Absorption liquid of carbon dioxide, and separation and recovery method of carbon dioxide

Abstract

To provide an absorption liquid of carbon dioxide which exhibits high absorption capability of carbon dioxide and high emission capability of carbon dioxide at low temperature, and is scarcely degraded even when absorption and emission cycles are repeated, and a separation and recovery method of carbon dioxide.SOLUTION: An absorption liquid, which is an absorption liquid for separating and recovering carbon dioxide from gas containing carbon dioxide, contains an amine compound (A) represented by the following general formula (1), at least one kind of amine compound (C) selected from the group consisting of an amine compound (A), amino alcohols, cyclic polyamines and chain polyamines, and at least one kind of liquid medium (B) selected from the group consisting of an organic solvent and an ionic liquid.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to an absorbent for highly efficiently separating and recovering carbon dioxide from a gas containing carbon dioxide, and a method for separating and recovering carbon dioxide using the absorbent.

Background Art

[0002] In recent years, the rapid increase in the emissions of greenhouse gases such as carbon dioxide and methane accompanying social activities has been cited as one of the causes of global warming. In particular, carbon dioxide is the most major among greenhouse gases, and in accordance with the Paris Agreement that came into force in 2016, measures for reducing carbon dioxide emissions have become an urgent task.

[0003] As a measure for reducing carbon dioxide emissions, the separation and recovery of carbon dioxide has attracted attention, and the development of carbon dioxide absorbents has been actively carried out. Therefore, in recent years, the development of carbon dioxide separation and recovery technology by a chemical absorption method mainly using an aqueous solution of an amine compound has been vigorously promoted for carbon dioxide-containing gases discharged from power plants and steelworks.

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

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

[0006] However, in the method for separating and recovering carbon dioxide using such an aqueous amine solution, a large amount of water in the solvent evaporates during the regeneration process of heating the absorption liquid. Therefore, the latent heat of evaporation must be input as excessive regeneration energy. In addition, the aqueous solution has a large specific heat, and more than twice the sensible heat is required compared to organic solvents. Furthermore, the evaporation of water in the solvent promotes the entrainment of the amine, which is the reaction substrate. Therefore, attention must be paid to the control of the material balance in managing the separation and recovery process. Thus, it requires extra cooling energy, such as equipping condensers for amine recovery in the absorption tower and regeneration tower, which leads to the complication of the process. Furthermore, since the amine deteriorates during the heating regeneration process at high temperatures, regular replenishment of the absorption liquid is required due to the disappearance of the reaction substrate, and there is concern about an increase in running costs. In order to solve such problems, the study of non-aqueous solutions of amine compounds has been carried out.

[0007] For example, Patent Document 2 reports a non-aqueous carbon dioxide absorption liquid containing a carbon dioxide chemisorbing amine having a nitrogen-hydrogen bond and a tertiary polyamine having an oxygen atom and / or a nitrogen atom via a hydrocarbon group with 2 or more carbon atoms in the main chain and having a hydrogen bond accepting property with a total of 2 or more oxygen atoms and nitrogen atoms.

[0008] Patent Document 3 reports a carbon dioxide absorption liquid composed of a non-aqueous solution formed by a chemisorbing component having a nitrogen base and a physical absorption component having an organic diluent.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] The present disclosure aims to provide a carbon dioxide absorption and release liquid and a method for separating and recovering carbon dioxide, which exhibit a high carbon dioxide absorption capacity, a high carbon dioxide release capacity at low temperatures, and little deterioration even when the absorption and release cycles are repeated.

Means for Solving the Problems

[0011] 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, The absorption liquid contains an amine compound (A) represented by formula (1), at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines, and at least one liquid medium (B) selected from the group consisting of an organic solvent and an ionic liquid. Formula (1)

Chemical formula

Chemical formula

[10] 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 bringing the absorbent according to any one of [1] to [9] into contact with a gas containing carbon dioxide to obtain an absorbent that has absorbed carbon dioxide from the gas containing carbon dioxide. Step B: A step of heating the absorbent that has absorbed carbon dioxide obtained in Step A to desorb and dissipate carbon dioxide from the absorbent, and recovering the dissipated carbon dioxide.

[11] The method according to

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

Advantages of the Invention

[0012] According to the present disclosure, the absorbent has a high carbon dioxide recovery amount and absorption rate, has the ability to release carbon dioxide with low energy, and the deterioration of the material due to the repetition of carbon dioxide recovery and release is suppressed. As a result, carbon dioxide separation and recovery with low energy can be achieved for the entire system. Furthermore, by improving the absorption efficiency, it becomes possible to design a more compact carbon dioxide separation and recovery facility, and the initial cost is reduced.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the absorbent and the method for separating and recovering carbon dioxide will be described. In the present disclosure, "~" indicating a numerical range includes the numerical values described before and after it as the lower limit value and the upper limit value, unless otherwise specified. In addition, when there are a plurality of the same symbols in a chemical formula, the same symbols are not limited to representing the same substituents, unless otherwise specified, and may be different substituents from each other within the range defined by the symbols.

[0014] [Absorbent] The absorbent of the present disclosure is an absorbent for separating and recovering carbon dioxide from a gas containing carbon dioxide, and includes an amine compound (A) represented by the following general formula (1), at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines, and water.

Chem.

[0015] In the formula, R 1 is a hydrogen atom or a hydrocarbon group which may have a substituent and may have a hetero atom in the carbon chain, and the carbon atom adjacent to N is a primary carbon atom or a carbon atom constituting a ring. R 2is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms where the carbon atom adjacent to N is a primary carbon atom, or -CH2CH(OH)CH2X 2 A 2 is X 1 a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3 -. A 1 is a hydrogen atom or an n-valent organic residue (however, when 1 X 1 is a direct bond and A X 2 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3 -. A 2 is a hydrogen atom or a monovalent organic residue (however, when 2 X 2 is a direct bond and A 3 is a hydrogen atom or a monovalent organic residue.)

[0016] The inventors have found that by using the above-specified amine compound (A) and at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines, a high carbon dioxide recovery amount and a low energy consumption required for the carbon dioxide recovery amount can be suppressed. The absorbent of the present disclosure using the above-specified amine compound (A) and at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines can efficiently absorb carbon dioxide, release it with low energy, and not only recover high-purity carbon dioxide with high efficiency, but also is less likely to deteriorate even when absorption and release are repeated.

[0017] <Amine compound (A)> The amine compound (A) is a compound represented by the following general formula (1). [Chemical]

[0018] 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 shown in formula (1).

[0019] Examples of the hydrocarbon group in which the carbon atom adjacent to N is a primary carbon atom include linear alkyl groups. Examples of the hydrocarbon group in which the carbon atom adjacent to N is a carbon atom constituting a ring include cycloalkyl groups and aryl groups. Examples of the heteroatom that may be present in the carbon chain include O, N, S, Si, etc., and O or N is preferred. The carbon chain may have two or more heteroatoms. Also, R 1 Examples of the "substituent" that R may have include halogen atoms, linear or branched alkyl groups, cycloalkyl groups, alkoxy groups, cyano groups, trifluoromethyl groups, nitro groups, hydroxyl groups, carbamoyl groups, N-substituted carbamoyl groups, sulfamoyl groups, N-substituted sulfamoyl groups, carboxyl groups, sulfo groups, amino groups, imino groups, phenyl groups, sulfanyl groups, etc. The above substituents may further have a substituent, and examples of such a substituent include the above substituents.

[0020] R 1 Among them, a hydrogen atom, an alkyl group which may have a substituent and 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.

[0021] R 1In the formula, the alkyl group which may have a substituent and may have a hetero atom in the carbon chain includes, for example, methyl group, ethyl group, propyl group, butyl group, isobutyl group, neopentyl group, n-hexyl group, n-octyl group, stearyl group, 2-ethylhexyl group, trichloromethyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group, 2,2-dibromoethyl group, 2,2,3,3-tetrafluoropropyl group, 2-ethoxyethyl group, 2-butoxyethyl group, 2-nitropropyl group, benzyl group, 4-methylbenzyl group, 4-tert-butylbenzyl 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,N-(hydroxyethyl)aminoethyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 4-hydroxybutyl group, cyclopropylmethyl group, cyclobutylmethyl group, cyclopentylmethyl group, cyclohexylmethyl group, cyclopentylethyl group, cyclohexylethyl group, cyclopentylpropyl group, cyclohexylpropyl group, 2-(1-piperazinyl)ethyl group, and the like. Examples of the alkyl group having a substituent include aminoethyl group, N-methylaminoethyl group, N-ethylaminoethyl group, N-(aminoethyl)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, aminobutyl group, 2-(1-piperazinyl)ethyl group, with aminoethyl group, N-methylaminoethyl group, N-ethylaminoethyl group, and N-(aminoethyl)aminoethyl group being preferred, and aminoethyl group, N-methylaminoethyl group, and N-ethylaminoethyl group being more preferred.

[0022] The heterocyclic group which may have a substituent includes, for example, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrrolyl group, 3-pyrrolyl group, 2-furyl group, 3-furyl group, 2-thienyl group, 3-thienyl group, 2-imidazolyl group, 2-oxazolyl group, 2-thiazolyl group, piperidino group, 4-piperidyl group, morpholino group, 2-morpholinyl group, N-indolyl group, 2-indolyl group, 2-benzofuryl group, 2-benzothienyl group, 2-quinolino group, N-carbazolyl group, piperidinyl group, and the like.

[0023] The cycloalkyl group which may have a substituent includes, for example, cyclopropyl group, methylcyclopropyl group, cyclobutyl group, cyclopentyl group, methylcyclopentyl group, ethylcyclopentyl group, cyclohexyl group, methylcyclohexyl group, ethylcyclohexyl group, propylcyclohexyl group, 4,4'-methylenebis(cyclohexyl) group, and the like.

[0024] From the standpoint of achieving both carbon dioxide adsorption and the ability to release carbon dioxide at low temperatures, R 1 preferably 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). In the formula, * represents a bond with N in formula (1).

Chemical formula

[0025] 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 viewpoints of carbon dioxide adsorption and low-temperature release properties, R 3 to R 6 are preferably methyl groups. Also, from the viewpoints of carbon dioxide adsorption and low-temperature release properties, R 7 is preferably a hydrogen atom.

[0026] In formula (3), R 8 is a hydrogen atom or a methyl group, and p is an integer from 0 to 4. From the viewpoints of carbon dioxide adsorption and low-temperature release properties, R 8 is preferably a hydrogen atom. Also, from the viewpoints of carbon dioxide adsorption, low-temperature release properties, and ease of synthesis, p is preferably from 1 to 4, more preferably from 2 to 3.

[0027] In formula (4), R 9 is an alkyl group having 1 to 8 carbon atoms, and m is an integer from 0 to 4. Examples of the alkyl group in R 9 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, an octyl group, etc. From the viewpoints of carbon dioxide adsorption and low-temperature release properties, R 9 is preferably an alkyl group having 1 to 4 carbon atoms, and among them, a methyl group is preferred. Also, m is R 9Represents the number of substitutions, and from the viewpoints of carbon dioxide adsorbability and low-temperature release property, 0 to 2 is preferable, and 0 to 1 is more preferable.

[0028] 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 wherein R 13 is a hydroxy group or -N(R 14 )R 15 wherein 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, and from the viewpoints of carbon dioxide adsorbability and low-temperature release property, q is preferably 3 and r is preferably 3. R 10 ~R 12 Examples of the alkyl group having 1 to 8 carbon atoms in R 9 are the same as those of R 10 ~R 12 above, and from the viewpoints of carbon dioxide adsorbability and low-temperature release property, R 10 ~R 12 are preferably alkyl groups having 1 to 4 carbon atoms, and preferably methyl groups or ethyl groups. R 10 ~R 12 、R 14 and R 15 In the hydroxyalkyl group in R

[0029] From the viewpoints of carbon dioxide adsorbability and low-temperature release property, R 1 Among these, the group represented by the general formula (5) is preferable. R 1 Specific examples of R

[0030] 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 as follows.

[0031] R 2 Examples of the alkyl group having 1 to 8 carbon atoms for R 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, a 2-ethylhexyl group, and the like.

[0032] R 2 is -CH2CH(OH)CH2X 2 A 2 In the case of, n in formula (1) is preferably 1. In this case, formula (1) is A 2 X 2 CH2CH(OH)CH2N(R 1 )CH2CH(OH)CH2X 1 A 1 : represented by formula (1a). When the amine compound (A) is represented by formula (1a), from the viewpoints of carbon dioxide adsorption property, low-temperature release property, and ease of synthesis, X 1 A 1 and X 2 A 2 are preferably the same substituent.

[0033] From the viewpoints of carbon dioxide adsorption property, low-temperature release property, and ease of synthesis, R 2 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom, among these.

[0034] X 1 and X 2 are each independently a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA 3- is. From the viewpoints of carbon dioxide adsorption property, low-temperature release property, and suppression of deterioration of the absorbent during repeated use, X 1 and X 2 are each independently preferably a direct bond or -O-, and more preferably -O-. Also, when there are a plurality of X 1 (that is, when n is 2 or more), the plurality of X 1 may be the same or different, but from the viewpoints of carbon dioxide adsorption property, low-temperature release property, and ease of synthesis, the plurality of X 1 are preferably the same.

[0035] A 1 is a hydrogen atom or an n-valent organic residue. However, when X 1 is a direct bond, A 1 is an n-valent organic residue. The n-valent organic residue represents a residue obtained by removing n hydrogen atoms from an organic group. In the specific examples described later, the names of monovalent substituents are used, but A 1 is further a residue obtained by removing any n - 1 hydrogen atoms. Examples of the n-valent organic residue in A 1 include, for example, a linear or branched aliphatic hydrocarbon residue which may have a substituent and may have a hetero atom in the carbon chain; a (meth)acryloyl residue which may have a substituent; an alicyclic hydrocarbon residue which may have a substituent and may have a hetero atom in the carbon chain; an aromatic hydrocarbon residue which may have a substituent; an aromatic heterocyclic residue which may have a substituent, etc. Examples of the hetero atom include O, N, S, Si, etc. As the hetero atom in the aliphatic hydrocarbon residue, O or N is preferable, and O is more preferable. Also, as the hetero atom in the alicyclic hydrocarbon residue, O or N is preferable, and N is more preferable. The organic residue may have two or more hetero atoms. Examples of the linear or branched aliphatic hydrocarbon residue having a hetero atom include a linear or branched polyoxyalkyl residue, etc. Also, n represents an integer from 1 to 6, preferably from 1 to 4, and more preferably from 1 to 2.

[0036] Examples of the aliphatic hydrocarbon residue which may have an n-valent substituent include an alkyl group, an alkenyl group, and an alkynyl group.

[0037] Specific examples of the alkyl group include alkyl groups having 1 to 18 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, pentadecyl group, and octadecyl group.

[0038] Examples of the alkenyl group include alkenyl groups having 2 to 18 carbon atoms such as vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-octenyl group, 1-decenyl group, and 1-octadecenyl group.

[0039] Examples of the alkynyl group include alkynyl groups having 2 to 18 carbon atoms such as ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, 1-octynyl group, 1-decynyl group, and 1-octadecynyl group.

[0040] Examples of the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent include linear or branched alkyl groups, alkoxy groups, polyoxyalkyl groups, phenyl groups, 4-nitrophenyl groups, 2-methoxyphenyl groups, hydroxyl groups, halogen atoms, epoxy groups, etc. The above substituents may further have substituents, and examples of the substituents include the above substituents.

[0041] The specific alkyl group as the substituent has the same meaning as the alkyl group of the linear or branched hydrocarbon residue which may have an n-valent substituent described above.

[0042] Specific examples of the alkoxy group as the substituent include methoxy group, ethoxy group, etc.

[0043] Specific polyoxyalkyl groups as substituents include ethylene oxide groups with a repeat number of 4 to 16, linear or branched propylene oxide groups with a repeat number of 4 to 16.

[0044] Specific halogen atoms as substituents include chlorine atoms, bromine atoms, and iodine atoms.

[0045] Linear or branched polyoxyalkyl groups that may have an n-valent substituent include ethylene oxide groups with a repeat number of 4 to 16, linear or branched propylene oxide groups with a repeat number of 4 to 16. Regarding the substituents, they are the same as those in the linear or branched hydrocarbon residues that may have an n-valent substituent mentioned above, and alkyl groups, phenyl groups, hydroxyl groups, etc. are preferred.

[0046] (Meth)acryloyl residues that may have an n-valent substituent, as (meth)acryloyl groups, include methacryl groups and acryloyl groups. Regarding the substituents, they are the same as those in the linear or branched hydrocarbon residues that may have an n-valent substituent mentioned above.

[0047] Alicyclic hydrocarbon groups of alicyclic hydrocarbon residues that may have an n-valent substituent include cycloalkyl groups. Specifically, cycloalkyls with 3 to 18 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclooctadecyl group, and 2-indeno group are included. Also, as alicyclic hydrocarbon groups, groups in which a plurality of cycloalkyl groups are linked by an alkylene group or the like are included. Regarding the substituents in the alicyclic hydrocarbon residues that may have an n-valent substituent, they are the same as those in the linear or branched hydrocarbon residues that may have an n-valent substituent mentioned above, preferably a branched alkylene group, and particularly preferably a tert-butylene group.

[0048] Examples of the aromatic hydrocarbon of the aromatic hydrocarbon residue having an n-valent substituent include aromatic hydrocarbons having 1 to 4 condensed rings, specifically, benzene, biphenyl, naphthalene, anthracene, phenanthrene, tetracene, pyrene, 9,9-diphenylfluorene, bis(3-methylphenyl)fluorene, binaphthyl, and the like.

[0049] Regarding the substituent in the aromatic hydrocarbon residue having an n-valent substituent, it is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent described above. Preferably, it is 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.

[0050] Examples of the aromatic heterocyclic ring of the aromatic heterocyclic residue having an n-valent substituent include aromatic heterocyclic rings having 1 to 4 condensed rings, such as pyrrole, imidazole, pyridine, triazine, indole, quinoline, carbazole, phthalimide, and the like. Regarding the substituent, it is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent described above.

[0051] A 1 (X 1 ) n As the structure of, for example, it can also be regarded as 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.

[0052] Examples of the alkoxy group of the linear or branched alkoxy residue which may have an n-valent substituent include a methoxy group, an ethoxy group, and the like. Regarding the substituent, it is the same as the substituent in the linear or branched hydrocarbon residue which may have an n-valent substituent described above.

[0053] 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, a 1,2-cyclohexene diester group, etc. The substituents are the same as those in the linear or branched hydrocarbon residue which may have an n-valent substituent described above.

[0054] Examples of the aromatic ester group of the aromatic ester residue which may have an n-valent substituent include a phenyl ester group, a 4-tert-butylphenyl ester group, etc. The substituents are the same as those in the linear or branched hydrocarbon residue which may have an n-valent substituent described above.

[0055] Examples of the amino group of the amino residue which may have an n-valent substituent include an aniline group. The substituents are the same as those in the linear or branched hydrocarbon residue which may have an n-valent substituent described above, preferably an alkyl group, more preferably a methyl group.

[0056] 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, particularly preferably an n-valent linear hydrocarbon residue. A 1 The number of carbon atoms of A is preferably from 1 to 15, more preferably from 1 to 10, still more preferably from 2 to 8.

[0057] A 2 and A 3 are each independently a hydrogen atom or a monovalent organic residue. However, when X 2 is a direct bond, A 2 is a monovalent organic residue. A 2 and A3 The monovalent organic residue in the above A 1 is the same as the one obtained by reading n of the n-valent organic residue in the above A as 1.

[0058] Hereinafter, compounds (A1) to (A128) which are representative examples of the amine compound (A) are shown in Tables 1-1 to 1-8, but the present embodiment is not limited to this representative example.

[0059] [Table 1-1]

[0060] [Table 1-2]

[0061] [Table 1-3]

[0062] [Table 1-4]

[0063] [Table 1-5]

[0064] [Table 1-6]

[0065] [Table 1-7]

[0066] [Table 1-8]

[0067] (Method for Producing Amine Compound (A)) An example of the method for producing the amine compound (A) will be described, but the method for producing the amine compound (A) is not limited to the following method. Also, if there are commercially available products, such commercially available products may be used.

[0068] The amine compound (A) is, for example, HNR 1 (R 2 ) can be obtained by reacting a compound (1b) represented by and a monofunctional or polyfunctional epoxy compound (1c) in a solvent. Examples of the solvent include alkanols (e.g., methanol, ethanol, propanol, butanol, etc.), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), etc. The reaction is preferably carried out under anhydrous conditions in order to obtain the amine compound (A) represented by formula (1) which is the target product.

[0069] For example, when producing an amine compound (A) in which R 1 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) also include compounds (b1) to (b26) in Table 2 below.

[0070]

Table 2

[0071] The mixing amount of the compound (1b) and the epoxy compound (1c) is preferably in the range of 0.95 to 1.1 equivalents in terms of the primary amino group equivalent ratio of the compound (1b) to the epoxy equivalent of the epoxy compound (1c), for example.

[0072] 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 is a compound having two or more epoxy groups in one molecule.

[0073] Examples of the monofunctional epoxy compound include monofunctional aliphatic epoxy compounds and monofunctional aromatic epoxy compounds.

[0074] Examples of the monofunctional aliphatic epoxy compound include glycidyl ethers of aliphatic alcohols and glycidyl esters of alkyl carboxylic acids. Specific examples thereof include allyl glycidyl ether, butyl glycidyl ether, sec-butyl phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, alkyl glycidyl ether in which carbons 12 and 13 are mixed, glycidyl ether of alcohol, monoglycidyl ether of higher aliphatic alcohol, glycidyl ester of higher fatty acid, and the like.

[0075] As the above monofunctional aliphatic epoxy compound, synthesized ones may be used, or commercially available products may also be used. In the case of commercially available products, for example, Denacol EX-121, Denacol EX-171, Denacol EX-192 (manufactured by Nagase ChemteX Corporation); Epolite M-1230 (manufactured by Kyoeisha Chemical Co., Ltd.), Adeka Glycerol ED-502, Adeka Glycerol ED-502S, Adeka Glycerol ED-509E, Adeka Glycerol ED-509S, Adeka Glycerol ED-529 (manufactured by ADEKA Corporation), and the like.

[0076] Examples of the above monofunctional aromatic epoxy compound include monoglycidyl ethers of phenolic compounds such as phenol, cresol, and butylphenol, or alkylene oxide adducts thereof; Monoglycidyl etherified products of aromatic compounds having two or more phenolic hydroxyl groups such as resorcinol, hydroquinone, and catechol; Monoglycidyl etherified products of aromatic compounds having two or more alcoholic hydroxyl groups such as phenyldimethanol, phenyldiethanol, and phenyldibutanol; Monoglycidyl esters of polybasic acid aromatic compounds having two or more carboxylic acids such as phthalic acid, terephthalic acid, and trimellitic acid; Examples include glycidyl esters of benzoic acid, styrene oxide, or monoepoxides of divinylbenzene.

[0077] As the above monofunctional aromatic epoxy compound, commercially available products may be used, and commercially available products can be used. In the case of commercially available products, for example, Denacol EX-141, Denacol EX-146, Denacol EX-147 (manufactured by Nagase ChemteX Corporation), etc. can be mentioned.

[0078] The polyfunctional epoxy compound may be one commonly used in the epoxy resin composition, and the type is not particularly limited as long as it has two or more epoxy groups in one molecule.

[0079] Examples of the polyfunctional epoxy compound include polyfunctional aliphatic epoxy compounds and polyfunctional aromatic epoxy compounds.

[0080] As the polyfunctional aliphatic epoxy compound, synthesized ones may be used, or commercially available products may be used.

[0081] Examples of the polyfunctional aliphatic epoxy compound include bifunctional 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, 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, 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 ChemteX Corporation), such as trimethylolpropane polyglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol heptaglycidyl ether, sorbitol hexaglycidyl ether, resorcinol diglycidyl ether, etc. can be mentioned.

[0082] Commercially available products can be used as the polyfunctional aliphatic epoxy compound, for example, "EP-4088S" (manufactured by ADEKA Corporation, etc.), "EHPE3150" (manufactured by Daicel Corporation, etc.), "EX-211L", "EX-212L" (both manufactured by Nagase ChemteX Corporation, etc.) can be mentioned.

[0083] As the polyfunctional aromatic epoxy compound, a polyglycidyl etherified product of a polyhydric phenol having at least one aromatic ring such as bisphenol A and bisphenol F, or its alkylene oxide adduct; Epoxy novolac resin; Polyglycidyl ether compounds of aromatic compounds having two or more phenolic hydroxyl groups such as resorcinol, hydroquinone, and catechol; Polyglycidyl ether compounds of aromatic compounds having two or more alcoholic hydroxyl groups such as phenyldimethanol, phenyldiethanol, and phenyldibutanol; Polyglycidyl esters of polybasic acid aromatic compounds having two or more carboxylic acids such as phthalic acid, terephthalic acid, and trimellitic acid; Examples include diepoxides of divinylbenzene.

[0084] As the polyfunctional aromatic epoxy compound, a synthesized one may be used, or a commercially available product may be used.

[0085] As the polyfunctional aromatic epoxy compound, commercially available products can be used. For example, "Denacol EX-201", "Denacol EX-711", and "Denacol EX-721" (all of the above are manufactured by Nagase ChemteX Corporation); "Oxsol EG-280" and "Oxsol CG-400" (both of the above are manufactured by Osaka Gas Chemical Co., Ltd.); "EXA-80CRP" and "HP4032D" (both of the above are manufactured by DIC Corporation); "jER828" and "jER828EL" (both of the above are manufactured by Mitsubishi Chemical Corporation); "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", "Adeka Resin EP-4901E" (all of the above are manufactured by Adeka Corporation), etc.

[0086] The monofunctional epoxy compound and the polyfunctional epoxy compound used to obtain the amine compound represented by the formula (3) in the present embodiment may be used alone or in combination of a plurality of different types.

[0087] The structures of specific monofunctional or polyfunctional epoxy compounds (c1) to (c75) are shown in Tables 3-1 to 3-5.

[0088] [Table 3-1]

[0089] [Table 3-2]

[0090] [Table 3-3]

[0091] [Table 3-4]

[0092] [Table 3-5]

[0093] <Amine compound (C)> By using the amine compound (C) in combination, improvements or enhancements can be achieved in, for example, the carbon dioxide absorption amount, carbon dioxide release amount, carbon dioxide absorption rate, and carbon dioxide release rate of the absorption liquid. Compounds that can apply to both the amine compound (A) and the amine compound (C) are treated as those corresponding to the amine compound (A). That is, the amino alcohols in the amine compound (C) represent amino alcohols that do not correspond to the general formula (1).

[0094] The amine compound (C) used to obtain the absorption liquid in this embodiment may be used alone or in combination of a plurality of different types.

[0095] 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 of them can be used in combination.

[0096] Among these, as amino alcohols, from the viewpoint of further improving the reactivity or release ability of the amine compound (A) with carbon dioxide, at least one selected from the group consisting of 2-(isopropylamino)ethanol, 2-aminobutanol, and 2-amino-2-methyl-1-propanol is preferable.

[0097] Suitable cyclic polyamines are compounds in which two or more nitrogen atoms are substituted in the cycloalkyl group. Specifically, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethylpiperazine, N-(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, and 1-hydroxyethylpiperazine, diazabicycloundecene, and diazabicyclononene can be mentioned. One of these compounds can be used alone, or two or more of them can be used in combination.

[0098] Among these, as cyclic polyamines, from the viewpoint of further improving the reactivity or release ability of the amine compound (A) with carbon dioxide, at least one selected from the group consisting of piperazine, N-(2-aminoethyl)piperazine, and diazabicycloundecene is preferable.

[0099] Suitable chain polyamines specifically include compounds in which two or more nitrogen atoms are substituted, and between them, there is a linear or branched alkyl group having 2 to 6 carbon atoms, such as ethylenediamine, N-isopropylethylenediamine, N-methylethylenediamine, N-ethylethylenediamine, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, diethylenetriamine, 2,2-diamino-N-methyl diethylamine, 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, N,N-diethyl-N',N'-dimethylethylenediamine, 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-methyl dipropylamine, 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 of them can be used in combination.

[0100] Among these, as the chain polyamines, from the viewpoint of further improving the reactivity or releasability of the amine compound (A) with carbon dioxide, at least one selected from the group consisting of 1,4-diaminobutane, 1,3-diaminopropane, 3,3-diaminodipropylamine, 3,3-diamino-N-methyl dipropylamine, N,N'-bis(3-aminopropyl)ethylenediamine, and N,N-dibutyl-1,3-propanediamine is preferable.

[0101] <Liquid medium (B)> The liquid medium (B) contains at least one selected from the group consisting of an organic solvent and an ionic liquid, and is not particularly limited as long as it can be miscible with the amine compound (A). The above amine compound (A) can absorb carbon dioxide and release carbon dioxide by heating, but high energy is required for the separation of carbon dioxide. By using a liquid medium, the separation efficiency of the amine compound (A) and carbon dioxide can be improved, the release temperature of carbon dioxide can be lowered, and the release efficiency of carbon dioxide can be increased.

[0102] Specific examples of the liquid medium (B) include an organic solvent, an ionic liquid, or a mixed solvent thereof. Since the amine compound (A) has a hydroxyl group, an alkyl group, and an organic residue as shown by the above formula (1), it can be preferably dissolved in the aforementioned liquid medium (B).

[0103] The ionic liquid consists of a cation and an anion, and examples thereof include salts that are liquid at 100°C and atmospheric pressure. The ionic liquid is preferably liquid especially 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. Also, the lower limit of the melting point of the ionic liquid is not particularly limited. Note that the ionic liquid often undergoes supercooling and becomes a liquid state even below the melting point, and such an ionic liquid can be preferably used as long as it can maintain such a liquid state. Also, the melting point of the ionic liquid may decrease due to the mixing of amines, and such an ionic liquid can also be used as a carbon dioxide absorbent.

[0104] Examples of the anion constituting the ionic liquid include anions of phosphoric acid, phosphonic acid, phosphate ester, or phosphonate ester.

[0105] In the ionic liquid, the cation is not particularly limited, but is preferably an imidazolium, ammonium, or phosphonium.

[0106] Specific examples of the organic solvent that can be used as the liquid medium (B) are described in Tables 4-1 and 4-2 together with the total Hansen solubility parameter (δT).

[0107] (Total Hansen solubility parameter (δT)) The Hansen solubility parameter divides the total Hildebrand value into three parts: the dispersion force (δD), the polar component (δP), and the hydrogen bond (δH) component. The Hildebrand value is calculated using the relationship between vaporization, van der Waals force, and solubility. The total Hansen solubility parameter (δT) is decomposed into dispersion (δD), polarity (δP), and hydrogen bond (δH) forces and calculated using Equation (1). δT 2 =δD 2 +δP 2 +δH 2 (1) In the formula, ·δD is the dispersion component, ·δP is the polar component, ·δH is the hydrogen bond component.

[0108] In this specification, the calculation of the "Hansen solubility parameter" means the value calculated using the computer software "Hansen Solubility Parameters in Practice (HSPiP)". The version of "HSPiP" used in the calculation is "5.4.02".

[0109] When using a mixed solvent, first calculate the Hansen solubility parameters of each solvent, then obtain the weighted average with the mass fraction of each solvent as the weight, and use this as the total Hansen solubility parameter (δT) of the liquid medium (B).

[0110] Tables 4-1 and 4-2 show the dispersion component, polar component, and hydrogen bond component of different solvents, as well as the calculation results of the total Hansen solubility parameter (δT) for different solvents.

[0111]

Table 4-1

[0112]

Table 4-2

[0113] As the liquid medium (B), an organic solvent or ionic liquid with a total Hansen solubility parameter (δT) of 17 MPa 1 / 2 ~35 MPa 1 / 2 is preferred, an organic solvent or ionic liquid with 20 MPa 1 / 2 ~35 MPa 1 / 2 is more preferred, and an organic solvent or ionic liquid with 23 MPa 1 / 2 ~35 MPa 1 / 2 is even more preferred.

[0114] In the absorbent of this embodiment, the mass ratio of the sum of the amine compound (A) and the amine compound (C) to the liquid medium (B) is preferably in the range of 5:95 to 95:5, more preferably in the range of 15:85 to 85:15, and particularly preferably in the range of 30:70 to 80:20. The content of the amine compound (A) and the amine compound (C) in the absorbent is preferably 25% by mass or more, more preferably 30% by weight or more, and particularly preferably 80% by mass or less from the viewpoint of the absorption efficiency of the absorbent.

[0115] In the absorbent of the present embodiment, the mass ratio of the amine compound (A) and the amine compound (C) in the absorbent is preferably (A):(C) = 80:20 to 20:80, more preferably 70:30 to 30:70, and particularly preferably in the range of 60:40 to 40:60. By being in this ratio, the viscosity of the absorbent is low and the volatility of the absorbent is suppressed, making it possible to realize an efficient carbon dioxide absorption and release ability.

[0116] The absorbent of the present embodiment contains at least one liquid medium (B) selected from the group consisting of an organic solvent and an ionic liquid, and consists of the amine compound (A) represented by the formula (1). Further, it may contain at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines, and may or may not dissolve the reaction product with carbon dioxide.

[0117] In the absorbent of the present disclosure, the mass ratio of the amine compound (A) and the liquid medium (B) in the absorbent 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 absorbent is preferably 5% by mass or more, more preferably 10% by weight or more, and particularly preferably 25% by mass or more. 75% by mass or less is preferable from the viewpoint of the absorption efficiency of the absorbent.

[0118] The liquid medium (B) used in the absorbent may or may not dissolve the reaction product of the amine compound (A) and carbon dioxide. Further, the liquid medium (B) may contain a small amount of water of about 10% by mass or less.

[0119] <Optional component> The absorbent liquid of the present disclosure may further contain other components within the scope where the effects of the present invention are achieved. Examples of other components include stabilizers (side reaction inhibitors such as antioxidants) for ensuring the chemical or physical stability of the absorbent liquid; inhibitors (such as corrosion inhibitors) for preventing deterioration of the materials of the devices and equipment using the absorbent liquid. The total content of these other components in the absorbent liquid is preferably 5% by mass or less. Compounds that may correspond to both the amine compound (A) and the amine compound (C) are treated as corresponding to the amine compound (A). That is, the amino alcohols in the amine compound (C) represent amino alcohols that do not correspond to the general formula (1).

[0120] (Antioxidant) Examples of the above antioxidant include dibutylhydroxytoluene, butylhydroxyanisole, sodium erythorbate, sodium sulfite, sulfur dioxide, and the like.

[0121] (Corrosion inhibitor) Examples of the above 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, maleic acid-based polymers (such as copolymers of maleic acid and amylene, or terpolymers of maleic acid, acrylic acid, and styrene), and the like.

[0122] (Defoamer) Examples of the above defoamer include silicone-based, polyether-based, acetylenediol-based, metal soap-based, phosphate ester-based, fatty acid ester-based, and the like.

[0123] (pH adjuster) Examples of the pH adjuster include inorganic acids (such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, etc.), organic acids (such as citric acid, formic acid, acetic acid, oxalic acid, p-toluenesulfonic acid, etc.), inorganic bases (such as sodium hydrogen carbonate, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, ammonia, etc.), organic bases (such as methylamine, dimethylamine, trimethylamine, diazabicycloundecene, piperazine, ethanolamine, triethanolamine, etc.).

[0124] (Viscosity modifier) Examples of the viscosity modifier include polyimine, polyvinyl alcohol, polyethylene oxide, etc.

[0125] <Gas containing carbon dioxide> Examples of the gas containing carbon dioxide include exhaust gases from thermal power plants using coal, heavy oil, natural gas, etc. as fuels, boilers in manufacturing plants, kilns in cement factories, blast furnaces for reducing iron oxide with coke, converters for steelmaking by burning carbon in pig iron, integrated gasification combined cycle power plants, etc., natural gas during mining, reformed gas, etc. The carbon dioxide concentration in the gas is usually about 5 to 50% by volume concentration, particularly about 10 to 40% by volume concentration. In such a carbon dioxide concentration range, the action effect of this absorption liquid is preferably exerted. The gas containing carbon dioxide may contain, in addition to carbon dioxide, gases such as nitrogen, water vapor, carbon monoxide, hydrogen sulfide, carbonyl sulfide, sulfur dioxide, nitrogen dioxide, methane, hydrogen, etc.

[0126] The absorption liquid of the present disclosure is also excellent in absorbing hydrogen sulfide in addition to carbon dioxide.

[0127] [Method for separating and recovering carbon dioxide by absorption liquid] The carbon dioxide separation and recovery method of the present disclosure is a method for separating and recovering carbon dioxide in a gas containing carbon dioxide. The method includes step A of bringing the absorbent of the present disclosure into contact with the gas containing carbon dioxide to obtain an absorbent that has absorbed carbon dioxide from the gas containing carbon dioxide, and step B of heating the absorbent that has absorbed carbon dioxide obtained in step A to desorb and dissipate carbon dioxide from the absorbent and recover the dissipated carbon dioxide.

[0128] (Step A) In step A, the absorbent is brought into contact with the gas containing carbon dioxide, so that the carbon dioxide in the gas containing carbon dioxide is absorbed by the absorbent and separated.

[0129] In step A, the method of bringing the absorbent into contact with the gas containing carbon dioxide is not particularly limited. For example, there are a method of bubbling the gas containing carbon dioxide into the absorbent, a method of spraying the absorbent in a mist form into the gas containing carbon dioxide (spraying or spraying method), and a method of countercurrently contacting the gas containing high-pressure carbon dioxide with the absorbent in an absorption tower filled with a filler made of magnetic or metal mesh.

[0130] The temperature in step A can be 25 to 40 °C. Within this range, the absorbent is excellent in the carbon dioxide recovery amount and the carbon dioxide absorption rate. The temperature in step A is preferably 25 to 35 °C.

[0131] The pressure in step A is usually 1.0 bar or more, preferably 1.0 to 3.5 bar. Further, higher carbon dioxide absorption performance can be obtained by performing at a higher pressure.

[0132] (Step B) In step B, the absorbent that has absorbed carbon dioxide obtained in step A is heated to desorb and dissipate carbon dioxide from the absorbent and recover the dissipated carbon dioxide.

[0133] In the process of desorbing and releasing carbon dioxide in Process B, the temperature can be set to 50 - 160 °C. Within this range, the absorbent has excellent carbon dioxide release rate. The heating temperature in Process B is preferably 50 - 80 °C, more preferably 50 - 60 °C.

[0134] In the process of desorbing and releasing carbon dioxide in Process B, the pressure can usually be 3.5 bar or less, preferably 1.0 - 3.5 bar. Moreover, even higher carbon dioxide release performance can be obtained by performing the process at a lower pressure.

[0135] The method of heating the absorbent that has absorbed carbon dioxide to desorb and release carbon dioxide and then recovering it is not particularly limited. For example, similar to distillation, methods such as heating the absorbent and bubbling it in a kettle for desorption, or heating while expanding the liquid interface in a stripping tower filled with packing materials such as tray towers, spray towers, magnetic materials, and wire meshes can be mentioned. By these methods, pure or very high-concentration carbon dioxide can be recovered.

[0136] After carbon dioxide is released in Process B, the absorbent can be returned to Process A and recycled. In this recycling process, the heat added in Process B is utilized for raising the temperature of the absorbent through heat exchange with the absorbent that has absorbed carbon dioxide. Through this heat exchange, energy reduction for the entire carbon dioxide separation and recovery process is planned.

[0137] The carbon dioxide separated and recovered by the method for separating and recovering carbon dioxide using the absorbent of the present disclosure usually has a volume concentration of 95 - 100%, and can be pure or very high-concentration. The separated and recovered carbon dioxide can be used for underground or undersea isolation storage (CCS) and enhanced oil recovery (EOR) methods for which the technology is currently being developed. In addition, the uses of the separated and recovered carbon dioxide are not particularly limited. For example, synthetic raw materials such as chemical products, or refrigerants for food refrigeration can be mentioned.

Examples

[0138] Hereinafter, the present invention will be described in more detail 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 apparatus name: AutoFlexII manufactured by Bruker Daltonics

[0139] 1. Example Group 1 Synthesis method of compound (A7) [Chemical formula]

[0140] Under a nitrogen atmosphere, 16.09 g (103.0 mmol) of 4-amino-2,2,6,6-tetramethylpiperidine mixed with 50 ml of methanol and 11.15 g (51.5 mmol) of neopentyl glycol diglycidyl ether (c7) were added and stirred. After the addition, stirring was carried out at room temperature for 24 hours, and the progress of the reaction was confirmed by the fact that (c7) as the reactant was not detected by TOF-MS. The solvent methanol was removed by decompression at 40 °C or lower to obtain the target compound (A7).

[0141] [TOF-MS measurement results of compound (A7)] Calculated molecular weight: C29H60N4O4, Mol.Wt. 528.8; Observed molecular weight: m / z 528.9

[0142] [Synthesis Examples 2 - 8] In the same manner as in Synthesis Example 1, the amine compounds in Table 2 above and the epoxy compounds in Tables 3-1 to 3-5 in the previous period were combined to synthesize compounds (A13), (A32), (A116), (A122), (A123), (A124), and (A125). The obtained compounds were identified by TOF-MS in the same manner as in Synthesis Example 1. The yields and mass spectrum results of the synthesized compounds are shown in Table 5. The compound numbers are the same as those described in Tables 1-1 to 1-8 of this specification.

[0143] [Table 5]

[0144] (Method for Measuring Carbon Dioxide Gas Emission Efficiency) 100 g of the carbon dioxide absorbent adjusted in the examples described below (while contained in a gas absorption bottle with a volume of 200 ml) was temperature-controlled 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 blown into this carbon dioxide absorbent while bubbling for 1 hour. The amount of carbon dioxide gas absorbed at this time (the amount of carbon dioxide absorbed in 1 hour (L)) was measured using a gas flow meter and a carbon dioxide concentration meter. Using this amount of carbon dioxide absorbed in 1 hour (L), the amount of carbon dioxide absorbed per 1 kg of the carbon dioxide absorbent (L) was calculated.

[0145] Next, the temperature of this carbon dioxide absorbent was adjusted to 60°C in a water bath. Nitrogen gas at 500 ml / min was blown into this carbon dioxide absorbent while bubbling for 2 hours. The amount of carbon dioxide gas released at this time (the amount of carbon dioxide released in 2 hours (L)) was measured using a gas flow meter and a carbon dioxide concentration meter. Using the amount of carbon dioxide released in 2 hours (L), the amount of carbon dioxide released per 1 kg of the carbon dioxide absorbent (L) was calculated. From the amount of carbon dioxide released in the above-mentioned 2 hours (L) and the amount of carbon dioxide absorbed in the above-mentioned 1 hour (L), the carbon dioxide gas emission efficiency (= amount of carbon dioxide released in 2 hours (L) ÷ amount of carbon dioxide absorbed in 1 hour (L)) was calculated.

[0146] From the measurement of the calculated carbon dioxide gas emission efficiency, criteria were set and evaluated as follows, and SS, S, A, and B were defined as the practically usable regions. The evaluation results are shown in Table 6. SS: Emission efficiency is 0.9 or more S: Emission efficiency is 0.8 or more and less than 0.9 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

[0147] [Materials and Gas Types Used for Evaluation] For the sake of brevity in notation, the following abbreviations were used. AMP: 2-Amino-2-methylpropanol IPAE: 2-(Isopropylamino)ethanol AEAE: 2-(2-Aminoethylamino)ethanol AB: 2-Aminobutanol DPTA: Dipropylenetriamine MDEA: N-Methyldiethanolamine Pz: Piperazine AEPz: N-(2-Aminoethyl)piperazine DBU: Diazabicycloundecene MEA: Monoethanolamine

[0148] The gas species used for the evaluation are as shown in Table 6.

Table 6

[0149] Example 1 (Absorbent 1)] 20 g of the compound (A7) obtained in Synthesis Example 1 and 10 g of AMP were added, and 70 g of dimethyl sulfoxide was added and mixed and stirred to prepare a carbon dioxide absorbent (100 g). This was placed in a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured.

[0150] The carbon dioxide absorption amount (L) in 1 hour was 2.12 L in terms of standard state conversion. That is, the carbon dioxide absorption amount (L) per 1 kg of the carbon dioxide absorbent in 1 hour was 21.2 L in the standard state. (The carbon dioxide absorption amount (ml / min) per minute per 1 kg of the carbon dioxide absorbent was 353 ml / min (= 21.2 [L / hour] × 1000 [ml / L] ÷ 60 [min / hour]). The carbon dioxide release amount (L) in 2 hours was 1.92 L in terms of standard state conversion. That is, the carbon dioxide release amount (L) per 1 kg of the carbon dioxide absorbent in 2 hours was 19.2 L in terms of standard state conversion. (The carbon dioxide emission rate per kg of the carbon dioxide absorbent per minute (mL / min) was 160 ml / min (= 19.2 [L / 2 hours] × 1000 [ml / L] ÷ 120 [min / hour]).

[0151] From these, the emission efficiency of carbon dioxide gas was 0.91. The above results are shown in Table 7.

[0152] [Example 2 (Absorbent 2)] 20 g of the compound (A7) in Example 1 was changed to the compound (A13), and similarly, a carbon dioxide absorbent (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the emission efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0153] [Example 3 (Absorbent 3)] 20 g of the compound (A7) in Example 1 was changed to the compound (A32), and similarly, a carbon dioxide absorbent (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the emission efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0154] [Example 4 (Absorbent 4)] 20 g of the compound (A7) and 10 g of AMP in Example 1 were changed to the compound (A116) and AEAE 10 g respectively, and similarly, a carbon dioxide absorbent (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the emission efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0155] [Example 5 (Absorbent 5)] 20 g of the compound (A7) and 10 g of AMP in Example 1 were changed to the compound (A122) and AEAE 10 g respectively, and similarly, a carbon dioxide absorbent (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the emission efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0156] [Example 6 (Absorbent 6)] In Example 5, 10 g of AEAE was changed to 10 g of DPTA, and similarly, a carbon dioxide absorption solution (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0157] [Example 7 (Absorbent 7)] In Example 1, 20 g of Compound (A7) and 10 g of AMP were respectively changed to Compound (A123) and 10 g of IPAE, and similarly, a carbon dioxide absorption solution (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0158] [Example 8 (Absorbent 8)] In Example 7, 10 g of IPAE was changed to 10 g of MDEA, and similarly, a carbon dioxide absorption solution (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0159] [Example 9 (Absorbent 9)] In Example 1, 20 g of Compound (A7) and 10 g of AMP were respectively changed to 20 g of Compound (A124) and 10 g of Pz, and similarly, a carbon dioxide absorption solution (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7. [Example 10 (Absorbent 10)] In Example 7, 10 g of Pz was changed to 10 g of AEPz, and similarly, a carbon dioxide absorption solution (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0160] [Example 11 (Absorbent 11)] In Example 8, 20 g of Compound (A7) and 10 g of AMP were respectively changed to 20 g of Compound (A125) and 10 g of DBU, and similarly, a carbon dioxide absorption solution (100 g) was prepared. This was placed in a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0161] [Example 12 (Absorbent 12)] 20 g of the compound (A122) in Example 6 and 10 g of DPTA were respectively changed to 25 g of the compound (A125) and 15 g of DPTA. Similarly, a carbon dioxide absorbent (100 g) was prepared, put into a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0162] [Example 13 (Absorbent 13)] 20 g of the compound (A122) in Example 6 and 10 g of DPTA were respectively changed to 30 g of the compound (A125) and 20 g of DPTA. Similarly, a carbon dioxide absorbent (100 g) was prepared, put into a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0163] [Example 14 (Absorbent 14)] 20 g of the compound (A122) in Example 6 and 10 g of DPTA were respectively changed to 35 g of the compound (A125) and 25 g of DPTA. Similarly, a carbon dioxide absorbent (100 g) was prepared, put into a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0164] [Comparative Example 1] 20 g of the compound (A7) in Example 1 and 10 g of AMP were changed to 30 g of MEA. Similarly, a carbon dioxide absorbent (100 g) was prepared, put into a 200 ml gas absorption bottle, and the release efficiency of carbon dioxide gas was measured. The evaluation results are shown in Table 7.

[0165] [Table 7]

[0166] [Examples 15 to 28, Comparative Example 2] (Degree of change in absorption amount after repeated evaluation of carbon dioxide gas absorption / release) Using the absorbents 1 to 14 prepared in Table 7, the absorption / discharge measurement of the aforementioned carbon dioxide gas was repeated 10 times. Thereafter, in the same manner as in the first test, the absorption amount at the 11th time was calculated, and the degree of decrease with respect to the absorption amount at the first time was evaluated. The evaluation criteria were as follows, and S, A, and B were defined as the practically usable ranges. The evaluation results are shown in Table 8. S: The absorption amount at the 11th time is 99.5% or more with respect to the absorption amount at the first time A: The absorption amount at the 11th time is more than 99% and less than 99.5% with respect to the absorption amount at the first time B: The absorption amount at the 11th time is more than 98% and less than 99% with respect to the absorption amount at the first time C: The absorption amount at the 11th time is less than 98% with respect to the absorption amount at the first time

[0167]

Table 8

[0168] [Examples 29 to 42, Comparative Example 3] (Absorption rate of carbon dioxide gas) The absorption rates were evaluated using the absorbents 1 to 14 prepared in Table 7. 100 g of the prepared carbon dioxide absorbent (in a gas absorption bottle with a volume 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 absorbent. The absorption amount of carbon dioxide gas at this time (the absorption amount of carbon dioxide for 10 minutes (L)) was measured using a gas flow meter and a carbon dioxide concentration meter. The value obtained by dividing the absorption amount by 10 was defined as the absorption rate (L / min).

[0169] The evaluation criteria were as follows, and S, A, and B were defined as the practically usable ranges. The evaluation results are shown in Table 9. For comparison, the results of Comparative Example 3 using the absorbent 15 described in <Example 1> are also shown. S: The absorption rate is 1.00 L / min or more A: The absorption rate is 0.75 L / min or more and less than 1.00 L / min B: The absorption rate is 0.50 L / min or more and less than 0.75 L / min C: Absorption rate is less than 0.50 L / min

[0170]

Table 9

[0171] As described in the above embodiments, the carbon dioxide absorption liquid of the present invention has an excellent effect in terms of the carbon dioxide release rate and release efficiency (release amount / absorption amount) compared to conventionally known carbon dioxide absorption liquids. Also, it has been found that the absorption liquid of the present disclosure can efficiently release carbon dioxide at a release temperature of 60°C under the experimental conditions of this time, as opposed to 120°C, which is the release temperature of the generally known MEA aqueous solution.

Claims

1. An absorbent for separating and recovering carbon dioxide from a gas containing carbon dioxide, wherein the absorbent contains an amine compound (A) represented by formula (1), at least one amine compound (C) selected from the group consisting of amino alcohols, cyclic polyamines, and chain polyamines, and at least one liquid medium (B) selected from the group consisting of an organic solvent and an ionic liquid. Formula (1) 【Chemical 1】 In the formula, R １ is a hydrogen atom or a hydrocarbon group which may have a substituent and may have a hetero atom 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, wherein 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 is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA ３ -. A １ is a hydrogen atom or an n-valent organic residue (however, when １ is a direct bond and A １ is a hydrogen atom, it is excluded). n is an integer from 1 to 6, X ２ is a direct bond, -O-, -OC(=O)-, -CO(=O)-, or -NA ３ -. A ２ is a hydrogen atom or a monovalent organic residue (however, when ２ X is a direct bond and A ２ is a hydrogen atom, this case is excluded). A ３ is a hydrogen atom or a monovalent organic residue.

2. The aforementioned R １ The absorbent liquid according to claim 1, wherein R has a nitrogen atom.

3. Said R １ is a group represented by the following general formula (2), general formula (3), general formula (4) or general formula (5), the absorbent liquid according to claim 1. 【Chemical Formula 2】 In the formula, R ３ 、 R ４ 、 R ５ 、 and R ６ is, independently of one another, 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 wherein R １３ is a hydroxy group or -N(R １４ )R １５ wherein 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. Said A １ The absorbent liquid according to claim 1, wherein A is an n-valent organic residue.

5. Said A １ , A ２ and A ３ are each independently a linear or branched aliphatic hydrocarbon residue which may have a substituent and 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 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, The absorbent according to claim 1.

6. The aforementioned R ２ The absorbent liquid according to claim 1, wherein R is a hydrogen atom.

7. The liquid medium (B) has a total Hansen solubility parameter (δT) of 17 MPa １／２ or more, and the absorbent according to claim 1.

8. The absorbent according to claim 1, wherein the absorbent contains 5% by mass or more of the amine compound (A) represented by the formula (1).

9. Furthermore, the absorbent according to claim 1, wherein the gas contains hydrogen sulfide and the hydrogen sulfide is absorbed.

10. A method for separating and recovering carbon dioxide from a gas containing carbon dioxide, the method including the following steps A and B: Step A: A step of bringing the absorbent according to any one of claims 1 to 9 into contact with a gas containing carbon dioxide to obtain an absorbent that has absorbed carbon dioxide from the gas containing carbon dioxide. Step B: A step of heating the absorbent that has absorbed carbon dioxide obtained in step A to desorb and dissipate carbon dioxide from the absorbent and recover the dissipated carbon dioxide.

11. The method according to claim 10, wherein the heating temperature in step B is 50°C or higher and 160°C or lower.

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