl groups represented by R1 include substituted or unsubstituted aryl groups with 6 to 30 carbon atoms, such as phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecylaminophenyl, etc., preferably aryl groups with 12 or fewer carbon atoms, and more preferably phenyl.

[0151] A can independently represent CH, CR5, or N, and R5 can represent alkyl, aryl, aralkyl, amino, hydroxyl, or alkoxy.

[0152] Examples of alkyl groups represented by R5 include straight-chain, branched, and cyclic substituted or unsubstituted alkyl groups. Preferably, alkyl groups with 1 to 30 carbon atoms are alkyl groups such as methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-octyl, eicosyl, and 2-ethylhexyl. From the viewpoint of ease of raw material supply, alkyl groups with 12 or fewer carbon atoms are preferred, and methyl is particularly preferred.

[0153] Examples of aryl groups represented by R5 include substituted or unsubstituted aryl groups with 6 to 30 carbon atoms, such as phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecylaminophenyl, etc., preferably aryl groups with 12 or fewer carbon atoms, and more preferably phenyl.

[0154] As R5 represents an aralkyl group, examples include substituted or unsubstituted aralkyl groups with 30 or fewer carbon atoms, such as triphenylmethyl, benzyl, phenethyl, triphenylmethylmethyl, diphenylmethyl, naphthylmethyl, etc., and preferably aralkyl groups with 12 or fewer carbon atoms.

[0155] As the alkoxy group represented by R5, preferably substituted or unsubstituted alkoxy groups having 1 to 30 carbon atoms, such as methoxy, ethoxy, isopropoxy, tert-butoxy, n-octyloxy, 2-methoxyethoxy, etc.

[0156] X represents a halogen atom, preferably a chlorine atom.

[0157] n represents an integer from 0 to 3, indicating the number of ligands located in ruthenium. From the viewpoint of catalyst stability, n is preferably 2 or 3.

[0158] In the presence of multiple L, each independently represents a neutral or anionic ligand.

[0159] Examples of neutral ligands represented by L include ammonia, carbon monoxide, phosphine derivatives (e.g., triphenylphosphine, tri(4-methoxyphenyl)phosphine), phosphine oxides (e.g., triphenylphosphine oxide), thioethers (e.g., dimethyl sulfide), sulfoxides (e.g., dimethyl sulfoxide), ethers (e.g., diethyl ether), nitriles (e.g., p-methylbenzonitrile), heterocyclic compounds (e.g., pyridine, N,N-dimethyl-4-aminopyridine, tetrahydrothiophene, tetrahydrofuran), etc., with triphenylphosphine being preferred.

[0160] Examples of anionic ligands represented by L include hydride ions (hydrogen atoms), nitrate ions, and cyanide ions, with hydride ions (hydrogen atoms) being the most preferred.

[0161] In general formula (1), preferably, A represents CH and Q1 represents NH.

[0162] In addition, preferably, n represents 1 to 3, and L independently represents a hydrogen atom, carbon monoxide, or triphenylphosphine.

[0163] The ruthenium complex represented by general formula (1) can be used alone or in combination with two or more.

[0164] The ruthenium complex represented by the above general formula (1) is preferably the ruthenium complex represented by the following general formula (3).

[0165] [Chemical Formula 4]

[0166]

[0167] (In general formula (3), R0 represents a hydrogen atom or an alkyl group,

[0168] Q2 can be represented independently as NH or O.

[0169] R3 represents aryl groups independently.

[0170] A can independently represent CH, CR5, or N, and R5 can represent alkyl, aryl, aralkyl, amino, hydroxyl, or alkoxy.

[0171] X represents a halogen atom.

[0172] n represents 0 to 3.

[0173] In the presence of multiple L ligands, each ligand can independently represent a neutral or anionic ligand.

[0174] In general formula (3), R0, A, R5, X, n and L are synonyms of R0, A, R5, X, n and L in general formula (1), and the preferred range is also the same.

[0175] In general formula (3), R3 represents an aryl group that is synonymous with R1 in general formula (1), and the preferred range is also the same.

[0176] The ruthenium complexes represented by general formulas (1) and (3) can also be ruthenium complexes prepared by known methods, etc. As a known method, for example, the method described in E. Pidko et al., ChemCatChem 2014, 6, 1526-1530, etc., can be used.

[0177] The ruthenium complexes represented by general formulas (1) and (3) can sometimes produce stereoisomers depending on the coordination mode and conformation of the ligands. They can be a mixture of these stereoisomers or a single pure isomer.

[0178] As specific examples of ruthenium complexes, ruthenium complexes represented by general formulas (1) and (3), and ligands, the compounds described below can be exemplified.

[0179] In the compounds illustrated below, tBu represents tert-butyl and Ph represents phenyl.

[0180] [Chemical Formula 5]

[0181]

[0182] [Chemical Formula 6]

[0183]

[0184] Regarding the amount of catalyst (preferably a ruthenium complex) used, there is no particular limitation as long as it is sufficient to produce formate. To fully exhibit catalytic activity, the amount of catalyst (preferably a ruthenium complex) used is preferably 0.1 μmol or more, more preferably 0.5 μmol or more, and even more preferably 1 μmol or more, relative to 1 L of solvent. Furthermore, from a cost perspective, it is preferably 1 mol or less, more preferably 10 mmol or less, and even more preferably 1 mmol or less. It should be noted that when using two or more catalysts, their total amount used is acceptable as long as it falls within the above-mentioned range.

[0185] In the method for producing formate according to embodiments of the present invention, it is preferable that the catalyst is a metal complex catalyst, and that the ligands of the metal complex catalyst are present in excess in the reaction mixture. Therefore, it is preferable to further add ligands of the complex used.

[0186] That is, in the method for manufacturing formate according to the embodiments of the present invention, it is preferable that the catalyst is a metal complex catalyst, and a ligand of the metal complex catalyst is further added. For example, when the catalyst is a ruthenium complex represented by general formula (1), it is preferable to further add a ligand represented by the following general formula (4).

[0187] [Chemical Formula 7]

[0188]

[0189] (In general formula (4), R0 represents a hydrogen atom or an alkyl group,

[0190] Q2 can be represented independently as NH or O.

[0191] R3 represents aryl groups independently.

[0192] A can independently represent CH, CR5, or N, and R5 can represent alkyl, aryl, aralkyl, amino, hydroxyl, or alkoxy.

[0193] In general formula (4), R0, Q2, R3, A and R5 are synonyms of R0, Q2, R3, A and R5 in general formula (3), and the preferred range is also the same.

[0194] By adding excess ligands that form complexes to the reaction system, even if the ligands are oxidized and degraded due to oxygen or impurities in the system, the degraded ligands will exchange with the added ligands, and the catalyst function will be restored, thus improving the stability of the catalyst.

[0195] The addition of the ligand represented by the above general formula (4) to the reaction mixture can be carried out during the preparation of the reaction mixture or during the reaction, but from the point of view of process management, it is preferred to carry it out during the preparation of the reaction mixture.

[0196] (Phase transfer catalyst)

[0197] The method for producing formic acid according to embodiments of the present invention requires the reaction to be carried out in a two-phase system. Therefore, a phase transfer catalyst can be used to facilitate the movement of substances between the two phases. Examples of phase transfer catalysts include quaternary ammonium salts, quaternary phosphates, macrocyclic polyethers such as crown ethers, nitrogen-containing macrocyclic polyethers such as cryptane ethers, nitrogen-containing chain polyethers, polyethylene glycol and its alkyl ethers, etc. Among these, quaternary ammonium salts are preferred from the viewpoint that the movement of substances between aqueous and organic solvents is easy even under mild reaction conditions.

[0198] Examples of quaternary ammonium salts include methyltrioctylammonium chloride, benzyltrimethylammonium chloride, trimethylphenylammonium bromide, tributylammonium tribromide, tetrahexylammonium hydrogen sulfate, decyltrimethylammonium bromide, diallyldimethylammonium chloride, dodecyltrimethylammonium bromide, dimethylbisoctadecylammonium bromide, tetraethyltetrafluoroborate ammonium, ethyltrimethylammonium iodide tris(2-hydroxyethyl)methylammonium hydroxide, tetramethylammonium acetate, tetramethylammonium bromide, and tetraethylammonium iodide, with methyltrioctylammonium chloride being the most preferred.

[0199] Regarding the amount of phase transfer catalyst used, there is no particular limitation as long as it is sufficient to produce formate. For efficient assistance in the movement of carbonates or bicarbonates, the amount of phase transfer catalyst used is preferably 0.1 mmol or more, more preferably 0.5 mmol or more, and even more preferably 1 mmol or more, relative to 1 L of the organic and aqueous solvent phases. Furthermore, from a cost perspective, it is preferably 1 mol or less, more preferably 500 mmol or less, and even more preferably 100 mmol or less. It should be noted that when using two or more phase transfer catalysts, their total usage is acceptable as long as it falls within the above-mentioned range.

[0200] (Carbon dioxide and hydrogen)

[0201] The hydrogen used in embodiments of the present invention can be any type of hydrogen from hydrogen storage cylinders and liquid hydrogen. For example, hydrogen produced during iron smelting or soda production can be used as a hydrogen supply source. Alternatively, hydrogen produced by the electrolysis of water can also be used effectively.

[0202] The carbon dioxide used in embodiments of the present invention can be pure carbon dioxide gas or a mixture of gases containing components other than carbon dioxide. The carbon dioxide gas and other gases can be introduced separately, or the mixture can be prepared before introduction.

[0203] Other components besides carbon dioxide include any other components contained in inactive gases such as nitrogen and argon, water vapor, and exhaust gases.

[0204] Carbon dioxide can be obtained from various sources, including carbon dioxide gas cylinders, liquid carbon dioxide, supercritical carbon dioxide, and dry ice.

[0205] Hydrogen and carbon dioxide gases can be introduced into the reaction system separately or as a mixture.

[0206] The preferred ratio of hydrogen to carbon dioxide is equal in molar terms or hydrogen in excess.

[0207] When using a hydrogen storage cylinder as hydrogen in the formic acid manufacturing method according to embodiments of the present invention, from the viewpoint of sufficiently ensuring reactivity, the pressure is preferably 0.1 MPa or more, more preferably 0.2 MPa or more, and even more preferably 0.5 MPa or more. Furthermore, from the viewpoint of easily scaling up the equipment, a pressure of 50 MPa or less is preferred, more preferably 20 MPa or less, and even more preferably 10 MPa or less.

[0208] Furthermore, from the viewpoint of ensuring sufficient reactivity, the pressure of carbon dioxide used in the formic acid manufacturing method according to embodiments of the present invention is preferably 0.1 MPa or more, more preferably 0.2 MPa or more, and even more preferably 0.5 MPa or more. Additionally, from the viewpoint of easily scaling up the equipment, the pressure is preferably 50 MPa or less, more preferably 20 MPa or less, and even more preferably 10 MPa or less.

[0209] Hydrogen and carbon dioxide gases can be bubbled (blown) into the catalyst solution. Alternatively, after introducing gases containing hydrogen and carbon dioxide, the catalyst solution and the hydrogen and carbon dioxide gases can be stirred using a stirring device or by rotating the reaction vessel.

[0210] There are no particular restrictions on the methods used to introduce carbon dioxide, hydrogen, catalysts, solvents, etc., into the reaction vessel. All the raw materials can be introduced at once, a portion or all of the raw materials can be introduced in stages, or a portion or all of the raw materials can be introduced continuously. Alternatively, a combination of these methods can be used.

[0211] (Bicarbonates and carbonates)

[0212] Examples of bicarbonates and carbonates used in embodiments of the present invention include alkali metal carbonates or bicarbonates.

[0213] Examples of bicarbonates include sodium bicarbonate and potassium bicarbonate, with potassium bicarbonate being preferred from the viewpoint of high solubility in water.

[0214] Examples of carbonates include sodium carbonate, potassium carbonate, sodium potassium carbonate, and sodium sesquicarbonate.

[0215] In the first step, as mentioned above, the alkali concentration (alkali concentration in the aqueous phase) in the reaction of hydrogen with carbon dioxide, bicarbonate or carbonate must be above 2.5 mol / L.

[0216] Regarding the concentration of alkali in the reaction, from the viewpoint of maximizing the production of formate, it is preferably 2.5 mol / L or more, more preferably 5 mol / L or more, and even more preferably 10 mol / L or more. Furthermore, to prevent an excessive increase in the amount of salt precipitated from the alkali from reducing the reaction stirring efficiency, it is preferably 30 mol / L or less, more preferably 25 mol / L or less, and even more preferably 20 mol / L or less.

[0217] (Reaction conditions)

[0218] The reaction conditions in the method for manufacturing formate according to the embodiments of the present invention are not particularly limited, and the reaction conditions can be appropriately changed during the reaction process. The shape of the reaction vessel used in the reaction is not particularly limited.

[0219] The reaction temperature is not particularly limited, but for efficient reaction, it is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher. Furthermore, from the viewpoint of energy efficiency, it is preferably 200°C or lower, more preferably 150°C or lower, and even more preferably 100°C or lower.

[0220] The reaction time is not particularly limited. However, from the viewpoint of ensuring sufficient formic acid production, it is preferably 0.5 hours or more, more preferably 1 hour or more, and even more preferably 2 hours or more. In addition, from the viewpoint of cost, it is preferably 24 hours or less, more preferably 20 hours or less, and even more preferably 18 hours or less.

[0221] Regarding the concentration of formate generated in the first process (the concentration of formate in the aqueous phase), in order to improve TON and produce formate with high yield and excellent productivity, it is preferably 2.5 mol / L or more, more preferably 5 mol / L or more, and even more preferably 10 mol / L or more. Furthermore, in order to simplify the production process by producing in a dissolved state of formate, it is preferably 30 mol / L or less, more preferably 25 mol / L or less, and even more preferably 20 mol / L or less.

[0222] <Second Process>

[0223] The second step is to protonate at least a portion of the aforementioned formate salt to generate formic acid and water via electrodialysis.

[0224] The method for manufacturing formic acid according to the embodiments of the present invention preferably includes a step of manufacturing formic acid salts using the method for manufacturing formic acid salts according to the embodiments of the present invention, and a second step.

[0225] In an embodiment of the present invention, the formate generated in the first process dissolves into the aqueous phase, and therefore, an aqueous solution of formate can be obtained by separating the aqueous phase.

[0226] Preferably, the aqueous phase from the first step is separated, and the resulting formate aqueous solution is treated in a second step using an electrodialysis device to generate formic acid. The separated aqueous phase is the aqueous phase after the first step.

[0227] In the second step, the formate aqueous solution obtained from the first step can be used directly as described above, or the formate concentration can be adjusted by concentration or dilution as needed.

[0228] One method for diluting formate aqueous solutions is to add pure water.

[0229] Methods for concentrating aqueous formate solutions include distillation to remove water from the aqueous formate solution and using a separation membrane unit equipped with a reverse osmosis membrane to concentrate the aqueous formate solution.

[0230] From the viewpoint of suppressing formate loss caused by concentration diffusion of high-concentration formate aqueous solutions during treatment using an electrodialysis apparatus, it is preferable to separate the aqueous phase in the first step, adjust the formate concentration in the aqueous phase by dilution, and then use it in the second step.

[0231] Since a high-concentration formate aqueous solution is obtained through the first process, and the formate concentration is adjusted to a suitable concentration for electrodialysis before being supplied to the second process, TON can be further improved, and formic acid can be manufactured with higher yield and better productivity.

[0232] The degree of concentration adjustment (preferably dilution) of the formate aqueous solution obtained in the first step can be appropriately selected. The formate concentration in the formate aqueous solution after concentration adjustment is preferably a concentration suitable for electrodialysis, preferably 2.5 mol / L or more, more preferably 3 mol / L or more, and even more preferably 5 mol / L or more. Furthermore, from the viewpoint of suppressing formate loss due to concentration diffusion of the high-concentration formate aqueous solution during treatment using an electrodialysis apparatus, it is preferably 20 mol / L or less, more preferably 15 mol / L or less, and even more preferably 10 mol / L or less.

[0233] Pure water can be used for dilution. Alternatively, the water generated in the second process can also be used for dilution. By reusing the water generated in the second process during dilution, it is preferable to reduce the cost of wastewater treatment and the environmental impact.

[0234] In the formic acid manufacturing method according to embodiments of the present invention, acid may be added to the formic acid aqueous solution obtained from the first step to perform decarbonation treatment before use in the second step. That is, the aqueous phase in the first step may be separated, acid may be added to perform decarbonation treatment before use in the second step.

[0235] The formate aqueous solution obtained from the first process sometimes contains unreacted carbonates and bicarbonates generated by side reactions. If the solution containing carbonates and bicarbonates is subjected to electrodialysis, there is a concern that carbon dioxide will be generated, reducing dialysis efficiency. Therefore, by adding acid to the formate aqueous solution obtained from the first process for decarbonation followed by electrodialysis, TON can be further improved, resulting in the production of formic acid with higher yield and better productivity.

[0236] Examples of acids used in decarbonation treatment include formic acid, citric acid, acetic acid, malic acid, lactic acid, succinic acid, tartaric acid, butyric acid, fumaric acid, propionic acid, hydrochloric acid, nitric acid, and sulfuric acid, with formic acid being preferred.

[0237] Regarding the amount of acid used, from the viewpoint of suppressing the amount of carbonic acid generated during electrodialysis treatment, the amount of acid used is preferably 50% or more, more preferably 80% or more, relative to the amount of carbonic acid present in the solution. Furthermore, from the viewpoint of suppressing the deterioration of the electrodialysis apparatus by pre-neutralizing the pH of the formate solution during electrodialysis treatment, the amount of acid used is preferably 150% or less, more preferably 120% or less, relative to the amount of carbonic acid present in the solution.

[0238] In embodiments of the present invention, regarding the proportion of formate protonated in the second step, from the viewpoint of improving the purity of the recovered formic acid aqueous solution, it is preferable that 10% or more is protonated relative to the initial molar amount of formate in the formate aqueous solution, more preferably 20% or more is protonated, and even more preferably 30% or more is protonated.

[0239] Examples of electrodialysis devices include two-compartment electrodialysis devices that use bipolar membranes and anion exchange membranes or cation exchange membranes, and three-compartment electrodialysis devices that use bipolar membranes and anion exchange membranes or cation exchange membranes.

[0240] Figure 1 A schematic diagram illustrating an example of a three-chamber electrodialysis apparatus. Figure 1The electrodialysis apparatus shown comprises multiple bipolar membranes, anion exchange membranes, and cation exchange membranes, which are arranged between the anode and cathode to form an alkali tank, a sample tank (salt tank), and an acid tank. A formate aqueous solution is circulated into the sample tank while an electric current is applied, thereby continuously converting the formate into formic acid. Formic acid is recovered from the acid tank, water is recovered from the sample tank, and hydroxide is recovered from the alkali tank.

[0241] A two-chamber electrodialysis device has multiple bipolar membranes and cation exchange membranes, which are alternately arranged between the anode and the cathode. A salt chamber is formed between each bipolar membrane and the cation exchange membrane arranged on its cathode side, and an alkali tank is formed between each bipolar membrane and the cation exchange membrane arranged on its anode side. While the device is energized, an aqueous formate solution is circulated into the salt chamber. As a result, hydroxide is generated in the alkali tank, and the formate circulated into the salt chamber is continuously converted into formic acid.

[0242] Through the second step, a formate solution can be obtained by protonating the formate salt using a simple method.

[0243] [Formate manufacturing system and formic acid manufacturing system]

[0244] The formate manufacturing system according to embodiments of the present invention includes a formate manufacturing apparatus that reacts hydrogen with carbon dioxide, bicarbonate or carbonate to generate formate in a reaction solution, wherein the solvent in the aforementioned reaction is a two-phase system existing in a state of being separated into an organic phase and an aqueous phase, and the alkali concentration in the aforementioned reaction is 2.5 mol / L or more.

[0245] The formic acid manufacturing system according to the embodiments of the present invention may include, in addition to the formate manufacturing system described above, an electrodialysis device for generating formic acid by protonating at least a portion of the formate through electrodialysis.

[0246] The formic acid manufacturing system according to embodiments of the present invention may further include a device for adjusting the concentration of the formic acid salt in the aforementioned aqueous phase by dilution, which may be a dilution device.

[0247] The formic acid manufacturing system according to the embodiments of the present invention only needs to have a formate manufacturing device 10 and an electrodialysis device 30, and can also supply the products obtained from each device to other devices after transportation and storage.

[0248] Figure 2 A figure illustrating an example of a formic acid manufacturing system according to an embodiment of the present invention.

[0249] Figure 2The formic acid manufacturing system 100 shown includes a formate manufacturing apparatus 10 and an electrodialysis apparatus 30, and may also include a dilution apparatus 20 and a dilution water storage unit 40.

[0250] It may also include a carbon dioxide storage cylinder 60 for introducing carbon dioxide into the formate manufacturing apparatus 10, and a hydrogen storage cylinder 50 for introducing hydrogen into the formate manufacturing apparatus 10. The concentration and pressure of carbon dioxide and hydrogen can be adjusted using valves 1 and 2 in piping L1 and piping L2.

[0251] For the formate produced in the formate manufacturing apparatus 10, it is supplied to the electrodialysis apparatus 30 in the form of an aqueous formate solution by separating the aqueous phase, but it can also be as follows: Figure 2 As shown, liquid is fed to the dilution device 20 through flow path L3, and the concentration of formate in the aqueous phase is adjusted by dilution.

[0252] For the formate solution obtained by adjusting the formate concentration using the dilution device 20, at least a portion of the formate is protonated using the electrodialysis device 30 to generate formic acid and water. The generated formic acid can be removed via flow path L5. Additionally, the generated water can be delivered to the dilution water storage unit 40 via flow path L7.

[0253] Regarding the dilution water storage unit 40, a portion of the formic acid generated by the electrodialysis apparatus 30 can also be supplied to the dilution water storage unit 40 via the flow path L6. The dilution water storage unit 40 may include a water supply unit 70 and a formic acid supply unit 80, and the formic acid aqueous solution adjusted in the dilution water storage unit 40 can also be supplied to the dilution apparatus 20 via the flow path L9 for decarbonization treatment.

[0254] Each flow path can be equipped with valves to adjust pressure and supply.

[0255] The formate manufacturing method and formic acid manufacturing method, as well as the formate manufacturing system and formic acid manufacturing system according to this embodiment, can manufacture formate and formic acid with high yield and excellent productivity.

[0256] [Manufacturing method of antifreeze]

[0257] The method for manufacturing the antifreeze in this embodiment preferably includes a step of manufacturing formate using the formate manufacturing method of this embodiment.

[0258] The formate produced by the formate manufacturing method and formate manufacturing system of this embodiment can not only be used as a hydrogen storage material, but also for conventional applications such as oil field extraction, tanning, livestock feed, and antifreeze, thus contributing to the problems of global warming and fossil fuel depletion.

[0259] For example, in the application of antifreeze, formates have attracted attention as non-chloride-based antifreeze agents for the purpose of preventing salt damage caused by calcium chloride and other substances. Examples of formates used in antifreeze include sodium formate and potassium formate. Compared to sodium formate, potassium formate has higher solubility in water; therefore, sodium formate is characterized by its ease of drying an aqueous solution obtained using the formate manufacturing method and formate manufacturing system of this embodiment into a powder. Therefore, sodium formate is preferred when it is desired to distribute the antifreeze in powder or granular form. Conversely, when distributed in aqueous solution, potassium formate, which dissolves in high concentrations, is characterized by its ability to easily achieve antifreeze effects relative to the unit distribution amount.

[0260] The formate obtained using the formate manufacturing method and formate manufacturing system of this embodiment sometimes contains unreacted carbonates, bicarbonates, etc. Since carbonates and bicarbonates do not provide antifreeze protection, the antifreeze effect can be improved by neutralizing some or all of the present carbonates and bicarbonates with an acid.

[0261] Examples of acids used for neutralization include the acids described above used in the decarbonation treatment of the formate aqueous solution obtained from the first step. It is preferable to improve the environmental friendliness of the resulting antifreeze by using acids derived from non-fossil fuels. Examples include formic acid obtained using the formic acid manufacturing method of the present invention, citric acid, acetic acid, lactic acid, succinic acid, tartaric acid, etc., produced from crops or through fermentation, preferably at least one acid selected from the group consisting of formic acid and acetic acid.

[0262] That is, the method for manufacturing the antifreeze in this embodiment preferably further includes a step of adding at least one acid selected from the group consisting of formic acid and acetic acid to the formate.

[0263] Example

[0264] The present invention will now be described in detail with examples and comparative examples. However, the present invention is not limited to these examples.

[0265] [Catalyst Synthesis]

[0266] (Synthetic Example 1) Synthesis of Ru Catalyst 1

[0267] Ru catalyst 1 was synthesized through the following procedures.

[0268] Under an inactive atmosphere, ligand A of 40 mg (0.1 mmol) was added to a suspension of [RuHCl(PPh3)3(CO)] in 95.3 mg (0.1 mmol) of THF (tetrahydrofuran) (5 ml). The mixture was stirred and heated at 65 °C for 3 hours to carry out the reaction. Then it was cooled to room temperature (25 °C).

[0269] The resulting yellow solution was filtered, and the filtrate was evaporated to dryness under vacuum. The resulting yellow residual oil was dissolved in a very small amount of THF (1 mL), and hexane (10 mL) was slowly added to precipitate the yellow solid. The precipitate was filtered and dried under vacuum to obtain Ru catalyst 1 (55 mg, 97%) as yellow crystals. In the following description of Ru catalyst 1 and ligand A, tBu represents tert-butyl.

[0270] [Chemical Formula 8]

[0271]

[0272] 31 P{ 1 H}(C6D6): 90.8(s), 1 H (C6D6): -14.54 (t, 1H, J = 20.0Hz), 1.11 (t, 18H, J = 8.0Hz), 1.51 (t, 18H, J = 8.0Hz), 2.88 (dt, 2H, J = 16.0Hz, J=4.0Hz), 3.76 (dt, 2H, J=16.0Hz, J=4.0Hz), 6.45 (d, 2H, J=8.0Hz), 6.79 (t, 1H, J=8.0Hz). 13 C{ 1 H}NMR(C6D6): 29.8(s), 30.7(s), 35.2(t, J=9.5Hz), 37.7(t, J=6.0Hz), 37.9 (t, J=6.5Hz), 119.5 (t, J=4.5Hz), 136.4 (s), 163.4 (t, J=5.0Hz), 209.8 (s).

[0273] (Synthetic Example 2) Synthesis of Ru Catalyst 7

[0274] Ru catalyst 7 was synthesized through the following procedures.

[0275] Under an inactive atmosphere, 142.6 mg of ligand G and 284.6 mg of [RuHCl(PPh3)3(CO)] were mixed in 5 mL of benzene, and the suspension was refluxed overnight. The resulting yellow precipitate was collected on a filter and washed four times with 5 mL of ether.

[0276] The precipitate was dried in a vacuum to obtain 154.0 mg of Ru catalyst 7.

[0277] In the Ru catalyst 7 and ligand G shown below, Ph represents phenyl.

[0278] [Chemical Formula 9]

[0279]

[0280] 31 P{ 1 H}NMR (CDC3): 95.58 (br, s), 29.71 (s). 1 H

[0281] NMR (400MHz, CD2Cl2) δ9.92 (s, 2H), 8.11 (q, J=6.6Hz, 4H), 7.38-7.24 (m, 4H), 7.20 (t, J=7.5Hz, 3H), 7.16-7.04 (m, 4H), 7.0 4-6.92 (m, 14H), 6.87 (td, J=7.6, 2.1Hz, 6H), 6.51 (d, J=8.0Hz, 1H), 6.61 (d, J=8.0Hz, 2H), -7.22 (dt, J=89.2, 23.1Hz, 1H).

[0282] <Example 1>

[0283] (Formate formation reaction)

[0284] In a glove box under inert gas conditions, 1 mL of water was measured in a glass vial equipped with a stir bar, and 2.5 mmol of potassium bicarbonate was added. Then, 0.12 μmol of Ru catalyst 1 and 54 μmol of methyltrioctylammonium chloride were added to 1 mL of toluene. The vial was then placed in an autoclave, which was sealed and removed from the glove box. In the autoclave, the mixture was heated to 90 °C with stirring. When the target temperature was reached, the autoclave was pressurized to 4.5 MPa using hydrogen. After stirring the reaction mixture for 2.5 hours, the reaction mixture was cooled in an ice bath, and the pressure was carefully released. The upper layer of the reacted solution was removed, leaving a lower aqueous solution containing potassium formate and unreacted potassium bicarbonate. 100 μL of the lower aqueous solution was dissolved in 500 μL of heavy water, and 300 μL of dimethyl sulfoxide was added as an internal standard. Then the reaction proceeded... 1 ¹H NMR was used to determine the TON of the catalyst and the conversion efficiency of potassium bicarbonate to formate. The results showed that the TON of the catalyst was 13000 and the conversion efficiency of potassium bicarbonate to formate was 0.64.

[0285] (Formate protonation reaction)

[0286] Add the solution obtained by dissolving 14g of potassium hydroxide in 500mL of water to the alkali tank. Add the solution obtained by dissolving 105.15g of potassium formate in 500mL of water to the salt tank. Add 500mL of ion-exchanged water to the acid tank. If the electrodialysis device is started, the voltage becomes 28V and the current becomes 0.24A. At this time, the conductivity of the salt tank is 154.1S / m. As the dialysis treatment proceeds, the conductivity gradually decreases, and after 87 minutes, the conductivity becomes 0, and the dialysis treatment ends. At this time, the voltage is 28.0V and the current is 0.87A. After the dialysis is completed, the solution volume (salt solution) in the salt tank becomes 350mL, the solution volume (acid solution) in the acid tank becomes 556mL, and the liquid volume (alkali solution) in the alkali tank becomes 595mL. Take 100μL of acid solution, dissolve it in 500μL of heavy water, add 300μL of dimethyl sulfoxide as an internal standard, and proceed. 1 The formic acid in the acid solution after dialysis was quantified by ¹H NMR determination. The formic acid recovery rate was calculated to be 0.85. Furthermore, to quantify potassium in the acid solution after dialysis, 20 mg of acid solution was diluted 50.5 times with water and measured using a potassium ion meter. The ratio of (formic acid / (potassium formate + formic acid)) in the acid solution was calculated to be 0.98.

[0287] Finally, based on the results of the formate formation and formate protonation reactions, the recovery rate of potassium bicarbonate to formic acid was 0.54%.

[0288] <Example 2>

[0289] (Formate formation reaction)

[0290] In a glove box under inert gas conditions, 1 mL of water was measured in a glass vial equipped with a stir bar. 5 mmol of potassium bicarbonate was added, followed by the addition of 0.12 μmol of Ru catalyst 1 and 54 μmol of methyltrioctylammonium chloride to 1 mL of toluene. The vial was then placed in an autoclave, sealed, and removed from the glove box. In the autoclave, the mixture was heated to 90 °C with stirring. When the target temperature was reached, the autoclave was pressurized to 4.5 MPa using hydrogen. After stirring the reaction mixture for 2.5 hours, the mixture was cooled in an ice bath, and the pressure was carefully released. The supernatant of the reacted solution was removed, leaving a lower aqueous solution containing potassium formate and unreacted potassium bicarbonate. 100 μL of the lower aqueous solution was dissolved in 500 μL of heavy water, and 300 μL of dimethyl sulfoxide was added as an internal standard. Then, the reaction proceeded... 1 ¹H NMR was used to determine the TON of the catalyst and the conversion efficiency of potassium bicarbonate to formate. The results showed that the TON of the catalyst was 27500 and the conversion efficiency of potassium bicarbonate to formate was 0.66.

[0291] (Formate protonation reaction)

[0292] Add the liquid obtained by dissolving 14g of potassium hydroxide in 500mL of water to the alkali tank. Add the liquid obtained by dissolving 210.3g of potassium formate in 500mL of water to the salt tank. Add 500mL of ion-exchanged water to the acid tank. If the electrodialysis device is started, the voltage becomes 28V and the current becomes 0.28A. At this time, the conductivity of the salt tank is 229.8S / m. As the dialysis treatment proceeds, the conductivity gradually decreases, and after 137 minutes, the conductivity becomes 0, and the dialysis treatment ends. At this time, the voltage is 28.0V and the current is 1.29A. After the dialysis is completed, the volume of solution (salt solution) in the salt tank becomes 275mL, the volume of solution (acid solution) in the acid tank becomes 590mL, and the volume of liquid (alkali solution) in the alkali tank becomes 685mL. Take 100μL of acid solution, dissolve it in 500μL of heavy water, add 300μL of dimethyl sulfoxide as an internal standard, and proceed. 1 ¹H NMR was used to quantify formic acid in the acid solution after dialysis. The formic acid recovery rate was calculated to be 0.90. Furthermore, to quantify potassium in the acid solution after dialysis, 20 mg of acid solution was diluted 50 times with water and measured using a potassium ion meter. The ratio of (formic acid / (potassium formate + formic acid)) in the acid solution was calculated to be 0.99.

[0293] Finally, based on the results of the formate formation and formate protonation reactions, the recovery rate of potassium bicarbonate to formic acid was 0.59%.

[0294] <Example 3>

[0295] (Formate formation reaction)

[0296] In a glove box under inert gas conditions, 1 mL of water was measured into a glass vial equipped with a stir bar, and 10 mmol of potassium bicarbonate was added. Then, 0.12 μmol of Ru catalyst 1 and 54 μmol of methyltrioctylammonium chloride were added to 1 mL of toluene. The vial was then placed in an autoclave, which was sealed and removed from the glove box. In the autoclave, the mixture was heated to 90 °C with stirring. When the target temperature was reached, the autoclave was pressurized to 4.5 MPa using hydrogen. After stirring the reaction mixture for 2.5 hours, the reaction mixture was cooled in an ice bath, and the pressure was carefully released. The upper layer of the reacted solution was removed, leaving a lower aqueous solution containing potassium formate and unreacted potassium bicarbonate. 100 μL of the lower aqueous solution was dissolved in 500 μL of heavy water, and 300 μL of dimethyl sulfoxide was added as an internal standard. Then the reaction proceeded... 1¹H NMR was used to determine the TON of the catalyst and the conversion efficiency of potassium bicarbonate to formate. The results showed that the TON of the catalyst was 65,000 and the conversion efficiency of potassium bicarbonate to formate was 0.78.

[0297] (Formate protonation reaction)

[0298] Add the solution obtained by dissolving 14g of potassium hydroxide in 500mL of water to the alkali tank. Add the solution obtained by dissolving 210.3g of potassium formate in 250mL of water, and then further diluting with 250mL of water (twice the amount of water) to the salt tank. Add 500mL of ion-exchange water to the acid tank. If the electrodialysis device is started, the voltage becomes 28V and the current becomes 0.28A. At this time, the conductivity of the salt tank is 230.0S / m. As the dialysis treatment proceeds, the conductivity gradually decreases, reaching 0 after 140 minutes, indicating the end of the dialysis treatment. At this point, the voltage is 28.0V and the current is 1.30A. After the dialysis is completed, the volume of solution (salt solution) in the salt tank becomes 280mL, the volume of solution (acid solution) in the acid tank becomes 590mL, and the volume of liquid (alkali solution) in the alkali tank becomes 680mL. Take 100 μL of acid solution, dissolve it in 500 μL of heavy water, and add 300 μL of dimethyl sulfoxide as an internal standard. 1 ¹H NMR was used to quantify formic acid in the acid solution after dialysis. The formic acid recovery rate was calculated to be 0.89. Furthermore, to quantify potassium in the acid solution after dialysis, 20 mg of acid solution was diluted 50 times with water and measured using a potassium ion meter. The ratio of (formic acid / (potassium formate + formic acid)) in the acid solution was calculated to be 0.99.

[0299] Finally, based on the results of the formate formation and formate protonation reactions, the recovery rate of potassium bicarbonate to formic acid was 0.69%.

[0300] <Example 4>

[0301] (Formate formation reaction)

[0302] In a glove box under inert gas conditions, 1 mL of water was measured into a glass vial equipped with a stir bar, and 14 mmol of potassium bicarbonate was added. Then, 0.12 μmol of Ru catalyst 1 and 54 μmol of methyltrioctylammonium chloride were added to 1 mL of toluene. The vial was then placed in an autoclave, which was sealed and removed from the glove box. In the autoclave, the mixture was heated to 90 °C with stirring. When the target temperature was reached, the autoclave was pressurized to 4.5 MPa using hydrogen. After stirring the reaction mixture for 2.5 hours, the reaction mixture was cooled in an ice bath, and the pressure was carefully released. The upper layer of the reacted solution was removed, leaving a lower aqueous solution containing potassium formate and unreacted potassium bicarbonate. 100 μL of the lower aqueous solution was dissolved in 500 μL of heavy water, and 300 μL of dimethyl sulfoxide was added as an internal standard. Then the reaction proceeded... 1 ¹H NMR measurements were performed to calculate the TON of the catalyst and the conversion efficiency of potassium bicarbonate to formate. The results showed that the TON of the catalyst was 99,000 and the conversion efficiency of potassium bicarbonate to formate was 0.85.

[0303] (Formate protonation reaction)

[0304] Add the solution obtained by dissolving 14g of potassium hydroxide in 500mL of water to the alkali tank. Add the solution obtained by dissolving 210.3g of potassium formate in 180mL of water and then further diluting with 320mL of water to the salt tank. Add 500mL of ion-exchanged water to the acid tank. If the electrodialysis device is started, the voltage becomes 28V and the current becomes 0.28A. At this time, the conductivity of the salt tank is 230.1S / m. As the dialysis treatment proceeds, the conductivity gradually decreases, and after 140 minutes, the conductivity becomes 0, and the dialysis treatment ends. At this time, the voltage is 28.0V and the current is 1.3A. After the dialysis is completed, the volume of solution (salt solution) in the salt tank becomes 280mL, the volume of solution (acid solution) in the acid tank becomes 590mL, and the volume of liquid (alkali solution) in the alkali tank becomes 680mL. Take 100 μL of acid solution, dissolve it in 500 μL of heavy water, and add 300 μL of dimethyl sulfoxide as an internal standard. 1 ¹H NMR was used to quantify formic acid in the acid solution after dialysis. The formic acid recovery rate was calculated to be 0.89. Furthermore, to quantify potassium in the acid solution after dialysis, 20 mg of acid solution was diluted 50 times with water and measured using a potassium ion meter. The ratio of (formic acid / (potassium formate + formic acid)) in the acid solution was calculated to be 0.99.

[0305] Finally, based on the results of the formate formation and formate protonation reactions, the recovery rate of potassium bicarbonate to formic acid was 0.76%.

[0306] <Example 5>

[0307] (Formate formation reaction)

[0308] In a glove box under inert gas conditions, 1 mL of water was measured in a glass vial equipped with a stir bar, and 5 mmol of potassium bicarbonate was added. Then, 0.12 μmol of Ru catalyst 7 and 54 μmol of methyltrioctylammonium chloride were added to 1 mL of toluene. The vial was then placed in an autoclave, which was sealed and removed from the glove box. In the autoclave, the mixture was heated to 90 °C with stirring. When the target temperature was reached, the autoclave was pressurized to 4.5 MPa using hydrogen. After stirring the reaction mixture for 12 hours, the reaction mixture was cooled in an ice bath, and the pressure was carefully released. The supernatant of the reacted solution was removed, leaving a lower aqueous solution containing potassium formate and unreacted potassium bicarbonate. 100 μL of the lower aqueous solution was dissolved in 500 μL of heavy water, and 300 μL of dimethyl sulfoxide was added as an internal standard. Then the reaction proceeded... 1 ¹H NMR was used to determine the TON of the catalyst and the conversion efficiency of potassium bicarbonate to formate. The results showed that the TON of the catalyst was 25000 and the conversion efficiency of potassium bicarbonate to formate was 0.60.

[0309] (Formate protonation reaction)

[0310] Add the liquid obtained by dissolving 14g of potassium hydroxide in 500mL of water to the alkali tank. Add the liquid obtained by dissolving 210.3g of potassium formate in 500mL of water to the salt tank. Add 500mL of ion-exchanged water to the acid tank. If the electrodialysis device is started, the voltage becomes 28V and the current becomes 0.27A. At this time, the conductivity of the salt tank is 230.1S / m. As the dialysis treatment proceeds, the conductivity gradually decreases, and after 140 minutes, the conductivity becomes 0, and the dialysis treatment ends. At this time, the voltage is 28.0V and the current is 1.3A. After the dialysis is completed, the volume of solution (salt solution) in the salt tank becomes 280mL, the volume of solution (acid solution) in the acid tank becomes 590mL, and the volume of liquid (alkali solution) in the alkali tank becomes 680mL. Take 100μL of acid solution, dissolve it in 500μL of heavy water, add 300μL of dimethyl sulfoxide as an internal standard, and proceed. 1 The formic acid in the acid solution after dialysis was quantified by ¹H NMR determination. The formic acid recovery rate was calculated to be 0.90. Furthermore, to quantify potassium in the acid solution after dialysis, 20 mg of acid solution was diluted 50 times with water, and the potassium ion was measured using a potassium ion meter. The ratio of (formic acid / (potassium formate + formic acid)) in the acid solution was calculated to be 0.98.

[0311] Finally, based on the results of the formate formation and formate protonation reactions, the recovery rate of potassium bicarbonate to formic acid was 0.54%.

[0312] <Example 6>

[0313] (Formate formation reaction)

[0314] In a glove box under inert gas conditions, 1 mL of water was measured in a glass vial equipped with a stir bar, and 10 mmol of potassium bicarbonate was added. Then, 0.12 μmol of Ru catalyst 7 and 54 μmol of methyltrioctylammonium chloride were added to 1 mL of toluene. The vial was then placed in an autoclave, which was sealed and removed from the glove box. In the autoclave, the mixture was heated to 90 °C with stirring. When the target temperature was reached, the autoclave was pressurized to 4.5 MPa using hydrogen. After stirring the reaction mixture for 18 hours, the reaction mixture was cooled in an ice bath, and the pressure was carefully released. The supernatant of the reacted solution was removed, leaving a lower aqueous solution containing potassium formate and unreacted potassium bicarbonate. 100 μL of the lower aqueous solution was dissolved in 500 μL of heavy water, and 300 μL of dimethyl sulfoxide was added as an internal standard. Then the reaction proceeded... 1 ¹H NMR was used to determine the TON of the catalyst and the conversion efficiency of potassium bicarbonate to formate. The results showed that the TON of the catalyst was 56,000 and the conversion efficiency of potassium bicarbonate to formate was 0.68.

[0315] (Formate protonation reaction)

[0316] A solution obtained by dissolving 14g of potassium hydroxide in 500mL of water was added to the alkali tank. A solution obtained by dissolving 210.3g of potassium formate in 250mL of water was added to the salt tank, and then further diluted with 250mL of water (twice the amount of water). If the electrodialysis apparatus was started, the voltage became 28V and the current became 0.27A, with a conductivity of 230.1 S / m in the salt tank. As dialysis progressed, the conductivity gradually decreased, reaching 0 after 140 minutes, indicating the end of the dialysis process. At this point, the voltage was 28.0V and the current was 1.30A. After dialysis, the volume of solution (salt solution) in the salt tank became 280mL, the volume of solution (acid solution) in the acid tank became 590mL, and the volume of liquid (alkali solution) in the alkali tank became 680mL. 100μL of the acid solution was dissolved in 500μL of heavy water, and 300μL of dimethyl sulfoxide was added as an internal standard for further analysis. 1 HNMR analysis was used to quantify formic acid in the acid solution after dialysis. The formic acid recovery rate was calculated to be 0.88. Furthermore, to quantify potassium in the acid solution after dialysis, 20 mg of acid solution was diluted 50 times with water and measured using a potassium ion meter. The ratio of (formic acid / (potassium formate + formic acid)) in the acid solution was calculated to be 0.98.

[0317] Finally, based on the results of the formate formation and formate protonation reactions, the recovery rate of potassium bicarbonate to formic acid was 0.60%.

[0318] <Comparative Example 1>

[0319] (Formate formation reaction)

[0320] In a glove box under inert gas conditions, 1 mL of water was measured into a glass vial equipped with a stir bar. 1 mmol of potassium bicarbonate was added, followed by 0.12 μmol of Ru catalyst 1 and 54 μmol of methyltrioctylammonium chloride to 1 mL of toluene. The vial was then placed in an autoclave, sealed, and removed from the glove box. In the autoclave, the mixture was heated to 90 °C with stirring. When the target temperature was reached, the autoclave was pressurized to 4.5 MPa using hydrogen. After stirring the reaction mixture for 2.5 hours, the mixture was cooled in an ice bath, and the pressure was carefully released. The supernatant of the reacted solution was removed, leaving a lower aqueous solution containing potassium formate and unreacted potassium bicarbonate. 100 μL of the lower aqueous solution was dissolved in 500 μL of heavy water, and 300 μL of dimethyl sulfoxide was added as an internal standard. Then, the reaction proceeded... 1 ¹H NMR was used to determine the TON of the catalyst and the conversion efficiency of potassium bicarbonate to formate. The results showed that the TON of the catalyst was 5600 and the conversion efficiency of potassium bicarbonate to formate was 0.67.

[0321] (Formate protonation reaction)

[0322] Add the liquid obtained by dissolving 14g of potassium hydroxide in 500mL of water to the alkali tank. Add the liquid obtained by dissolving 42.06g of potassium formate in 500mL of water to the salt tank. Add 500mL of ion-exchanged water to the acid tank. If the electrodialysis device is started, the voltage becomes 28V and the current becomes 0.16A. At this time, the conductivity of the salt tank is 74.8S / m. As the dialysis process proceeds, the conductivity gradually decreases, and after 46 minutes, the conductivity becomes 0, and the dialysis process ends. At this time, the voltage is 28.0V and the current is 0.78A. After the dialysis is completed, the volume of solution (salt solution) in the salt tank becomes 425mL, the volume of solution (acid solution) in the acid tank becomes 510mL, and the volume of liquid (alkali solution) in the alkali tank becomes 547mL. Take 100μL of acid solution, dissolve it in 500μL of heavy water, add 300μL of dimethyl sulfoxide as an internal standard, and proceed. 1¹H NMR was used to quantify formic acid in the acid solution after dialysis. The formic acid recovery rate was calculated to be 0.86. Furthermore, to quantify potassium in the acid solution after dialysis, 22 mg of acid solution was diluted 55 times with water and measured using a potassium ion meter. The ratio of (formic acid / (potassium formate + formic acid)) in the acid solution was calculated to be 0.98.

[0323] Finally, based on the results of the formate formation and formate protonation reactions, the recovery rate of potassium bicarbonate to formic acid was 0.58%.

[0324] <Quantitative methods for potassium formate or formic acid in solution>

[0325] Take 100 μL of sample solution, dissolve it in 500 μL of heavy water, add 300 μL of dimethyl sulfoxide as an internal standard, and then proceed. 1 H NMR determination. The molar amount X (mol) of potassium formate or formic acid contained in the solution is calculated by the following formula (the molar amount (mol) of potassium formate or formic acid produced in the reaction).

[0326] X=(W / M)×(Ia×Ib / R)×(A / B) Formula 2

[0327] (In Formula 2, W represents the amount of dimethyl sulfoxide (g) used in the quantitative determination of potassium formate.)

[0328] M represents the molecular weight of dimethyl sulfoxide.

[0329] R represents the ratio of the number of protons in dimethyl sulfoxide to the number of protons in potassium formate.

[0330] Ia represents the proton NMR integral value of potassium formate.

[0331] Ib represents the proton NMR integral value of dimethyl sulfoxide.

[0332] A represents the mass (g) of the lower aqueous solution obtained in the following reaction.

[0333] B represents the mass (g) of the aqueous solution used in the quantitative determination of potassium formate.

[0334] Here, W is 0.33, M is 78.13, and R is 6, so Equation 2 becomes the following equation.

[0335] X = 0.0007 × Ia × Ib × (A / B)

[0336] <Calculation of the conversion number (TON) of the catalyst>

[0337] The calculation of "TON of the catalyst" as recorded in Table 1 is obtained by dividing the molar amount (mol) of potassium formate generated in the reaction by the molar amount (mol) of the catalyst used in the reaction, which is 0.00012 (mol).

[0338] <Calculation Method for Potassium Bicarbonate to Formate Conversion Efficiency>

[0339] The efficiency of potassium bicarbonate to formate is calculated by dividing the molar amount (mol) of potassium formate produced in the reaction by the molar amount (mol) of potassium bicarbonate used in the reaction.

[0340] <Method for calculating the purity of formic acid in acid solution>

[0341] To quantify (mol) the potassium ions in the acid bath solution (acid solution) after dialysis, a compact potassium ion meter, HORIBA LAQUAtwin, was used. <k-11>The purity of formic acid in the acid solution after dialysis (the ratio of (formic acid / (potassium formate + formic acid)) in the acid solution) is calculated as follows: subtract the amount of potassium ions (mol) from the amount of potassium formate or formic acid present in the acid solution, and divide the resulting value by the amount of potassium formate and formic acid present in the acid solution (mol).

[0342] <Method for calculating the recovery rate of formic acid in acid solution>

[0343] The recovery rate of formic acid in the acid solution during the protonation reaction of formate is calculated by dividing the molar amount (mol) of formic acid present in the acid solution after dialysis treatment by the molar amount (mol) of potassium formate in the solution (salt solution) added to the salt tank.

[0344] <Calculation Method for Potassium Bicarbonate to Formic Acid Conversion Rate>

[0345] Assuming that formic acid can be recovered from potassium bicarbonate via a process from formate formation reaction to formate protonation reaction, the efficiency is calculated by multiplying the efficiency of potassium bicarbonate conversion to formate formation in the formate formation reaction by the formic acid recovery rate in the acid solution in the formate protonation reaction.

[0346] The results obtained are judged using the following criteria.

[0347] ◎: Catalyst TON is 50,000 or higher, and potassium bicarbonate to formic acid recovery rate is 0.6 or higher. 〇: Catalyst TON is 20,000 or higher but less than 50,000, and potassium bicarbonate to formic acid recovery rate is 0.5 or higher but less than 0.6. △: Catalyst TON is 10,000 or higher but less than 20,000, and potassium bicarbonate to formic acid recovery rate is 0.5 or higher but less than 0.6. ×: Catalyst TON is less than 10,000.

[0348] The above embodiments and comparative examples are described in Table 1.

[0349] [Table 1]

[0350]

[0351] In Examples 1 to 6, where formate production reactions were carried out using the formate production method of the present invention, it was confirmed that a high TON (Turnover Number) was observed under each reaction condition, and the conversion efficiency of potassium bicarbonate to formate was also high, enabling the production of formate with high yield and excellent productivity.

[0352] Furthermore, for Examples 1 to 6, in which formic acid was produced using the formic acid production method of the present invention, it can be confirmed that a high TON (Turnover Number) is exhibited under each reaction condition, and formic acid can be produced with high yield and excellent productivity.

[0353] It should be noted that the TON values ​​of Ru catalyst 1 and Ru catalyst 7 used in this embodiment are 66,000 and 56,000 respectively, calculated using the TON calculation method specified above.

[0354] The following describes examples and comparative examples that confirm the antifreeze effect of the formate obtained in this invention.

[0355] <Example 7>

[0356] The formate formation reaction was carried out on a 10-fold scale (using 10 mL of water) according to the method described in Example 3. The lower aqueous solution after the reaction was evaporated using an evaporator and then further dried in an oven at 60°C to obtain a white powder.

[0357] <Example 8>

[0358] The formate formation reaction was carried out on a 10-fold scale (using 10 mL of water) according to the method described in Example 3. 1.0 g of formic acid (manufactured by FUJIFILM Wako Pure Chemical Corporation, product number 063-05895) was added to the lower aqueous layer after the reaction. After evaporating the water using an evaporator, the mixture was further dried in an oven at 60°C to obtain a white powder.

[0359] <Example 9>

[0360] The formate formation reaction was carried out on a 10-fold scale (using 10 mL of water) according to the method described in Example 3. 1.3 g of acetic acid (manufactured by FUJIFILM Wako Pure Chemical Corporation, product number 017-00256) was added to the lower aqueous layer after the reaction. After evaporating the water using an evaporator, the mixture was further dried in an oven at 60°C to obtain a white powder.

[0361] (Evaluation method for antifreeze performance)

[0362] Place 6-7g of ice in a petri dish, and sprinkle 0.5g of the white powder obtained in Examples 7-9, and calcium chloride (manufactured by FUJIFILM Wako Pure Chemical Corporation, product number 038-24985) (Comparative Example 2) and urea (manufactured by FUJIFILM Wako Pure Chemical Corporation, product number 213-00173) (Comparative Example 3) on top. Place the dish in a constant temperature bath at -5°C, and measure the amount of ice melted after 1 hour. The melting rate is taken as the proportion relative to the initial ice weight. The amount of ice melted is determined by the increase in weight when water is absorbed into a paper towel.

[0363] The results are shown in Table 2 below.

[0364] [Table 2]

[0365] Table 2

[0366] Ice melting rate (%) Remark Example 7 42 Example 8 48 Formic acid added Example 9 55 Acetic acid added Comparative Example 2 47 Calcium chloride Comparative Example 3 36 Urea

[0367] It has been confirmed that the formate produced in this invention has higher ice-melting performance than urea, a representative example of a non-chloride antifreeze. Furthermore, the performance is improved by neutralizing the remaining carbonate or bicarbonate with acid after the formate manufacturing process.

[0368] Industrial availability

[0369] According to the present invention, a method for manufacturing formate, a precursor of formic acid, a method for manufacturing formic acid, and a method for manufacturing antifreeze can be provided, which can produce formate salts with high yield and excellent productivity.

[0370] The invention has been described in detail and with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

[0371] This application is made based on Japanese patent applications filed on September 3, 2020 (Japanese Patent Application No. 2020-148562), February 12, 2021 (Japanese Patent Application No. 2021-021223), February 12, 2021 (Japanese Patent Application No. 2021-021224), February 12, 2021 (Japanese Patent Application No. 2021-021225), May 10, 2021 (Japanese Patent Application No. 2021-079887), and May 17, 2021 (Japanese Patent Application No. 2021-083416), the contents of which are incorporated herein by reference.

[0372] Explanation of reference numerals in the attached figures

[0373] Valve 1, 2, 3, 5

[0374] 10 Formate manufacturing facility

[0375] 20 Dilution apparatus

[0376] 30 Electrodialysis Unit

[0377] 40. Dilution Water Storage Section

[0378] 50 hydrogen storage cylinders

[0379] 60 carbon dioxide storage cylinder

[0380] 70 Water Supply Department

[0381] 80 Formic Acid Supply Department

[0382] 100 Formic Acid Manufacturing System

[0383] L1, L2 piping

[0384] L3, L4, L5, L6, L7, L9 flow path

Claims

1. A method for producing formate, comprising a first step of reacting hydrogen with a bicarbonate or carbonate in the presence of a solvent using a metal complex catalyst to generate formate in a reaction solution. In the reaction, the solvent is a two-phase system existing in a state where it is separated into an organic phase and an aqueous phase. In the reaction, the concentration of bicarbonate or carbonate added to the aqueous phase is 2.5 mol / L or higher.

2. The method for producing a formate salt according to claim 1, wherein The concentration of the added bicarbonate or carbonate is below 30 mol / L.

3. The method for manufacturing formate as described in claim 1 or 2, wherein, Further addition of ligands to the metal complex catalyst.

4. The method for manufacturing formate as described in claim 1 or 2, wherein, The metal complex catalyst is a ruthenium complex represented by the following general formula (1). [Chemical Formula 1] In general formula (1), R0 represents an alkyl group having 1 to 30 hydrogen atoms. Q1 can independently represent CH2, NH, or O. R1 independently represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, wherein, when Q1 represents NH or O, at least one of R1 represents an aryl group having 6 to 30 carbon atoms. A can independently represent CH, CR5, or N. R5 represents an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, an aralkyl group having fewer than 30 carbon atoms, an amino group, a hydroxyl group, or an alkoxy group having 1 to 30 carbon atoms. X represents a halogen atom. n represents 0 to 3. In the presence of multiple L, each independently represents a neutral or anionic ligand.

5. The method for manufacturing formate as described in claim 4, wherein, Further adding the ligand represented by the following general formula (4), [Chemical Formula 2] In general formula (4), R0 represents an alkyl group having 1 to 30 hydrogen atoms. Q2 can be represented independently as NH or O. R3 independently represents aryl groups with 6 to 30 carbon atoms. A can be independently represented by CH, CR5, or N, and R5 can be represented by an alkyl group with 1 to 30 carbon atoms, an aryl group with 6 to 30 carbon atoms, an aralkyl group with less than 30 carbon atoms, an amino group, a hydroxyl group, or an alkoxy group with 1 to 30 carbon atoms.

6. The method for manufacturing formate as described in claim 1 or 2, wherein, The organic phase comprises toluene or dioxane.

7. The method for manufacturing formate as described in claim 1 or 2, wherein, In the first step, a quaternary ammonium salt is further used as a phase transfer catalyst.

8. A method for manufacturing formic acid, comprising the following steps: The process of manufacturing formate using the method of any one of claims 1 to 7; and The second step involves protonating at least a portion of the formate salt via electrodialysis to generate formic acid and water.

9. The method for producing formic acid as described in claim 8, wherein, The aqueous phase is separated, and the concentration of the formate in the aqueous phase is adjusted by dilution before being used in the second process.

10. The method for producing formic acid as described in claim 9, wherein, The water generated in the second step will be used for the dilution.

11. The method for producing formic acid as described in claim 8, wherein, The aqueous phase is separated, and after decarbonation treatment with acid, it is used in the second process.

12. A method for manufacturing an antifreeze, comprising a step of manufacturing a formate using the formate manufacturing method according to any one of claims 1 to 7.

13. The method for manufacturing the antifreeze as claimed in claim 12, further comprising the step of adding at least one acid selected from the group consisting of formic acid and acetic acid to the formate.

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