Carbon dioxide separation and capture material, and carbon dioxide separation or capture method using the same

Abstract

To provide a CO2 separation and recovery material in which polyamine does not easily desorb even in reduced pressure drying treatment during production or in reduced pressure treatment during CO2 desorption treatment, the amount of polyamine compound carried is sufficiently maintained, and the stability over time is excellent.SOLUTION: Provided is a CO2 separation and recovery material that includes a carrier and a polyamine compound carried on the carrier, and in which, characterized, the polyamine compound is mainly composed of N=CH2 group-terminated linear polyethyleneimine in which at least one of the NH2 groups of a NH2 group-terminated linear polyethyleneimine having 4 to 7 ethylene groups (-CH2-CH2-) bonded via NH group and / or N atom is converted to a N=CH2 group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a carbon dioxide separation and recovery material and a method for separating or recovering carbon dioxide using the same.

Background Art

[0002] Conventionally, as one of the measures against global warming, in order to reduce the emission of carbon dioxide (CO2), which is a greenhouse gas, the development of a CO2 separation and recovery material for separating and recovering CO2 in a gas has been carried out. For example, Japanese Patent Application Laid-Open No. 2015-9185 (Patent Document 1) discloses a CO2 separation material containing a polyamine carrier in which a polyamine having at least two isopropyl groups on a nitrogen atom is supported on a support, and it is also described that not only the absorption efficiency of CO2 is high but also the desorption efficiency is high. However, since the polyamine having at least two isopropyl groups used in this CO2 separation material has high volatility, the polyamine is desorbed from the CO2 separation material by the reduced-pressure drying treatment during the production of the CO2 separation material or the reduced-pressure treatment during the desorption treatment of CO2, resulting in a decrease in the supported amount of the polyamine or a decrease in the stability of the CO2 separation material over time.

[0003] Further, Japanese Patent Application Laid-Open No. 2020-58967 (Patent Document 2) discloses a CO2 separation composition containing a polyethylene polyamine having 4 or more amino groups, diethylenetriamine, and silica, and it is also described that the absorbed CO2 can be released at low temperature and with low energy. However, also in this CO2 separation composition, since the polyethylene polyamine having 4 or more amino groups has high volatility, the polyethylene polyamine supported on silica is desorbed by the reduced-pressure drying treatment during the production of the CO2 separation composition or the reduced-pressure treatment during the desorption treatment of CO2, resulting in a decrease in the supported amount of the polyethylene polyamine or a decrease in the stability of the CO2 separation composition over time.

[0004] Furthermore, Japanese Patent Application Laid-Open No. 2020-168624 (Patent Document 3) discloses a CO₂ adsorbent / desorbent comprising a carrier and polyethyleneimine supported on the carrier, wherein the polyethyleneimine is a branched polyethyleneimine containing primary amines, secondary amines, and tertiary amines in specific ratios, and at least a part of the primary amines and the secondary amines among them are alkylated with lower alkyl groups having 1 to 5 carbon atoms, and it is an alkylated branched polyethyleneimine, and a CO₂ adsorbent / desorbent is disclosed in which the ratio of the number of the lower alkyl groups bonded to nitrogen atoms by the alkylation to the number of the primary amines in the branched polyethyleneimine is within a specific range. The alkylated branched polyethyleneimine used in this CO₂ adsorbent / desorbent has low volatility, and the alkylated branched polyethyleneimine is hardly desorbed even in the vacuum drying treatment during the production of the CO₂ adsorbent / desorbent or the vacuum treatment during the desorption treatment of CO₂, the supported amount of the alkylated branched polyethyleneimine is sufficiently maintained, and the stability over time of the CO₂ adsorbent / desorbent is also excellent. However, the CO₂ adsorption performance of this CO₂ adsorbent / desorbent is not necessarily sufficiently high.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the problems of the above prior art, and even in the vacuum drying treatment during production or the vacuum treatment during the CO2 desorption treatment, the polyamine compound is difficult to desorb, the loading amount of the polyamine compound is sufficiently maintained, and a CO2 separation and recovery material excellent in stability over time, and a method for separating or recovering CO2 using the same are provided.

Means for Solving the Problems

[0007] As a result of intensive studies to achieve the above object, the present inventors have found that in a CO2 separation and recovery material containing a carrier and a polyamine compound supported on the carrier, as the polyamine compound, at least one of the NH2 groups of a chain polyethyleneimine having an NH2 group at the terminal is converted to an N=CH2 group, and by using a polyamine compound mainly composed of a chain polyethyleneimine having an N=CH2 group at the terminal, the polyamine compound is difficult to desorb even in the vacuum drying treatment during production or the vacuum treatment during the CO2 desorption treatment, the loading amount of the polyamine compound is sufficiently maintained, and a CO2 separation and recovery material excellent in stability over time can be obtained, and the present invention has been completed.

[0008] That is, the CO2 separation and recovery material of the present invention contains a carrier and a polyamine compound supported on the carrier, and at least one of the NH2 groups of a chain polyethyleneimine having an NH2 group at the terminal, in which 4 to 7 ethylene groups (-CH2-CH2-) are bonded by an NH group and / or an N atom, is converted to an N=CH2 group, and a chain polyethyleneimine having an N=CH2 group at the terminal Contains, the N=CH 2 The content of the chain polyethyleneimine at the N=CH group terminal is the maximum among all components It is characterized by being.

[0009] In the CO2 separation and recovery material of the present invention, the chain polyethyleneimine having an NH2 group at the terminal and the chain polyethyleneimine having an N=CH2 group at the terminal have the following formula: -[CH2-CH2-NH]- It is preferably one containing one or more repeating units represented by.

[0010] In the CO₂ separation and recovery material of the present invention, it is preferable that the double bond equivalent number (DBE) of the linear polyethyleneimine at the terminal of the N=CH₂ group is DBE = 1. Further, the linear polyethyleneimine at the terminal of the N=CH₂ group is represented by the following formula (1): C7H 18 N4(C2H4NH) n (1) [In formula (1), n is an integer from 1 to 4.] and is preferably represented by it.

[0011] Furthermore, in the CO₂ separation and recovery material of the present invention, the polyamine compound is represented by the following formulas (1-1) to (1-3):

[0012]

Chemical formula

[0013] [In formulas (1-1) to (1-3), n is an integer from 1 to 4.] a linear polyethyleneimine with an N=CH₂ group terminal represented by All of is Contains, the N=CH represented by the formulas (1-1) to (1-3) 2 The total content of the chain polyethyleneimine at the N=CH group terminal is the maximum among all components and is preferably the following formula (1-1):

[0014]

Chemical formula

[0015] [In formula (1-1), n is an integer from 1 to 4.] a linear polyethyleneimine with an N=CH₂ group terminal represented by Contains, the N=CH represented by the formula (1-1) 2 The content of the chain polyethyleneimine at the N=CH group terminal is the maximum among all components is more preferable.

[0016] The method for separating or recovering CO₂ of the present invention comprises an adsorption step of bringing a gas containing CO₂ to be treated into contact with the CO₂ separation and recovery material according to any one of claims 1 to 6 to adsorb CO₂ onto the CO₂ separation and recovery material, and the CO₂ separation and recovery material that has adsorbed CO₂ in the adsorption step is (A) Method of placing under reduced pressure conditions, (B) Method of contacting with hydrogen, (C) Method of heating, By any one of the methods or a combination thereof, a desorption step of desorbing CO2 from the CO2 separation and recovery material and A method characterized by comprising.

[0017] In the method for separating or recovering CO2 of the present invention, in the desorption step, it is preferable to desorb CO2 from the CO2 separation and recovery material by a combination of the method (A) and the method (C).

Effect of the Invention

[0018] According to the present invention, it is possible to obtain a CO2 separation and recovery material in which the polyamine compound is hardly desorbed even in the reduced pressure drying treatment during production or the reduced pressure treatment during the desorption treatment of CO2, the supported amount of the polyamine compound is sufficiently maintained, and the stability over time is excellent. Further, by using such a CO2 separation and recovery material, it is possible to stably separate or recover CO2 from a gas containing CO2 over time.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0020] Hereinafter, the present invention will be described in detail according to its preferred embodiments.

[0021] 〔CO2 separation and recovery material〕 First, the CO2 separation and recovery material of the present invention will be described. The CO2 separation and recovery material of the present invention contains a carrier and a polyamine compound supported on the carrier. The polyamine compound is mainly composed of a chain-like polyethyleneimine with a terminal N=CH2 group in which at least one of the NH2 groups of a chain-like polyethyleneimine with a terminal NH2 group, in which 4 to 7 ethylene groups (-CH2-CH2-) are bonded by NH groups and / or N atoms, is converted to an N=CH2 group.

[0022] The chain-like polyethyleneimine with a terminal NH2 group is not particularly limited as long as it is a chain-like polyethyleneimine in which 4 to 7 ethylene groups (-CH2-CH2-) are bonded by NH groups and / or N atoms and the terminal is an NH2 group. For example, known chain-like polyethyleneimines such as tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, and heptaethyloctamine can be mentioned. When the number of ethylene groups is less than the lower limit, the volatility of the polyamine compound increases, and the supported amount of the polyamine compound tends to decrease during the drying process. On the other hand, when it exceeds the upper limit, the viscosity of the polyamine compound increases, and it tends to be difficult to support the polyamine compound on the carrier. Further, such a chain-like polyethyleneimine may be linear or branched. However, when it is branched, the branch point becomes a tertiary amino group and is not converted to an N=CH2 group, so there is a concern that the utilization rate of the amino group decreases and the content of the N=CH2 group decreases. Therefore, it is preferably linear.

[0023] In addition, as the chain-like polyethyleneimine at the NH2 group terminal, the following formula: -[CH2-CH2-NH]- It preferably contains one or more repeating units represented by the following formula (a): C6H 18 N4(C2H4NH) n (a) 〔In formula (a), n is an integer from 1 to 4.〕 Those represented by are more preferable, and the following formulas (a-1) and (a-2):

[0024]

Chemical formula

[0025] 〔In formulas (a-1) and (a-2), n is an integer from 1 to 4.〕 The linear and branched chain polyethyleneimines with NH2 group terminals represented by are even more preferable, and the linear polyethyleneimine with NH2 group terminal represented by the formula (a-1) is particularly preferable. By converting at least one of the NH2 groups at the terminal of such a chain-like polyethyleneimine with NH2 group terminal into an N=CH2 group, the NH2 group content in the polyamine compound decreases, and the volatility of the polyamine compound decreases. Therefore, the polyamine compound is less likely to desorb even during the reduced-pressure drying treatment during production or the reduced-pressure treatment during the CO2 desorption treatment, the supported amount of the polyamine compound is sufficiently maintained, and a CO2 separation and recovery material with excellent stability over time can be obtained.

[0026] As a method for converting at least one of the NH2 groups at the terminal of the chain-like polyethyleneimine with NH2 group terminal into an N=CH2 group, for example, a method of reacting a raw material polyamine compound mainly composed of the chain-like polyethyleneimine with NH2 group terminal with formaldehyde can be mentioned.

[0027] In the raw material polyamine compound, the content of the chain-like polyethyleneimine with an NH2 group at the terminal is not particularly limited as long as it is the largest amount among all components, but it is preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more with respect to the total amount of the raw material polyamine compound.

[0028] Also, in the raw material polyamine compound, it is preferable that the content of the chain-like polyethyleneimine with an NH2 group represented by the formula (a) is the largest amount among all components, and it is more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more with respect to the total amount of the raw material polyamine compound.

[0029] Furthermore, in the raw material polyamine compound, it is preferable that the total amount of the chain-like polyethyleneimine with an NH2 group represented by the formulas (a-1) and (a-2) is the largest amount among all components, and it is more preferably 40% by mass or more, still more preferably 50% by mass or more, and particularly preferably 60% by mass or more with respect to the total amount of the raw material polyamine compound.

[0030] Also, in the raw material polyamine compound, it is preferable that the content of the linear polyethyleneimine with an NH2 group represented by the formula (a-1) is the largest amount among all components, and it is more preferably 30% by mass or more, still more preferably 40% by mass or more, and particularly preferably 50% by mass or more with respect to the total amount of the raw material polyamine compound.

[0031] The polyamine compound used in the present invention mainly comprises a chain-like polyethyleneimine with an N=CH2 group at the end, in which at least one of the NH2 groups at the end of the chain-like polyethyleneimine with an NH2 group at the end is converted into an N=CH2 group. Further, the chain-like polyethyleneimine with an N=CH2 group at the end may be linear or branched. However, when it is branched, the branching point becomes a tertiary amino group and is not converted into an N=CH2 group. Therefore, there is concern that the utilization rate of the amino group may decrease and the content of the N=CH2 group may decrease. Thus, it is preferably linear.

[0032] As the chain-like polyethyleneimine with an N=CH2 group at the end, the following formula: -[CH2-CH2-NH]- It preferably contains one or more repeating units represented by the following formula (1): C7H 18 N4(C2H4NH) n (1) [In formula (1), n is an integer from 1 to 4.] Those represented by the following formula (1-1) to (1-3) are more preferred:

[0033]

Chemical formula

[0034] [In formulas (1-1) to (1-3), n is an integer from 1 to 4.] The linear and branched chain-like polyethyleneimines with an N=CH2 group at the end represented by the above are even more preferred, and the linear chain-like polyethyleneimine with an N=CH2 group at the end represented by the above formula (1-1) is particularly preferred. By using a polyamine compound mainly comprising such a chain-like polyethyleneimine with an N=CH2 group at the end, the polyamine compound is less likely to desorb even during the reduced-pressure drying treatment during production or the reduced-pressure treatment during the CO2 desorption treatment, the supported amount of the polyamine compound is sufficiently maintained, and a CO2 separation and recovery material excellent in stability over time can be obtained.

[0035] In addition, as the chain-like polyethyleneimine at the terminal of the N=CH2 group, those having a double bond equivalent number (DBE) of DBE = 1 are preferable. The double bond equivalent number (DBE) is represented as the sum of the number of double bonds and the number of ring structures. Therefore, the chain-like polyethyleneimine with a DBE of 1 at the terminal of the N=CH2 group is a chain-like polyethyleneimine having one N=CH2 group at the terminal and all the remaining atoms bonded by single bonds.

[0036] In the polyamine compound, the content of the chain-like polyethyleneimine at the terminal of the N=CH2 group is not particularly limited as long as it is the largest amount among all components, but it is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more with respect to the total amount of the polyamine compound.

[0037] In addition, in the polyamine compound, it is preferable that the content of the chain-like polyethyleneimine at the terminal of the N=CH2 group represented by the formula (1) is the largest amount among all components, and it is more preferably 50% by mass or more, still more preferably 60% by mass or more, and particularly preferably 70% by mass or more with respect to the total amount of the polyamine compound.

[0038] Furthermore, in the polyamine compound, it is preferable that the content of the chain-like polyethyleneimine at the terminal of the N=CH2 group represented by the formulas (1-1) to (1-3) is the largest amount among all components, and it is more preferably 40% by mass or more, still more preferably 50% by mass or more, and particularly preferably 60% by mass or more with respect to the total amount of the polyamine compound.

[0039] In addition, in the polyamine compound, it is preferable that the content of the chain-like polyethyleneimine at the terminal of the N=CH2 group represented by the formula (1-1) is the largest amount among all components, and it is more preferably 20% by mass or more, still more preferably 30% by mass or more, and particularly preferably 40% by mass or more with respect to the total amount of the polyamine compound.

[0040] Furthermore, in the polyamine compound, from the viewpoint of improving the CO2 adsorption performance of the CO2 separation and recovery material, the atomic ratio of N atom to C atom (N / C ratio) is preferably 0.2 to 0.8, more preferably 0.3 to 0.7.

[0041] The CO2 separation and recovery material of the present invention is one in which a polyamine compound mainly composed of such a chain-like polyethyleneimine with an N=CH2 group terminal is supported on a carrier. Examples of the carrier include porous solids such as silica gel, mesoporous silica, alumina, silica alumina, clay minerals, magnesia, zirconia, zeolites and their analogous compounds, activated carbon, and carbon fibers. These porous solids may be used alone or in combination of two or more.

[0042] Although there is no particular limitation on the specific surface area of such a carrier, from the viewpoint of increasing the loading amount of the polyamine compound and improving the CO2 adsorption performance of the CO2 separation and recovery material, it is preferably 100 to 500 m 2 / g, more preferably 200 to 400 m 2 / g. Also, from the same viewpoint, the average pore diameter of the carrier is preferably 3 to 30 nm, more preferably 5 to 15 nm.

[0043] In the CO2 separation and recovery material of the present invention, the loading amount of the polyamine compound is preferably 30 to 50% by mass, more preferably 35 to 50% by mass, and particularly preferably 40 to 45% by mass, based on the total amount of the CO2 separation and recovery material, from the viewpoint of obtaining a CO2 separation and recovery material having excellent CO2 adsorption performance.

[0044] [Method for Separating or Recovering CO2] Next, the method for separating or recovering CO2 of the present invention will be described. The method for separating or recovering CO2 of the present invention includes an adsorption step of bringing a gas containing CO2 to be treated into contact with the CO2 separation and recovery material of the present invention to adsorb CO2 onto the CO2 separation and recovery material, and the CO2 separation and recovery material that has adsorbed CO2 in the adsorption step is (A) a method of placing it under reduced pressure conditions, (B) A method of contacting with hydrogen, (C) A method of heating, By any one of these methods or a combination thereof, a desorption step of desorbing CO2 from the CO2 separation and recovery material and It is a method including.

[0045] The gas to be treated is not particularly limited as long as it is a gas containing CO2. For example, exhaust gas from power plants, factories, exhaust gas from automobiles, etc. can be mentioned.

[0046] (Adsorption step) In the method for separating or recovering CO2 of the present invention, first, the gas containing CO2 to be treated is brought into contact with the CO2 separation and recovery material of the present invention, and CO2 is adsorbed on the CO2 separation and recovery material.

[0047] The temperature when bringing the gas containing CO2 into contact with the CO2 separation and recovery material is not particularly limited, but 20 to 90 ° C is preferable, and 50 to 80 ° C is more preferable.

[0048] (Desorption step) Next, the CO2 separation and recovery material on which CO2 has been adsorbed in this way is (A) A method of placing it under reduced pressure conditions, (B) A method of contacting with hydrogen, (C) A method of heating, By any one of these methods or a combination thereof, CO2 is desorbed from the CO2 separation and recovery material. The methods (A) to (C) are preferably carried out in a gas atmosphere not containing CO2.

[0049] In the method (A), by reducing the pressure around the CO2 separation and recovery material, the CO2 adsorbed on the CO2 separation and recovery material is desorbed. In this case, as the pressure condition around the CO2 separation and recovery material, 5 to 40 Pa is preferable, and 10 to 30 Pa is more preferable. When the pressure around the CO2 separation and recovery material is less than the lower limit, CO2 tends to be difficult to desorb. On the other hand, when it exceeds the upper limit, the energy efficiency tends to decrease.

[0050] In the above method (B), by bringing the CO₂ separation and recovery material into contact with hydrogen, the partial pressure of CO₂ around the CO₂ separation and recovery material is reduced, and the CO₂ adsorbed on the CO₂ separation and recovery material is desorbed. This method can be carried out under atmospheric pressure, but the pressure around the CO₂ separation and recovery material may also be reduced.

[0051] In the above method (C), by heating the CO₂ separation and recovery material, the CO₂ adsorbed on the CO₂ separation and recovery material is desorbed. In this case, from the viewpoint of energy efficiency, the heating temperature of the CO₂ separation and recovery material is preferably 20 to 90°C, more preferably 50 to 80°C. Further, the above method (C) is preferably carried out in combination with one or both of the above method (A) and the above method (B).

[0052] Furthermore, in the CO₂ separation or recovery method of the present invention, from the viewpoint of energy efficiency, it is preferable to maintain the temperature in the adsorption step and the temperature in the desorption step at the same temperature.

Examples

[0053] Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples.

[0054] (Preparation Example 1) Pentaethylenehexamine (ethyleneamine mixture) (pentaethylenehexamine (ethyleneamine mixture) manufactured by Fujifilm Wako Pure Chemical Corporation, for chemical use) was placed in a beaker, and formaldehyde (manufactured by Fujifilm Wako Pure Chemical Corporation) was added at room temperature while stirring using a stirrer. Then, when the generation of reaction heat subsided and the temperature of the reaction solution dropped to room temperature, stirring was stopped to terminate the reaction. The obtained reaction product was vacuum dried at room temperature for 12 hours.

[0055] <Infrared spectroscopic analysis> The infrared absorption spectra of the raw material pentaethylenehexamine (ethyleneamine mixture) and the reaction product after vacuum drying were measured by the total reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer ("FT-IR AVATAR360" manufactured by Nicolet) in the atmosphere at room temperature. The results are shown in Figure 1.

[0056] As shown in Figure 1, in the infrared absorption spectrum of the reaction product, an absorption derived from the C=N bond that was not observed in the infrared absorption spectrum of the raw material pentaethylenehexamine (ethyleneamine mixture) was observed between the wavenumbers of 1615 to 1700 cm -1 . That is, it was confirmed that the reaction product contains a C=N bond.

[0057] <Mass spectrometry> Methanol was added to each of the raw material pentaethylenehexamine (ethyleneamine mixture) and the reaction product after vacuum drying so that the concentrations of the ethyleneamine mixture and the reaction product were approximately 50 μg / ml to prepare a sample solution. A liquid chromatograph time-of-flight mass spectrometer (LC-QTOF-MS, "Q-Time-Of-Flight (TOF)" manufactured by Agilent) was used, and each sample solution was introduced into the mass spectrometer (MS) by the infusion method. Mass spectrometry was performed by the electrospray ionization method (positive ion mode) without column separation. Figure 2 shows the mass spectrum of the raw material pentaethylenehexamine (ethyleneamine mixture), and Figure 3 shows the mass spectrum of the reaction product.

[0058] From the mass spectrum shown in Figure 2, the raw material pentaethylenehexamine (ethyleneamine mixture) is composed of 8 types of NH2-terminal ethyleneamines (composition formula: C8H 23 N5, C 10 H 25 N5, C 10 H 28 N6, C 12 H 30 N6, C 12 H 33 N7, C 14 H 35 N7, C 14 H38 N8, C 16 H 40 It was found to be a mixture of N8). Since these ethyleneamines are all polyethyleneimines having a repeating unit -[CH2-CH2-NH]-, the molecular formulas are the following formulas (a) and (b): C6H 18 N4(C2H4NH) n (a) C8H 20 N4(C2H4NH) n (b) 〔In formulas (a) and (b), n is an integer from 1 to 4.〕 It is considered that the double bond equivalent number of molecular formula (a) is DBE = 0, and the double bond equivalent number of molecular formula (b) is DBE = 1.

[0059] Furthermore, referring to R. Numaguchi et al., Energy Procedia, 2017, Vol. 114, pp. 2304 - 2312, the molecular structures of the polyethyleneimines represented by molecular formulas (a) and (b) and the abundance ratios of each polyethyleneimine in the raw material pentaethylenehexamine (ethyleneamine mixture) were examined. As a result, the polyethyleneimine represented by molecular formula (a) is a chain-like polyethyleneimine with an NH2 terminus represented by the following formulas (a-1) and (a-2) (NH2-terminated chain-like PEI), and the ethyleneamine represented by molecular formula (b) is considered to be a polyethyleneimine containing a piperazine ring with an NH2 terminus represented by the following formulas (b-1) and (b-2). Also, each polyethyleneimine is considered to be present in the raw material pentaethylenehexamine (ethyleneamine mixture) at the ratios shown in Table 1. In the following formulas (a-1) to (b-2), n is an integer from 1 to 4.

[0060]

Chem.

[0061]

Chem.

[0062]

Table 1

[0063] From the above results, it is considered that the raw material pentaethylenehexamine (ethyleneamine mixture) is a polyamine compound mainly composed of NH2-terminal chain-like PEI represented by the above formulas (a-1) and (b-2).

[0064] Also, from the mass spectrum shown in FIG. 3, the reaction product was found to be a mixture of 15 components (C9H 23 N5, C 10 H 23 N5, C 11 H 25 N5, C 11 H 28 N6, C 12 H 28 N6, C 13 H 28 N6, C 13 H 30 N6, C 13 H 33 N7, C 14 H 33 N7, C 15 H 33 N7, C 15 H 35 N7, C 15 H 38 N8, C 16 H 38 N8, C 17 H 38 N8, C 17 H 40 N8). Since all of these components are polyethyleneimine having a repeating unit -[CH2-CH2-NH]-, the molecular formulas are the following formulas (1) to (4): C7H 18 N4(C2H4NH) n (1) C8H 18 N4(C2H4NH) n (2) C9H 18 N5(C2H4NH) n (3) C9H 20N4(C2H4NH) n (4) [In formulas (1) to (4), n is an integer from 1 to 4.] It is considered that the double bond equivalence number of formula (1) is DBE = 1, the double bond equivalence number of formula (2) is DBE = 2, the double bond equivalence number of formula (3) is DBE = 3, and the double bond equivalence number of formula (4) is DBE = 2.

[0065] Furthermore, referring to R. Numaguchi et al., Energy Procedia, 2017, Vol. 114, pp. 2304 - 2312, the molecular structures of the polyethyleneimines represented by formulas (1) to (4) and the abundance ratios of each polyethyleneimine in the reaction products were examined. As a result, the polyethyleneimine represented by formula (1) is a chain - shaped polyethyleneimine having an N=CH2 end represented by the following formulas (1 - 1) to (1 - 3) (N=CH2 - end - chain - shaped PEI), the component represented by formula (2) is a piperazine - ring - containing polyethyleneimine having a CH=NH end represented by the following formulas (2 - 1) to (2 - 3), the component represented by formula (3) is a piperazine - ring - containing polyethyleneimine having an N=CH2 end and a CH=NH end represented by the following formula (3 - 1), and the component represented by formula (4) is considered to be a piperazine - ring - containing polyethyleneimine having an N=CH2 end represented by the following formulas (4 - 1) to (4 - 3). Also, each polyethyleneimine is considered to be present in the reaction product at the ratios shown in Table 2. In the following formulas (1 - 1) to (4 - 3), n is an integer from 1 to 4.

[0066]

Chemical formula

[0067]

Chemical formula

[0068]

Chemical formula

[0069]

Chem.

[0070]

Table 2

[0071] From the above results, it is considered that the reaction product is a polyamine compound mainly composed of N=CH2-terminated linear PEI represented by the above formulas (1-1) to (1-3), in which at least one terminal NH2 group of the NH2-terminated linear PEI represented by the above formulas (a-1) and (a-2) is converted to an N=CH2 group.

[0072] (Comparative Preparation Example 1) Tetraethylenepentamine (ethyleneamine mixture) (manufactured by Tokyo Chemical Industry Co., Ltd.) and methanol (manufactured by Fujifilm Wako Pure Chemical Corporation) were placed in a reaction vessel and stirred. Acetone (manufactured by Fujifilm Wako Pure Chemical Corporation) was added dropwise to the obtained solution at room temperature, and stirring was continued for 2 hours. Then, the reaction vessel was cooled with ice, and while maintaining the temperature of the reaction solution at 15 °C or lower, sodium borohydride (manufactured by Kanto Chemical Co., Inc.) was added little by little, followed by stirring for 2 hours. Further, ion-exchanged water was added dropwise and stirred overnight. After completion of stirring, chloroform (manufactured by Fujifilm Wako Pure Chemical Corporation) was added to the reaction solution for extraction, and sodium sulfate (manufactured by Fujifilm Wako Pure Chemical Corporation) was added to the obtained organic layer to dry the reaction product. Then, sodium sulfate was removed by filtration, the filtrate was concentrated under reduced pressure, and further dried under reduced pressure at 60 °C to obtain N-IP group-terminated tetraethylenepentamine (IP-TEPA) in which the terminal NH2 group of tetraethylenepentamine (TEPA) was converted to an N-IP group (IP represents an isopropyl group).

[0073] (Comparative Preparation Example 2) Instead of tetraethylenepentamine (ethyleneamine mixture), polyethyleneimine with an average molecular weight of about 600 (manufactured by Fujifilm Wako Pure Chemical Corporation) was used, and N-IP group-terminated polyethyleneimine (IP-PEI(600)) in which the terminal NH2 groups of the polyethyleneimine (PEI(600)) were converted to N-IP groups was obtained in the same manner as in Comparative Preparation Example 1.

[0074] (Example 1) The polyamine compound mainly composed of N=CH2-terminated linear PEI obtained in Preparation Example 1 was placed in a beaker, and crushed catalyst carrier silica gel (「CARiACT-G10」manufactured by Fuji Silysia Chemical Ltd., average pore diameter: 10 nm, pore volume: 1.3 ml / g, specific surface area: 300 m 2 / g, particle size: 1.0 to 1.7 mm) was added. The resulting dispersion was left at room temperature for 20 hours to obtain a CO2 separation and recovery material in which the polyamine compound mainly composed of N=CH2-terminated linear PEI was supported on the silica gel carrier. This CO2 separation and recovery material was recovered by filtration and air-dried at room temperature for 20 hours.

[0075] <Thermal analysis> The obtained CO2 separation and recovery material was placed in an aluminum pan, and thermal analysis from room temperature to 800 °C was performed under a stream of air using a thermal analyzer (「Thermo Plus TG8120」manufactured by Rigaku Corporation). In the obtained results, the weight loss rate between about 200 °C and 800 °C was taken as the ratio of the polyamine compound, and the ratio of the residue at 800 °C was taken as the ratio of the silica gel, and the ratio of the polyamine compound contained in the CO2 separation and recovery material (polyamine loading rate (before drying)) was calculated. The results are shown in Table 3.

[0076] Next, the CO2 separation and recovery material was vacuum-dried at 100 °C for 2 hours starting from a state containing water vapor at room temperature dew point. Thermal analysis was performed on the CO2 separation and recovery material after vacuum drying in the same manner as above, and the ratio of the polyamine compound contained in the CO2 separation and recovery material (polyamine loading rate (after drying)) was calculated. The results are shown in Table 3.

[0077] (Example 2) The polyamine compound mainly composed of N=CH2 terminal chain-like PEI obtained in Preparation Example 1 was placed in a beaker, and methanol (manufactured by Fujifilm Wako Pure Chemical Corporation) was added thereto. After sufficient stirring, further, silica gel for crushed catalyst carrier (``CARiACT-G10'' manufactured by Fuji Silysia Chemical Ltd., average pore diameter: 10 nm, pore volume: 1.3 ml / g, specific surface area: 300 m 2 / g, particle size: 1.0 to 1.7 mm) was added. The obtained dispersion was left at room temperature for 20 hours to obtain a CO2 separation and recovery material in which the polyamine compound mainly composed of N=CH2 terminal chain-like PEI was supported on the silica gel carrier.

[0078] This CO2 separation and recovery material was recovered by filtration and air-dried at room temperature for 20 hours. Then, in the same manner as in Example 1, the ratio of the polyamine compound contained in the CO2 separation and recovery material (polyamine loading rate (before drying)) was calculated. Further, this CO2 separation and recovery material was vacuum-dried at 100 °C for 2 hours from a state containing water vapor at room temperature dew point, and then, in the same manner as in Example 1, the ratio of the polyamine compound contained in the CO2 separation and recovery material (polyamine loading rate (after drying)) was calculated. These results are shown in Table 3.

[0079] (Comparative Example 1) Instead of the polyamine compound mainly composed of the N=CH2 terminal chain-like PEI, pentaethylenehexamine (ethyleneamine mixture) mainly composed of NH2 terminal chain-like PEI (pentaethylenehexamine (ethyleneamine mixture) for chemical use, manufactured by Fujifilm Wako Pure Chemical Corporation) was used. In the same manner as in Example 1, a CO2 separation and recovery material in which an ethyleneamine mixture mainly composed of NH2 terminal chain-like PEI was supported on a silica gel carrier was obtained. The polyamine loading rates before and after vacuum drying of this CO2 separation and recovery material were calculated in the same manner as in Example 1. The results are shown in Table 3.

[0080] (Comparative Example 2) Instead of the polyamine compound mainly composed of the N=CH2 terminal chain-like PEI, a CO2 separation and recovery material with IP-TEPA supported on a silica gel carrier was obtained in the same manner as in Example 1, except that N-IP group-terminated tetraethylenepentamine (IP-TEPA) obtained in Comparative Preparation Example 1 was used. The polyamine loading rate of this CO2 separation and recovery material before and after vacuum drying was calculated in the same manner as in Example 1. The results are shown in Table 3.

[0081] (Comparative Example 3) Instead of the polyamine compound mainly composed of the N=CH2 terminal chain-like PEI, a CO2 separation and recovery material with IP-PEI(600) supported on a silica gel carrier was obtained in the same manner as in Example 1, except that N-IP group-terminated polyethyleneimine (IP-PEI(600)) obtained in Comparative Preparation Example 2 was used. The polyamine loading rate of this CO2 separation and recovery material before and after vacuum drying was calculated in the same manner as in Example 1. The results are shown in Table 3.

[0082] [Table 3]

[0083] As shown in Table 3, there was no change in the polyamine loading rate of the CO2 separation and recovery materials obtained in Examples 1 to 2 and Comparative Example 3 before and after vacuum drying. On the other hand, the polyamine loading rate of the CO2 separation and recovery material obtained in Comparative Example 1 decreased by 14% before and after vacuum drying, and the polyamine loading rate of the CO2 separation and recovery material obtained in Comparative Example 2 decreased by 46% before and after vacuum drying. From the above results, it was confirmed that the CO2 separation and recovery materials obtained in Examples 1 to 2 carried a polyamine compound that was less volatile compared to the CO2 separation and recovery materials obtained in Comparative Examples 1 to 2.

[0084] [CO2 Adsorption-Desorption Test (Cycle Test)] First, each CO2 separation and recovery material (about 4 g) after vacuum drying obtained in Examples 1 to 2 and Comparative Examples 1 to 3 was filled into a SUS sample cell with an inner diameter of 7.93 mm. A heat medium was circulated around this sample cell, and while maintaining the temperature of the CO2 separation and recovery material at the temperature at which the previously measured CO2 adsorption amount was the highest (Examples 1 to 2 and Comparative Example 1: about 76°C, Comparative Example 2: 56°C, Comparative Example 3: 63°C), humidified N2 gas with a dew point temperature of 45°C DP (Dew Point) was supplied to the CO2 separation and recovery material at a flow rate of 100 ml / min for about 1 hour for pretreatment.

[0085] Next, while maintaining the temperature of the CO2 separation and recovery material at the above temperature, a CO2-containing gas (CO2 (5.4 ml / min) + N2 gas (51 ml / min)) humidified so that the dew point temperature was 45°C DP was supplied to the pretreated CO2 separation and recovery material as simulated exhaust gas, and CO2 was adsorbed on the CO2 separation and recovery material [adsorption treatment]. At this time, the CO2 concentration in the outlet gas was measured with an infrared gas analyzer ("IR400" manufactured by Yokogawa Electric Corporation), and the adsorption treatment was terminated when the CO2 concentration in the outlet gas exceeded 1 vol%.

[0086] Next, while maintaining the temperature of the CO2 separation and recovery material at the above temperature, humidified N2 gas (6 ml / min) with a dew point temperature of 45°C DP was supplied to the CO2 separation and recovery material on which CO2 was adsorbed, and the pressure was reduced using a vacuum pump to desorb the CO2 adsorbed on the CO2 separation and recovery material [desorption treatment]. This desorption treatment was carried out for the same time as the above adsorption treatment. Also, at this time, the CO2 concentration in the outlet gas was measured with the above infrared gas analyzer. When the CO2 concentration was high, N2 gas (50 ml / min) was added to the outlet gas to dilute the outlet gas and measure the CO2 concentration.

[0087] Such adsorption treatment and desorption treatment were alternately repeated, and the CO2 adsorption amount and CO2 desorption amount per cycle (adsorption treatment + desorption treatment) were determined as follows. That is, first, the following formula (i):

[0088]

Equation

[0089] 〔In formula (i), Q1 represents the flow rate of the CO2-containing gas (= 0.056 L / min), F0 represents the CO2 concentration in the CO2-containing gas (= 9.6 vol%), t1 represents the start time of the adsorption treatment (unit: second), and t2 represents the end time of the adsorption treatment (= the time when the CO2 concentration in the outlet gas during the adsorption treatment reaches 1 vol%) (unit: second).〕 Based on this, the CO2 supply amount A1 (unit: L) supplied to the CO2 separation and recovery material during the adsorption treatment is obtained. Also, the following formula (ii):

[0090]

Number

[0091] 〔In formula (ii), Q2 represents the flow rate of N2 in the outlet gas during the adsorption treatment (= 0.051 L / min), F1 represents the CO2 concentration in the outlet gas during the adsorption treatment, t1 represents the start time of the adsorption treatment (unit: second), and t2 represents the end time of the adsorption treatment (= the time when the CO2 concentration in the outlet gas during the adsorption treatment reaches 1 vol%) (unit: second).〕 Based on this, the CO2 leakage amount A2 (unit: L) that leaks without being adsorbed by the CO2 separation and recovery material during the adsorption treatment is obtained. Based on the obtained CO2 supply amount A1 and CO2 leakage amount A2, the following formula (iii):

[0092]

Number

[0093] 〔In formula (iii), A1 represents the CO2 supply amount (unit: L), A2 represents the CO2 leakage amount (unit: L), ρ represents the density of CO2 (= 0.04179 mol / L), MW represents the molecular weight of CO2 (= 44.01 g / mol), and W represents the mass of the CO2 separation and recovery material (unit: g).〕 Based on this, the CO2 adsorption amount A3 (unit: g / g) per 1 g of the CO2 separation and recovery material is obtained.

[0094] Also, the following formula (iv):

[0095]

Number

[0096] 〔In formula (iv), Q3 represents the flow rate of N2 gas during the desorption process (= 0.006 L / min), Q4 represents the flow rate of N2 gas for dilution (= 0.050 L / min), F2 represents the CO2 concentration in the off-gas during the desorption process, t3 represents the start time of the desorption process (unit: second), t4 represents the end time of the desorption process (unit: second), and t4 - t3 = t2 - t1.〕 Based on this, the amount of CO2 A4 (unit: L) in the off-gas during the desorption process is obtained, and based on the obtained amount of CO2 A4, the following formula (v):

[0097]

Number

[0098] 〔In formula (v), A4 represents the amount of CO2 A4, ρ represents the density of CO2 (= 0.04179 mol / L), MW represents the molecular weight of CO2 (= 44.01 g / mol), and W represents the mass of the CO2 separation and recovery material (unit: g).〕 Based on this, the CO2 desorption amount A5 (unit: g / g) per 1 g of the CO2 separation and recovery material is obtained.

[0099] Based on the CO2 adsorption amount A3 and the CO2 desorption amount A5 per 1 g of the CO2 separation and recovery material in each cycle obtained in this way, the change rates of the CO2 adsorption amount A3 and the CO2 desorption amount A5 in the nth cycle with respect to the (n - 1)th cycle are obtained (n is an integer of 2 or more). Figure 4 shows the CO2 adsorption and desorption cycle test results of the CO2 separation and recovery material obtained in Example 1, and Figure 5 shows the CO2 adsorption and desorption cycle test results of the CO2 separation and recovery material obtained in Comparative Example 1.

[0100] In FIGS. 4 and 5, when three or more consecutive cycles in which the change rate of the CO2 adsorption amount or the CO2 desorption amount is within ±5% are defined as the steady state, as shown in FIG. 4, in the CO2 separation and recovery material obtained in Example 1, in the 4th to 6th cycles, it was found that the change rates of the CO2 adsorption amount and the CO2 desorption amount were within ±5%, and the steady state was reached. On the other hand, as shown in FIG. 5, in the CO2 separation and recovery material obtained in Comparative Example 1, the change rate of the CO2 adsorption amount or the CO2 desorption amount did not become within ±5% for three consecutive cycles, and the steady state was not reached.

[0101] From the above results, it was found that the CO2 separation and recovery material (Example 1) supporting the polyamine compound mainly composed of N=CH2 terminal chain-like PEI is superior in the temporal stability of the CO2 adsorption / desorption performance compared to the CO2 separation and recovery material (Comparative Example 1) supporting the ethyleneamine mixture mainly composed of NH2 terminal chain-like PEI.

[0102] Also, for the CO2 separation and recovery materials obtained in Examples 1 to 2 and Comparative Examples 2 to 3, the CO2 adsorption amount per 1 g of the CO2 separation and recovery material in the steady state was determined and compared based on the CO2 separation and recovery material obtained in Comparative Example 2. The results are shown in FIG. 6.

[0103] As shown in FIG. 6, the CO2 separation and recovery materials (Examples 1 to 2) supporting the polyamine compound mainly composed of N=CH2 terminal chain-like PEI were superior in the CO2 adsorption performance in the steady state compared to the CO2 separation and recovery material (Comparative Example 2) supporting TEPA with an N-IP group terminal. This is because in the CO2 separation and recovery materials obtained in Examples 1 to 2, a polyamine compound that is difficult to volatilize is supported, and as shown in Table 3, the supported amount of the polyamine did not change before and after vacuum drying, whereas in the CO2 separation and recovery material obtained in Comparative Example 2, a polyamine compound that is easy to volatilize is supported, and as shown in Table 3, the supported amount of the polyamine decreased due to vacuum drying.

[0104] 6, the CO2 separation and capture materials obtained in Examples 1 and 2 had superior CO2 adsorption performance in a steady state compared to a CO2 separation and capture material (Comparative Example 3) supporting N-IP group-terminated PEI(600) with a similar amount of polyamine supported. This is thought to be because the isopropyl groups introduced in the CO2 separation and capture material obtained in Comparative Example 3 to improve CO2 desorption performance by utilizing their bulkiness reduced the ratio of N atoms to C atoms (N / C ratio) of the polyamine compound due to their own bulkiness, thereby reducing the number of CO2 adsorption sites. [Industrial Applicability]

[0105] As described above, according to the present invention, it is possible to obtain a CO2 separation and capture material that is less likely to desorb even during the reduced pressure drying process during production or the reduced pressure process during the CO2 desorption process, maintains a sufficient amount of polyamine compound carried, and has excellent stability over time.

[0106] Therefore, since the CO2 separation or capture method of the present invention uses such a CO2 separation and capture material, it is useful as a method for separating or capturing CO2 from exhaust gases from power plants and factories, automobiles, etc.

Claims

1. comprising a carrier and a polyamine compound supported on the carrier, The polyamine compound has 4 to 7 ethylene groups (—CH ２ -CH ２ -) is bonded via an NH group and / or an N atom ２ The NH of the chain polyethyleneimine at the group end ２ At least one of the groups is N=CH ２ N=CH ２ a CO2 copolymer containing a chain polyethyleneimine having an N=CH2 group terminal, the content of the chain polyethyleneimine having an N=CH2 group terminal being the largest among all components; ２ Separated and recovered materials.

2. The NH ２ chain-like polyethyleneimine at the N-terminal and the N=CH ２ chain-like polyethyleneimine at the N-terminal are represented by the following formula: - [CH ２ - CH ２ - NH] - The CO according to claim 1, characterized in that it contains one or more repeating units represented by ２ Separation and recovery material.

3. The N=CH ２ The double bond equivalent number (DBE) of the chain polyethyleneimine at the N=CH group terminal is DBE = 1, and the CO according to claim 1 or 2 ２ Separation and recovery material.

4. The N=CH ２ The chain polyethyleneimine at the N=CH group terminal is represented by the following formula (1): C ７ H １８ N ４ (C ２ H ４ NH) ｎ (1) 〔In formula (1), n is an integer of 1 to 4.〕 The CO according to any one of claims 1 to 3, characterized in that it is represented by ２ Separation and recovery material.

5. wherein the polyamine compound is represented by the following formulas (1-1) to (1-3): 【Chemical 1】 〔In formulas (1-1) to (1-3), n is an integer of 1 to 4.〕 represented by N=CH ２ including all of the chain polyethyleneimine at the N=CH group terminal, and the total content of the chain polyethyleneimine at the N=CH₂ group terminal represented by the formulas (1-1) to (1-3) is the maximum amount among all components. The CO according to any one of claims 1 to 4 ２ separation and recovery material.

6. wherein the polyamine compound is represented by the following formula (1-1): 【Chemical Formula 2】 〔In formula (1-1), n is an integer of 1 to 4.〕 N=CH represented by ２ It contains a chain polyethyleneimine at the N=CH2 group terminal represented by the above (1-1), and the content of the chain polyethyleneimine at the N=CH2 group terminal represented by the above (1-1) is the largest among all components. The CO according to any one of claims 1 to 5, characterized in that ２ Separation and recovery material.

7. CO to be processed ２ The gas containing ２ is brought into contact with the CO ２ separation and recovery material to adsorb CO ２ onto the CO separation and recovery material in an adsorption step; CO in the adsorption step ２ The CO adsorbed ２ separation and recovery material is (A) a method of placing under reduced pressure conditions, (B) a method of contacting with hydrogen, (C) a method of heating, by any one of the methods or a combination thereof, the CO ２ from the separated and recovered material, CO ２ desorption step of desorbing A method for separating or recovering CO, characterized by including ２ this.

8. In the separation step, by combining the method (A) and the method (C), the CO ２ is separated from the separation and recovery material ２ and removed. The method for separating or recovering CO according to claim 7 is characterized in that ２ such separation or recovery is performed.

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