Carbon dioxide absorbing liquid, and method for separating and recovering carbon dioxide

Abstract

To provide a carbon dioxide absorbing and releasing liquid having high carbon dioxide absorption capacity, high carbon dioxide release capacity at a low temperature, and little deterioration even when absorption and release cycles are repeated, and to provide a method for separating and recovering carbon dioxide.SOLUTION: There is provided an absorbing liquid for separating and recovering carbon dioxide from a gas containing carbon dioxide, comprising an amine compound (A) represented by the following general formula (1) and a liquid medium (B), and having a chloride content of 1000 ppm or less. In the formula: R1 is a hydrogen atom or a hydrocarbon group optionally having a substituent; R2 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or -CH2CH(OH)CH2X2A2; X1 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA3-; A1 is a hydrogen atom or an n-valent organic residue; n is an integer of 1 to 6; X2 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA3-; A2 is a hydrogen atom or a monovalent organic residue; and A3 is a hydrogen atom or a monovalent organic residue.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an absorption liquid for separating and recovering carbon dioxide from a gas containing carbon dioxide with high efficiency, and a method for separating and recovering carbon dioxide using the absorption liquid. [Background technology]

[0002] In recent years, the rapid increase in greenhouse gas emissions such as carbon dioxide and methane associated with social activities has been cited as one of the causes of global warming. Carbon dioxide in particular is the most significant greenhouse gas, and measures to reduce carbon dioxide emissions are urgently needed in accordance with the Paris Agreement that came into effect in 2016.

[0003] Carbon dioxide separation and capture has attracted attention as an effort to reduce carbon dioxide emissions, and the development of carbon dioxide absorbents has been actively pursued. For this reason, in recent years, the development of carbon dioxide separation and capture technology using a chemical absorption method, primarily an aqueous solution of an amine compound, has been actively promoted for carbon dioxide-containing gases emitted from power plants and steelworks.

[0004] Known examples of the amine compounds include primary alkanolamines such as monoethanolamine (MEA), diglycolamine (DGA), and 2-amino-2-methyl-1-propanol (AMP); secondary alkanolamines such as 2-(methylamino)ethanol (MAE), 2-(ethylamino)ethanol (EAE), 2-(isopropylamino)ethanol (IPAE), and 3-(isopropylamino)propanol (IPAP); diethanolamine (DEA), and diisopropanolamine (DIPA); tertiary alkanolamines such as N-methyldiethanolamine (MDEA), 2-(dimethylamino)ethanol (DMAE), and triethanolamine (TEA); and tertiary alkylamines such as N,N,N',N'-tetramethyl-1,6-diaminohexane (TMDAH), N,N,N',N'-tetramethyl-1,4-diaminobutane (TMDAB), and bis(2-dimethylaminoethyl)ether (BDER). MEA is particularly widely used.

[0005] As a conventional technique for separating and recovering carbon dioxide using less energy, for example, Patent Document 1 describes a method for removing carbon dioxide from combustion exhaust gas by bringing an aqueous solution of a secondary alkanolamine having a steric hindrance such as an alkyl group around the amino group into contact with the combustion exhaust gas under atmospheric pressure to absorb the carbon dioxide.

[0006] As one of the amine compounds contained in a carbon dioxide absorbent in a method for deacidifying a gaseous effluent containing at least one acidic compound selected from the group consisting of hydrogen sulfide (H2S) and carbon dioxide (CO2), there is a description of an absorbent comprising a compound obtained by reacting ethylenediamine with neopentyl glycol diglycidyl ether (Patent Document 2), and a description of an absorbent comprising a compound obtained by adding diethylenetriamine with propylene oxide (Patent Document 3).

[0007] In any of the amine compounds, a compound having a glycidyl group is used as an epoxy raw material. Generally, these compounds having a glycidyl group contain a chlorine-containing compound consisting of epichlorohydrin, which is the raw material. However, the influence of these chlorine-containing compounds in the carbon dioxide absorbing solution is not known at all. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 5-301023 [Patent Document 2] Patent Application No. 2023-091519 [Patent Document 3] Japanese Patent Publication No. 2020-157211 Summary of the Invention [Problem to be solved by the invention]

[0009] The present disclosure aims to provide a carbon dioxide absorption / release liquid that has a high carbon dioxide absorption capacity, a high carbon dioxide release capacity at low temperatures, and that is less susceptible to deterioration even after repeated absorption and release cycles, and a method for separating and recovering carbon dioxide. [Means for solving the problem]

[0010] The present disclosure provides the following carbon dioxide absorption liquid and carbon dioxide separation and recovery method. [1] An absorption liquid for separating and recovering carbon dioxide from a gas containing carbon dioxide, An absorbing solution comprising an amine compound (A) represented by the following general formula (1) and a liquid medium (B), the absorbing solution having a chlorine (Cl) content of 1000 ppm or less: [ka] During the ceremony, R 1represents a hydrogen atom or a hydrocarbon group which may have a substituent and which may have a heteroatom in the carbon chain, and the carbon atom adjacent to N is a primary carbon atom or a carbon atom constituting a ring, R 2 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms in which the carbon atom adjacent to N is a primary carbon atom, or -CH2CH(OH)CH2X 2 A 2 and X 1 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3 - and A 1 is a hydrogen atom or an n-valent organic residue (where X 1 is a direct bond, and A 1 becomes a hydrogen atom), n is an integer from 1 to 6, X 2 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3 - and A 2 is a hydrogen atom or a monovalent organic residue (where X 2 is a direct bond, and A 2 becomes a hydrogen atom), A 3 is a hydrogen atom or a monovalent organic residue. [2] R 1 The absorbing solution according to [1], wherein the absorbing solution has a nitrogen atom. [3] R 1 is a group represented by the following general formula (2), general formula (3), general formula (4) or general formula (5): [ka] During the ceremony, R 3 , R 4 , R 5 , and R 6 are each independently a hydrogen atom or a methyl group, R 7is a hydrogen atom or a methyl group, R 8 is a hydrogen atom or a methyl group, p is an integer from 0 to 4, R 9 is an alkyl group having 1 to 8 carbon atoms, m is an integer from 0 to 4, R 10 , and R 12 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a hydroxyalkyl group, R 11 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a hydroxyalkyl group, or -(CH2) s -R 13 and R 13 is a hydroxy group or -N(R 14 )R 15 and R 14 and R 15 are each independently a hydrogen atom, a methyl group, or a hydroxyalkyl group, q is 2 or 3; r is 2 or 3; s is 2 or 3. [4] A. 1 is an n-valent organic residue. [5] A. 1 , A 2 and A 3 are each independently a linear or branched aliphatic hydrocarbon residue which may have a substituent and which may have a heteroatom in the carbon chain; a (meth)acryloyl residue which may have a substituent; an alicyclic hydrocarbon residue which may have a substituent and which may have a heteroatom in the carbon chain; an aromatic hydrocarbon residue which may have a substituent; or an aromatic heterocyclic residue which may have a substituent. [6] R 2 The absorbing solution according to any one of [1] to [5], wherein is a hydrogen atom. [7] The absorbing solution according to any one of [1], wherein the chlorine (Cl) content is 10 to 500 ppm. [8] The absorbing liquid according to any one of [1] to [6], further comprising at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines. [9] The liquid medium (B) has a total Hansen solubility parameter (δT) of 17 MPa. 1 / 2 The absorbing solution according to any one of [1] to [7] above.

[10] The absorbing liquid according to any one of [1] to [8], wherein the proportion of water in the liquid medium (B) is 50 mass % or less.

[11] The absorbing liquid according to any one of [1] to [9], which contains 5 mass % or more of the amine compound (A) represented by the formula (1).

[12] The absorbing solution according to any one of [1] to

[10] , further comprising a gas containing hydrogen sulfide, the absorbing solution absorbing the hydrogen sulfide.

[13] A method for separating and recovering carbon dioxide from a gas containing carbon dioxide, comprising the following steps A and B: Step A: A step of contacting the absorbing solution according to any one of [1] to

[12] with a gas containing carbon dioxide to obtain an absorbing solution that has absorbed carbon dioxide from the gas containing carbon dioxide; Step B: A step of heating the absorption liquid that has absorbed carbon dioxide and is obtained in Step A to desorb and release the carbon dioxide from the absorption liquid, and recovering the released carbon dioxide.

[14] The method according to

[13] , wherein the heating temperature in step B is 50°C or higher and 160°C or lower. [Effects of the Invention]

[0011] According to the present disclosure, the absorption liquid has a high carbon dioxide capture capacity, is capable of releasing carbon dioxide with low energy, and suppresses material deterioration due to repeated capture and release of carbon dioxide, making it possible for the entire system to separate and capture carbon dioxide with low energy. Furthermore, improved absorption efficiency makes it possible to design a more compact carbon dioxide separation and capture facility, reducing initial costs. Furthermore, by using an absorption liquid that is corrosive to the steel materials that make up the carbon dioxide separation and capture system, it is possible to realize an absorption system that can be used for a long period of time. DETAILED DESCRIPTION OF THE INVENTION

[0012] The absorbing solution and the method for separating and recovering carbon dioxide will be described below. In the present disclosure, unless otherwise specified, the symbol "to" indicating a range of values ​​includes the values ​​before and after it as the lower and upper limits. Furthermore, when there are multiple identical symbols in a chemical formula, unless otherwise specified, the identical symbols are not limited to representing the same substituent, and may represent different substituents within the scope defined by the symbols.

[0013] [Absorbent] The absorbing liquid of the present disclosure is an absorbing liquid for separating and recovering carbon dioxide from a gas containing carbon dioxide, and contains an amine compound (A) represented by the following general formula (1) and a liquid medium (B). [ka] During the ceremony, R 1 represents a hydrogen atom or a hydrocarbon group which may have a substituent and which may have a heteroatom in the carbon chain, and the carbon atom adjacent to N is a primary carbon atom or a carbon atom constituting a ring, R 2 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms in which the carbon atom adjacent to N is a primary carbon atom, or -CH2CH(OH)CH2X 2 A 2 and X 1 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3 - and A 1 is a hydrogen atom or an n-valent organic residue (where X 1 is a direct bond, and A 1 becomes a hydrogen atom), n is an integer from 1 to 6, X 2 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3 - and A 2 is a hydrogen atom or a monovalent organic residue (where X 2 is a direct bond, and A 2 becomes a hydrogen atom), A 3 is a hydrogen atom or a monovalent organic residue.

[0014] The present inventors have found that by using an absorption liquid comprising the above-mentioned specific amine compound (A) and a specific chlorine content, a high amount of carbon dioxide can be recovered and the energy consumption required for the amount of carbon dioxide recovered can be reduced. The absorption liquid of the present disclosure comprising the above-mentioned specific composition not only efficiently absorbs carbon dioxide and releases it with low energy consumption, thereby enabling highly pure carbon dioxide to be recovered with high efficiency, but also resists deterioration even when absorption and release are repeated.

[0015] <Amine compound (A)> The amine compound (A) is a compound represented by the following general formula (1). [ka]

[0016] R 1 is a hydrogen atom or a hydrocarbon group which may have a substituent and may have a heteroatom in the carbon chain, and the carbon atom adjacent to N is a primary carbon atom or a carbon atom constituting a ring. Here, N represents N as explicitly shown in formula (1).

[0017] Examples of hydrocarbon groups in which the carbon atom adjacent to N is a primary carbon atom include linear alkyl groups. Examples of hydrocarbon groups in which the carbon atom adjacent to N is a ring carbon atom include cycloalkyl groups and aryl groups. Examples of heteroatoms that may be contained in the carbon chain include O, N, S, and Si, and O or N is preferred. The carbon chain may contain two or more heteroatoms. Also, R 1 Examples of the "substituent" that may be introduced into the group include a halogen atom, a linear or branched alkyl group, a cycloalkyl group, an alkoxy group, a cyano group, a trifluoromethyl group, a nitro group, a hydroxyl group, a carbamoyl group, an N-substituted carbamoyl group, a sulfamoyl group, an N-substituted sulfamoyl group, a carboxyl group, a sulfo group, an amino group, an imino group, a phenyl group, and a sulfanyl group. The above-mentioned substituents may further have a substituent, and examples of the substituent include the above-mentioned substituents.

[0018] R 1 Among these, a hydrogen atom, an alkyl group which may have a substituent and which may have a heteroatom in the carbon chain, a heterocyclic group which may have a substituent, or a cycloalkyl group which may have a substituent is preferred.

[0019] R 1Examples of the alkyl group in the formula (I) which may have a substituent and which may have a heteroatom in the carbon chain include a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a neopentyl group, an n-hexyl group, an n-octyl group, a stearyl group, a 2-ethylhexyl group, a trichloromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 2,2-dibromoethyl group, a 2,2,3,3-tetrafluoropropyl group, a 2-ethoxyethyl group, a 2-butoxyethyl group, a 2-nitropropyl group, a benzyl group, a 4-methylbenzyl group, a 4-tert-butylbenzyl group, a 4-tert-butylbenzyl group, a 4-methyl ...methylbenzyl group, a 4-tert-butylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-tert-butylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group, a 4-methylbenzyl group methylsulfanyl group, 4-methoxybenzyl group, 4-nitrobenzyl group, 2,4-dichlorobenzyl group, methylsulfanyl group, ethylsulfanyl group, propylsulfanyl group, butylsulfanyl group, pentylsulfanyl group, hexylsulfanyl group, octylsulfanyl group, decylsulfanyl group, dodecylsulfanyl group, octadecylsulfanyl group, methoxyethylsulfanyl group, aminoethylsulfanyl group, benzylaminoethylsulfanyl group, methylcarbonylaminoethylsulfanyl group, phenylcarbonylaminoethylsulfanyl group , sulfanylmethyl group, 2-sulfanylethyl group, 1-sulfanylethyl group, aminomethyl group, aminoethyl group, N-methylaminoethyl group, N-dimethylaminoethyl group, N-ethylaminoethyl group, N-(aminoethyl)aminoethyl group, N-(hydroxyethyl)aminoethyl group, N-propylaminoethyl group, N-isopropylaminoethyl group, N-butylaminoethyl group, aminopropyl group, N-methylaminopropyl group, N-ethylaminopropyl group, N-propylaminopropyl group, N-(aminopropyl)aminopropyl group, N -isopropylaminopropyl group, N-butylaminopropyl group, dibutylaminopropyl group, dimethylaminopropyl group, diethylaminopropyl group, aminobutyl group, aminopentyl group, aminohexyl group, aminooctyl group, aminodecyl group, aminododecyl group, aminooctadecyl group, aminoethoxymethyl group, aminoethoxyethyl group, aminoethylaminoethyl group, aminoethylaminomethylphenyl group, aminoethylaminocarbonylmethyl group, aminoethylaminocarbonylphenyl group, hydroxymethyl group, 2-hydroxyethyl group,Examples include an N-(hydroxyethyl)aminoethyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 4-hydroxybutyl group, a cyclopropylmethyl group, a cyclobutylmethyl group, a cyclopentylmethyl group, a cyclohexylmethyl group, a cyclopentylethyl group, a cyclohexylethyl group, a cyclopentylpropyl group, a cyclohexylpropyl group, and a 2-(1-piperazinyl)ethyl group. The alkyl group having a substituent is preferably an aminoethyl group, an N-methylaminoethyl group, an N-ethylaminoethyl group, an N-(aminoethyl)aminoethyl group, an N-propylaminoethyl group, an N-isopropylaminoethyl group, an N-butylaminoethyl group, an aminopropyl group, an N-methylaminopropyl group, an N-ethylaminopropyl group, an N-propylaminopropyl group, an N-(aminopropyl)aminopropyl group, an N-isopropylaminopropyl group, an N-butylaminopropyl group, an aminobutyl group, or a 2-(1-piperazinyl)ethyl group, more preferably an aminoethyl group, an N-methylaminoethyl group, an N-ethylaminoethyl group, or an N-(aminoethyl)aminoethyl group.

[0020] Examples of the heterocyclic group which may have a substituent include a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a 2-pyrrolyl group, a 3-pyrrolyl group, a 2-furyl group, a 3-furyl group, a 2-thienyl group, a 3-thienyl group, a 2-imidazolyl group, a 2-oxazolyl group, a 2-thiazolyl group, a piperidino group, a 4-piperidyl group, a morpholino group, a 2-morpholinyl group, an N-indolyl group, a 2-indolyl group, a 2-benzofuryl group, a 2-benzothienyl group, a 2-quinolino group, an N-carbazolyl group, and a piperidinyl group.

[0021] Examples of the cycloalkyl group which may have a substituent include a cyclopropyl group, a methylcyclopropyl group, a cyclobutyl group, a cyclopentyl group, a methylcyclopentyl group, an ethylcyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, an ethylcyclohexyl group, a propylcyclohexyl group, and a 4,4'-methylenebis(cyclohexyl) group.

[0022] R is a material that combines carbon dioxide adsorption and carbon dioxide release at low temperatures. 1 Among these, it is preferable that the group has a nitrogen atom, and more preferably is a group represented by the following general formula (2), general formula (3), general formula (4) or general formula (5), where * represents a bond to N in formula (1). [ka]

[0023] In formula (2), R 3 , R 4 , R 5 , and R 6 are each independently a hydrogen atom or a methyl group, and R 7 is a hydrogen atom or a methyl group. From the viewpoint of carbon dioxide adsorption and low-temperature release, R 3 ~R 6 In terms of carbon dioxide adsorption and low-temperature release, R 7 is preferably a hydrogen atom.

[0024] In formula (3), R 8 is a hydrogen atom or a methyl group, and p is an integer of 0 to 4. From the viewpoint of carbon dioxide adsorption and low-temperature release, R 8 is preferably a hydrogen atom. In terms of carbon dioxide adsorption, low-temperature release, and ease of synthesis, p is preferably 1 to 4, and more preferably 2 or 3.

[0025] In formula (4), R 9 is an alkyl group having 1 to 8 carbon atoms, and m is an integer of 0 to 4. R 9 Examples of the alkyl group in R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a hexyl group, and an octyl group. 9 is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. 9It is preferably 0 to 2, more preferably 0 to 1, from the viewpoint of carbon dioxide adsorption and low-temperature release.

[0026] In formula (5), R 10 and R 12 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a hydroxyalkyl group, and R 11 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a hydroxyalkyl group, or -(CH2) s -R 13 and R 13 is a hydroxy group or -N(R 14 )R 15 and R 14 and R 15 are each independently a hydrogen atom, a methyl group, or a hydroxyalkyl group, q is 2 or 3, r is 2 or 3, and s is 2 or 3. From the viewpoints of carbon dioxide adsorption ability and low-temperature release ability, it is preferable that q is 3 and r is 3. R 10 ~R 12 The alkyl group having 1 to 8 carbon atoms in the above R 9 In terms of carbon dioxide absorption and low-temperature release, R 10 ~R 12 is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group. R 10 ~R 12 , R 14 and R 15 In the hydroxyalkyl group above, from the viewpoints of carbon dioxide adsorption and low-temperature release, the number of carbon atoms in the alkyl group is preferably 1 to 8, and more preferably 1 to 4. Specific examples of the hydroxyalkyl group include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, and a hydroxybutyl group.

[0027] In terms of carbon dioxide absorption and low-temperature release, 1 Among these, the group represented by general formula (5) is preferred. R 1 Specific examples of the amine compound (A) will be described later.

[0028] R 2 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms in which the carbon atom adjacent to N is a primary carbon atom, or -CH2CH(OH)CH2X 2 A 2 is.

[0029] R 2 In the formula (I), examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, a secondary butyl group, an isobutyl group, a neopentyl group, an isopentyl group, a secondary pentyl group, a 1-hexyl group, a 2-hexyl group, a heptyl group, a methylcyclohexyl group, an octyl group, and a 2-ethylhexyl group.

[0030] R 2 -CH2CH(OH)CH2X 2 A 2 In this case, n in formula (1) is preferably 1. In this case, formula (1) is 2 X 2 CH2CH(OH)CH2N(R 1 )CH2CH(OH)CH2X 1 A 1 When the amine compound (A) is represented by formula (1a), X is preferably selected from the viewpoints of carbon dioxide adsorption, low-temperature release, and ease of synthesis. 1 A 1 and X 2 A 2 are preferably the same substituents.

[0031] In terms of carbon dioxide adsorption, low-temperature release, and ease of synthesis, R 2 Among these, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms is preferred, and a hydrogen atom is more preferred.

[0032] X 1 and X 2 each independently represents a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3In terms of carbon dioxide adsorption, low-temperature release, and suppression of deterioration of the absorption solution during repeated use, X 1 and X 2 are each independently preferably a direct bond or -O-, more preferably -O-. Also, X 1 If there are multiple (i.e. n is 2 or more), there are multiple X 1 may be the same or different, but in terms of carbon dioxide adsorption, low-temperature release, and ease of synthesis, it is preferable to use a plurality of X 1 are preferably the same.

[0033] A 1 is a hydrogen atom or an n-valent organic residue, provided that X 1 If is a direct bond, A 1 is an n-valent organic residue. An n-valent organic residue is a residue obtained by removing n hydrogen atoms from an organic group. In the specific examples below, the names of monovalent substituents are used, but A 1 is a residue obtained by further removing any n-1 hydrogen atoms. A 1 Examples of the n-valent organic residue in the formula (I) include linear or branched aliphatic hydrocarbon residues which may have a substituent and which may have a heteroatom in the carbon chain; (meth)acryloyl residues which may have a substituent; alicyclic hydrocarbon residues which may have a substituent and which may have a heteroatom in the carbon chain; aromatic hydrocarbon residues which may have a substituent; and aromatic heterocyclic residues which may have a substituent. Examples of heteroatoms include O, N, S, Si, and the like. The heteroatom in the aliphatic hydrocarbon residue is preferably O or N, more preferably O. The heteroatom in the alicyclic hydrocarbon residue is preferably O or N, more preferably N. The organic residue may have two or more heteroatoms. Examples of linear or branched aliphatic hydrocarbon residues which have a heteroatom include linear or branched polyoxyalkyl residues. Furthermore, n represents an integer of 1 to 6, preferably 1 to 4, and more preferably 1 or 2.

[0034] The aliphatic hydrocarbon residue which may have an n-valent substituent includes an alkyl group, an alkenyl group, and an alkynyl group.

[0035] Specific examples of the alkyl group include alkyl groups having 1 to 18 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, tetradecyl, pentadecyl, and octadecyl groups.

[0036] Examples of the alkenyl group include alkenyl groups having 2 to 18 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-octenyl, 1-decenyl, and 1-octadecenyl.

[0037] Examples of the alkynyl group include alkynyl groups having 2 to 18 carbon atoms, such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-octynyl, 1-decynyl, and 1-octadecynyl.

[0038] Examples of the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent include a linear or branched alkyl group, an alkoxy group, a polyoxyalkyl group, a phenyl group, a 4-nitrophenyl group, a 2-methoxyphenyl group, a hydroxyl group, a halogen atom, and an epoxy group. The above-mentioned substituents may further have a substituent, and examples of the substituent include the above-mentioned substituents.

[0039] Specific alkyl groups as the substituent have the same meanings as the alkyl groups of the linear or branched hydrocarbon residues which may have an n-valent substituent, as described above.

[0040] Specific examples of the alkoxy group as a substituent include a methoxy group and an ethoxy group.

[0041] Specific examples of the polyoxyalkyl group as a substituent include an ethylene oxide group having a repeat number of 4 to 16, and a linear or branched propylene oxide group having a repeat number of 4 to 16.

[0042] Specific examples of the halogen atom as a substituent include a chlorine atom, a bromine atom, and an iodine atom.

[0043] Examples of the linear or branched polyoxyalkyl group which may have an n-valent substituent include an ethylene oxide group having a repeat number of 4 to 16 and a linear or branched propylene oxide group having a repeat number of 4 to 16. The substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent, and an alkyl group, a phenyl group, a hydroxyl group, etc. are preferred.

[0044] Examples of the (meth)acryloyl residue which may have an n-valent substituent include a methacryl group and an acryloyl group as the (meth)acryloyl group, and the substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent described above.

[0045] Examples of the alicyclic hydrocarbon group of the alicyclic hydrocarbon residue which may have an n-valent substituent include a cycloalkyl group, specifically a cycloalkyl group having 3 to 18 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclooctadecyl group, or a 2-indeno group. Alicyclic hydrocarbon groups also include groups in which multiple cycloalkyl groups are linked via alkylene groups or the like. The substituent in the alicyclic hydrocarbon residue which may have an n-valent substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent, and is preferably a branched alkylene group, and particularly preferably a tert-butylene group.

[0046] Examples of the aromatic hydrocarbon of the aromatic hydrocarbon residue which may have an n-valent substituent include aromatic hydrocarbons having a condensation number of 1 to 4, and specific examples thereof include benzene, biphenyl, naphthalene, anthracene, phenanthrene, tetracene, pyrene, 9,9-diphenylfluorene, bis(3-methylphenyl)fluorene, and binaphthyl.

[0047] The substituent in the aromatic hydrocarbon residue which may have an n-valent substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent, and is preferably an alkyl group, an alkylene group, or a halogen atom, and particularly preferably a methyl group, a methylene group, a tert-butylene group, or a bromine atom.

[0048] The aromatic heterocycle of the aromatic heterocyclic residue which may have an n-valent substituent is an aromatic heterocycle having 1 to 4 condensed rings, and examples thereof include pyrrole, imidazole, pyridine, triazine, indole, quinoline, carbazole, phthalimide, etc. The substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent.

[0049] A 1 (X 1 ) n The structure of can also be understood as, for example, a linear or branched alkoxy residue which may have an n-valent substituent, an alkyl ester residue which may have an n-valent substituent, an aromatic ester residue which may have an n-valent substituent, or an amino residue which may have an n-valent substituent.

[0050] Examples of the alkoxy group of the linear or branched alkoxy residue which may have an n-valent substituent include a methoxy group and an ethoxy group, and the substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent.

[0051] Examples of the alkyl ester group of the alkyl ester residue which may have an n-valent substituent include a methyl ester group, an ethyl ester group, a propyl ester group, a butyl ester group, a pentyl ester group, a heptyl ester group, a hexyl ester group, an octyl ester group, a hexadecyl ester group, a cyclohexyl ester group, a 1,2-cyclohexane diester group, and a 1,2-cyclohexene diester group. The substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent.

[0052] Examples of the aromatic ester group of the aromatic ester residue which may have an n-valent substituent include a phenyl ester group and a 4-tert-butylphenyl ester group, and the substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent.

[0053] The amino group of the amino residue which may have an n-valent substituent can be an aniline group. The substituent is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent, preferably an alkyl group, more preferably a methyl group.

[0054] A 1 is preferably a linear or branched hydrocarbon residue which may have an n-valent substituent, or an aromatic hydrocarbon residue which may have an n-valent substituent, more preferably a linear or branched hydrocarbon residue which may have an n-valent substituent, and particularly preferably an n-valent linear hydrocarbon residue. A 1 The number of carbon atoms is preferably 1 to 15, more preferably 1 to 10, and even more preferably 2 to 8.

[0055] A 2 and A 3 are each independently a hydrogen atom or a monovalent organic residue, provided that X 2 If is a direct bond, A 2 is a monovalent organic residue. A 2 and A3 The monovalent organic residue in 1 This is the same as replacing n in the n-valent organic residue with 1.

[0056] Representative examples of the amine compound (A), compounds (A1) to (A124), are shown in Tables 1-1 to 1-8 below, but the present embodiment is not limited to these representative examples.

[0057] [Table 1-1]

[0058] [Table 1-2]

[0059] [Table 1-3]

[0060] [Table 1-4]

[0061] [Table 1-5]

[0062] [Table 1-6]

[0063] [Table 1-7]

[0064] [Table 1-8]

[0065] (Method for producing amine compound (A)) An example of a method for producing the amine compound (A) will be described below, but the method for producing the amine compound (A) is not limited to the method described below. In addition, commercially available products may be used if available.

[0066] The amine compound (A) is, for example, HNR 1 (R 2 ) with a monofunctional or polyfunctional epoxy compound (1c) in a solvent. Examples of the solvent include solvents with a relatively low boiling point, such as alkanols (e.g., methanol, ethanol, propanol, butanol, etc.). It is preferable to carry out vacuum distillation to reduce the chlorine content in the resulting solution containing the amine compound (A). From the viewpoint of reducing the chlorine content, the boiling point of the solvent is preferably 150°C or lower, more preferably 130°C or lower. The temperature of the vacuum distillation is not particularly limited, but from the viewpoint of reducing the chlorine content, it is preferably 50°C or higher, more preferably 60°C or higher.

[0067] For example, R 1 When producing an amine compound (A) in which is a group represented by the above general formula (2), 4-amino-2,2,6,6-tetramethylpiperidine or the like can be used as the above compound (1b). Examples of the compound (1b) include compounds (b1) to (b26) in Table 2 below.

[0068] [Table 2]

[0069] The mixing amount of compound (1b) and epoxy compound (1c) is preferably in the range of 0.95 to 1.1 equivalents in terms of the epoxy equivalent of epoxy compound (1c) to the primary amino group equivalent of compound (1b).

[0070] In the epoxy compound (1c), the monofunctional epoxy compound refers to a compound having one epoxy group in one molecule, and the polyfunctional epoxy compound refers to a compound having two or more epoxy groups in one molecule.

[0071] The monofunctional epoxy compound includes a monofunctional aliphatic epoxy compound and a monofunctional aromatic epoxy compound.

[0072] Examples of monofunctional aliphatic epoxy compounds include glycidyl ethers of aliphatic alcohols and glycidyl esters of alkylcarboxylic acids, and specific examples thereof include allyl glycidyl ether, butyl glycidyl ether, sec-butylphenyl glycidyl ether, 2-ethylhexyl glycidyl ether, a mixed alkyl glycidyl ether containing 12 and 13 carbon atoms, glycidyl ethers of alcohols, monoglycidyl ethers of higher aliphatic alcohols, and glycidyl esters of higher fatty acids.

[0073] The monofunctional aliphatic epoxy compound may be a synthesized product or a commercially available product, such as Denacol EX-121, Denacol EX-171, or Denacol EX-192 (manufactured by Nagase ChemteX Corporation); Examples include Epolight M-1230 (manufactured by Kyoeisha Chemical Co., Ltd.), Adeka Glysilol ED-502, Adeka Glysilol ED-502S, Adeka Glysilol ED-509E, Adeka Glysilol ED-509S, and Adeka Glysilol ED-529 (manufactured by ADEKA Corporation).

[0074] Examples of the monofunctional aromatic epoxy compound include monoglycidyl ethers of phenolic compounds such as phenol, cresol, and butylphenol, or alkylene oxide adducts thereof; Monoglycidyl ethers of aromatic compounds with two or more phenolic hydroxyl groups, such as resorcinol, hydroquinone, and catechol; Monoglycidyl ethers of aromatic compounds having two or more alcoholic hydroxyl groups, such as phenyldimethanol, phenyldiethanol, and phenyldibutanol; Monoglycidyl esters of polybasic aromatic compounds having two or more carboxylic acids, such as phthalic acid, terephthalic acid, trimellitic acid, etc.; Examples include glycidyl ester of benzoic acid, styrene oxide, and monoepoxidized divinylbenzene.

[0075] The monofunctional aromatic epoxy compound may be a commercially available product, such as Denacol EX-141, Denacol EX-146, or Denacol EX-147 (manufactured by Nagase ChemteX Corporation).

[0076] The polyfunctional epoxy compound may be any compound commonly used in epoxy resin compositions, and the type is not particularly limited as long as it has two or more epoxy groups in one molecule.

[0077] The polyfunctional epoxy compound includes a polyfunctional aliphatic epoxy compound and a polyfunctional aromatic epoxy compound.

[0078] As the polyfunctional aliphatic epoxy compound, a synthesized product or a commercially available product may be used.

[0079] Examples of polyfunctional aliphatic epoxy compounds include difunctional aliphatic epoxy compounds having two epoxy groups in the molecule, such as alkylene glycol diglycidyl ether and alkenylene glycol diglycidyl ether; Polyfunctional aliphatic epoxy compounds having three or more epoxy groups in the molecule, such as polyglycidyl ethers of trifunctional or higher alcohols such as trimethylolpropane, pentaerythritol, and dipentaerythritol [trimethylolpropane triglycidyl ether, pentaerythritol (tri- or tetra-)glycidyl ether, dipentaerythritol (tri-, tetra-, penta-, or hexa-)glycidyl ether, etc.], ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, butanediol diglycidyl ether, hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether Examples of such glycidyl ethers include trimethylolpropane polyglycidyl ethers such as polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, or a mixture of trimethylolpropane diglycidyl ether and trimethylolpropane triglycidyl ether (e.g., Denacol EX-321L, manufactured by Nagase Chemitex Corporation), pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol heptaglycidyl ether, sorbitol hexaglycidyl ether, and resorcinol diglycidyl ether.

[0080] Commercially available polyfunctional aliphatic epoxy compounds can be used, such as "EP-4088S" (both manufactured by ADEKA Corporation), "EHPE3150" (both manufactured by Daicel Corporation), "EX-211L" and "EX-212L" (all manufactured by Nagase ChemteX Corporation).

[0081] Examples of polyfunctional aromatic epoxy compounds include polyglycidyl ethers of polyhydric phenols having at least one aromatic ring, such as bisphenol A and bisphenol F, or alkylene oxide adducts thereof; Epoxy novolac resin; Polyglycidyl ethers of aromatic compounds having two or more phenolic hydroxyl groups, such as resorcinol, hydroquinone, and catechol; Polyglycidyl ethers of aromatic compounds having two or more alcoholic hydroxyl groups, such as phenyldimethanol, phenyldiethanol, and phenyldibutanol; Polyglycidyl esters of polybasic aromatic compounds having two or more carboxylic acids, such as phthalic acid, terephthalic acid, trimellitic acid, etc.; Examples include diepoxidized products of divinylbenzene.

[0082] As the polyfunctional aromatic epoxy compound, a synthesized compound or a commercially available product may be used.

[0083] Commercially available polyfunctional aromatic epoxy compounds can be used, for example, "Denacol EX-201", "Denacol EX-711", and "Denacol EX-721" (all manufactured by Nagase ChemteX Corporation); "Oxol EG-280" and "Oxol CG-400" (both manufactured by Osaka Gas Chemicals Co., Ltd.); "EXA-80CRP" and "HP4032D" (both manufactured by DIC Corporation); "jER828" and "jER828EL" (both manufactured by Mitsubishi Chemical Corporation); Examples include "ADEKA RESIN EP-4100", "ADEKA RESIN EP-4100G", "ADEKA RESIN EP-4100E", "ADEKA RESIN EP-4100L", "ADEKA RESIN EP-4100TX", "ADEKA RESIN EP-4000", "ADEKA RESIN EP-4005", "ADEKA RESIN EP-4901", and "ADEKA RESIN EP-4901E" (all manufactured by ADEKA Corporation).

[0084] The monofunctional epoxy compound and polyfunctional epoxy compound used to obtain the amine compound represented by formula (1) in the present embodiment may be used alone or in combination of different types.

[0085] Monofunctional epoxy compounds and polyfunctional epoxy compounds contain chlorine-containing compounds such as epichlorohydrin, which are raw materials, as impurities. The chlorine (Cl) content in the monofunctional epoxy compounds and polyfunctional epoxy compounds is preferably low; specifically, the value measured by the alkali decomposition Mohr method is preferably 5% or less, more preferably 0.5% or less, and particularly preferably 0.05% or less. Within the above range, the carbon dioxide absorbing solution is less likely to deteriorate even when the absorption and desorption cycles are repeated, and corrosion of steel materials is easily suppressed.

[0086] Specific structures of the monofunctional or polyfunctional epoxy compounds (c1) to (c75) are shown in Tables 3-1 to 3-5.

[0087] [Table 3-1]

[0088] [Table 3-2]

[0089] [Table 3-3]

[0090] [Table 3-4]

[0091] [Table 3-5]

[0092] <Liquid medium (B)> The liquid medium (B) is not particularly limited as long as it is miscible with the amine compound (A). The amine compound (A) can absorb carbon dioxide and release it by heating, but high energy is required to separate the carbon dioxide. By using a liquid medium, the separation efficiency of the amine compound (A) and carbon dioxide is improved, the carbon dioxide release temperature can be lowered, and the carbon dioxide release efficiency is increased.

[0093] Specific examples of the liquid medium (B) include water, an organic solvent, an ionic liquid, or a mixture thereof. As shown in the above formula (1), the amine compound (A) has a hydroxyl group, an alkyl group, and an organic residue, and therefore can be suitably dissolved not only in water but also in an organic solvent.

[0094] Examples of ionic liquids include salts composed of cations and anions that are liquid at 100°C and atmospheric pressure. Ionic liquids are particularly preferably liquid at room temperature (25°C). That is, the melting point of the ionic liquid is not particularly limited as long as it is 100°C or lower, but is preferably less than 50°C, more preferably less than 25°C, and particularly preferably less than 10°C. Furthermore, there are no particular limitations on the lower limit of the melting point of the ionic liquid. Ionic liquids often become supercooled and assume a liquid state even below their melting point, and as long as they can maintain this liquid state, they can be used favorably because they have a high melting point. Furthermore, the melting point of ionic liquids can be lowered by mixing them with amines, and such ionic liquids can also be used as carbon dioxide absorbing liquids.

[0095] Examples of anions constituting the present ionic liquid include anions of phosphoric acid, phosphonic acid, phosphate ester, and phosphonate ester.

[0096] In the ionic liquid, the cation is not particularly limited, but is preferably an imidazolium, ammonium, or phosphonium cation.

[0097] Specific examples of water and organic solvents that can be used as the liquid medium (B) are listed in Tables 4-1 and 4-2 along with their total Hansen solubility parameters (δT).

[0098] (Total Hansen Solubility Parameter (δT)) The Hansen solubility parameter divides the total Hildebrand value into three parts: dispersion (δD), polar (δP), and hydrogen bonding (δH) components. The Hildebrand value is calculated using the relationship between vaporization, van der Waals forces, and solubility. The total Hansen solubility parameter (δT) is decomposed into dispersion (δD), polar (δP), and hydrogen bonding (δH) forces and calculated using equation (1). δT 2 =δD 2 +δP 2 +δH 2 (1) During the ceremony, δD is the variance component, δP is the polar component, ·δH is the hydrogen bonding component.

[0099] In this specification, the calculation of "Hansen solubility parameters" refers to values ​​calculated using computer software "Hansen Solubility Parameters in Practice (HSPiP)." The version of "HSPiP" used for the calculation is "5.4.02."

[0100] When a mixed solvent is used, first, the total Hansen solubility parameter of each solvent is calculated, and a weighted average is calculated using the mass fraction of each solvent as a weight, and this is used as the total Hansen solubility parameter (δT) of the liquid medium (B).

[0101] Tables 4-1 and 4-2 show the dispersive, polar, and hydrogen bonding components of different solvents, as well as the total Hansen solubility parameter (δT) calculation results for different solvents.

[0102] [Table 4-1]

[0103] [Table 4-2]

[0104] As a liquid medium (B), the total Hansen solubility parameter (δT) is 17 MPa. 1 / 2 ~35MPa 1 / 2 Preferably, the organic solvent or ionic liquid is 20 MPa. 1 / 2 ~35MPa 1 / 2 More preferably, the organic solvent or the ionic liquid is 23 MPa. 1 / 2 ~35MPa 1 / 2 More preferred are organic solvents such as those listed above or ionic liquids.

[0105] Furthermore, the absorbing liquid of the present disclosure has high carbon dioxide absorption and release capacities even with a low water content. Specifically, the water content in the liquid medium (B) may be 50% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less. Note that, during use of the absorbing liquid, the water content in the liquid medium (B) may vary depending on the gas composition. However, the water content here is the initial value (at the start of use), and does not prevent the water content in the liquid medium (B) from exceeding 50% by mass due to such variation.

[0106] In the absorbing liquid of the present disclosure, the mass ratio of the amine compound (A) to the liquid medium (B) in the absorbing liquid is preferably in the range of 5:95 to 95:5, more preferably in the range of 5:95 to 50:50, and particularly preferably in the range of 10:90 to 25:75. The content of the amine compound (A) in the absorbing liquid is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 25% by mass or more and 75% by mass or less, from the viewpoint of the absorption efficiency of the absorbing liquid.

[0107] The liquid medium (B) used in the absorption liquid may or may not dissolve the reaction product of the amine compound (A) and carbon dioxide.

[0108] <Chlorine (Cl) content> The absorbing liquid of the present disclosure preferably has a chlorine (Cl) content of 1000 ppm or less, more preferably 10 to 800 ppm, even more preferably 10 to 500 ppm, and particularly preferably 10 to 300 ppm. The source of the chlorine is not particularly limited, but common commercially available materials used to obtain the raw materials for the absorbing liquid may contain trace amounts of chlorine-containing compounds (D) as impurities. Examples of chlorine-containing compounds (D) include epichlorohydrin and dichlorohydrin. By controlling the chlorine content within the above range, the corrosiveness of the absorbing liquid can be suppressed. A method for reducing the chlorine content of the absorbing liquid is vacuum distillation of the raw materials, preferably vacuum distillation of the amine compound (A). Alternatively, an epoxy compound with a low chlorine content as an impurity may be used in the synthesis of the amine compound (A). While distillation under a high vacuum can be used to reduce the chlorine content to 10 ppm or less, this increases the number of steps and time, resulting in increased costs. Therefore, it is desirable to appropriately adjust the content taking these factors into consideration.

[0109] <Optional ingredients> The absorbing liquid of the present disclosure may further contain other components as long as the effects of the present invention are achieved. Examples of other components include at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and linear polyamines; stabilizers (side reaction inhibitors such as antioxidants) for ensuring the chemical or physical stability of the absorbing liquid; and inhibitors (corrosion inhibitors, etc.) for preventing deterioration of the materials of the equipment and facilities that use the absorbing liquid. The total content of these other components in the absorbing liquid is preferably 5% by mass or less. Compounds that can be classified as either amine compound (A) or amine compound (C) are treated as amine compound (A). That is, the amino alcohols in the amine compound (C) represent amino alcohols that do not fall under the general formula (1).

[0110] (Amine compound (C)) By using the amine compound (C), it is possible to improve or enhance, for example, the absorption amount, release amount, absorption rate, and release rate of the absorbing liquid.

[0111] Suitable amino alcohols include, for example, monoethanolamine, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3-dipropanol, 2-aminobutanol, 4-aminobutanol, diethanolamine, bis(2-hydroxy-1-methylethyl)amine, methyldiethanolamine, dimethylethanolamine, diethylethanolamine, triethanolamine, dimethylamino-1-methylethanol, 2-methylaminoethanol, 2-ethylaminoethanol, 2-propylaminoethanol, n-butylaminoethanol, 2-(isopropylamino)ethanol, 3-ethylaminopropanol, triethanolamine, diethanolamine, etc. One of these compounds can be used alone, or two or more can be used in combination.

[0112] Among these, the amino alcohol is preferably at least one selected from the group consisting of 2-(isopropylamino)ethanol, 2-aminobutanol, and 2-amino-2-methyl-1-propanol, from the viewpoint of further improving the ability of the amine compound (A) to react with or release carbon dioxide.

[0113] Suitable cyclic polyamines are compounds in which two or more nitrogen atoms are substituted in a cycloalkyl group, and specific examples include piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethylpiperazine, N-(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, 1-hydroxyethylpiperazine, diazabicycloundecene, and diazabicyclononene. One of these compounds can be used alone, or two or more can be used in combination.

[0114] Among these, the cyclic polyamines are preferably at least one selected from the group consisting of piperazine, N-(2-aminoethyl)piperazine, and diazabicycloundecene, from the viewpoint of further improving the reactivity or release ability of the amine compound (A) with carbon dioxide.

[0115] Specific examples of suitable chain polyamines include compounds having two or more nitrogen atoms substituted thereon and having a linear or branched alkyl group having 2 to 6 carbon atoms between them, such as ethylenediamine, N-isopropylethylenediamine, N-methylethylenediamine, N-ethylethylenediamine, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, diethylenetriamine, 2,2-diamino-N-methyldiethylamine, N,N'-diisopropylethylenediamine, N,N'-di-TERT-butylethylenediamine, N,N',N''-trimethylethylenediamine, triethylenetetramine, triethylenepentamine, N,N,N',N'-tetramethylethylenediamine, N,N-diethyl-N',N'-dimethylethylenediamine, and N,N-diethyl-N',N'-dimethylethylenediamine. Examples of the diaminobenzoates include ethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, tetraethylenepentamine, 1,3-diaminopropane, 3-(methylamino)propylamine, N-methyl-1,3-propanediaminopropane, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, N,N-dibutyl-1,3-propanediamine, 3,3-diaminodipropylamine, tris(3-aminopropyl)amine, 3,3-diamino-N-methyldipropylamine, N,N'-bis(3-aminopropyl)ethylenediamine, N,N,N',N'-tetramethyl-1,3-propanediamine, N,N,N',N'-tetraethyl-1,3-propanediamine, 1,4-diaminobutane, aminoethylaminoethanol, and guanidine derivatives. One of these compounds can be used alone, or two or more can be used in combination.

[0116] Among these, the chain polyamine is preferably at least one selected from the group consisting of 1,4-diaminobutane, 1,3-diaminopropane, 3,3-diaminodipropylamine, 3,3-diamino-N-methyldipropylamine, N,N'-bis(3-aminopropyl)ethylenediamine, and N,N-dibutyl-1,3-propanediamine, from the viewpoint of further improving the reactivity or release ability of the amine compound (A) with carbon dioxide.

[0117] (antioxidant) Examples of the antioxidant include dibutylhydroxytoluene, butylhydroxyanisole, sodium erythorbate, sodium sulfite, and sulfur dioxide.

[0118] (corrosion inhibitor) Examples of the corrosion inhibitor include 1-hydroxyethane-1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-phosphonopropane-2-dicarboxylic acid, phosphonosuccinic acid, 2-hydroxyphosphonoacetic acid, and maleic acid-based polymers (e.g., copolymers of maleic acid and amylene, or terpolymers of maleic acid, acrylic acid, and styrene).

[0119] (Antifoaming agent) Examples of the antifoaming agent include silicone-based, polyether-based, acetylene diol-based, metal soap-based, phosphate ester-based, and fatty acid ester-based agents.

[0120] (pH adjuster) Examples of the pH adjuster include inorganic acids (hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, etc.), organic acids (citric acid, formic acid, acetic acid, oxalic acid, p-toluenesulfonic acid, etc.), inorganic bases (sodium bicarbonate, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, ammonia, etc.), and organic bases (methylamine, dimethylamine, trimethylamine, diazabicycloundecene, piperazine, ethanolamine, triethanolamine, etc.).

[0121] (Viscosity modifier) Examples of the viscosity modifier include polyimine, polyvinyl alcohol, and polyethylene oxide.

[0122] <Gas containing carbon dioxide> Examples of carbon dioxide-containing gases include exhaust gases from thermal power plants fueled by coal, heavy oil, natural gas, etc., boilers in manufacturing plants, kilns in cement factories, blast furnaces in steelmaking that reduce iron oxide with coke, converters in steelmaking that burn carbon in pig iron to make steel, integrated coal gasification combined cycle power generation facilities, natural gas produced during mining, and reformed gases. The carbon dioxide concentration in these gases is typically about 5 to 50%, particularly about 10 to 40%, by volume. Within this carbon dioxide concentration range, the effects of the present absorbent are optimally exhibited. The carbon dioxide-containing gas may also contain gases such as nitrogen, water vapor, carbon monoxide, hydrogen sulfide, carbonyl sulfide, sulfur dioxide, nitrogen dioxide, methane, and hydrogen in addition to carbon dioxide.

[0123] The absorbing solution of the present disclosure is also excellent at absorbing hydrogen sulfide in addition to carbon dioxide.

[0124] [Method for separating and capturing carbon dioxide using an absorption liquid] The method for separating and recovering carbon dioxide disclosed herein is a method for separating and recovering carbon dioxide from a gas containing carbon dioxide, and includes step A of contacting the absorption liquid disclosed herein with a gas containing carbon dioxide to obtain an absorption liquid that has absorbed carbon dioxide from the gas containing carbon dioxide, and step B of heating the absorption liquid that has absorbed carbon dioxide obtained in step A to desorb and release the carbon dioxide from the absorption liquid, and recovering the released carbon dioxide.

[0125] (Process A) In step A, the absorbing liquid is brought into contact with a gas containing carbon dioxide, so that the carbon dioxide in the gas containing carbon dioxide is absorbed into the absorbing liquid and separated.

[0126] In step A, the method for contacting the absorbing liquid with the gas containing carbon dioxide is not particularly limited. Examples include a method of bubbling the gas containing carbon dioxide into the absorbing liquid, a method of dropping the absorbing liquid in the form of mist into the gas containing carbon dioxide (atomization or spraying method), and a method of countercurrently contacting the high-pressure gas containing carbon dioxide with the absorbing liquid in an absorption tower containing a porcelain or metal mesh filler.

[0127] The temperature in step A can be set to 25 to 40°C. Within this range, the absorbing liquid is excellent in the amount of carbon dioxide recovered and the carbon dioxide absorption rate. The temperature in step A is preferably 25 to 35°C.

[0128] The pressure in step A can usually be 1.0 bar or more, preferably 1.0 to 3.5 bar. Furthermore, by carrying out the step at a higher pressure, even higher carbon dioxide absorption performance can be obtained.

[0129] (Process B) In step B, the absorption liquid obtained in step A that has absorbed carbon dioxide is heated to desorb and release the carbon dioxide from the absorption liquid, and the released carbon dioxide is recovered.

[0130] The temperature in step B, in which carbon dioxide is desorbed and released, can be set to 50 to 160°C. Within this range, the absorbing liquid has an excellent carbon dioxide release rate. The heating temperature in step B is preferably 50 to 80°C, and more preferably 50 to 60°C.

[0131] The pressure in the step of desorbing and releasing carbon dioxide in step B can usually be 3.5 bar or less, preferably 1.0 to 3.5 bar. Furthermore, even higher carbon dioxide release performance can be obtained by performing the step at a lower pressure.

[0132] The method of heating the absorption liquid that has absorbed carbon dioxide to desorb, strip, and recover the carbon dioxide is not particularly limited. Examples include a method in which the absorption liquid is heated and foamed in a vessel to desorb the carbon dioxide, as in distillation, and a method in which the liquid interface is widened and heated in a stripping tower containing a filler such as a plate tower, a spray tower, or a porcelain or metal mesh. These methods make it possible to recover pure or very highly concentrated carbon dioxide.

[0133] The absorption liquid after carbon dioxide release in step B can be recycled and reused by returning it to step A. In this recycling process, the heat added in step B is used to raise the temperature of the absorption liquid through heat exchange with the absorption liquid that has absorbed carbon dioxide. This heat exchange reduces the energy consumption of the entire carbon dioxide separation and capture process.

[0134] The carbon dioxide separated and recovered by the carbon dioxide separation and recovery method using the absorbent of the present disclosure typically has a volume concentration of 95 to 100%, and can be pure or of very high concentration. The separated and recovered carbon dioxide can be used for underground or seabed sequestration and storage (CCS) or enhanced oil recovery (EOR), technologies for which are currently being developed. The separated and recovered carbon dioxide can also be used for other purposes, but is not limited to these. Examples include a synthetic raw material for chemical products, or a refrigerant for freezing food. [Example]

[0135] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. The molecular weight was measured by a time-of-flight mass spectrometer (TOF-MS). TOF-MS instrument name: AutoFlexII manufactured by Bruker Daltonics

[0136] 1. Example Group 1 [Synthesis Example 1] Method for synthesizing compound (A1) [ka]

[0137] Under a nitrogen atmosphere, 25.68 g (164.3 mmol) of 4-amino-2,2,6,6-tetramethylpiperidine and 14.31 g (82.2 mmol) of ethylene glycol diglycidyl ether (c1) were mixed with 50 mL of methanol and stirred. After the addition, the mixture was stirred at room temperature for 24 hours, and the progress of the reaction was confirmed by TOF-MS, which showed that the reactant (c1) was no longer detected. The solvent (methanol) was then removed by reducing the pressure at 60 °C, and the chlorine-containing compounds were reduced, yielding the target compound (A1).

[0138] <TOF-MS measurement results of compound (A1)> Calculated molecular weight: C26H54N4O4, Mol.Wt. 486.7; Observed molecular weight: m / z 486.9

[0139] [Synthesis Examples 2 to 74] As in Synthesis Example 1, compounds (A2) to (A74) were synthesized using 4-amino-2,2,6,6-tetramethylpiperidine and monofunctional or polyfunctional epoxy compounds ((c2) to (c74)) shown in Tables 3-1 to 3-5. The obtained compounds were identified by TOF-MS as in Synthesis Example 1. The mass spectrum results of the synthesized compounds are shown in Table 5. The compound numbers are the same as those shown in Tables 1-1 to 1-5 of this specification.

[0140] [Table 5]

[0141] [Preparation of carbon dioxide absorbing solution] [Production Example 1 (Absorption Solution 1)] 70 g of dimethyl sulfoxide was added to 30 g of the compound (A1) obtained in Synthesis Example 1, and the mixture was mixed and stirred to prepare a carbon dioxide absorbing solution (100 g). [Production Example 2 (Absorption Solution 2)] A carbon dioxide absorbing solution (100 g) was prepared in the same manner except that the amount of compound (A1) was changed from 30 g to 15 g and the amount of dimethyl sulfoxide was changed from 70 g to 85 g.

[0142] [Manufacturing Examples 3 to 112, E1 to E20, G1 to G99 (Absorption Solutions 3 to 112, E1 to E20, G1 to G99)] The compounds and liquid media described in Production Example 1 were changed to the compounds and liquid media described in Tables 7-1 to 7-8, respectively, to prepare absorption solutions.

[0143] [Quantitative determination of chlorine in absorption solution] The chlorine content (mass basis) in the carbon dioxide absorbing solution prepared in the above-mentioned production example was measured by the following method. First, 30 μL of the sample was placed on the sample board of the combustion pretreatment device. After that, the sample board is moved to the combustion section and burned in an automatic combustion device, and the gasified components are The absorbed solution was injected into an ion chromatograph to quantify the target components. Details of the pre-combustion treatment device and ion chromatograph used are described below. Pre-combustion treatment device: Automatic combustion device manufactured by Mitsubishi Analytech Model: AQF-2100H Furnace temperature: Inlet 1000℃ Outlet 1000℃ Gas flow rate: Ar: 200 mL / min, O2: 400 mL / min, Humidified Ar: 100 mL / min Measurement equipment: Ion chromatograph manufactured by Tosoh Corporation Model: IC-2010 Guard column: TSKgel guard column SuperIC-AZ Separation column: TSKgel SuperIC-AZ Flow rate: 1.0mL / min Eluent: 7.5mmol / L sodium bicarbonate + 1.1mmol / L sodium carbonate

[0144] The chlorine contents in the absorbing solution measured under the above conditions are shown in Tables 7-1 to 7-8.

[0145] [Method for measuring carbon dioxide gas release efficiency] 100 g of the carbon dioxide absorbing solution prepared in the above-mentioned Production Example (contained in a gas absorption bottle with a capacity of 200 ml) was adjusted to 25°C in a water bath. A mixed gas (500 ml / min) of carbon dioxide gas at 100 ml / min and nitrogen gas at 400 ml / min was bubbled into this carbon dioxide absorbing solution for 1 hour. The amount of carbon dioxide gas absorbed at this time (amount of carbon dioxide absorbed per hour (L)) was measured using a gas flow meter and a carbon dioxide concentration meter. The amount of carbon dioxide absorbed per hour (L) was calculated using this amount of carbon dioxide absorbed per hour (L).

[0146] Next, the temperature of this carbon dioxide absorbing solution was adjusted to 60°C in a water bath. Nitrogen gas was bubbled into this carbon dioxide absorbing solution at a rate of 500 ml / min for 2 hours. The amount of carbon dioxide gas released at this time (amount of carbon dioxide released in 2 hours (L)) was measured using a gas flow meter and a carbon dioxide concentration meter. The amount of carbon dioxide released in 2 hours (L) was used to calculate the amount of carbon dioxide released (L) per 1 kg of carbon dioxide absorbing solution. The carbon dioxide gas release efficiency (= amount of carbon dioxide released in 2 hours (L) ÷ amount of carbon dioxide absorbed in 1 hour (L)) was calculated from the amount of carbon dioxide released in 2 hours (L) and the amount of carbon dioxide absorbed in 1 hour (L).

[0147] From the calculated carbon dioxide gas release efficiency, the following criteria were established and evaluated, with S, A, and B being designated as practically usable ranges. The evaluation results are shown in Tables 7-1 to 7-8. S: Emission efficiency is 0.8 or more A: Emission efficiency is 0.7 or more and less than 0.8 B: Emission efficiency is 0.6 or more and less than 0.7 C: Emission efficiency is less than 0.6

[0148] [Materials and gases used in the evaluation] For simplicity of notation, the following abbreviations have been used: ATMP: 4-amino-2,2,6,6-tetramethylpiperidine MDEA: N-methyldiethanolamine MBZA: Methylbenzylamine MEA: Monoethanolamine AB: 2-aminobutanol DMAPA: dimethylaminopropylamine

[0149] The gases used in the evaluation are listed in Table 6.

[0150] [Table 6]

[0151] [Example 1 (Absorbing Solution 1)] 100 g of the carbon dioxide absorbing solution obtained in Production Example (1) was placed in a 200 ml gas absorption bottle, and the carbon dioxide gas release efficiency was measured.

[0152] The amount of carbon dioxide absorbed (L) per hour was 2.12 L when converted to standard conditions. In other words, the amount of carbon dioxide absorbed (L) per hour per 1 kg of carbon dioxide absorbing solution was 21.2 L under standard conditions. (The amount of carbon dioxide absorbed (ml / min) per hour per 1 kg of carbon dioxide absorbing solution was 353 ml / min (= 21.2 [L / hr] x 1000 [ml / L] ÷ 60 [min / hr]). The amount of carbon dioxide released (L) over two hours was 1.83 L under standard conditions. That is, the amount of carbon dioxide released (L) per 1 kg of carbon dioxide absorbing solution in 2 hours was 18.3 L converted to standard conditions. (The amount of carbon dioxide released (mL / min) per 1 kg of carbon dioxide absorbing solution over 2 hours was 152 ml / min (= 18.3 [L / 2 hours] × 1000 [ml / L] ÷ 120 [min / hour]).

[0153] From these results, the carbon dioxide gas release efficiency was 0.85. The above results are shown in Table 7-1.

[0154] [Examples 2 to 112, E1 to E20, G1 to G99 (Absorbing Solutions 2 to 112, E1 to E20, G1 to G99)] Similar experiments were carried out, except that the compounds and liquid media described in Example 1 were replaced with the compounds and liquid media described in Tables 7-1 to 7-8, respectively. The evaluation results are shown in Tables 7-1 to 7-8.

[0155] [Table 7-1]

[0156] [Table 7-2]

[0157] [Table 7-3]

[0158] [Table 7-4]

[0159] [Table 7-5]

[0160] [Table 7-6]

[0161] [Table 7-7]

[0162] [Table 7-8]

[0163] [Example 113 (Absorption liquid 113)] 25g of compound (A1) and 5g of MDEA were mixed and stirred with 70g of dimethyl sulfoxide to prepare a carbon dioxide absorbing solution (100g), which was then placed in a 200ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 8-1.

[0164] [Example 114 (Absorption liquid 114)] 25g of compound (A7) and 5g of MBZA were mixed with 60g of sulfolane and 10g of water, and the mixture was stirred to prepare a carbon dioxide absorbing solution (100g). This was placed in a 200ml gas absorption bottle, and the same experiment was carried out. The evaluation results are shown in Table 8-1.

[0165] [Example 115 (Absorption liquid 115)] 25g of compound (A30) and 5g of MBZA were mixed with 60g of dimethyl sulfoxide and 10g of water, and the mixture was stirred to prepare a carbon dioxide absorbing solution (100g). This was placed in a 200ml gas absorption bottle, and the same experiment was carried out. The evaluation results are shown in Table 8-1.

[0166] [Example 116 (Absorption liquid 116)] 25 g of compound (A1) and 5 g of compound (A77) were mixed with 70 g of dimethyl sulfoxide and stirred to prepare a carbon dioxide absorbing solution (100 g), which was then placed in a 200 ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 8-1.

[0167] [Example 117 (Absorption liquid 117)] 25 g of compound (A7) and 5 g of compound (A78) were mixed with 70 g of dimethyl sulfoxide and stirred to prepare a carbon dioxide absorbing solution (100 g), which was then placed in a 200 ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 8-1.

[0168] [Example 118 (Absorption liquid 118)] 25g of compound (A7), 2g of ATMP, 60g of dimethyl sulfoxide and 10g of N-methyl-2-pyrrolidone were added and mixed and stirred to prepare a carbon dioxide absorbing solution (100g), which was then placed in a 200ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 8-1.

[0169] [Example 119 (Absorption liquid 119)] 30 g of compound (A1) was mixed with 60 g of dimethyl sulfoxide and 10 g of N-methyl-2-pyrrolidone and stirred to prepare a carbon dioxide absorbing solution (100 g), which was then placed in a 200 ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 8-1.

[0170] [Comparative Example 1 (Absorbing Liquid 120)] [ka]

[0171] Under a nitrogen atmosphere, 25.68 g (164.3 mmol) of 4-amino-2,2,6,6-tetramethylpiperidine and 14.31 g (82.2 mmol) of ethylene glycol diglycidyl ether (c1) were mixed with 50 mL of dimethyl sulfoxide and stirred. After the addition, the mixture was stirred at room temperature for 24 hours. The progress of the reaction was confirmed by TOF-MS, and a dimethyl sulfoxide solution of compound (A1') was obtained. Dimethyl sulfoxide was added to a dimethyl sulfoxide solution of the compound (A1'), and the mixture was mixed and stirred to achieve the concentration conditions shown in Table 8-1 to prepare a carbon dioxide absorbing solution (100 g). This was placed in a 200 ml gas absorption bottle and the same experiment was carried out. The evaluation results are shown in Table 8-1.

[0172] [Quantitative determination of chlorine in absorption solution] The chlorine content of the absorbing solution 120 measured under the above conditions is shown in Table 8-1.

[0173] [Examples A1 to A83 (Absorbing Solutions A1 to A83)] The compounds and liquid media were changed to those shown in Tables 8-2 to 8-4, respectively, and the amount of carbon dioxide gas absorbed was measured by the method described in the above [Method for measuring carbon dioxide gas release efficiency], and the amount of carbon dioxide absorbed (L) per 1 kg of carbon dioxide absorbing solution and the carbon dioxide gas release efficiency were calculated. The gas species used in the evaluation were as shown in Table 6. From the calculated carbon dioxide gas release efficiency, the following criteria were established and evaluated, with S, A, and B being designated as practically usable ranges. The evaluation results are shown in Tables 8-1 to 8-4. S: Emission efficiency is 0.8 or more A: Emission efficiency is 0.7 or more and less than 0.8 B: Emission efficiency is 0.6 or more and less than 0.7 C: Emission efficiency is less than 0.6

[0174] [Table 8-1]

[0175] [Table 8-2]

[0176] [Table 8-3]

[0177] [Table 8-4]

[0178] [Examples 120 to 238, Examples F1 to F103, Examples H101 to H199, Comparative Example 2] (Degree of change in absorption amount after repeated evaluation of carbon dioxide gas absorption / release) The above-mentioned carbon dioxide gas absorption / desorption measurement was repeated 10 times using the absorption solutions shown in Tables 7-1 to 7-5 and Tables 8-1 to 8-4. Thereafter, the absorption amount for the 11th test was calculated in the same manner as the first test, and the degree of reduction compared to the absorption amount for the first test was evaluated. The evaluation criteria were as follows, with S, A, and B being defined as practically usable ranges. The evaluation results are shown in Tables 9-1 to 9-3. S: The 11th absorption amount is 99.5% or more of the 1st absorption amount. A: The 11th absorption amount is 99% or more but less than 99.5% of the 1st absorption amount. B: The 11th absorption amount is 98% or more but less than 99% of the 1st absorption amount. C: The 11th absorption amount is less than 98% of the 1st absorption amount.

[0179] (Steel corrosion of absorbent samples) Using the absorption solutions shown in Tables 7-1 to 7-8 and Tables 8-1 to 8-4, the aforementioned carbon dioxide gas was absorbed 11 times, and then an absorption solution saturated with carbon dioxide gas was prepared. Then, SS400 steel (25 mm long x 20 mm wide x 2 mm thick) was added to the glass container of the absorption solution, sealed, and stored in an oven at 100°C for 7 days, and the corrosion resistance of the steel was evaluated. The evaluation criteria were as follows, with S, A, and B representing the practical usable range. The evaluation results are shown in Tables 9-1 to 9-3. S: The appearance of the absorbent is colorless and transparent, and there is no deterioration of the steel surface. A: The appearance of the absorbed liquid is light yellow, and there is no deterioration of the steel surface. B: The appearance of the absorbed liquid turns yellow to brown, and the surface of the steel material turns black. C: The appearance of the absorbent liquid turns black, and the surface of the steel material turns black. [Table 9-1]

[0180] [Table 9-2]

[0181] [Table 9-3]

[0182] As described in the above examples, the carbon dioxide absorbing solution of the present disclosure not only has excellent repeated carbon dioxide release efficiency (amount released / amount absorbed) but also has the effect of reducing corrosiveness to steel materials by reducing the chlorine component in the absorbing solution compared to conventionally known carbon dioxide absorbing solutions.

[0183] 2. Example Group 2

[0184] [Synthesis Example 75] Method for synthesizing compound (A75)

[0185] [ka]

[0186] Under a nitrogen atmosphere, 30.0 g (665.5 mmol) of ethylamine (b1) and 72.0 g (332.7 mmol) of neopentyl glycol glycidyl ether (c7) mixed with 300 mL of methanol were added and stirred. After the addition, the mixture was stirred at room temperature for 24 hours, and the progress of the reaction was confirmed by TOF-MS, which showed that the reactant (b1) was no longer detected. The solvent methanol was removed by reducing the pressure at 60 °C, and the chlorine-containing compounds were reduced, yielding the target compound (A75). (TOF-MS measurement results) Calculated molecular weight: C15H34N2O4, Mol.Wt.306.4; Observed molecular weight: m / z 306.5

[0187] [Synthesis Examples 76-118] As in Synthesis Example 75, compounds (A76) to (A124) were synthesized by appropriately combining the amine compounds in Table 2 and the epoxy compounds in Tables 3-1 to 3-5. The obtained compounds were identified by TOF-MS as in Synthesis Example 79. The yields and mass spectrum results of the synthesized compounds are shown in Table 11. The compound numbers are the same as those listed in Tables 1-6 to 1-8 of this specification.

[0188] [Table 10]

[0189] [Preparation of carbon dioxide absorbing solution]

[0190] [Manufacturing example B1] 70 g of dimethyl sulfoxide was added to 30 g of the compound (A75) obtained in Synthesis Example 75, and the mixture was stirred to prepare a carbon dioxide absorbing solution (100 g).

[0191] [Example B2 (Absorption Solution B2)] A carbon dioxide absorbing solution (100 g) was prepared in the same manner except that the amount of compound (A75) was changed from 30 g to 15 g and the amount of dimethyl sulfoxide was changed from 70 g to 85 g.

[0192] [Examples B3 to B54, E21 to 40, (Absorption solutions B3 to B54, E21 to 40)] Carbon dioxide absorbing solutions (100 g) were prepared in the same manner, except that the compounds and liquid media described in Example B1 were changed to the compounds and liquid media described in Tables 11-1 and 11-2, respectively.

[0193] [Quantitative determination of chlorine in absorption solution] The chlorine content (mass basis) in the carbon dioxide absorbing solution prepared in the above manufacturing example was determined by the following method. First, 30 μL of the sample was placed on the sample board of the pre-combustion treatment device. After that, the sample board is moved to the combustion section and burned in an automatic combustion device, and the gasified components are The absorbed solution was injected into an ion chromatograph to quantify the target components. Details of the pre-combustion treatment device and ion chromatograph used are described below. Pre-combustion treatment device: Automatic combustion device manufactured by Mitsubishi Analytech Model: AQF-2100H Furnace temperature: Inlet 1000℃ Outlet 1000℃ Gas flow rate: Ar: 200 mL / min, O2: 400 mL / min, Humidified Ar: 100 mL / min Measurement equipment: Ion chromatograph manufactured by Tosoh Corporation Model: IC-2010 Guard column: TSKgel guard column SuperIC-AZ Separation column: TSKgel SuperIC-AZ Flow rate: 1.0mL / min Eluent: 7.5mmol / L sodium bicarbonate + 1.1mmol / L sodium carbonate

[0194] The chlorine contents in the absorbing solution measured under the above conditions are shown in Tables 11-1 and 11-2.

[0195] (Method for measuring carbon dioxide gas release efficiency) 100 g of the carbon dioxide absorbing solution prepared in the above-mentioned Production Example (contained in a gas absorption bottle with a capacity of 200 ml) was adjusted to 25°C in a water bath. A mixed gas (500 ml / min) of carbon dioxide gas at 100 ml / min and nitrogen gas at 400 ml / min was bubbled into this carbon dioxide absorbing solution for 1 hour. The amount of carbon dioxide gas absorbed at this time (amount of carbon dioxide absorbed per hour (L)) was measured using a gas flow meter and a carbon dioxide concentration meter. The amount of carbon dioxide absorbed per hour (L) was calculated using this amount of carbon dioxide absorbed per hour (L).

[0196] Next, the temperature of this carbon dioxide absorbing solution was adjusted to 60°C in a water bath. Nitrogen gas was bubbled into this carbon dioxide absorbing solution at a rate of 500 ml / min for 2 hours. The amount of carbon dioxide gas released at this time (amount of carbon dioxide released in 2 hours (L)) was measured using a gas flow meter and a carbon dioxide concentration meter. The amount of carbon dioxide released in 2 hours (L) was used to calculate the amount of carbon dioxide released (L) per 1 kg of carbon dioxide absorbing solution. The carbon dioxide gas release efficiency (= carbon dioxide release amount (L) in 2 hours ÷ carbon dioxide absorption amount (L) in 1 hour) was calculated from the carbon dioxide release amount (L) in 2 hours and the carbon dioxide absorption amount (L) in 1 hour.

[0197] From the calculated carbon dioxide gas release efficiency, the following criteria were established and evaluated, with S, A, and B being designated as practically usable ranges. The evaluation results are shown in Tables 11-1 and 11-2. S: Emission efficiency is 0.8 or more A: Emission efficiency is 0.7 or more and less than 0.8 B: Emission efficiency is 0.6 or more and less than 0.7 C: Emission efficiency is less than 0.6

[0198] [Materials and gases used in the evaluation] For simplicity of notation, the following abbreviations have been used: ATMP: 4-amino-2,2,6,6-tetramethylpiperidine MDEA: N-methyldiethanolamine MBZA: Methylbenzylamine MEA: Monoethanolamine AB: 2-aminobutanol DMAPA: dimethylaminopropylamine

[0199] The gas species used in the evaluation are the same as those in Table 6 above. [Table 11-1]

[0200] [Table 11-2]

[0201] [Example D1 (Absorbing Solution B55)] 25g of compound (A84) and 5g of MDEA were mixed and stirred with 70g of dimethyl sulfoxide to prepare a carbon dioxide absorbing solution (100g), which was then placed in a 200ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 12-1.

[0202] [Example D2 (Absorbing Solution B56)] 25g of compound (A85) and 5g of MBZA were mixed with 60g of sulfolane and 10g of water, and the mixture was stirred to prepare a carbon dioxide absorbing solution (100g). This was placed in a 200ml gas absorption bottle, and the same experiment was carried out. The evaluation results are shown in Table 12-1.

[0203] [Example D3 (Absorbing Solution B57)] 25g of compound (A89) and 5g of MBZA were mixed with 60g of dimethyl sulfoxide and 10g of water, and the mixture was stirred to prepare a carbon dioxide absorbing solution (100g). This was placed in a 200ml gas absorption bottle, and the same experiment was carried out. The evaluation results are shown in Table 12-1.

[0204] [Example D4 (Absorption Solution B58)] 25 g of compound (A84) and 5 g of compound (A93) were mixed with 70 g of dimethyl sulfoxide and stirred to prepare a carbon dioxide absorbing solution (100 g), which was then placed in a 200 ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 12-1.

[0205] [Example D5 (Absorption Solution B59)] 25 g of compound (A85) and 5 g of compound (A94) were mixed with 70 g of dimethyl sulfoxide and stirred to prepare a carbon dioxide absorbing solution (100 g), which was then placed in a 200 ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 12-1.

[0206] [Example D6 (Absorbing Solution B60)] 25g of compound (A85), 2g of ATMP, 60g of dimethyl sulfoxide and 10g of N-methyl-2-pyrrolidone were added and mixed and stirred to prepare a carbon dioxide absorbing solution (100g), which was then placed in a 200ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 12-1.

[0207] [Example D7 (Absorbing solution B61)] 30 g of compound (A84) was mixed with 60 g of dimethyl sulfoxide and 10 g of N-methyl-2-pyrrolidone, and the mixture was stirred to prepare a carbon dioxide absorbing solution (100 g). This was placed in a 200 ml gas absorption bottle, and the same experiment was carried out. The evaluation results are shown in Table 12-1.

[0208] [Examples C1 to C83, K1 to 128 (Absorption Solutions C1 to C83, K1 to 128)] The compound and liquid medium described in Example D1 were changed to the compound and liquid medium described in Table 11-1 to Table 11-2, respectively, and the amount of carbon dioxide gas absorbed was measured by the method described in the above [Method for measuring carbon dioxide gas release efficiency], and the amount of carbon dioxide absorbed (L) per 1 kg of carbon dioxide absorbing solution and the carbon dioxide gas release efficiency were calculated. The gas species used in the evaluation are as shown in Table 6. From the calculated carbon dioxide gas release efficiency, the following criteria were established and evaluated, with the practically usable ranges being S, A, and B. The evaluation results are shown in Tables 12-1 to 12-7. S: Emission efficiency is 0.8 or more A: Emission efficiency is 0.7 or more and less than 0.8 B: Emission efficiency is 0.6 or more and less than 0.7 C: Emission efficiency is less than 0.6

[0209] [Comparative Example 3 (Absorbent K129)] [ka]

[0210] Under a nitrogen atmosphere, 30.0 g (665.5 mmol) of ethylamine (b1) and 72.0 g (332.7 mmol) of neopentyl glycol glycidyl ether (c7) mixed with 50 mL of dimethyl sulfoxide were added and stirred. After the addition, the mixture was stirred at room temperature for 24 hours, and the progress of the reaction was confirmed by TOF-MS, which showed that the reactant (b1) was no longer detected. A dimethyl sulfoxide solution of the target compound (A79') was obtained. Dimethyl sulfoxide was added to the dimethyl sulfoxide solution of the obtained compound (A79'), and the mixture was stirred to prepare a carbon dioxide absorbing solution (100 g) having the composition shown in Table 12-7. This was placed in a 200 ml gas absorption bottle, and the same experiment was carried out. The evaluation results are shown in Table 12-7.

[0211] [Comparative Example 4 (Absorbent K130)] A dimethyl sulfoxide solution of compound (A79) described in Absorption Solution K129 was used, and dimethyl sulfoxide was added as the liquid medium and a predetermined amount of epichlorohydrin was added as the chlorine component to prepare 100 g of absorption solution. This was then placed in a 200 ml gas absorption bottle and subjected to the same experiment. The evaluation results are shown in Table 12-7.

[0212] [Table 12-1]

[0213] [Table 12-2]

[0214] [Table 12-3]

[0215] [Table 12-4]

[0216] [Table 12-5]

[0217] [Table 12-6]

[0218] [Table 12-7]

[0219] [Examples M1 to 61, H1 to 103, L1 to 128, Comparative Examples 5 and 6] (Degree of change in absorption amount after repeated evaluation of carbon dioxide gas absorption / release) The above-mentioned carbon dioxide gas absorption / desorption measurement was repeated 10 times using absorption solutions B1 to 61, C1 to 83, E21 to 40, and K1 to 130 listed in Tables 11-1 to 12-7. Thereafter, the absorption amount for the 11th test was calculated in the same manner as the first test, and the degree of reduction compared to the absorption amount for the first test was evaluated. The evaluation criteria were as follows, with S, A, and B being defined as practically usable ranges. The evaluation results are shown in Tables 13-1 to 13-3. S: The 11th absorption amount is 99.5% or more of the 1st absorption amount. A: The 11th absorption amount is 99% or more but less than 99.5% of the 1st absorption amount. B: The 11th absorption amount is 98% or more but less than 99% of the 1st absorption amount. C: The 11th absorption amount is less than 98% of the 1st absorption amount.

[0220] (Steel corrosion of absorbent samples) Using the absorbent solutions B1 to 61, C1 to 83, E21 to 40, and K1 to 130 listed in Tables 11-1 to 12-7, the above-mentioned carbon dioxide gas was absorbed 11 times, and then further carbon dioxide gas was absorbed to prepare absorbent solutions. Then, a steel material made of SUS316 steel (1 cm long x 1 cm wide x 3 mm thick) was added to the glass container of the absorbent solution, which was then sealed and stored in an oven at 100°C for 7 days, and the corrosion resistance of the steel material was evaluated. The evaluation criteria were as follows, with S, A, and B being the practical usable ranges. The evaluation results are shown in Tables 13-1 to 13-3.

[0221] S: The appearance of the absorbent is colorless and transparent, and there is no deterioration of the steel surface. A: The appearance of the absorbed liquid is light yellow, and there is no deterioration of the steel surface. B: The appearance of the absorbed liquid turns yellow to brown, and the surface of the steel material turns black. C: The appearance of the absorbent liquid turns black, and the surface of the steel material turns black.

[0222] [Table 13-1]

[0223] [Table 13-2]

[0224] [Table 13-3]

[0225] As described in the above examples, the carbon dioxide absorbing solution of the present disclosure not only has excellent repeated carbon dioxide release efficiency (amount released / amount absorbed) but also has the effect of reducing corrosiveness to steel materials by reducing the chlorine component in the absorbing solution compared to conventionally known carbon dioxide absorbing solutions.

Claims

1. An absorption liquid for separating and recovering carbon dioxide from a gas containing carbon dioxide, An absorbing solution comprising an amine compound (A) represented by the following general formula (1) and a liquid medium (B), and having a chlorine (Cl) content of 1000 ppm or less: 【Chemistry 1】 During the ceremony, R １ represents a hydrogen atom or a hydrocarbon group which may have a substituent and which may have a heteroatom in the carbon chain, and the carbon atom adjacent to N is a primary carbon atom or a carbon atom constituting a ring, R ２ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms in which the carbon atom adjacent to N is a primary carbon atom, or -CH ２ CH(OH)CH ２ X ２ A ２ and X １ represents a direct bond, —O—, —OC(═O)—, —CO(═O)—, or —NA ３ - and A １ is a hydrogen atom or an n-valent organic residue (wherein X １ is a direct bond, and A １ becomes a hydrogen atom), n is an integer from 1 to 6, X ２ represents a direct bond, —O—, —OC(═O)—, —CO(═O)—, or —NA ３ - and A ２ is a hydrogen atom or a monovalent organic residue (wherein X ２ is a direct bond, and A ２ becomes a hydrogen atom), A ３ is a hydrogen atom or a monovalent organic residue.

2. The R １ The absorbing solution according to claim 1 , wherein

3. The R １ The absorbing liquid according to claim 1, wherein is a group represented by the following general formula (2), general formula (3), general formula (4) or general formula (5): 【Chemistry 2】 During the ceremony, R ３ , R ４ , R ５ , and R ６ are each independently a hydrogen atom or a methyl group, R ７ is a hydrogen atom or a methyl group, R ８ is a hydrogen atom or a methyl group, p is an integer from 0 to 4, R ９ is an alkyl group having 1 to 8 carbon atoms, m is an integer from 0 to 4, R １０ , and R １２ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a hydroxyalkyl group, R １１ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a hydroxyalkyl group, or -(CH ２ ) ｓ -R １３ and R １３ is a hydroxy group or —N(R １４ ) R １５ and R １４ and R １５ are each independently a hydrogen atom, a methyl group, or a hydroxyalkyl group, q is 2 or 3; r is 2 or 3; s is 2 or 3.

4. The above A １ The absorbing solution according to claim 1, wherein is an n-valent organic residue.

5. The above A １ , A ２ and A ３ are each independently a linear or branched aliphatic hydrocarbon residue which may have a substituent and which may have a heteroatom in the carbon chain; a (meth)acryloyl residue which may have a substituent; an alicyclic hydrocarbon residue which may have a substituent and which may have a heteroatom in the carbon chain; an aromatic hydrocarbon residue which may have a substituent; or an aromatic heterocyclic residue which may have a substituent.

6. The R ２ The absorbing solution according to claim 1, wherein is a hydrogen atom.

7. 2. The absorbing solution according to claim 1, wherein the chlorine (Cl) content is 10 to 500 ppm.

8. The absorbing solution according to claim 1, further comprising at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines.

9. The liquid medium (B) has a total Hansen solubility parameter (δT) of 17 MPa. １／２ The absorbing solution according to claim 1 .

10. The absorbing liquid according to claim 1, wherein the proportion of water in the liquid medium (B) is 50 mass % or less.

11. The absorbing solution according to claim 1, comprising 5 mass % or more of the amine compound (A) represented by the formula (1).

12. 2. The absorbing solution of claim 1, further comprising: the gas containing hydrogen sulfide; and the absorbing solution absorbs the hydrogen sulfide.

13. A method for separating and recovering carbon dioxide from a gas containing carbon dioxide, comprising the following steps A and B: Step A: A step of contacting the absorbing solution according to any one of claims 1 to 12 with a gas containing carbon dioxide to obtain an absorbing solution that has absorbed carbon dioxide from the gas containing carbon dioxide; Step B: A step of heating the absorption liquid that has absorbed carbon dioxide and is obtained in Step A to desorb and release carbon dioxide from the absorption liquid, and recovering the released carbon dioxide.

14. The method according to claim 13, wherein the heating temperature in step B is 50°C or higher and 160°C or lower.

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