Amine composition for carbon dioxide separation

Abstract

To provide a carbon dioxide absorbent composition having high absorption performance and a long lifetime.SOLUTION: A composition comprises: a compound (A) represented by the general formula (1) in the figure [where R1 to R6 each independently represent a hydrogen atom, or an alkyl or alkoxy group having 1 to 4 carbon atoms, and a, b and c each independently represent 0 or 1]; and an antioxidant (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide separation composition for separating carbon dioxide from a mixed gas containing carbon dioxide. [Background technology]

[0002] In recent years, due to the issue of global warming, carbon dioxide separation and capture has attracted attention, and the development of carbon dioxide absorbents has been actively pursued.

[0003] The most common carbon dioxide absorbing solution is an aqueous solution of monoethanolamine. Monoethanolamine is inexpensive and easily available industrially, but it has the property that it absorbs carbon dioxide at low temperatures and does not release it until the temperature is raised to 120°C or higher.

[0004] Therefore, efforts are being made to develop amines that have a lower carbon dioxide release temperature and require less carbon dioxide recovery energy than monoethanolamine. For example, N-methyldiethanolamine (Patent Document 1) has been proposed. In addition, an amine compound (Patent Document 2) has also been proposed that aims to improve carbon dioxide absorption performance.

[0005] On the other hand, carbon dioxide separation and capture involves mixing an absorption medium with a gas containing carbon dioxide to absorb it, and then separating the carbon dioxide from the absorption medium through the action of heat, etc. It is expected that this process, in which the absorption medium absorbs carbon dioxide again, will be operated continuously for a long period of time. In this case, there is concern that the absorption medium will deteriorate due to the long-term heat environment and the accompanying oxygen, etc., and that the carbon dioxide separation and capture performance will decrease. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2006-528062 [Patent Document 2] Japanese Patent Application Publication No. 2023-5949 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, due to growing environmental concerns, there has been a demand for further improvements in carbon dioxide absorption performance and for longer lifespans through prevention of degradation. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and as a result have completed the present invention described below.

[0009] That is, the present invention relates to a composition for carbon dioxide separation as shown below.

[0010] [1] General formula (1)

[0011] [ka]

[0012] [In formula (1), R 1 ~R 6 each independently represents a hydrogen atom, or an alkyl group or alkoxyl group having 1 to 4 carbon atoms. a, b, and c each independently represent 0 or 1.] A composition for carbon dioxide separation comprising a compound (A) represented by the following formula (I): and an antioxidant (B).

[0013] [2] The composition for carbon dioxide separation according to [1], further comprising one or more compounds (C) represented by general formulas (2) to (6).

[0014] [ka]

[0015] [In formula (2), R 1 R each independently represents an alkyl group having 1 to 3 carbon atoms. 2represents an alkylene group having 2 to 6 carbon atoms or an oxybisalkylene group having a total of 2 to 6 carbon atoms. 3 represents an alkyl group having 1 to 3 carbon atoms, a 2-hydroxyethyl group, or a 2-hydroxypropyl group, and n represents 0 or an integer of 1 to 4.

[0016] [ka]

[0017] [In formula (3), R 1 each independently represents an alkyl group having 1 to 3 carbon atoms.]

[0018] [ka]

[0019] [In formula (4), R 1 , and R 2 each independently represents an alkylene group having 2 to 3 carbon atoms.]

[0020] [ka]

[0021] [In formula (5), R 1 , and R 2 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, a 2,3-dihydroxypropyl group, a 2,3-dialkoxypropyl group having a total of 5 to 11 carbon atoms, an aminoalkyl group having 2 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 10 carbon atoms. The alkyl group may be a cycloalkyl group that forms a ring.]

[0022] [ka]

[0023] [In formula (6), R 1represents an alkyl group having 1 to 6 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, a 2,3-dihydroxypropyl group, a 2,3-dialkoxypropyl group having a total of 5 to 11 carbon atoms, an aminoalkyl group having 2 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 10 carbon atoms. 2 , and R 3 each independently represents an alkylene group having 2 to 3 carbon atoms.] [3] The composition for carbon dioxide separation according to [1], wherein the compound represented by formula (1) is 1,4-diazabicyclo[2.2.2]octane-2-methanol or 1,4-diazabicyclo[2.2.2]octane.

[0024] [4] The carbon dioxide separation composition according to [1], wherein the compound represented by formula (2) is at least one selected from the group consisting of N,N,N',N'-tetramethylethylenediamine, N,N,N',N'',N''-pentamethyldiethylenetriamine, N,N,N',N'',N''-pentamethyldipropylenetriamine, N,N,N',N'',N'''',N'''-hexamethyltriethylenetetramine, N,N,N',N'-tetramethylhexylenediamine, 2-[[2-(dimethylamino)ethyl]methylamino]ethanol, bis(2-dimethylaminoethyl)ether, N-(2-hydroxypropyl)-N,N',N'',N''-tetramethyldiethylenetriamine, N-methyldiethanolamine, N,N-dimethylethanolamine, N-methyldipropanolamine, and N,N-dimethylpropanolamine.

[0025] [5] The composition for carbon dioxide separation according to [1], wherein the compound represented by formula (3) is 1-(2-dimethylaminoethyl)-4-methylpiperazine.

[0026] [6] The composition for carbon dioxide separation according to [1], wherein the compound represented by formula (4) is piperazine or homopiperazine.

[0027] [7] The carbon dioxide separation composition according to [1], wherein the compound represented by formula (5) is N-(2-aminoethyl)-2-aminoethanol, N-methyl-1,3-diaminopropane, N-methylethylenediamine, N-isopropylethylenediamine, monoethanolamine, diethanolamine, 1-(aminoethylamino)-2,3-dihydroxypropane, or ethylenediamine.

[0028] [8] The composition for carbon dioxide separation according to [1], wherein the compound represented by formula (6) is 1-(2,3-dihydroxypropyl)-piperazine, N-(2-aminoethyl)piperazine, or N-(2-hydroxyethyl)piperazine.

[0029] [9] The composition for carbon dioxide separation according to [1], wherein the antioxidant (B) is at least one selected from a phosphorus-based compound, ascorbic acid, and a hindered amine-based compound.

[0030]

[10] The composition for carbon dioxide separation according to [1], wherein the antioxidant (B) is contained in an amount of 0.1 to 5.0 parts by weight (wt %) relative to the total weight of the composition for carbon dioxide separation.

[0031]

[11] The composition for carbon dioxide separation according to [1], which contains water, and the concentration of the water is 30 to 75 mass % of the total composition for carbon dioxide separation.

[0032]

[12] The carbon dioxide separation composition according to [1], wherein 10 to 150 carbon dioxide molecules (CO2) are contained per 100 parts by mass (molar parts) of the total amount of nitrogen atoms (N) in the composition.

[0033]

[13] A method for separating carbon dioxide, comprising a step of contacting a gas containing carbon dioxide with a composition containing a compound (A) represented by formula (1) and an antioxidant (B). [Effects of the Invention]

[0034] The carbon dioxide separation composition of the present invention is characterized by its excellent carbon dioxide absorption and release properties as well as its high stability. Therefore, the present invention is extremely useful industrially in that it can efficiently absorb and separate carbon dioxide emitted in large quantities from large-scale thermal power plants and the like over a long period of time even under severe operating conditions. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be described in detail below.

[0036] The composition for carbon dioxide separation of the present invention is characterized by containing a compound (A) represented by general formula (1) and an antioxidant (B).

[0037] The carbon dioxide separation composition of the present invention may further contain a group of compounds (C) represented by general formulas (2) to (6).

[0038] In the present invention, the amine compounds represented by general formula (1) and general formulas (2), (3), (4), (5), and (6) all play a role in adsorbing and desorbing carbon dioxide (International Application Publication No. WO2021 / 153650 A1, Japanese Patent Application Laid-Open No. 2022-101908, Japanese Patent Application Laid-Open No. 2022-168949).

[0039] In general formula (1), R 1 ~R 6 each independently represents a hydrogen atom, or an alkyl or alkoxy group having 1 to 4 carbon atoms.

[0040] a, b, and c each independently represent 0 or 1.

[0041] When a=1, b=1, and c=0, general formula (1) is represented by general formula (1a).

[0042] [ka]

[0043] [In formula (1a), R 1 ~R 6 is defined as in equation (1). When a=0, b=1, and c=1, general formula (1) is represented by general formula (1b).

[0044] [ka]

[0045] [In formula (1b), R 1 ~R 6 is the same as the definition in equation (1)] When a=0 and b=0, general formula (1) is represented by general formula (1c).

[0046] [ka]

[0047] [In formula (1c), R 1 ~R 6 is the same as the definition in equation (1)] When a=0, b=1, and c=0, general formula (1) is represented by general formula (1d).

[0048] [ka]

[0049] [In formula (1d), R 1 ~R 6 is defined as in equation (1). The compound represented by general formula (1) is preferably one in which a = 0, since it has excellent carbon dioxide diffusion efficiency. That is, it is preferably an amine compound represented by general formula (1b), (1c), or (1d).

[0050] In general formula (1), R 1 ~R 6are not particularly limited as long as they correspond to the defined substituents, but examples thereof include, for example, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Among these, R is preferred because it has excellent carbon dioxide diffusion efficiency. 1 ~R 6 are each independently preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably all are hydrogen atoms.

[0051] Examples of the compound represented by general formula (1) include the following specific examples (exemplary compounds 1 to 58), but the present invention is not limited to these.

[0052] [ka]

[0053] [ka]

[0054] The compound represented by general formula (1) is preferably 1,4-diazabicyclo[2.2.2]octane-2-methanol (R 1 =R 2 =R 3 =R 4 =R 5 =R 6 = hydrogen atom, a = 0, b = 1) or 1,4-diazabicyclo[2.2.2]octane (R 1 =R 2 =R 3 =R 4 =R 5 =R 6 = hydrogen atom, a=0, b=0). That is, it is preferable that the amine compound is an amine compound represented by the following exemplary compound 1 or 31.

[0055] [ka]

[0056] In general formula (2), R 1 each independently represents an alkyl group having 1 to 3 carbon atoms, and R 2 represents an alkylene group having 2 to 6 carbon atoms or an oxybisalkylene group having a total of 2 to 6 carbon atoms, and R 3 represents an alkyl group having 1 to 3 carbon atoms, a 2-hydroxyethyl group, or a 2-hydroxypropyl group; and n represents an integer of 1 to 4.

[0057] In general formula (2), R 1 are not particularly limited as long as they fall within the above definition, but examples thereof include, for example, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Among these, R is preferred because it has excellent carbon dioxide diffusion efficiency. 1 is preferably a methyl group.

[0058] In general formula (2), R 2 is not particularly limited as long as it satisfies the above definition, but examples thereof include an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, and an ethyleneoxyethylene group. Among these, R is preferred because it can be easily produced industrially. 2 is preferably an ethylene group, an n-propylene group, an n-hexylene group, or an ethyleneoxyethylene group, and more preferably a 1,2-ethylene group, a 1,2-propylene group, a 1,3-propylene group, a 1,6-hexylene group, or a 3-oxa-1,5-pentylene group.

[0059] In general formula (2), R 3 is not particularly limited as long as it satisfies the above definition, but examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a 2-hydroxyethyl group, and a 2-hydroxypropyl group. Among these, R is preferred because it has excellent carbon dioxide diffusion efficiency. 3 is preferably a methyl group, a 2-hydroxyethyl group, or a 2-hydroxypropyl group.

[0060] In general formula (2), n is preferably 1, 2, or 3, and more preferably 1 or 2, in terms of ease of industrial production.

[0061] Specific examples of the amine compound represented by general formula (2) include at least one selected from the group consisting of N,N,N',N'-tetramethylethylenediamine, N,N,N',N'',N''-pentamethyldiethylenetriamine, N,N,N',N'',N''-pentamethyldipropylenetriamine, N,N,N',N'',N'''',N'''-hexamethyltriethylenetetramine, N,N,N',N'-tetramethylhexylenediamine, 2-[[2-(dimethylamino)ethyl]methylamino]ethanol, bis(2-dimethylaminoethyl)ether, and N-(2-hydroxypropyl)-N,N',N'',N''-tetramethyldiethylenetriamine.

[0062] [ka]

[0063] In general formula (3), R 1 each independently represents an alkyl group having 1 to 3 carbon atoms.

[0064] In general formula (3), R 1 are not particularly limited as long as they fall within the above definition, but examples thereof include, for example, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Among these, R is preferred because it has excellent carbon dioxide diffusion efficiency. 1 are preferably all methyl groups.

[0065] A specific example of the amine compound represented by the general formula (3) is 1-(2-dimethylaminoethyl)-4-methylpiperazine.

[0066] [ka]

[0067] In general formula (4), R 1 , and R 2 each independently represents an alkylene group having 2 to 3 carbon atoms.

[0068] In general formula (4), R 1 , and R 2 is not particularly limited as long as it satisfies the above definition, but examples of R include an ethylene group and a propylene group. 1 , and R 2 are each independently preferably a 1,2-ethylene group, a 1,2-propylene group, or a 1,3-propylene group, in terms of excellent carbon dioxide diffusion efficiency, and R 1 , and R 2 are the same group, and more preferably a 1,2-ethylene group, a 1,2-propylene group, or a 1,3-propylene group.

[0069] Specific examples of the amine compound represented by the general formula (4) include piperazine and homopiperazine.

[0070] [ka]

[0071] In general formula (5), R 1 , and R 2 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, a 2,3-dihydroxypropyl group, a 2,3-dialkoxypropyl group having a total of 5 to 11 carbon atoms, an aminoalkyl group having 2 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 10 carbon atoms, provided that the alkyl group may be a cycloalkyl group that forms a ring.

[0072] R in general formula (5) 1 , and R 2With regard to the groups, it is preferable that each of them independently be a hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 2-aminoethyl group, or a 3-aminopropyl group, in terms of excellent carbon dioxide adsorption / desorption efficiency.

[0073] Specific examples of the compound represented by general formula (5) include cyclohexylamine, dicyclohexylamine, N-methylethylenediamine, N-isopropylethylenediamine, ethanolamine, N-methylethanolamine, N-isopropylethanolamine, N,N-dimethylethanolamine, diethanolamine, N-methyldiethanolamine, N,N-dimethyl-1,4-diaminobutane, N-methyl-1,3-diaminopropane, and N,N-dimethyl-1,3-diaminopropane. Aminopropane, N,N-dimethyl-1,2-diaminopropane, N,N-dimethyl-1,2-diaminoethane, N,N-diethyl-1,4-diaminobutane, N,N-diethyl-1,3-diaminopropane, N,N-diethyl-1,2-diaminopropane, N,N-diethyl-1,2-diaminoethane, N,N-dipropyl-1,4-diaminobutane, N,N-dipropyl-1,3-diaminopropane, N,N-dipropyl-1,2-diaminopropane, N,N-dipropyl-1,2-Diaminoethane, N-(2-aminoethyl)-2-aminoethanol, N-(3-aminopropyl)-2-aminoethanol, N-(2-aminopropyl)-2-aminoethanol, N-(4-aminobutyl)-2-aminoethanol, N-(2-aminoethyl)-3-aminopropanol, N-(3-aminopropyl)-3-aminopropanol, N-(2-aminopropyl)-3-aminopropanol, N-(4-aminobutyl)-3-aminopropanol, N-(2-aminoethyl)-4-aminobutanol, N-(3-aminopropyl)-4-aminobutanol, N-(2-aminopropyl)-4-aminobutanol, or N-(4-aminobutyl)-4-amino Examples of such aminocyclopentanol include N-(2-aminocyclopentyl)-2-aminoethanol, N-(3-aminocyclopentyl)-2-aminoethanol, N-(2-aminocyclohexyl)-2-aminoethanol, N-(3-aminocyclohexyl)-2-aminoethanol, N-(4-aminocyclohexyl)-2-aminoethanol, N-(2-aminocyclopentyl)-3-aminopropanol, N-(3-aminocyclopentyl)-3-aminopropanol, N-(2-aminocyclohexyl)-3-aminopropanol, N-(3-aminocyclohexyl)-3-aminopropanol, and N-(4-aminocyclohexyl)-3-aminopropanol.

[0074] The compound represented by general formula (5) is preferably at least one amine compound selected from the group consisting of N-(2-aminoethyl)-2-aminoethanol, N-methyl-1,3-diaminopropane, N-methylethylenediamine, N-isopropylethylenediamine, monoethanolamine, diethanolamine, 1-(aminoethylamino)-2,3-dihydroxypropane, and ethylenediamine, in terms of excellent carbon dioxide diffusion efficiency, and more preferably at least one compound selected from the group consisting of N-(2-aminoethyl)-2-aminoethanol, monoethanolamine, diethanolamine, and 1-(aminoethylamino)-2,3-dihydroxypropane.

[0075] In general formula (6), R 1 represents an alkyl group having 1 to 6 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, a 2,3-dihydroxypropyl group, a 2,3-dialkoxypropyl group having a total of 5 to 11 carbon atoms, an aminoalkyl group having 2 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 10 carbon atoms. 2 , and R 3 each independently represents an alkylene group having 2 to 3 carbon atoms.

[0076] R in equation (6) 1 The alkyl group having 1 to 6 carbon atoms in the formula (I) is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a cyclobutyl group, an n-pentyl group, a sec-pentyl group, an isopentyl group, a tert-pentyl group, a cyclopentyl group, an n-hexyl group, a sec-hexyl group, an isohexyl group, a tert-hexyl group, and a cyclohexyl group.

[0077] R in equation (6) 1 The 2,3-dialkoxypropyl group having a total of 5 to 11 carbon atoms in the formula (I) is not particularly limited, but examples thereof include a 2,3-dimethoxypropyl group (total carbon number: 5), a 2,3-diethoxypropyl group (total carbon number: 7), a 2,3-dipropoxypropyl group (total carbon number: 9), and a 2,3-dibutoxypropyl group (total carbon number: 11).

[0078] R in equation (6) 1 The aminoalkyl group having 2 to 6 carbon atoms in the formula (I) is not particularly limited, but examples thereof include a 2-aminoethyl group, a 3-aminopropyl group, and a 4-aminobutyl group.

[0079] R in equation (6) 1The hydroxyalkyl group having 2 to 10 carbon atoms in the formula (I) is not particularly limited, and examples thereof include a 2-hydroxypropyl group, a 2-hydroxybutyl group, a 2-hydroxypentyl group, a 2-hydroxyhexyl group, a 2-hydroxyheptyl group, a 2-hydroxycyclopentyl group, a 2-hydroxycyclohexyl group, a 2-hydroxycycloheptyl group, a 2-hydroxycyclooctyl group, a 2-hydroxycyclononyl group, and a 2-hydroxycyclodecyl group.

[0080] R in equation (6) 1 With regard to the groups, it is preferable that each of them is independently a methyl group, an ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 2-aminoethyl group, or a 3-aminopropyl group, in view of excellent carbon dioxide adsorption / desorption efficiency.

[0081] R in equation (6) 2 , and R 3 The alkylene group having 2 to 3 carbon atoms in the formula (I) is not particularly limited, but examples thereof include an ethylene group and a propylene group.

[0082] R in Equation (6) 2 , and R 3 are each independently preferably a 1,2-ethylene group, a 1,2-propylene group, or a 1,3-propylene group, in terms of excellent carbon dioxide diffusion efficiency, and R 1 , and R 2 are the same group, and more preferably a 1,2-ethylene group, a 1,2-propylene group, or a 1,3-propylene group.

[0083] The compound represented by formula (6) is preferably an amine compound represented by general formula (5c).

[0084] [ka]

[0085] [In formula (5c), R 4is R in general formula (6) 1 is equivalent to.] Specific examples of the compound represented by general formula (6) include N-methylpiperazine, N-ethylpiperazine, N-(2-hydroxyethyl)piperazine, N-(2-hydroxypropyl)piperazine, N-(2-aminoethyl)piperazine, N-(3-aminopropyl)piperazine, and N-(2,3-dihydroxypropyl)piperazine.

[0086] The compound represented by general formula (6) is preferably at least one amine compound selected from the group consisting of 1-(2,3-dihydroxypropyl)-piperazine, N-(2-aminoethyl)piperazine, and N-(2-hydroxyethyl)piperazine, and more preferably at least one amine compound selected from the group consisting of 1-(2,3-dihydroxypropyl)-piperazine, N-(2-aminoethyl)piperazine, and N-(2-hydroxyethyl)piperazine, in terms of excellent carbon dioxide diffusion efficiency.

[0087] The antioxidant (B) is not particularly limited, but it is desirable that the antioxidant suppresses oxidative degradation of the amine compound for carbon dioxide separation without reducing the carbon dioxide separation performance. For example, phenol-based compounds include 2,6-di-t-butyl-4-methylphenol, 4-t-butylphenol, 2,2'-methylene-bis-(4-methyl-6-t-butylphenol), octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-di-octylthiomethyl-6-t-butylphenol, 4-methoxyphenol, 2,6-di-t-butyl-4-methoxyphenol, etc., and phosphoric acid-based antioxidants include tris(2,4-di-t-butylphenyl)phosphite, tri-ortho-tolylphosphite, triphenylphosphite, 3,9-bis(2,4-di-t-butylphenoxy)-2,4,8,1 Examples of antioxidants include 0-tetraoxa-3,9-diphosphaspiro[5.5]undecane, tris(2-ethylhexyl)phosphite, tris(nonylphenyl)phosphite, 2-ethylhexyldiphenylphosphite, and triisodecylphosphite. Other examples include amine-based antioxidants such as p-phenylenediamine, N,N'-diisopropyl-p-phenylenediamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate and bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, and ascorbic acid. These antioxidants may be used alone or in combination.

[0088] In the carbon dioxide separation composition or its production method, the compounds represented by general formula (1), (2), (3), (4), (5), or (6) or other amine compounds may be commercially available or may be synthesized by known methods. The purity of these amine compounds is not particularly limited, but is preferably 90% or higher, and more preferably 95% or higher.

[0089] The carbon dioxide separation composition is not particularly limited, but specific examples include the following compositions.

[0090] [Table 1]

[0091] The components of the following composition are as follows: (A-1-1) 1,4-diazabicyclo[2.2.2]octane-2-methanol (A-1-2) 1,4-Diazabicyclo[2.2.2]octane (A-2-1) N,N,N',N'-Tetramethylethylenediamine (A-2-2) N,N,N',N'',N''-Pentamethyldiethylenetriamine (A-2-3) N,N,N',N'',N''',N'''-Hexamethyltriethylenetetramine (A-2-4) 2-[[2-(dimethylamino)ethyl]methylamino]ethanol (A-2-5) Bis(2-dimethylaminoethyl) ether (A-3-1) 1-(2-dimethylaminoethyl)-4-methylpiperazine (A-4-1) Piperazine (A-4-2) Homopiperazine (A-5-1) 1-(2,3-dihydroxypropyl)-piperazine (A-5-2) N-(2-aminoethyl)piperazine (A-5-3) N-(2-hydroxyethyl)piperazine (A-5-4) Monoethanolamine (A-5-5) Diethanolamine (A-5-6) 1-(aminoethylamino)-2,3-dihydroxypropane (B-1) 2,6-di-t-butyl-4-methylphenol (B-2) Tris(2,4-di-t-butylphenyl)phosphite (B-3) 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate (B-4) Ascorbic Acid The content of the antioxidant (B) is not particularly limited, but in order to exhibit good resistance to deterioration while maintaining the properties as a carbon dioxide separating agent, it is preferably 0.05 to 10.0 parts by weight (wt%), and more preferably 0.1 to 5.0 parts by weight (wt%), relative to the total weight of the composition.

[0092] The total content of the amine compounds in the carbon dioxide separation composition is not particularly limited, but is preferably 5.0 to 60.0 parts by mass, more preferably 10.0 to 50.0 parts by mass, and even more preferably 20.0 to 40.0 parts by mass, based on 100 parts by mass of the entire carbon dioxide separation composition.

[0093] The carbon dioxide separation composition may contain carbon dioxide, and although there are no particular limitations on the amount, it is preferably 5.0 to 40.0 parts by mass, more preferably 7.0 to 30.0 parts by mass, and even more preferably 10.0 to 20.0 parts by mass, based on 100 parts by mass of the entire carbon dioxide separation composition.

[0094] The carbon dioxide separation composition may contain an amine compound (C) other than the amine compound (A).

[0095] When the carbon dioxide separation composition contains an amine compound (C), the content of the amine compound (C) is not particularly limited, but is preferably 2.0 to 30.0 parts by mass, more preferably 5.0 to 25.0 parts by mass, and even more preferably 10.0 to 20.0 parts by mass, relative to 100 parts by mass of the entire carbon dioxide separation composition.

[0096] The carbon dioxide separation composition may further contain water, and the water content is preferably in the range of 30.0 to 75.0 mass%, more preferably in the range of 35.0 to 70.0 mass%, and even more preferably in the range of 40.0 to 65.0 mass%, with the entire carbon dioxide separation composition in a water-containing state being 100 mass%.

[0097] The carbon dioxide separation composition may further contain a solvent other than water, which is not particularly limited, but may include, for example, methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, glycerin, or ethylene glycol monomethyl ether.

[0098] The solvent content is preferably in the range of 1.0 to 30.0 mass%, more preferably in the range of 2.0 to 25.0 mass%, and even more preferably in the range of 5.0 to 20.0 mass%, with the entire carbon dioxide separation composition including the solvent being 100 mass%.

[0099] The carbon dioxide separation composition may contain carbon dioxide, and may contain carbon dioxide in any form as long as it is in a mixed state with various compounds, water, a solvent, or the like.

[0100] The carbon dioxide separating composition containing carbon dioxide can be produced by contacting the compound (A) and the antioxidant (B) with gaseous, liquid, or solid carbon dioxide, and is preferably produced by contacting the composition with a gas containing carbon dioxide or dry ice.

[0101] The method for contacting a composition containing the amine composition (A) and the antioxidant (B) with a gas containing carbon dioxide is not particularly limited, and any known method can be used, such as a bubbling method or a head-on contact method using a packed column or a plate column.

[0102] The gas containing carbon dioxide may be pure carbon dioxide gas or a mixed gas containing carbon dioxide and other gases. The other gases are not particularly limited, but examples thereof include air, nitrogen, oxygen, hydrogen, argon, neon, helium, carbon monoxide, water vapor, methane, ethane, propane, butane, ethylene, propylene, butene, isobutene, butadiene, and nitrogen oxides.

[0103] The method for bringing the composition containing the amine composition (A) and the antioxidant (B) into contact with dry ice is not particularly limited, and examples thereof include a method in which dry ice is introduced into the composition while the temperature of the composition is adjusted to a range of −30° C. to 60° C., followed by mixing and stirring. [Example]

[0104] The present invention will be described below using examples, but the present invention should not be construed as being limited to these examples.

[0105] The oxidation degradation resistance test was carried out by sealing the sample O2 in a pressure-resistant container containing the amine composition for carbon dioxide separation (O2 pressure = 0.50 MPaG) and storing it at 120°C for 15 hours. The compositions before and after degradation were analyzed by gas chromatography, and the results were judged as follows: "Good" if the amount of degradation product was less than 3.0 wt%, "Average" if it was 3.0 to 8.0 wt%, and "Poor" if it was 8.0% or more.

[0106] [Example 1] 15 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (Tosoh), 25 g of piperazine (Tokyo Chemical Industry, anhydrous), 1.0 g of 2,6-di-t-butyl-4-methylphenol, and 60 g of purified water were placed in a 200 mL gas absorption bottle, heated to 40°C in a water bath, and mixed and stirred to obtain a homogeneous solution. Oxygen was blown into this solution at 0.50 MPaG, and a degradation test was conducted at 120°C for 15 hours. The solution was analyzed by gas chromatography before and after the test, and the amount of degradation product was calculated, which was 2.9 wt%.

[0107] [Example 2] 15 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (Tosoh), 15 g of 1-(2-dimethylaminoethyl)-4-methylpiperazine (Tokyo Chemical Industry Co., Ltd.), 10 g of piperazine (Tokyo Chemical Industry Co., Ltd., anhydrous), 1.0 g of tris(2,4-di-t-butylphenyl)phosphite, and 60 g of purified water were placed in a 200 mL gas absorption bottle, heated to 40 °C in a water bath, and mixed and stirred to obtain a homogeneous solution. Oxygen was blown into the solution at 0.50 MPaG, and a degradation test was conducted at 120 °C for 15 hours. The solution was analyzed by gas chromatography before and after the test, and the amount of degradation product was calculated, which was 1.5 wt%.

[0108] [Example 3] 15 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (Tosoh Corporation), 5 g of N,N,N',N'-tetramethylethylenediamine, 10 g of piperazine (Tokyo Chemical Industry Co., Ltd., anhydrous), 10 g of N-(2-aminoethyl)piperazine, 1.0 g of tris(2,4-di-t-butylphenyl)phosphite, and 60 g of purified water were placed in a 200 mL gas absorption bottle, heated to 40 °C in a water bath, and mixed and stirred to obtain a homogeneous solution. Oxygen was blown into the solution at 0.50 MPaG, and a degradation test was conducted at 120 °C for 15 hours. The solution was analyzed by gas chromatography before and after the test, and the amount of degradation product was calculated, which was 2.3 wt%.

[0109] [Example 4] 15 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (Tosoh), 10 g of piperazine (Tokyo Chemical Industry Co., Ltd., anhydrous), 15 g of N-(2-aminoethyl)piperazine (Tokyo Chemical Industry Co., Ltd.), 1.0 g of 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, and 60 g of purified water were placed in a 200 mL gas absorption bottle, heated to 40 °C in a water bath, and mixed and stirred to obtain a homogeneous solution. Oxygen was blown into the solution at 0.50 MPaG, and a degradation test was conducted at 120 °C for 15 hours. The solution was analyzed by gas chromatography before and after the test, and the amount of degradation product was calculated, which was 2.7 wt%.

[0110] [Example 5] 10 g of 1,4-diazabicyclo[2.2.2]octane (manufactured by Tosoh), 10 g of N,N,N',N'',N''-pentamethyldiethylenetriamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous), 1 g of ascorbic acid, and 60 g of pure water were placed in a 200 mL gas absorption bottle, the temperature was adjusted to 40 °C in a water bath, and the mixture was mixed and stirred to obtain a homogeneous solution. Oxygen was blown into this solution at 0.50 MPaG, and a degradation test was conducted at 120 °C for 15 hours. The solution before and after the test was measured by gas chromatography, and the amount of degradation product was calculated, which was 4.7 wt%.

[0111] [Example 6] 15 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (Tosoh), 10 g of piperazine (Tokyo Chemical Industry Co., Ltd., anhydrous), 15 g of N-(2-aminoethyl)piperazine (Tokyo Chemical Industry Co., Ltd.), 1.0 g of tris(2,4-di-t-butylphenyl)phosphite, and 60 g of purified water were placed in a 200 mL gas absorption bottle, heated to 40 °C in a water bath, and mixed and stirred to obtain a homogeneous solution. A mixture of carbon dioxide gas and nitrogen gas was blown into the carbon dioxide absorption solution at 140 mL / min and 560 mL / min. The carbon dioxide gas was absorbed using a gas flow meter and a carbon dioxide concentration meter. The bottle was then heated to 60 °C, and nitrogen gas was blown in at 200 mL / min. The gas supply was stopped when the ratio of carbon dioxide to total amine compounds in the solution (moles of carbon dioxide divided by moles of total amine compounds) reached 0.51. Using the obtained solution, oxygen was blown in at 0.50 MPaG and a degradation test was carried out at 120°C for 15 hours. The solution was measured by gas chromatography before and after the test, and the amount of degradation products was calculated, which was found to be 1.1 wt%.

[0112] [Example 7] 15 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (Tosoh Corporation), 10 g of homopiperazine (Tokyo Chemical Industry Co., Ltd., anhydrous), 15 g of 1-(aminoethylamino)-2,3-dihydroxypropane (Tokyo Chemical Industry Co., Ltd.), 1.0 g of 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, and 60 g of purified water were placed in a 200 mL gas absorption bottle, heated to 40 °C in a water bath, and mixed and stirred to obtain a homogeneous solution. Oxygen was blown into the solution at 0.50 MPaG, and a degradation test was conducted at 120 °C for 15 hours. The solution was analyzed by gas chromatography before and after the test, and the amount of degradation product was calculated, which was 2.9 wt%.

[0113] [Comparative Example 1] A solution was obtained under the same conditions as in Example 1, except that the antioxidant 2,6-di-t-butyl-4-methylphenol was not added. Oxygen was blown into this solution at 0.50 MPaG, and a degradation test was carried out at 120°C for 15 hours. The solution was measured by gas chromatography before and after the test, and the amount of degradation products was calculated, which was found to be 11.7 wt%.

[0114] Comparative Example 2 A solution was obtained under the same conditions as in Example 4, except that the antioxidant 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate was not added. Oxygen was blown into this solution at 0.50 MPaG, and a degradation test was carried out at 120°C for 15 hours. The solution was measured by gas chromatography before and after the test, and the amount of degradation products was calculated, which was 9.7 wt%.

[0115] Comparative Example 3 20 g of piperazine (Tokyo Chemical Industry Co., Ltd., anhydrous), 20 g of 1-(aminoethylamino)-2,3-dihydroxypropane (Tokyo Chemical Industry Co., Ltd.), 1.0 g of 2,6-di-t-butyl-4-methylphenol, and 60 g of purified water were placed in a 200 mL gas absorption bottle, the temperature was adjusted to 40°C in a water bath, and the mixture was stirred to obtain a homogeneous solution. Oxygen was blown into the solution at 0.50 MPaG, and a degradation test was conducted at 120°C for 15 hours. The solution was analyzed by gas chromatography before and after the test, and the amount of degradation product was calculated, which was 10.7 wt%.

[0116] Comparative Example 4 40 g of N-(2-aminoethyl)piperazine (Tokyo Chemical Industry Co., Ltd.), 1.0 g of tris(2,4-di-t-butylphenyl)phosphite, and 60 g of pure water were placed in a 200 mL gas absorption bottle, the temperature was adjusted to 40°C in a water bath, and the mixture was mixed and stirred to obtain a homogeneous solution. Oxygen was blown into this solution at 0.50 MPaG, and a degradation test was conducted at 120°C for 15 hours. The solution was measured by gas chromatography before and after the test, and the amount of degradation product was calculated, which was found to be 14.1 wt%.

[0117]

Table 2

Claims

1. General formula (1) 【Chemical 1】 [In formula (1), R １ ~R ６ each independently represents a hydrogen atom, or an alkyl group or alkoxyl group having 1 to 4 carbon atoms; a, b, and c each independently represent 0 or 1. A composition for carbon dioxide separation comprising a compound (A) represented by the following formula (I): and an antioxidant (B).

2. The carbon dioxide separation composition according to claim 1, further comprising one or more compounds (C) represented by general formulas (2) to (6). 【Chemistry 2】 [In formula (2), R １ R each independently represents an alkyl group having 1 to 3 carbon atoms. ２ represents an alkylene group having 2 to 6 carbon atoms or an oxybisalkylene group having a total of 2 to 6 carbon atoms. ３ represents an alkyl group having 1 to 3 carbon atoms, a 2-hydroxyethyl group, or a 2-hydroxypropyl group, and n represents 0 or an integer of 1 to 4. 【Chemistry 3】 [In formula (3), R １ each independently represents an alkyl group having 1 to 3 carbon atoms. 【Chemistry 4】 [In formula (4), R １ , and R ２ each independently represents an alkylene group having 2 to 3 carbon atoms. 【Chemistry 5】 [In formula (5), R １ , and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, a 2,3-dihydroxypropyl group, a 2,3-dialkoxypropyl group having a total of 5 to 11 carbon atoms, an aminoalkyl group having 2 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 10 carbon atoms. The alkyl group may be a cycloalkyl group that forms a ring.] 【Chemistry 6】 [In formula (6), R １ represents an alkyl group having 1 to 6 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, a 2,3-dihydroxypropyl group, a 2,3-dialkoxypropyl group having a total of 5 to 11 carbon atoms, an aminoalkyl group having 2 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 10 carbon atoms. ２ , and R ３ each independently represents an alkylene group having 2 to 3 carbon atoms.

3. The carbon dioxide separation composition according to claim 1, wherein the compound represented by formula (1) is 1,4-diazabicyclo[2.2.2]octane-2-methanol or 1,4-diazabicyclo[2.2.2]octane.

4. The compound represented by formula (2) is N,N,N',N'-tetramethylethylenediamine, N,N,N',N'',N''-pentamethyldiethylenetriamine, N,N,N',N'',N''-pentamethyldipropylenetriamine, N,N,N',N'',N''',N'''-hexamethyltriethylenetetramine, N,N,N',N'-tetramethylhexylenediamine, 2-[[2-(dimethylamino)ethyl]methylamino]ethanol, bis(2-dimethylaminoethyl) ether, N-(2-hydroxypropyl)-N,N',N'',N''-tetramethyldiethylenetriamine, N-methyldiethanolamine, N,N-dimethylethanolamine, N-methyldipropanolamine, and N,N-dimethylpropanolamine. The carbon dioxide separation composition according to claim 2, which is at least one selected from the group consisting of:

5. The carbon dioxide separation composition according to claim 2, wherein the compound represented by formula (3) is 1-(2-dimethylaminoethyl)-4-methylpiperazine.

6. The composition for carbon dioxide separation according to claim 2, wherein the compound represented by formula (4) is piperazine or homopiperazine.

7. The carbon dioxide separation composition according to claim 2, wherein the compound represented by formula (5) is N-(2-aminoethyl)-2-aminoethanol, N-methyl-1,3-diaminopropane, N-methylethylenediamine, N-isopropylethylenediamine, monoethanolamine, diethanolamine, 1-(aminoethylamino)-2,3-dihydroxypropane, or ethylenediamine.

8. The carbon dioxide separation composition according to claim 2, wherein the compound represented by formula (6) is 1-(2,3-dihydroxypropyl)-piperazine, N-(2-aminoethyl)piperazine, or N-(2-hydroxyethyl)piperazine.

9. 2. The carbon dioxide separation composition according to claim 1, wherein the antioxidant (B) is at least one selected from the group consisting of phosphorus-based compounds, ascorbic acid, and hindered amine-based compounds.

10. 2. The carbon dioxide separation composition according to claim 1, wherein the antioxidant (B) is contained in an amount of 0.1 to 5.0 parts by weight (wt %) relative to the total weight of the carbon dioxide separation composition.

11. The carbon dioxide separation composition according to claim 1, which contains water, and the concentration of the water is 30 to 75 mass % of the total carbon dioxide separation composition.

12. The ratio of carbon dioxide molecules (CO ) to the total amount of nitrogen atoms (N) in the composition is 100 parts by mass (molar parts). ２ 2. The carbon dioxide separation composition according to claim 1, wherein the carbon dioxide separation composition contains 10 to 150 parts by mass (molar parts).

13. A method for separating carbon dioxide, comprising a step of contacting a gas containing carbon dioxide with a composition containing a compound (A) represented by formula (1) and an antioxidant (B).

Images