Amine composition for carbon dioxide separation

Abstract

To provide an amine-containing carbon dioxide absorbent exhibiting high antifoaming and defoaming effects despite a reduced amount of added antifoaming agents compared to conventionally known materials.SOLUTION: The carbon dioxide separation composition comprises an amine compound (A) represented by the general formula (1) and an antifoaming agent. [In formula (1): R1 to R5 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms; R6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and each a independently represents 0 or 1.]SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In recent years, due to the global warming problem, the separation and recovery of carbon dioxide have attracted attention, and the development of separation and recovery technologies has been actively carried out.

[0003] As a carbon dioxide separation and recovery technology, the chemical absorption method in which carbon dioxide is brought into contact with a basic absorbent for absorption and separation is the most common. In the chemical absorption method, carbon dioxide is absorbed by the absorbent in the absorption tower, and the absorbent is heated in the stripping tower to release carbon dioxide. As the absorbent, an aqueous amine solution is the most common, and various aqueous amine solutions have been studied.

[0004] In the process of the chemical absorption method, the absorption liquid introduced from the upper part of the absorption tower and the carbon dioxide-containing gas introduced from the lower part of the absorption tower come into countercurrent contact in the packing layer. At this time, if the foaming of the absorption liquid is remarkable, the pressure loss in the tower increases, imposing a large load on the equipment. Also, if the foaming property of the absorption liquid is high, flooding occurs in the packing layer in the tower, and the efficiency of countercurrent contact with the gas is significantly reduced. Therefore, the development of an absorbent added with an antifoaming agent to suppress foaming in the tower has been carried out. (For example, Patent Document 1, Patent Document 2) The effects of the antifoaming agent include an antifoaming effect of suppressing the generation of bubbles and a defoaming effect of breaking the generated bubbles. By combining both effects, the foaming property of the absorption liquid is reduced.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] Since an aqueous amine solution has high foaming properties, a carbon dioxide absorbent obtained by adding an antifoaming agent to a conventionally known aqueous amine solution has a problem in that a large amount of antifoaming agent is required to reduce the foaming properties. [Means for Solving the Problems]

[0007] As a result of intensive studies to solve the above problems, the present inventors have completed the present invention as shown below.

[0008] That is, the present invention is a composition for separating carbon dioxide as shown below. [1] A composition for separating carbon dioxide, comprising an amine compound (A) represented by the general formula (1) and an antifoaming agent.

[0009] [Chemical Formula]

[0010] [In the formula (1), R 1 ~R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms. R 6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. a each independently represents 0 or 1. ] [2] The composition for separating carbon dioxide according to [1], wherein the amine compound (A) is 1,4-diazabicyclo[2.2.2]octane-2-methanol. [3] The composition for separating carbon dioxide according to [1], further comprising an amine compound (B) other than the amine compound (A). [4] The composition for separating carbon dioxide according to [3], wherein the amine compound (B) is one or more selected from the group represented by the general formula (2), (3), (4) or (5).

[0011] [Chemical formula]

[0012] [In formula (2), each R 1 independently represents an alkyl group having 1 to 3 carbon atoms. 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. R 3 represents an alkyl group having 1 to 3 carbon atoms, a 2-hydroxyethyl group, or a 2-hydroxypropyl group. n represents 0 or an integer of 1 to 4.]

[0013] [Chemical formula]

[0014] [In formula (3), R 1 , R 2 , and R 3 each independently represents an alkyl group having 1 to 3 carbon atoms.]

[0015] [Chemical formula]

[0016] [In formula (4), R 1 represents hydrogen, 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. R 2 , and R 3 each independently represents an alkylene group having 2 to 3 carbon atoms.]

[0017] [Chemical formula]

[0018] [In formula (5), R 1 , and R 2Each 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 carbon number of 5 to 11, 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 forming a ring. [5] The composition for carbon dioxide separation according to [1] above, wherein the amine compound (B) is one or more selected from the group consisting of piperazine, N-(2-aminoethyl)piperazine, N-methyl-1,3-diaminopropane, N-methyldiethanolamine, N,N,N’,N’’,N’’-pentamethyldiethylenetriamine, 1-(2-dimethylaminoethyl)-4-methylpiperazine, bis(2-dimethylaminoethyl)ether, ethanolamine, and ethylenediamine. [6] The composition for carbon dioxide separation according to [1] above, wherein the antifoaming agent is a silicone-based antifoaming agent. [7] The composition for carbon dioxide separation according to [1] above, wherein the antifoaming agent is a self-emulsifying antifoaming agent. [8] The composition for carbon dioxide separation according to [1] above, wherein the content of the antifoaming agent is 0.0001 to 1% by weight of the entire composition for carbon dioxide separation. [9] The composition for carbon dioxide separation according to [1] above, wherein the composition contains water and the concentration of the water is 1 to 70% by weight of the entire composition for carbon dioxide separation.

[10] A method for separating carbon dioxide, comprising a step of bringing a gas containing carbon dioxide into contact with the composition for carbon dioxide separation according to [1] above to absorb carbon dioxide in the mixed gas into the composition for carbon dioxide separation, and a step of heating and / or depressurizing the composition for carbon dioxide separation that has absorbed the carbon dioxide to dissipate carbon dioxide from the composition for carbon dioxide separation.

Advantages of the Invention

[0019] The composition for carbon dioxide separation of the present invention can stably and efficiently separate and recover carbon dioxide in a gas. Further, the composition for carbon dioxide separation of the present invention has the characteristic that it exhibits a high defoaming effect and foam-breaking effect despite a small amount of defoaming agent added compared to conventionally known materials, and has the effect of reducing the amount of defoaming agent used.

Mode for Carrying Out the Invention

[0020] Hereinafter, the present invention will be described in detail.

[0021] As described above, in the chemical absorption method, if the foaming property of the absorption liquid is high, problems in the process such as an increase in the pressure loss in the tower and flooding in the packing layer occur. Since the carbon dioxide absorption liquid containing amine has a high foaming property, there has been a problem that a large amount of defoaming agent is required to suppress the foaming property of the conventionally known carbon dioxide absorption liquid containing amine.

[0022] The present invention has been made in view of the above problems, and an object thereof is to provide a composition for carbon dioxide separation that exhibits a high defoaming effect and foam-breaking effect with the addition of a small amount of defoaming agent and enables a stable process even on a plant scale.

[0023] First, the composition for carbon dioxide separation of the present invention will be described.

[0024] The composition for carbon dioxide separation of the present invention is characterized by containing an amine compound (A) represented by the general formula (1) and a defoaming agent.

[0025] Further, the composition for carbon dioxide separation of the present invention may further contain an amine compound (B) represented by the general formula (2), (3), (4), or (5).

[0026] In the present invention, the amine compounds represented by the general formulas (1), (2), (3), (4), and (5) all play a role of adsorbing or desorbing carbon dioxide (International Application Publication WO2021 / 153650 A1, JP 2022-101908 A, JP 2022-168949 A).

[0027] In general formula (1), R 1 ~R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms. R 6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. a represents 0 or 1.

[0028] When a = 1, general formula (1) is represented by general formula (1a).

[0029] [Chemical formula]

[0030] [In formula (1a), R 1 ~R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms. R 6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.] When a = 0, general formula (1) is represented by general formula (1b).

[0031] [Chemical formula]

[0032] [In formula (1b), R 1 ~R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms. R 6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.] Regarding the amine compound represented by general formula (1), when a = 0, it is preferable in terms of excellent carbon dioxide emission efficiency. That is, it is preferably an amine compound represented by general formula (1b).

[0033] In general formulas (1), (1a), and (1b), R 1 ~R 6 is not particularly limited as long as it meets the above definitions. For example, each can independently be a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Among these, in terms of excellent carbon dioxide emission efficiency, R 1 ~R 6 are each independently preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably all are hydrogen atoms.

[0034] Specific examples of the amine compound represented by general formula (1) include, for example, the following compounds (Exemplary Compounds 1 to 30), but the present invention is not limited thereto.

[0035]

Chemical formula

[0036] Regarding the amine compound represented by general formula (1), from the viewpoint of easy availability, 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) is preferred. That is, it is preferably an amine compound represented by Exemplary Compound 1 below.

[0037]

Chemical formula

[0038] In general formula (2), R 1 each independently represents an alkyl group having 1 to 3 carbon atoms, 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 3represents an alkyl group having 1 to 3 carbon atoms, 2-hydroxyethyl group, or 2-hydroxypropyl group, and n represents an integer of 0 or 1 to 4.

[0039] In general formula (2), R 1 may conform to the above definition and is not particularly limited. For example, each independently, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group can be mentioned. Among these, in terms of excellent carbon dioxide emission efficiency, R 1 is preferably a methyl group.

[0040] In general formula (2), R 2 may conform to the above definition and is not particularly limited. For example, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, or an ethyleneoxyethylene group can be mentioned. Among these, in terms of easy industrial production, the said R 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.

[0041] In general formula (2), R 3 may conform to the above definition and is not particularly limited. For example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a 2-hydroxyethyl group, or a 2-hydroxypropyl group can be mentioned. Among these, in terms of excellent carbon dioxide emission efficiency, the said R 3 is preferably a methyl group, a 2-hydroxyethyl group, or a 2-hydroxypropyl group.

[0042] In general formula (2), in terms of easy industrial production, n is preferably 1, 2, or 3, and more preferably 1 or 2.

[0043] Specific examples of the amine compound represented by the general formula (2) include, for example, 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.

[0044] In the general formula (3), R 1 each independently represents an alkyl group having 1 to 3 carbon atoms.

[0045] In the general formula (3), R 1 only needs to conform to the above definition and is not particularly limited. For example, each independently, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group can be mentioned. Among these, in terms of excellent carbon dioxide emission efficiency, it is preferable that all of R 1 are methyl groups.

[0046] Specific examples of the amine compound represented by the general formula (3) include, for example, 1-(2-dimethylaminoethyl)-4-methylpiperazine.

[0047] In the general formula (4), R 1 represents hydrogen, 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. R 2 , and R 3 each independently represents an alkylene group having 2 to 3 carbon atoms.

[0048] R in the general formula (4)1 In terms of excellent carbon dioxide adsorption and desorption efficiency, each is independently preferably 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.

[0049] R in the general formula (4) 2 and R 3 Regarding the alkylene group having 2 to 3 carbon atoms in, although not particularly limited, for example, an ethylene group or a propylene group can be mentioned.

[0050] R in the general formula (4) of the present invention 2 and R 3 In terms of excellent carbon dioxide dissipation efficiency, each is independently preferably a 1,2-ethylene group, a 1,2-propylene group, or a 1,3-propylene group, 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.

[0051] Specific examples of the amine compound represented by the general formula (4) include, for example, piperazine, homopiperazine, N-methylpiperazine, N-ethylpiperazine, N-(2-hydroxyethyl)piperazine, N-(2-hydroxypropyl)piperazine, N-(2-aminoethyl)piperazine, N-(3-aminopropyl)piperazine, or N-(2,3-dihydroxypropyl)piperazine, etc.

[0052] In the general formula (5), R 1 and R 2 each independently represent 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 carbon number of 5 to 11, an aminoalkyl group having 2 to 6 carbon atoms, or a hydroxyalkyl group having 2 to 10 carbon atoms. However, the alkyl group may be a cycloalkyl group forming a ring.

[0053] In general formula (5), R 1 and R 2 For the alkyl group having 1 to 6 carbon atoms, although not particularly limited, 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, or a cyclohexyl group.

[0054] In general formula (5), R 1 and R 2 For the 2,3-dialkoxypropyl group having a total carbon number of 5 to 11, although not particularly limited, 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), or a 2,3-dibutoxypropyl group (total carbon number 11).

[0055] For the aminoalkyl group having 2 to 6 carbon atoms, although not particularly limited, examples thereof include a 2-aminoethyl group, a 3-aminopropyl group, or a 4-aminobutyl group.

[0056] In general formula (5), R 1 and R 2 For the hydroxyalkyl group having 2 to 10 carbon atoms, although not particularly limited, 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, or a 2-hydroxycyclodecyl group.

[0057] R 1 , and R 2Regarding [the relevant substance], in terms of excellent carbon dioxide adsorption and desorption efficiency, each is preferably independently 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.

[0058] Specific examples of the amine compound represented by the general formula (5) include, for example, 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, N,N-dimethyl-1,3-diaminopropane, 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-aminobutanol, 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, or N-(4-aminocyclohexyl)-3-aminopropanol, etc. can be mentioned.,

[0059] Regarding the amine compound (B) represented by the general formula (2), (3), (4) or (5), in terms of excellent carbon dioxide absorption and desorption performance, it is preferably at least one amine compound selected from the group consisting of piperazine, N-(2-aminoethyl)piperazine, N-methyl-1,3-diaminopropane, N-methyldiethanolamine, N,N,N’,N’’,N’’-pentamethyldiethylenetriamine, 1-(2-dimethylaminoethyl)-4-methylpiperazine, bis(2-dimethylaminoethyl)ether, monoethanolamine, and ethylenediamine, and more preferably at least one amine compound selected from the group consisting of piperazine, N-(2-aminoethyl)piperazine, N-methyl-1,3-diaminopropane, N-methyldiethanolamine, N,N,N’,N’’,N’’-pentamethyldiethylenetriamine, 1-(2-dimethylaminoethyl)-4-methylpiperazine.

[0060] The composition for carbon dioxide separation of the present invention is characterized by containing an amine compound (A) and an antifoaming agent.

[0061] The content of the amine compound (A) in the composition for carbon dioxide separation of the present invention is not particularly limited, but it is preferably 5 to 60% by mass, and more preferably 10 to 40% by mass, with the total composition for carbon dioxide separation being 100% by mass.

[0062] Incidentally, the composition for carbon dioxide separation of the present invention may contain an amine compound other than the amine compound (A), for example, an amine compound (B). When the composition for carbon dioxide separation of the present invention contains the amine compound (B), the content of the amine compound (B) is not particularly limited, but it is preferably 2 to 40% by mass, more preferably 5 to 35% by mass, and even more preferably 10 to 30% by mass, with the total composition for carbon dioxide separation being 100% by mass.

[0063] Regarding the antifoaming agent used in the present invention, commercially available products can be used, or those synthesized by generally known methods can also be used. The antifoaming agent is not particularly limited, but silicone-based antifoaming agents are preferred in terms of higher defoaming effect and foam-breaking effect.

[0064] The antifoaming agent used in the present invention is not particularly limited, and examples include oil type, oil compound type, solution type, solid type, self-emulsifying type, emulsion type, etc. Among them, the self-emulsifying type is preferred in terms of higher defoaming effect and foam-breaking effect.

[0065] The content of the antifoaming agent in the composition for carbon dioxide separation of the present invention is not particularly limited, but it is preferably 0.0001 to 1% by mass, more preferably 0.001 to 0.1% by mass, based on 100% by mass of the entire composition for carbon dioxide separation.

[0066] In addition, the composition for carbon dioxide separation of the present invention may further contain water. Regarding the content of the water, it is preferably in the range of 30 to 75% by mass, more preferably in the range of 35 to 70% by mass, and even more preferably in the range of 40 to 65% by mass, based on 100% by mass of the entire composition for carbon dioxide separation in the state containing water.

[0067] The composition for carbon dioxide separation of the present invention may further contain a solvent other than water. The solvent is not particularly limited, and examples include methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, glycerin, ethylene glycol monomethyl ether, etc.

[0068] Regarding the content of the solvent other than water in the composition for carbon dioxide separation, it is preferably in the range of 1 to 30% by mass, more preferably in the range of 2 to 25% by mass, and even more preferably in the range of 5 to 20% by mass, based on 100% by mass of the entire composition for carbon dioxide separation in the state containing the solvent.

[0069] Regarding the content of the total amine compounds (total amount of amine compound (A) and amine compound (B)) in the composition for carbon dioxide separation of the present invention, from the viewpoint of increasing the amount of carbon dioxide emission per unit mass, with the total amount of the composition for carbon dioxide separation being 100% by mass, it is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 25 to 50% by mass.

Example

[0070] The present invention will be described below using examples, but the present invention should not be construed as being limited thereto. · Foaming property test 150 mL of each composition for carbon dioxide separation was filled into a glass tube with an inner diameter of 50 mm, and the foaming property was evaluated by blowing nitrogen gas. The blowing was performed through a blowing tube equipped with a glass filter at the tip of a glass tube with an inner diameter of 4 mm. The nitrogen gas was blown at a flow rate of 60 NL / h, and the height of the foam was measured when the height of the foam no longer changed after 30 seconds. Then, the blowing was stopped, and the time until the foam disappeared was measured. The evaluation was performed according to the following criteria. <Defoaming effect> The height of the foam at the time when 5 minutes have elapsed since the start of blowing, compared with each composition for carbon dioxide separation without addition of defoaming agent. A: Decrease by 30% or more B: Decrease by 10% or more C: Decrease by less than 10% <Foam-breaking effect> The time until the foam disappears after stopping the blowing, compared with each composition for carbon dioxide separation without addition of defoaming agent. A: Decrease by 50% or more B: Decrease by 25% or more C: Decrease by less than 25% [Example 1] 80 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. Using the obtained solution, the above-mentioned foaming property test was conducted, and the results are shown in Table 1. [Example 2] 80 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. Using the obtained solution, the results of the above-mentioned foaming property test were shown in Table 1. [Example 3] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. Using the obtained solution, the results of the above-mentioned foaming property test were shown in Table 1. [Example 4] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. Using the obtained solution, the results of the above-mentioned foaming property test were shown in Table 1. [Example 5] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 1. [Example 6] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 1. [Example 7] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 1. [Example 8] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 1. [Example 9] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 60 g, N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (manufactured by Tosoh Corporation) 20 g, and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 10] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 60 g, N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (manufactured by Tosoh Corporation) 20 g, and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 11] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 40 g, N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (manufactured by Tosoh Corporation) 40 g, and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 12] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (manufactured by Tosoh Corporation), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 13] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of 1-(2-dimethylaminoethyl)-4-methylpiperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 14] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of 1-(2-dimethylaminoethyl)-4-methylpiperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 15] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of 1-(2-dimethylaminoethyl)-4-methylpiperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 16] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of 1-(2-dimethylaminoethyl)-4-methylpiperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 2. [Example 17] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 18] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain 200 g of a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 19] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 20] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 21] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 22] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 23] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 24] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 3. [Example 25] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of bis(2-dimethylaminoethyl) ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 26] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of bis(2-dimethylaminoethyl) ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 27] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of bis(2-dimethylaminoethyl)ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 28] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of bis(2-dimethylaminoethyl)ether (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 29] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 30] 60 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 31] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 32] 40 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 40 g of ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 4. [Example 33] 50 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous), 10 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 5. [Example 34] 50 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous), 10 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 5. [Example 35] 30 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product), 30 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 5. [Example 36] 30 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product), 30 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 5. [Example 37] 10 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product), 50 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 5. [Example 38] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 10 g, piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 20 g, N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.) 50 g, and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 5. [Example 39] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 50 g, piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 20 g, N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 10 g, and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 6. [Example 40] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 50 g, piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 20 g, N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 10 g, and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 6. [Example 41] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 30 g, piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 20 g, N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 30 g, and pure water 120 g were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 6. [Example 42] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 30 g, piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 20 g, N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 30 g, and pure water 120 g were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 6. [Example 43] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 10 g, piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 20 g, N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 50 g, and pure water 120 g were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25 °C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 6. [Example 44] 1,4-Diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation) 10 g, piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 20 g, N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 50 g, and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 6. [Comparative Example 1] Piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 30 g and pure water 170 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 2] Piperazine (manufactured by Tokyo Chemical Industry Co., Ltd., anhydrous product) 30 g and pure water 170 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 3] N-(2-Aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.) 80 g and pure water 120 g were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based defoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 4] 80 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 5] 80 g of N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (manufactured by Tosoh Corporation) and 120 g of pure water were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 6] 80 g of N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (manufactured by Tosoh Corporation) and 120 g of pure water were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 7] 80 g of 1-(2-dimethylaminoethyl)-4-methylpiperazine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a homogeneous solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 8] 80 g of 1-(2-dimethylaminoethyl)-4-methylpiperazine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 7. [Comparative Example 9] 80 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 10] 80 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 11] 80 g of N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 12] 80 g of N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 13] 80 g of bis(2-dimethylaminoethyl) ether (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 14] 80 g of bis(2-dimethylaminoethyl) ether (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 15] 80 g of ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 16] 80 g of ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 17] 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., anhydrous), 60 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 18] 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., anhydrous), 60 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Comparative Example 19] 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., anhydrous), 60 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 1.6 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8. [Example 20] 20 g of piperazine (manufactured by Tokyo Chemical Industry Co., anhydrous), 60 g of N-methyldiethanolamine (manufactured by Tokyo Chemical Industry Co.), and 120 g of pure water were mixed and stirred to obtain 200 g of a uniform solution. 160 g of this solution and 16.0 mg of a self-emulsifying silicone-based antifoaming agent (KS-506: manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a glass bottle and mixed and stirred at room temperature of 25°C for 2 hours to obtain a solution. The results of the above foaming test using the obtained solution are shown in Table 8.

[0071] [Table 1]

[0072]

Table 2

[0073]

Table 3

[0074]

Table 4

[0075]

Table 5

[0076]

Table 6

[0077]

Table 7

[0078]

Table 8

[0079]

Table 9

[0080] As is clear from the comparison between Examples 1 to 44 and Comparative Examples 1 to 16, the composition for carbon dioxide separation of the present invention contains the amine compound (A), and thus has the characteristics that, although the addition amount of the antifoaming agent is less than that of the conventionally known composition for carbon dioxide separation, it exhibits a high defoaming effect and foam-breaking effect, and has the effect of reducing the usage amount of the antifoaming agent.

Claims

1. A composition for carbon dioxide separation, comprising an amine compound (A) represented by the general formula (1) and an antifoaming agent. 【Chemical Formula 1】 [In formula (1), R １ to R ５ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms. R ６ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. a each independently represents 0 or 1.]

2. The composition for carbon dioxide separation according to Claim 1, wherein the amine compound (A) is 1,4-diazabicyclo[2.2.2]octane-2-methanol.

3. The composition for carbon dioxide separation according to Claim 1, further comprising an amine compound (B) other than the amine compound (A).

4. The composition for carbon dioxide separation according to Claim 3, wherein the amine compound (B) is one or more selected from the group represented by the general formulas (2), (3), (4) or (5). 【Chemical Formula 2】 [In formula (2), R １ each independently represents an alkyl group having 1 to 3 carbon atoms. 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. R ３ represents an alkyl group having 1 to 3 carbon atoms, a 2-hydroxyethyl group, or a 2-hydroxypropyl group. n represents an integer of 0 or 1 to 4. ] 【Chemical Formula 3】 [In formula (3), R １ , R ２ , R ３ each independently represents an alkyl group having 1 to 3 carbon atoms.] 【Chemical Formula 4】 [In formula (4), R １ represents hydrogen, 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. R ２ , and R ３ each independently represent an alkylene group having 2 to 3 carbon atoms.] [Chemical Formula 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 forming a ring.]

5. The composition for carbon dioxide separation according to Claim 1, wherein the amine compound (B) is one or more selected from the group consisting of piperazine, N-(2-aminoethyl)piperazine, N-methyl-1,3-diaminopropane, N-methyldiethanolamine, N,N,N',N'',N''-pentamethyldiethylenetriamine, 1-(2-dimethylaminoethyl)-4-methylpiperazine, bis(2-dimethylaminoethyl)ether, ethanolamine and ethylenediamine.

6. The composition for carbon dioxide separation according to Claim 1, wherein the antifoaming agent is a silicone-based antifoaming agent.

7. The composition for carbon dioxide separation according to Claim 1, wherein the antifoaming agent is a self-emulsifying antifoaming agent.

8. The composition for carbon dioxide separation according to Claim 1, wherein the content of the antifoaming agent is 0.0001 to 1% by weight of the entire composition for carbon dioxide separation.

9. The composition for carbon dioxide separation according to Claim 1, wherein the composition contains water and the concentration of the water is 1 to 70% by weight of the entire composition for carbon dioxide separation.

10. A method for separating carbon dioxide, comprising: contacting a gas containing carbon dioxide with the composition for carbon dioxide separation according to Claim 1 to absorb carbon dioxide in the mixed gas into the composition for carbon dioxide separation; and heating and / or reducing the pressure of the composition for carbon dioxide separation that has absorbed the carbon dioxide to release carbon dioxide from the composition for carbon dioxide separation.

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