KR20220035292A - Mixed absorbent for capturing carbon dioxide - Google Patents

Abstract

The present invention relates to an absorbent for capturing carbon dioxide, which selectively absorbs carbon dioxide, and more specifically, to a mixed absorbent for capturing carbon dioxide, which is produced by mixing three or more other compounds and has excellent carbon dioxide absorption rates, absorption amounts, desorption speeds and desorption rates even under conditions of low concentration of carbon dioxide and high concentration of oxygen, as well as excellent durability of the absorbent.

Description

Mixed absorbent for carbon dioxide capture {MIXED ABSORBENT FOR CAPTURING CARBON DIOXIDE}

The present invention relates to an absorbent for trapping carbon dioxide that selectively absorbs carbon dioxide, and more particularly, to a mixed absorbent for trapping carbon dioxide in which three or more different compounds are mixed to improve absorption of carbon dioxide, etc.

Various methods such as absorption method, adsorption method, membrane separation method, and deep cooling method have been suggested as carbon dioxide capture and storage technology. This is easy. A process using monoethanolamine (hereinafter referred to as MEA) manufactured by ABB lummus Crest to capture CO ₂ by an absorption method is the United States Trona (Trona, CA, USA) and Sheddy Point (Shady Point, Oklahoma, USA).

However, while the absorption process using MEA as an absorbent has a fast reaction rate, a large amount of energy is consumed for carbon dioxide separation, a large amount of absorbent is used, and there is a problem of corrosion of equipment by the absorbent. development is urgently needed.

As another example of the absorption method, a method of separating and recovering acid gases such as CO ₂ , H ₂ S, and COS in the mixed gas discharged from steel mills and thermal power plants by using a chemical reaction with an aqueous alkanolamine solution has also been studied a lot. has been applied in the field. The alkanolamines that have been widely used in the past include primary series monoethanolamine (MEA), secondary series diethanolamine (DEA), tertiary series triethanolamine (TEA), N- Methyl diethanolamine (N-methyl diethanolamine, MDEA), triisopropanolamine (triisopropanolamine, TIPA), and the like.

However, the above monoethanolamine (MEA) and diethanolamine (DEA) have been widely used because of the advantage of having a high reaction rate. It is known that it is difficult to use as an absorbent. In addition, while N-methyldiethanolamine (MDEA) has low corrosiveness and heat of regeneration, it has a disadvantage in that its absorption rate is slow. Recently, research on hindered amines such as aminomethylpropanol (2-amino-2-methyl-1-propanol, AMP) as a new alkanolamine-based absorbent is being actively conducted. The characteristics of these hindered amines are their absorption capacity. And while it has the advantage that the selectivity of the acid gas is very high and the energy required for regeneration is small, there is a problem that the absorption rate is relatively slow.

Korean Patent No. 10-1746561

An object of the present invention in consideration of the above points is to provide a mixed absorbent for capturing carbon dioxide with improved efficiency and durability in separating and recovering carbon dioxide in a mixed gas. In particular, it has a relatively fast absorption rate and high regeneration rate applicable to flue gas compositions such as LNG combined cycle power plants, which have a relatively low carbon dioxide concentration compared to coal-fired power plants, and provides an absorbent that can be used for relatively many unreacted flue gases. want to Another object of the present invention is to provide a mixed absorbent for capturing carbon dioxide that is effectively used in flue gas composition such as LNG combined cycle power plants, which have a relatively high oxygen concentration compared to coal-fired power plants due to improved oxidative degradation.

The mixed absorbent for capturing carbon dioxide of the present invention for achieving the above object includes a compound represented by the following Chemical Formula 1 and the following Chemical Formula 2, and includes any one or more compounds from among the compounds represented by the following Chemical Formula 3 and the following Chemical Formula 4 can do.

In Formula 1, a is a hydrocarbon group having 0 to 1 carbon atoms, b and c are a hydrocarbon group having 0 to 3 carbon atoms, and R ₁ and R ₂ are -(CH ₂ ) _f -H, -(CH ₂ ) _m -NH ₂ , -CH-(CH ₃ ) ₂ and -C-(CH ₃ ) ₃ , wherein f and m are integers from 0 to 5.

The compound of Formula 1 is, for example, diethylenetriamine, 1,3-diamino-2-propanol (1,3-diamino-2-propanol), 1,5-diamino-3-pentane Ol (1,5-diamino-2-pentanol), butylenediamine (butylenediamine), pentamethylenediamine (pentamethylenediamine), hexamethylenediamine (hexamethylenediamine), bis (3-aminopropyl) amine (bis (3-aminopropyl) amine ), tetraethylenepentamine, N-isopropylethylenediamine, N-isopropyl-1,3-propanediamine and 1,8-dia It is any one selected from mino-para-mentane (1,8-diamino-p-menthane), and among them, tetraethylenepentamine may be most preferably used.

In Formula 2, R ₃ is -(CH ₂ NHCH ₂ ) _g -, where g is an integer of 1 to 2.

The compound of Formula 2 is, for example, 1,4,7-triazacyclononane (1,4,7-triazacyclononane) and 1,4,7,10-tetraazacyclododicane (1,4,7,10) -tetraazacyclododecane), preferably 1,4,7,10-tetraazacyclododecane (1,4,7,10-tetraazacyclododecane) may be used.

In Formula 3, d is a hydrocarbon group having 1 to 4 carbon atoms, and R ₄ is -(CH ₂ ) _h -CH ₃ , -CH-(CH ₃ ) ₂ and -C-(CH ₃ ) ₃ Any one selected from , where h is an integer from 0 to 3.

The compound of Formula 3 is, for example, 2- (methylamino) ethanol (2- (methylamino) ethanol), 2- (ethylamino) ethanol (2- (ethylamino) ethanol), 2- (propylamino) ethanol ( 2-(propylamino)ethanol), 2-(isopropylamino)ethanol (2-(isopropylamino)ethanol), 2-(butylamino)ethanol (2-(butylamino)ethanol), 2-(tert-butylamino)ethanol (2-(tert-butylamino)ethanol), 3-(methylamino)propanol (3-(methylamino)propanol), 3-(ethylamino)propanol (3-(ethylamino)propanol), 3-(propylamino)propanol (3- (propylamino) propanol), 3- (isopropylamino) propanol (3- (isopropylamino) propanol), 3- (butylamino) propanol (3- (butylamino) propanol), 3- (tert-butylamino) Propanol (3-(tert-butylamino)propanol), 4-(methylamino)butanol (4-(methylamino)butanol), 4-(ethylamino)butanol (4-(ethylamino)butanol), 4-(propylamino) Butanol (4-(propylamino)butanol), 4-(isopropylamino)butanol (4-(isopropylamino)butanol), 4-(butylamino)butanol (4-(butylamino)butanol), 4-(tert-butylamino) )Butanol (4-(tert-butylamino)butanol), 5-(methylamino)pentanol (5-(methylamino)pentanol), 5-(ethylamino)pentanol (5-(ethylamino)pentanol), 5-( Propylamino)pentanol (5-(propylamino)pentanol), 5-(isopropylamino)pentanol (5-(isopropylamino)pentanol), 5-(butylamino)pentanol (5-(butylamino)pentanol) and 5 -(tert-butylamino)pentanol (5-(tert-butylamino)pentanol) It may be any one selected from among. Among them, 2-(isopropylamino)ethanol (2-(isopropylamino)ethanol) may be preferably used.

In Formula 4, e is a hydrocarbon group having 0 to 3 carbon atoms, R ₅ is -(CH ₂ ) _i -H, or -CH-(CH ₃ ) ₂ , R ₆ is -H or CH ₃ , and R ₇ , R ₈ is -(CH ₂ ) _j -H, where i is an integer from 0 to 6, and j is an integer from 0 to 3.

The compound of Formula 4 is an alkanol amine-based absorbent, for example, 2-amino-2-methyl-1-propanol (2-amino-2-methyl-1-propanol), 2-amino-2-methyl-1 -Butanol (2-amino-2-methyl-1-butanol), 2-amino-2-methyl-1-pentanol (2-amino-2-methyl-1-pentanol), 3-amino-3-methyl- 1-butanol (3-amino-3-methyl-1-butanol), 4-amino-4-methyl-1-pentanol (4-amino-4-methyl-1-pentanol), N-methyl-2-amino -1-propanol (N-methyl-2-amino-1-propanol), N-ethyl-2-amino-1-propanol (N-ethyl-2-amino-1-propanol), N-isopropyl-2- Amino-1-propanol (N-isopropyl-2-amino-1-propanol), N-methyl-2-amino-1-butanol (N-methyl-2-amino-1-butanol), N-methyl-2- Amino-1-pentanol (N-methyl-2-amino-1-pentanol), N-isopropyl-2-amino-1-pentanol (N-isopropyl-2-amino-1-pentanol), 2-amino -1-propanol (2-amino-1-propanol), 2-amino-1-butanol (2-amino-1-butanol), 2-amino-3-methylbutanol (2-amino-3-methylbutanol), 2 -Amino-1-pentanol (2-amino-1-pentanol), 2-amino-1-hexanol (2-amino-1-hexanol), 3-amino-1-butanol (3-amino-1-butanol) ), 4-amino-1-pentanol (4-amino-1-pentanol), 5-amino-1-hexanol (5-amino-1-hexanol), 3-amino-1-pentanol (3-amino -1-pentanol), 3-amino-1-hexanol (3-amino-1-hexanol), 1-amino-2-propanol (1-amino-2-propanol), 1-amino-2-butanol (1 -amino-2-butanol), 1-amino-2-pentanol (1-amino-2-pentanol) and It may be any one selected from 1-amino-3-methyl-2-butanol (1-amino-3-methyl-2-butanol).

The mixed absorbent for capturing carbon dioxide of the present invention is based on 100 wt% of the total absorbent for capturing carbon dioxide, wherein the compound of Formula 1 is 5 to 15 wt%, the compound of Formula 2 is 5 to 15 wt%, and the formula 3 and at least one compound of Formula 4 may be included in an amount of 10 to 30% by weight, and the remaining amount of water.

Here, the component of the compound included in the mixed absorbent for capturing carbon dioxide may be included in an amount of 20 to 60% by weight based on 100% by weight of the total mixed absorbent for capturing carbon dioxide, preferably based on 100% by weight of the mixed absorbent for capturing carbon dioxide through the body , 50% by weight of the component of the compound and 50% by weight of water with the remaining balance.

If the content range of the compound in the mixed absorbent for carbon dioxide capture is out of the range suggested, the absorption rate, absorption amount, stripping rate and stripping rate of the carbon dioxide in the mixed absorbent for carbon dioxide capture are reduced, and also the durability of the absorbent is reduced. Therefore, it is preferable to satisfy the content range presented above.

The mixed absorbent for capturing carbon dioxide of the present invention may further include a thiadiazole-based degradation inhibitor, wherein the thiadiazole-based degradation inhibitor is preferably dimercaptothiadiazole.

The thiadiazole-based degradation inhibitor may be included in an amount of 0 or more and 1% by weight or less based on 100% by weight of the total carbon dioxide-collecting mixed absorbent. If the content of the degradation inhibitor is added in excess of 1% by weight, problems such as absorption of carbon dioxide and deterioration of the regeneration performance of the absorbent occur.

The mixed absorbent for capturing carbon dioxide of the present invention absorbs carbon dioxide in a temperature range of 0 to less than 70 °C, and is stripped in a range of 70 °C to 150 °C.

The mixed absorbent for capturing carbon dioxide of the present invention has a carbon dioxide absorption and stripping pressure of 1 bar to 2 bar.

The mixed absorbent for capturing carbon dioxide according to the present invention is applied to the separation process of wet carbon dioxide through carbon dioxide absorption and stripping tests and oxidative degradation tests. It can be seen that not only the removal rate but also the durability of the absorbent is excellent.

Therefore, the mixed absorbent for carbon dioxide capture of the present invention is compared to commercial or existing absorbents under low-concentration carbon dioxide flue gas conditions such as LNG combined cycle power plant flue gas, in addition to coal-fired power plant flue gas, considering the absorption rate, absorption amount, stripping rate, and stripping amount, the CAPEX and It is possible to efficiently capture carbon dioxide to reduce OPEX.

In addition, the mixed absorbent for capturing carbon dioxide of the present invention improves durability even under high-concentration oxygen flue gas conditions such as LNG combined cycle power plant flue gas in addition to coal-fired power plant flue gas, and at the same time reduces the loss of absorbent due to entrainment, enabling economical operation.

1 is a schematic diagram briefly showing a carbon dioxide absorption and stripping test apparatus.
2 is a schematic diagram schematically showing a reactor of an oxidative degradation test apparatus.

Hereinafter, the mixed absorbent for capturing carbon dioxide of the present invention will be described in more detail through Examples and Comparative Examples.

As used herein, terms such as “consisting of,” “comprising,” or “added” should not be construed as necessarily including all of the various components described in the specification, some of which may not be included. It should also be construed as being able to further include additional components.

In this specification, for convenience of explanation, the term 'absorbent' is used interchangeably with 'carbon dioxide absorbent' or 'absorbent for carbon dioxide capture'. In addition, the 'absorbent' of Examples 1 to 3, which will be described below, is also called a 'mixed absorbent for capturing carbon dioxide'.

A mixed absorbent for capturing carbon dioxide in an aqueous solution having the composition shown in Table 1 was prepared. Here, purified water was used as a solvent.

The following Examples 1 to 3 are mixed absorbents for capturing carbon dioxide in which three or more different compounds are mixed, and the mixed compound composition is 50% by weight based on 100% by weight of the total mixed absorbent for capturing carbon dioxide, and the rest are purified It was prepared at a compositional content of 50% by weight of water.

The following Comparative Examples 1 to 7 are single-component carbon dioxide-collecting absorbents for comparison with the carbon dioxide-collecting mixed absorbents of Examples 1 to 3, or a mixture of two different compounds for carbon dioxide capture As an absorbent, the compound composition was 30 wt% based on 100 wt% of the total absorbent for capturing carbon dioxide, and the remainder was prepared with a composition content of 70 wt% of purified water.

division absorbent density
(wt%) molarity
(M) Comparative Example 1 MEA 30 4.92 Comparative Example 2 MEA+DMTD 30:0.5 4.92 Comparative Example 3 TEPA 30 1.59 Comparative Example 4 IPAE+IPDEA 21:9 2.58 Comparative Example 5 AMP 30 3.37 Comparative Example 6 Pz 30 3.48 Comparative Example 7 TACD 30 1.74 Example 1 TEPA+IPAE+IPDEA+TACD 10:21:9:10 3.52 Example 2 TEPA+AMP+TACD 10:30:10 3.98 Example 3 TEPA+IPAE+IPDEA+AMP+TACD 10:14:6:10:10 3.66

In Table 1, MEA is monoethanolamine, DMTD is dimercaptothiadiazole as a thiadiazole-based degradation inhibitor, and TEPA is tetraethylenepentamine, which corresponds to the compound of Formula 1, IPAE is 2-(isopropylamino)ethanol (2-(isopropylamino)ethanol), which corresponds to the compound of Formula 3, and IPDEA is 2-(isopropyl)diethanolamine (2-(isopropyl)diethanolamine or N-isopropyl- 2,2′-iminodiethanol), AMP is aminomethylpropanol (2-amino-2-methyl-1-propanol), which corresponds to the compound of Formula 4, Pz is piperazine, and TACD is 1,4 ,7,10-tetraazacyclododecane (1,4,7,10-tetraazacyclododecane) corresponds to the compound of Formula 2.

As shown in Table 1 above, carbon dioxide absorption and stripping tests were performed to confirm the carbon dioxide absorption and stripping efficiency of the mixed absorbent for carbon dioxide capture of Examples and the absorbent for carbon dioxide capture of Comparative Examples, and at this time, carbon dioxide absorption as shown in FIG. and stripping test equipment.

In the carbon dioxide absorption and removal test, 50 g of the mixed absorbent for capturing carbon dioxide prepared in Examples 1 to 3 and Comparative Examples 1, 3, 4, 5, 6, and 7, respectively, was used. filled. A gas having a composition of 4% carbon dioxide and 96% nitrogen was injected and dispersed at a rate of 1.5 liters/min at atmospheric pressure through a tube with a porous diffuser into the reaction vessel. Thereafter, the concentration of carbon dioxide in the outlet gas was continuously measured using a carbon dioxide concentration meter of a non-dispersive infrared analysis method to measure the absorption rate and amount of carbon dioxide absorbed. At a certain point in time when the absorbent was saturated with carbon dioxide, the temperature of the reaction vessel was raised to 70° C. in about 90 minutes, and the stripping rate and amount of carbon dioxide stripped from the absorbent were measured for 30 minutes, and the results are shown in Table 2 below. shown in

division Absorption rate (min ^-1 ) Stripping speed (min ^-1 ) Absorption capacity (90 minutes) Removed amount (30 minutes) removal rate g/kg M/M g/kg M/M g/kg M/M g/kg M/M % Comparative Example 1 2.7 0.012 1.2 0.0055 118 0.55 13 0.06 11 Comparative Example 3 3.5 0.050 1.0 0.014 183 2.6 28 0.40 15 Comparative Example 4 2.2 0.019 2.0 0.018 73 0.64 42 0.37 58 Comparative Example 5 2.4 0.016 1.3 0.0088 114 0.77 36 0.24 32 Comparative Example 6 3.0 0.020 0.5 0.0033 136 0.89 18 0.12 13 Comparative Example 7 3.2 0.042 1.6 0.021 172 2.2 50 0.65 29 Example 1 5.4 0.035 2.6 0.017 232 1.5 82 0.53 35 Example 2 6.0 0.034 2.2 0.013 260 1.5 83 0.47 32 Example 3 5.8 0.036 2.6 0.016 245 1.5 84 0.52 34

As shown in Table 2, the carbon dioxide trapping absorbents according to Examples 1 to 3 were superior to the carbon dioxide trapping absorbents of Comparative Examples in terms of carbon dioxide absorption rate, stripping rate, absorption capacity, stripping amount, and stripping rate. .

In addition, in order to determine the degree of oxidative degradation of the absorbents for capturing carbon dioxide of the Examples and Comparative Examples prepared as shown in Table 1, an oxidative degradation test was performed using the oxidative degradation test apparatus shown in FIG. 2 .

Specifically, in the oxidative degradation test, 0.7 liters of the absorbent for capturing carbon dioxide prepared in Examples 1 to 3 and Comparative Examples 1 to 7, respectively, was filled in a 1 liter glass reaction vessel contained in a water bath set at 60°C. A gas having a composition of 98% oxygen (O ₂ ) and 2% carbon dioxide (CO ₂ ) is injected and dispersed at a rate of 100 mL/min through a humidifier at atmospheric pressure through a tube with a porous diffuser into the reaction vessel. made it Thereafter, 1 mL of the absorbent was collected at intervals of 50 to 100 hours for 1,200 hours and analyzed using gas chromatography. The analysis results obtained at this time are shown in Table 3 below.

division Oxidative Degradation
(wt%/hour) Boiling Point (℃) Comparative Example 1 3.8 170 Comparative Example 2 0.34 170 Comparative Example 3 2.9 340 Comparative Example 4 2.7 172 Comparative Example 5 1.5 165 Comparative Example 6 2.2 146 Comparative Example 7 1.8 284 Example 1 2.4 - Example 2 2.2 - Example 3 1.9 -

The degree of oxidative degradation is a value indicating the amount of the absorbent deteriorated per hour, and the smaller the value, the better the durability. Referring to [Table 2], as in Comparative Example 1 and Comparative Examples 3 to 7, the degree of oxidative degradation for each single component of the carbon dioxide trapping agent is Comparative Example 1 (MEA) > Comparative Example 3 (TEPA) » Comparative Example 6 ( Pz) ≒ Comparative Example 4 (IPAE+IPDEA) ≒ Comparative Example 7 (TACD) ≒ Comparative Example 5 (AMP). That is, Comparative Example 3 (TEPA), which has significantly higher carbon dioxide absorption rate and absorption amount, is also superior to Comparative Example 1 (MEA) in terms of oxidative degradation, and Comparative Example 4 (IPAE+IPDEA), Comparative Example 5 (AMP), Comparative Examples 6 (Pz) and Comparative Example 7 (TACD) are also significantly superior to Comparative Example 1 (MEA).

As shown in Table 3, Examples 1 to 3 are composed of a mixture of compounds having a low degree of oxidative degradation, and it can be seen that the degree of oxidative degradation is improved by 36% or more than that of monoethanolamine (MEA) of Comparative Example 1 as a conventional absorbent. can

As in Comparative Example 2 of Table 3, when dimercaptothiadiazole (DMTD), a thiadiazole-based degradation inhibitor, is mixed with the absorbent for capturing carbon dioxide in an amount of 0.5% by weight based on the total weight of the absorbent, the degree of oxidative degradation is greatly reduced.

Therefore, when the mixed absorbent for capturing carbon dioxide of Examples 1 to 3 was mixed with dimercaptothiadiazole (DMTD), a thiadiazole-based degradation inhibitor, in an amount of 0.5% by weight based on the total weight of the absorbent, from Comparative Example 2 of Table 3 It can be inferred that the degree of oxidative degradation is greatly reduced.

And, considering the boiling point of Comparative Examples 1 to 7 as shown in Table 3, Comparative Example 3 (TEPA) and Comparative Example 7 (TACD) showed the highest boiling point, so tetraethylenepentaamine (TEPA) and It can be seen that 1,4,7,10-tetraazacyclododicane (TACD) is effective in preventing volatilization and entrainment of the mixed absorbent for capturing carbon dioxide of Examples 1 to 3, which includes all of them.

Claims (11)

Including a compound represented by the following formula (1) and the following formula (2),
A mixed absorbent for capturing carbon dioxide, comprising any one or more compounds of the compounds represented by the following Chemical Formulas 3 and 4.
[Formula 1]

In Formula 1, a is a hydrocarbon group having 0 to 1 carbon atoms, b and c are a hydrocarbon group having 0 to 3 carbon atoms, and R ₁ and R ₂ are -(CH ₂ ) _f -H, -(CH ₂ ) _m -NH ₂ , -CH-(CH ₃ ) ₂ and -C-(CH ₃ ) ₃ , wherein f and m are integers from 0 to 5.
[Formula 2]

In Formula 2, R ₃ is -(CH ₂ NHCH ₂ ) _g -, where g is an integer of 1 to 2.
[Formula 3]

In Formula 3, d is a hydrocarbon group having 1 to 4 carbon atoms, and R ₄ is -(CH ₂ ) _h -CH ₃ , -CH-(CH ₃ ) ₂ and -C-(CH ₃ ) ₃ Any one selected from , where h is an integer from 0 to 3.
[Formula 4]

In Formula 4, e is a hydrocarbon group having 0 to 3 carbon atoms, R ₅ is -(CH ₂ ) _i -H, or -CH-(CH ₃ ) ₂ , R ₆ is -H or CH ₃ , and R ₇ , R ₈ is -(CH ₂ ) _j -H, where i is an integer from 0 to 6, and j is an integer from 0 to 3. The method of claim 1,
Based on 100% by weight of the mixed absorbent for capturing carbon dioxide,
5 to 15% by weight of the compound of Formula 1;
5 to 15% by weight of the compound of Formula 2; and
The mixed absorbent for capturing carbon dioxide, characterized in that; 10 to 30% by weight of any one or more compounds of the compounds of Formula 3 and Formula 4; The method of claim 1,
The mixed absorbent for capturing carbon dioxide,
A mixed absorbent for capturing carbon dioxide, characterized in that it contains a thiadiazole-based degradation control paper. 4. The method of claim 3,
The thiadiazole-based degradation inhibitor is a mixed absorbent for capturing carbon dioxide, characterized in that dimercaptothiadiazole. 4. The method of claim 3,
The thiadiazole-based anti-degradation agent, based on 100% by weight of the total carbon dioxide-collecting mixed absorbent, a mixed absorbent for carbon dioxide capture, characterized in that it contains 0 or more and 1% by weight or less. According to claim 1,
The mixed absorbent for capturing carbon dioxide,
A mixed absorbent for capturing carbon dioxide, characterized in that the carbon dioxide stripping temperature is 70 °C to 150 °C. According to claim 1,
The mixed absorbent for capturing carbon dioxide,
A mixed absorbent for capturing carbon dioxide, characterized in that the carbon dioxide absorption and stripping pressure is 1 bar to 2 bar. According to claim 1,
The compound of Formula 1 is,
Diethylenetriamine, 1,3-diamino-2-propanol, 1,5-diamino-3-pentanol, butylenediamine, pentamethylenediamine, hexamethylenediamine, bis(3-aminopropyl)amine, tetra A mixed absorbent for capturing carbon dioxide, characterized in that it is any one selected from ethylenepentaamine, N-isopropylethylenediamine, N-isopropyl-1,3-propanediamine, and 1,8-diamino-para-mentane. According to claim 1,
The compound of Formula 2 is,
A mixed absorbent for capturing carbon dioxide, characterized in that it is any one selected from 1,4,7-triazacyclononane and 1,4,7,10-tetraazacyclododicane. The method of claim 1,
The compound of Formula 3 is,
2-(methylamino)ethanol, 2-(ethylamino)ethanol, 2-(propylamino)ethanol, 2-(isopropylamino)ethanol, 2-(butylamino)ethanol, 2-(tert-butylamino)ethanol , 3-(methylamino)propanol, 3-(ethylamino)propanol, 3-(propylamino)propanol, 3-(isopropylamino)propanol, 3-(butylamino)propanol, 3-(tert-butylamino) Propanol, 4-(methylamino)butanol, 4-(ethylamino)butanol, 4-(propylamino)butanol, 4-(isopropylamino)butanol, 4-(butylamino)butanol, 4-(tert-butylamino) )butanol, 5-(methylamino)pentanol, 5-(ethylamino)pentanol, 5-(propylamino)pentanol, 5-(isopropylamino)pentanol, 5-(butylamino)pentanol and 5 A mixed absorbent for capturing carbon dioxide, characterized in that it is any one selected from -(tert-butylamino)pentanol. The method of claim 1,
The compound of Formula 4 is,
2-Amino-2-methyl-1-propanol, 2-amino-2-methyl-1-butanol, 2-amino-2-methyl-1-pentanol, 3-amino-3-methyl-1-butanol, 4 -Amino-4-methyl-1-pentanol, N-methyl-2-amino-1-propanol, N-ethyl-2-amino-1-propanol, N-isopropyl-2-amino-1-propanol, N -Methyl-2-amino-1-butanol, N-methyl-2-amino-1-pentanol, N-isopropyl-2-amino-1-pentanol, 2-amino-1-propanol, 2-amino- 1-Butanol, 2-amino-3-methylbutanol, 2-amino-1-pentanol, 2-amino-1-hexanol, 3-amino-1-butanol, 4-amino-1-pentanol, 5- amino-1-hexanol, 3-amino-1-pentanol, 3-amino-1-hexanol, 1-amino-2-propanol, 1-amino-2-butanol, 1-amino-2-pentanol and A mixed absorbent for capturing carbon dioxide, characterized in that it is any one selected from 1-amino-3-methyl-2-butanol.

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