A low-consolute solvent for absorbing carbon dioxide and a method for preparing the same and a use thereof

Abstract

The application provides an ionic low-eutectic solvent for absorbing carbon dioxide, the low-eutectic solvent comprising a hydrogen bond donor component and a ketone component; the ketone component is selected from 2-pyrrolidone and / or N-methyl pyrrolidone; and the hydrogen bond donor component is selected from an ether group-containing polybasic ring amine, or a functional ionic liquid, or a mixture thereof. The low-eutectic solvent has simple synthesis steps, is convenient for large-scale preparation, can quickly reach saturation in CO2 absorption, and can reach a large saturated absorption amount, and the cycle desorption rate is greater than 95%.

Description

Technical Field

[0001] This invention belongs to the field of gas separation technology, specifically relating to a eutectic solvent for absorbing carbon dioxide, its preparation method, and its uses. Background Technology

[0002] As the greenhouse effect intensifies, extreme weather events such as floods and typhoons are becoming more frequent globally. CO2, a major contributor to the greenhouse effect, has made controlling its emissions a major concern. CO2 emissions can be categorized into two types: natural sources and anthropogenic sources. Natural sources include CO2 emissions from natural processes such as volcanic eruptions, plant respiration, and the decomposition of organic matter. CO2 emitted from these natural processes is usually balanced by natural systems and does not have a significant impact on the environment. Anthropogenic sources include CO2 produced by human activities, such as burning fossil fuels like oil, natural gas, and coal, as well as CO2 generated during industrial production, transportation, construction, and agriculture. These anthropogenic CO2 emissions are very large and have a serious impact on global climate and the environment, making them one of the main causes of current global climate change. Therefore, to mitigate the catastrophic problems caused by the global greenhouse effect, measures must be taken to capture anthropogenic CO2 emissions into the atmosphere.

[0003] Ionic eutectic solvents are liquid salts composed of cations and anions, and they have wide applications in many chemical and industrial fields. In recent years, some researchers have attempted to apply ionic eutectic solvents to carbon dioxide storage and capture. Ionic eutectic solvents, as ionic liquids for absorbing carbon dioxide, possess many advantages, such as high solubility, good stability, and recyclability. Furthermore, the CO2 absorption performance of ionic eutectic solvents can be modified by adjusting their chemical structure.

[0004] Several literature reports on eutectic solvents capable of chemically absorbing CO2. One example, reported on 201910304938.5, is a highly efficient functional ionic eutectic solvent for carbon dioxide absorption. This solvent is composed of a doubly negatively charged anionic functional ionic liquid as a hydrogen bond acceptor and a polyol as a hydrogen bond donor. The doubly negatively charged anionic functional ionic liquid is synthesized in one step. The strong negative charge and basicity of the anion in the ionic liquid, along with the synergistic effect of weak acid-base and hydrogen bonding between the hydroxyl groups in the polyol and carbon dioxide, contribute to the efficient absorption of carbon dioxide. Therefore, in industrial production practice, there is still a pressing need for CO2 absorption solvents with greater CO2 absorption capacity and better recycling performance. Summary of the Invention

[0005] The present invention uses a eutectic solvent that absorbs carbon dioxide, which includes a hydrogen bond donor component and a ketone component. The eutectic solvent reduces the viscosity of the system and weakens the interaction between CO2 and the amino active sites, thereby reducing the regeneration energy consumption of the eutectic solvent.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a eutectic solvent for absorbing carbon dioxide, the eutectic solvent comprising a hydrogen bond donor component and a ketone component;

[0008] The ketone component is selected from 2-pyrrolidone and / or N-methylpyrrolidone;

[0009] The hydrogen bond donor component is selected from ether-containing polycyclic amines with the structure shown in Formula (I), or functional ionic liquids with the structure shown in Formula (II), or mixtures thereof:

[0010]

[0011] Wherein, G1, G2, G3, G4, and G5 are each independently selected from N or C(R); R, R', R1, R2, R3, R4, and R5 are each independently selected from the following substituted or unsubstituted groups: hydrogen atom, C0-C6 alkylene-amino, C0-C6 alkylene-hydroxy, C1-C6 alkyl, C1-C6 alkoxy, C0-C6 alkylene-NH-C1-C6 alkyl, C0-C6 alkylene-N(C1-C6 alkyl)2, C1-C6 alkylene-O-C 1-C6 alkyl, or C1-C6 alkylene-O-C0-C6 alkyl-amino; when G1, G2, G3, G4 and G5 are all selected from C(R), at least one of R, R', R1, R2, R3, R4 and R5 is selected from the following substituted or unsubstituted groups: C0-C6 alkylene-amino, C0-C6 alkylene-NH-C1-C6 alkyl, C0-C6 alkylene-N(C1-C6 alkyl)2, or C1-C6 alkylene-O-C0-C6 alkyl-amino;

[0012] When R, R', R1, R2, R3, R4 and R5 are each independently selected from substituted groups, the substituents are selected from one or more of amino, hydroxyl, C1-C6 alkyl, and C1-C6 alkoxy groups;

[0013] X - Selected from Cl - ,Br - I - BF4 - PF6 - NO3 - NTf2 - ClO4 - HSO3 - HSO4 - H2PO4 - CH3COO - CH3(CH2) nCOO - SCN - SbF6 - AsF6 - CF3 - CF3COO - CH3SO4 - C2H6SO4 - C8H 17 SO4 - C4F9SO3 - CF3 (CF2) n SO3 - (CF3SO2)3C - (C2F5SO2)2N - (CF3SO2)2N - CH3CH(OH)COO - One or more of dodecyl sulfonate, benzene sulfonate, and p-toluene sulfonate, wherein each of n is independently selected from an integer from 0 to 12.

[0014] The ether-containing polycyclic amine or functional ionic liquid, or a mixture thereof, serves as the hydrogen bond donor component. Due to its specific conjugated structure, the hydrogen bond donor component readily forms N-cations, resulting in higher CO2 absorption efficiency and greater CO2 absorption capacity in the eutectic solvent compared to conventional straight-chain alkanolamine eutectic solvents. The ketone component acts as the hydrogen bond acceptor. Due to the strong chemical interaction between the electronegative sites on pyrrolidone and CO2, as well as the physical interaction between pyrrolidone as a high-boiling-point organic solvent and CO2, and the interaction between the N-heterocyclic structure of the ketone component and CO2, the interaction between CO2 and the amine groups is weakened. This enables high-capacity CO2 absorption and selective separation. Furthermore, the addition of the high-boiling-point solvent reduces the viscosity of the ionic liquid system, promotes CO2 desorption cycling, and facilitates the regeneration process of the low eutectic solvent, reducing regeneration energy consumption.

[0015] X in the functional ionic liquid of formula (II) - It can also act as a hydrogen bond acceptor, X in functional ionic liquids - Its strong negative electronegativity, combined with the hydrogen bond donor component containing ether-based polycyclic rings, works together to provide more CO2 absorption sites, thereby increasing the CO2 absorption capacity.

[0016] Preferably, in formula (I), at least one of G1, G2, G3, G4 and G5 is N, and at least one of R, R1, R2, R3, R4 and R5 is independently selected from the following substituted or unsubstituted groups: C0-C6 alkylene-amino, C0-C6 alkylene-NH-C1-C6 alkyl, C0-C6 alkylene-N(C1-C6 alkyl)2, or C1-C6 alkylene-O-C0-C6 alkyl-amino; when R, R1, R2, R3, R4 and R5 are each independently selected from substituted groups, the substituent is selected from one or more of amino, hydroxyl, C1-C6 alkyl, and C1-C6 alkoxy.

[0017] The polycyclic amine containing ether groups has oxygen atoms in the polycyclic ring and nitrogen atoms in the polycyclic ring. The substituent structure of the polycyclic ring still contains nitrogen or oxygen atoms, which can enhance the conjugation of each atom and make it easier to form N positive ions, thereby further improving the CO2 absorption efficiency of the eutectic solvent and increasing the CO2 absorption capacity.

[0018] In some preferred embodiments, in formula (I), R, R1, R2, R3, R4, and R5 are each independently selected from -H, -NH2, -CH3, -C2H5, -(CH2)2-CH3, -CH(CH3)2, -(CH2)3-CH3, -CH2-CH(CH3)-CH3, -(CH3)CHCH2CH3, -CH2OH, -OCH3, -OC2H5, -O-(CH2)2-CH3, -CH2-NH2, -(CH2)2-NH2, -(CH2)3-NH2, -NH-CH3, -NH-C2H5, -NH-(CH2)3-CH3, - CH2-O-CH2-NH2, -CH2-O-(CH2)2-NH2, -CH2-OC(CH3)2-NH2, -CH2-O-CH(NH2)2, -(CH2)2-O-NH2, -O-CH2-NH2, -O-(CH2)2-NH2, -NH-CH2-O -CH3, -CH2-NH-O-CH3, -CH(CH2-NH2)2, -CH(OH)-CH2-NH2, -CH(CH2OH)-(CH2)2-NH2, -CH(CH3)-CH2-NH2, -CH(OH)-C(CH3)2-NH2, -CH2-C (CH3)2-NH2, -CH(CH3)-CH(CH3)-NH2, or -(CH2)2-NH-CH2CH(OCH3)2; when G1, G2, G3, G4, and G5 are all selected from C(R), at least one of R, R1, R2, R3, R4, and R5 is selected from -NH2, -CH2-NH2, -(CH2)2-NH2, -(CH2)3-NH2, -NH-CH3, -NH-C2H5, -NH-(CH2)3-CH3, -CH2-O-CH2-NH2, -CH2-O-(CH2)2-NH2, -CH2-OC(CH3)2-NH2, -CH2- O-CH(NH2)2, -(CH2)2-O-NH2, -O-CH2-NH2, -O-(CH2)2-NH2, -NH-CH2-O-CH3, -CH2-NH-O-CH3, -CH(CH2-NH2)2, -CH(OH)-CH2-NH2, -CH(CH 2OH)-(CH2)2-NH2, -CH(CH3)-CH2-NH2, -CH(OH)-C(CH3)2-NH2, -CH2-C(CH3)2-NH2, -CH(CH3)-CH(CH3)-NH2 or -(CH2)2-NH-CH2CH(OCH3)2.

[0019] Preferably, in formula (I), at least one of G1, G2, G3, G4, and G5 is N, and at least one of R, R1, R2, R3, R4, and R5 is selected from -NH2, -CH2-NH2, -(CH2)2-NH2, -(CH2)3-NH2, -NH-CH3, -NH-C2H5, -NH-(CH2)3-CH3, -CH2-O-CH2-NH2, -CH2-O-(CH2)2-NH2, -CH2-OC(CH3)2-NH2, -CH2-O-CH(NH2)2, -(CH2)2-O-NH2, -O-CH2-NH2, -O-(CH2)2-NH2, -NH-CH2-O-CH3, -CH2-NH-O-CH3, -CH(CH2-NH2)2, -CH(OH)-CH2-NH2,

[0020] -CH(CH2OH)-(CH2)2-NH2, -CH(CH3)-CH2-NH2, -CH(OH)-C(CH3)2-NH2, -CH2-C(CH3)2-NH2, -CH(CH3)-CH(CH3)-NH2 or

[0021] -(CH2)2-NH-CH2CH(OCH3)2.

[0022] In some preferred embodiments, the ether-containing polycyclic amine has the structure shown in the following formula:

[0023]

[0024]

[0025] In some preferred embodiments, in formula (II), R, R', R1, R2, R3, R4, and R5 are each independently selected from -H, -NH2, -CH3, -C2H5, -(CH2)2-CH3, -CH(CH3)2, -(CH2)3-CH3, -CH2-CH(CH3)-CH3, -(CH3)CHCH2CH3, -CH2OH, -OCH3, -OC2H5, -O-(CH2)2-CH3, -CH2-NH2, -(CH2)2-NH2, -(CH2)3-NH2, -NH-CH3, -NH-C2H5, -NH-(CH2)3-CH3, -CH2-O-CH2-NH2, and -CH2-O-(CH2). 2-NH2, -CH2-OC(CH3)2-NH2, -CH2-O-CH(NH2)2, -(CH2)2-O-NH2, -O-CH2-NH2, -O-(CH2)2-NH2, -NH-CH2-O-CH3, -CH2-NH-O-CH3, -CH(CH2-NH2)2, -CH(OH)- CH2-NH2, -CH(CH2OH)-(CH2)2-NH2, -CH(CH3)-CH2-NH2, -CH(OH)-C(CH3)2-NH2, -CH2-C(CH3)2-NH2, -CH(CH3)-CH(CH3)-NH2 or -(CH2)2-NH-CH2CH(OCH3)2;

[0026] Preferably, the X - Selected from NTf2 - NO3 - CH3COO - BF4 - One or more of them.

[0027] In some preferred embodiments, the functional ionic liquid has the structure shown in the following formula:

[0028]

[0029]

[0030] In some preferred embodiments, the mass ratio of the hydrogen bond donor component to the ketone component in the eutectic solvent is (1-10):1; preferably, the mass ratio is (1-5):1; more preferably, the mass ratio is (1-3):1. The selection of these mass ratios makes it easier for the hydrogen bond donor component to form N-cations and allows for better interaction between the N-heterocyclic structure of the ketone component and CO2, weakening the interaction between CO2 and the amine group, promoting the desorption cycle of CO2, thereby making the eutectic solvent regeneration process easier to occur and reducing regeneration energy consumption.

[0031] When the hydrogen bond donor component is selected from a mixture of the ether-containing polycyclic amine and the functional ionic liquid, the ether-containing polycyclic amine and the functional ionic liquid together act as hydrogen bond donors, exhibiting higher CO2 absorption capacity and absorption efficiency; and X - Together with the ketone component, it acts as a hydrogen bond acceptor, further enhancing the electronegativity of the mixture, providing more CO2 absorption sites, and increasing the CO2 absorption capacity. In some preferred embodiments, when the hydrogen bond donor component is selected from the mixture of the ether-containing polycyclic amine and the functional ionic liquid, the mass ratio of the ether-containing polycyclic amine to the functional ionic liquid is (1-5):1, preferably (1-2):1.

[0032] A third aspect of the present invention provides a method for preparing the above-mentioned eutectic solvent, wherein the hydrogen bond donor component and the ketone component are stirred and mixed at 50-80°C for 5-8 hours to obtain the eutectic solvent.

[0033] The fourth aspect of the present invention provides a method for applying the above-described eutectic solvent or the eutectic solvent prepared by the above-described preparation method to the absorption, separation or capture of CO2.

[0034] In some preferred embodiments, CO2 is absorbed at an absorption temperature of 40-60°C and CO2 is released at a desorption temperature of 90-110°C.

[0035] The technical solution provided by this invention has the following beneficial effects:

[0036] (1) This invention provides ether-containing polycyclic amines, functional ionic liquids, or mixtures thereof as hydrogen bond donor components. Due to their specific conjugated structures, these hydrogen bond donor components are more likely to form N-cations, resulting in higher CO2 absorption efficiency and greater CO2 absorption capacity in the eutectic solvent compared to conventional straight-chain alkanolamine eutectic solvents. By providing ketone components as hydrogen bond acceptors, the strong chemical interaction between the electronegative sites on pyrrolidone and CO2, as well as the physical interaction between pyrrolidone as a high-boiling-point organic solvent and CO2, and its synergistic effect with ether-containing polycyclic amines, enables high-capacity CO2 absorption and selective separation. Furthermore, the addition of pyrrolidone as a high-boiling-point solvent reduces the viscosity of the ionic liquid system, promotes CO2 desorption cycling, and further enhances CO2 absorption mass transfer efficiency.

[0037] (2) This invention utilizes X in functional ionic liquids - X, as a hydrogen bond acceptor, is a functional ionic liquid. - The strong negative charge of the nitrogen and the nitrogen cation formed by the hydrogen bond donor components work together to provide more CO2 absorption sites and increase the CO2 absorption capacity.

[0038] (3) The present invention uses a eutectic solvent including hydrogen bond donor components and ketone components as CO2 absorbent. The synthesis steps are simple and convenient for large-scale preparation. CO2 absorption can quickly reach saturation and can achieve a large saturation absorption capacity. The cycle desorption rate is >95%. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the CO2 absorption device used in one embodiment of the present invention.

[0040] Explanation of reference numerals in the attached drawings: 1—Air inlet device; 2—Stirring device; 3—Heating device; 4—Analyzing device. Detailed Implementation

[0041] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not imply that the scope of the invention is limited thereto.

[0042] The grouting material provided by this invention can be prepared and / or used using equipment known in the art, preferably the following equipment:

[0043] Figure 1 The invention illustrates a CO2 absorption device using an absorbent in one embodiment of the present invention. The CO2 absorption device is a phase equilibrium device, which includes: an air inlet device 1, a stirring device 2, a heating device 3, and an analysis device 4.

[0044] The air inlet device 1 is used to introduce a simulated mixed gas of CO2 and N2 into the CO2 absorption device; the stirring device 2 is used to stir the mixture of functional ionic liquid and ketone or the mixture of ether-containing polycyclic amine and ketone; the heating device 3 is used to heat the mixture of functional ionic liquid and ketone or the mixture of ether-containing polycyclic amine and ketone; and the analysis device 4 is used to measure and control various performance parameters of CO2 during the absorption and desorption process.

[0045] Instrumentation: Both the absorption and desorption amounts were obtained by integrating the CO2 concentration and flow rate read by the analyzer over time.

[0046] Example 1

[0047] Example 1-1

[0048] 50g of N-aminopropylmorpholine (1), 50g of N-butyl-N-aminopropylmorpholine acetate (1), and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8 hours to obtain a eutectic solvent. The absorption temperature was set at 40℃, the CO2 flow rate at 0.47L / min, the N2 flow rate at 3.1L / min, the stirring speed at 300r / min, and the CO2 concentration at approximately 14%. Saturation was achieved in approximately 25 minutes, with a saturation absorption capacity of 4mol CO2 / L solvent. During the desorption process, the solution was heated to 90℃ and kept constant, the stirring speed remained unchanged, and the N2 flow rate was set at 1.2L / min. Desorption was completed in approximately 20 minutes, with a desorption rate >95%.

[0049] Examples 1-2

[0050] 50g of N-aminopropylmorpholine (1), 50g of N-butyl-N-aminopropylmorpholine acetate (1), and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 60℃ for 7h to obtain a eutectic solvent. The absorption temperature was set at 50℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 24min, with a saturated absorption capacity of 3.7mol CO2 / L solvent. During the desorption process, the solution was heated to 100℃ and kept constant, with the stirring speed unchanged. The N2 flow rate was set at 1.2L / min, and desorption was completed in approximately 20min, with a desorption rate >95%.

[0051] Examples 1-3

[0052] 50g of N-aminopropylmorpholine (1), 50g of N-butyl-N-aminopropylmorpholine bis(trifluoromethanesulfonyl)imide salt (2), and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 80℃ for 5h to obtain a eutectic solvent. The absorption temperature was set at 60℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 22min, with a saturated absorption capacity of 3.4mol CO2 / L solvent. During the desorption process, the solution was heated to 110℃ and kept constant, with the stirring speed unchanged. The N2 flow rate was set at 1.2L / min, and desorption was completed in approximately 20min, with a desorption rate >95%.

[0053] Examples 1-4

[0054] 50g of N-aminopropylmorpholine (1), 50g of N-butyl-N-aminopropylmorpholine acetate (1), and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8 hours to obtain a eutectic solvent. The absorption temperature was set at 40℃, the CO2 flow rate at 0.25L / min, the N2 flow rate at 3.3L / min, the stirring speed at 300r / min, and the CO2 concentration at approximately 14%. Saturation was achieved in approximately 15 minutes, with a saturated absorption capacity of 3.0mol CO2 / L solvent. During the desorption process, the solution was heated to 90℃ and kept constant, the stirring speed remained unchanged, and the N2 flow rate was set at 1.2L / min. Desorption was completed in approximately 20 minutes, with a desorption rate >95%.

[0055] As can be seen from Examples 1-1 to 1-4: when CO2 flow rate is 0.25-0.47 L / min, N2 flow rate is 3.1-3.3 L / min, and absorption temperature is 40-60℃, CO2 reaches saturation within 25 minutes, and the saturated absorption capacity is greater than 3.0 mol CO2 / L solvent; when carbon dioxide is desorbed at a desorption temperature of 90-110℃ and N2 flow rate of 1.2-1.5 L / min, desorption is completed in about 20 minutes, and the desorption rate is >95%.

[0056] Example 2

[0057] 100g of an ether-containing polycyclic amine ② and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8 hours to prepare a eutectic solvent. The absorption temperature was set at 40℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 20 minutes, with a saturated absorption capacity of 3.6mol CO2 / L solvent. During desorption, the solution was heated to 100℃ and maintained at a constant temperature, with the stirring speed unchanged. The N2 flow rate was set at 1.5L / min, and desorption was completed in approximately 18 minutes, with a desorption rate >95%.

[0058] Example 3

[0059] 100g of an ether-containing polycyclic amine (③) and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8 hours to prepare a eutectic solvent. The absorption temperature was set at 40℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 18 minutes, with a saturated absorption capacity of 3.4mol CO2 / L solvent. During desorption, the solution was heated to 100℃ and maintained at a constant temperature, with the stirring speed unchanged. The N2 flow rate was set at 1.5L / min. Desorption was completed in approximately 16 minutes, with a desorption rate >95%.

[0060] Example 4

[0061] 50g of N-aminopropylmorpholine ①, 50g of tetrafluoroborate (3) containing ether-based polycyclic amines, and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8h to prepare a eutectic solvent. The absorption temperature was set at 40℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 20min, with a saturated absorption capacity of 4.1mol CO2 / L solvent. During the desorption process, the solution was heated to 100℃ and kept constant, with the stirring speed unchanged. The N2 flow rate was set at 1.5L / min, and desorption was completed in approximately 20min, with a desorption rate >95%.

[0062] Example 5

[0063] 100g of ether-containing polycyclic amine ④ and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8 hours to prepare a eutectic solvent. The absorption temperature was set at 40℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 20 minutes, with a saturation absorption capacity of 3.65mol CO2 / L solvent. During desorption, the solution was heated to 100℃ and maintained at a constant temperature, with the stirring speed unchanged. The N2 flow rate was set at 1.5L / min. Desorption was completed in approximately 20 minutes, with a desorption rate >95%.

[0064] Example 6

[0065] 100g of an ether-containing polycyclic amine (⑤) and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8 hours to prepare a eutectic solvent. The absorption temperature was set at 40℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 20 minutes, with a saturation absorption capacity of 3.6 mol CO2 / L solvent. During desorption, the solution was heated to 100℃ and maintained at a constant temperature with a constant stirring speed. The N2 flow rate was set at 1.5L / min, and desorption was completed in approximately 18 minutes, with a desorption rate >95%.

[0066] Example 7

[0067] 100g of N-butyl-N-aminopropylmorpholine bis(trifluoromethanesulfonyl)imide salt (2) and 50g of 2-pyrrolidone were added to a phase equilibrium apparatus and stirred at 50℃ for 8h to obtain a eutectic solvent. The absorption temperature was set at 40℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 20min, with a saturation absorption capacity of 4mol CO2 / L solvent. During the desorption process, the solution was heated to 100℃ and kept constant, with the stirring speed unchanged. The N2 flow rate was set at 1.5L / min, and desorption was completed in approximately 18min, with a desorption rate >95%.

[0068] As can be seen from Examples 1 to 7: by providing an ether-containing polycyclic amine as a hydrogen bond donor and pyrrolidone as a hydrogen bond acceptor, a eutectic solvent for absorbing CO2 can be prepared, as in Examples 1-6. Alternatively, by providing a nitrogen cation containing an ether-containing polycyclic ring in a functional ionic liquid as a hydrogen bond donor and X in the functional ionic liquid as a hydrogen bond acceptor, a eutectic solvent for absorbing CO2 can be prepared. - As a hydrogen bond acceptor, and with the addition of a ketone, as in Example 7, the CO2 absorption capacity and CO2 absorption mass transfer efficiency are increased. In the above examples, CO2 reaches saturation within 25 minutes, with a saturation absorption capacity greater than 3.0 mol CO2 / L solvent; desorption is completed in approximately 20 minutes, with a desorption rate >95%.

[0069] Comparative Example 1

[0070] 150g of 30% ethanolamine solution was added to a phase equilibrium apparatus and stirred at 50℃ for 8 hours to prepare a eutectic solvent. The absorption temperature was set at 40℃, CO2 flow rate at 0.47L / min, N2 flow rate at 3.1L / min, stirring speed at 300r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 35 minutes, with a saturation absorption capacity of 2.46mol CO2 / L solvent. During desorption, the solution was heated to 100℃ and maintained at a constant temperature, with the stirring speed unchanged. The N2 flow rate was set at 1.5L / min. Desorption was completed in approximately 30 minutes, with a desorption rate of ~88%.

[0071] Comparative Example 2

[0072] 150 g of N-butyl-N-aminopropylmorpholine acetate was added to a phase equilibrium apparatus and stirred at 50 °C for 8 h to prepare a eutectic solvent. The absorption temperature was set at 40 °C, CO2 flow rate at 0.47 L / min, N2 flow rate at 3.1 L / min, stirring speed at 300 r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 35 min, with a saturation absorption capacity of 5 mol CO2 / L solvent. During desorption, the solution was heated to 100 °C and maintained at a constant temperature, with the stirring speed unchanged. The N2 flow rate was set at 1.5 L / min, and desorption was completed in approximately 50 min, with a desorption rate of approximately 80%.

[0073] Comparative Example 3

[0074] 150 g of 2-pyrrolidone was added to a phase equilibrium apparatus and stirred at 50 °C for 8 h to prepare a eutectic solvent. The absorption temperature was set at 40 °C, CO2 flow rate at 0.47 L / min, N2 flow rate at 3.1 L / min, stirring speed at 300 r / min, and CO2 concentration at approximately 14%. Saturation was achieved in approximately 10 min, with a saturation absorption capacity of 0.05 mol CO2 / L solvent. During desorption, the solution was heated to 100 °C and maintained at a constant temperature with a constant stirring speed. The N2 flow rate was set at 1.5 L / min, and desorption was completed in approximately 10 min, with a desorption rate of approximately 100%.

[0075] In Comparative Example 1, because ethanolamine is a straight-chain amine, the CO2 saturation time increased, resulting in lower absorption and increased desorption time, leading to a lower desorption rate. Comparative Example 2, using only functional ionic liquids, showed a significant increase in desorption time and a marked decrease in desorption rate, resulting in poor recycling performance. Comparative Example 3, using only ketones, significantly reduced CO2 absorption and failed to solve the CO2 absorption problem.

[0076] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A deep eutectic solvent for absorbing carbon dioxide, characterized by comprising The eutectic solvent is composed of a hydrogen bond donor component and a ketone component, wherein the mass ratio of the hydrogen bond donor component to the ketone component is (1-5):1; The ketone component is selected from 2-pyrrolidone and / or N-methylpyrrolidone; The hydrogen bond donor component is selected from ether-containing polycyclic amines with the structure shown in Formula (I), or functional ionic liquids with the structure shown in Formula (II), or mixtures thereof: In formula (I), G1, G2, G4, and G5 are each independently selected from C(R), G3 is selected from N or C(R); R is selected from -H; R1, R2, R3, R4, and R5 are each independently selected from: -H, -NH2, -CH3, -C2H5, -(CH2)2-CH3, -CH(CH3)2, -(CH2)3-CH3, -CH2-CH(CH3)-CH3, -(CH3)CHCH2CH3, -CH2OH, -OCH3, -OC2H5, -O-(CH2)2-CH3, -CH2-NH2, -(CH2)2-NH2, -(CH2)3-NH2, -NH-CH3, -NH-C 2H5, -NH-(CH2)3-CH3, -CH2-O-CH2-NH2, -CH2-O-(CH2)2-NH2, -CH2-OC(CH3)2-NH2, -CH2-O-CH(NH2)2, -(CH2)2-O-NH2, -O-CH2-NH2, -O-(CH2) 2-NH2, -NH-CH2-O-CH3, -CH2-NH-O-CH3, -CH(CH2-NH2)2, -CH(OH)-CH2-NH2, -CH(CH2OH)-(CH2)2-NH2, -CH(CH3)-CH2-NH2, -CH(OH)-C(CH3)2- NH2, -CH2-C(CH3)2-NH2, -CH(CH3)-CH(CH3)-NH2 or -(CH2)2-NH-CH2CH(OCH3)2; when G1, G2, G3, G4 and G5 are all selected from C(R), R is selected from: -H; at least one of R1, R2, R3, R4 and R5 is selected from: -NH2, -CH2-NH2, -(CH2)2-NH2, -(CH2)3-NH2, -NH-CH3, -NH-C2H5, -NH-(CH2)3-CH3, -CH2-O-CH2-NH2, -CH2-O-(CH2)2-NH2, -CH2-OC(CH3)2- NH2, -CH2-O-CH(NH2)2, -(CH2)2-O-NH2, -O-CH2-NH2, -O-(CH2)2-NH2, -NH-CH2-O-CH3, -CH2-NH-O-CH3, -CH(CH2-NH2)2, -CH(OH)-CH2-NH2, -C H(CH2OH)-(CH2)2-NH2, -CH(CH3)-CH2-NH2, -CH(OH)-C(CH3)2-NH2, -CH2-C(CH3)2-NH2, -CH(CH3)-CH(CH3)-NH2 or -(CH2)2-NH-CH2CH(OCH3)2; In formula (II), G1, G2, G4, and G5 are each independently selected from C(R); R, R1, R2, R4, and R5 are each independently selected from -H; R' is selected from -CH3, -C2H5, -(CH2)2-CH3, -CH(CH3)2, -(CH2)3-CH3, -CH2-CH(CH3)-CH3, or -(CH3)CHCH2CH3; R3 is selected from -NH2, -CH2-NH2, -(CH2)2-NH2, -(CH2)3-NH2, -NH-CH3, -NH-C2H5, -NH-(CH2)3-CH3, -CH2-O-CH2-NH2, -CH2-O-(CH2)2-NH2, -CH2 -OC(CH3)2-NH2, -CH2-O-CH(NH2)2, -(CH2)2-O-NH2, -O-CH2-NH2, -O-(CH2)2-NH2, -NH-CH2-O-CH3, -CH2-NH-O-CH3, -CH(CH2-NH2)2, -CH(OH)-CH2-N H2, -CH(CH2OH)-(CH2)2-NH2, -CH(CH3)-CH2-NH2, -CH(OH)-C(CH3)2-NH2, -CH2-C(CH3)2-NH2, -CH(CH3)-CH(CH3)-NH2 or -(CH2)2-NH-CH2CH(OCH3)2; X - selected from one or more of BF4 - , NO3 - , NTf2 - , CH3COO - .

2. The eutectic solvent according to claim 1, characterized in that, The ether-containing polycyclic amine has the structure shown in the following formula: 。 3. The eutectic solvent according to claim 1, characterized in that, The functional ionic liquid has the structure shown in the following formula: 。 4. The eutectic solvent according to claim 1, characterized in that... In the eutectic solvent, the mass ratio of the hydrogen bond donor component to the ketone component is (1-3):

1.

5. The eutectic solvent according to any one of claims 1-4, characterized in that, When the hydrogen bond donor component is selected from a mixture of the ether-containing polycyclic amine and the functional ionic liquid, the mass ratio of the ether-containing polycyclic amine to the functional ionic liquid is (1-5):

1.

6. The eutectic solvent according to claim 5, characterized in that, When the hydrogen bond donor component is selected from a mixture of the ether-containing polycyclic amine and the functional ionic liquid, the mass ratio of the ether-containing polycyclic amine to the functional ionic liquid is (1-2):

1.

7. A method for preparing a eutectic solvent as described in any one of claims 1-6, characterized in that, The hydrogen bond donor component and the ketone component are stirred and mixed at 50-80°C for 5-8 hours to obtain a eutectic solvent.

8. The eutectic solvent according to any one of claims 1-6 or the eutectic solvent prepared by the preparation method according to claim 7, for use in the absorption, separation or capture of CO2.

9. The use according to claim 8, wherein the eutectic solvent absorbs CO2 at an absorption temperature of 40-60°C and releases CO2 at a desorption temperature of 90-110°C.

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