A complexing agent and separation method for carbon isotope separation

Abstract

The application provides a complexing agent and a separation method for carbon isotope separation, and belongs to the technical field of isotope production processes. The complexing agent comprises a first component and a second component. The first component is an organic amine, and the second component is any one of a small-molecule hydrocarbon, a small-molecule ether or a small-molecule ketone. The second component can destroy hydrogen bonds between amine molecules by being combined with the first component. In addition, the second component is a small-molecule organic substance, can be inserted into the gap between amine molecules by a molecular dilution effect, and can physically separate molecules, so that the viscosity of the organic amine liquid is further reduced. In the exchange reaction, the diffusion rate of the 13C-amine complex in the liquid phase is improved, the isotope exchange time is shortened, and the energy consumption is reduced.

Description

Technical Field

[0001] This disclosure belongs to the field of isotope production technology, specifically relating to a complexing agent and separation method for carbon isotope separation. Background Technology

[0002] Carbon has two stable isotopes, namely carbon-12 (98.89%) and carbon-13 (1.1%). These carbon-12 and carbon-13 have wide industrial applications. For example, the 1.1% carbon-13 is concentrated to 99% carbon-13 for use as a tracer in chemistry, biochemistry, and the environment. Carbon-13-labeled compounds of urea and glucose are used for non-invasive diagnosis and metabolite studies of various diseases. For instance, the breath test, which diagnoses various diseases by measuring the carbon-13 content of exhaled breath after ingesting a carbon-13-labeled compound, has seen its application expand due to its diagnostic accuracy and convenience.

[0003] Currently, the main industrial production method for carbon isotopes is cryogenic distillation, which relies solely on a single-stage separation process. This method suffers from drawbacks such as high slurry viscosity, high energy consumption, poor mass transfer, and susceptibility to clogging. Furthermore, the existing methods yield... 13 C isotopes and 12 The abundance of carbon isotopes is relatively low. Therefore, it is necessary to propose a new complexing agent to reduce viscosity, improve mass transfer efficiency, reduce energy consumption, and simultaneously increase the abundance of carbon isotopes. Summary of the Invention

[0004] This disclosure aims to at least address one of the technical problems existing in the prior art by providing a complexing agent and a separation method for carbon isotope separation.

[0005] In one aspect, this disclosure provides a complexing agent for carbon isotope separation, the complexing agent comprising a first component and a second component; wherein, The first component is an organic amine; The second component is any one of a small molecule hydrocarbon, a small molecule ether, or a small molecule ketone.

[0006] Optionally, the small molecule hydrocarbon is selected from C5-C64. 10 Alkanes, C5-C 10 Cycloalkanes, C5-C 10 Aromatic hydrocarbons, C5-C 10 heteroaromatics or C5-C 10 Olefins; the C5-C 10 The alkane is optionally substituted with 1, 2, or 3 halogens; the C5-C 10 The cycloalkanes are optionally substituted with 1, 2, or 3 halogens; the C5-C 10 The aryl hydrocarbon is optionally substituted with one, two, or three halogens; the C5-C10 The heteroaromatic hydrocarbons are optionally substituted with 1, 2 or 3 halogens or the C5-C... 10 The olefin is optionally substituted with one, two or three halogens; preferably, the halogens include one or more of fluorine, chlorine, and bromine; more preferably, the small molecule hydrocarbon is selected from 1-chloropentane, 1,2-dichloropentane, 1-chlorohexane, n-heptane, 1-chlorooctane, dichlorocyclohexane, and chlorocyclopentane.

[0007] Optionally, the small molecule ether is represented by the following compound with the general formula R1OR2. R1 and R2 are independently selected from C1-C 10 Alkyl, C3-C 10 cycloalkyl or C5-C 10 Aryl, the C1-C 10 The alkyl group may optionally be substituted with a C1-C3 alkyl group, wherein the C5-C 10 The aryl group may be optionally substituted with a C1-C3 alkyl group; the C3-C 10 The cycloalkyl group may be optionally substituted with a C1-C3 alkyl group; Preferably, R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, The ether is selected from one of isobutyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, phenyl, benzyl, etc.; more preferably, the small molecule ether is selected from diisopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether or di-n-propyl ether.

[0008] Optionally, the small molecule ketone is represented by the following general formula R1(C=O)R2, wherein R1 and R2 are independently selected from C1-C2. 10 Alkyl, C3-C 10 cycloalkyl, C5-C 10 Aryl groups or R1, R2 form cyclic ketones with C=O, wherein the C1-C 10 The alkyl group may optionally be substituted with a C1-C3 alkyl group, wherein the C5-C 10 The aryl group may be optionally substituted with a C1-C3 alkyl group, wherein the C3-C 10 The cycloalkyl group is optionally substituted with a C1-C3 alkyl group; the cycloketone is optionally substituted with a C1-C3 alkyl group; preferably, R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, phenyl, benzyl or R1 and R2 form a C4-C8 cycloketone with C=O; Further preferably, the small molecule ketone is selected from one of cyclopentanone, cyclohexanone, methylcyclopentanone, methylcyclohexanone, methyl isobutyl ketone, etc.

[0009] Optionally, the organic amine is selected from compounds of Formula 1 below.

[0010] R1, R2, and R3 can each be independently selected as hydrogen, C1-C8 alkyl, C5-C8 heteroaryl, C3-C8 cycloalkyl, C5-C8 aryl, or C3-C8 heterocyclic, and R1, R2, and R3 cannot all be hydrogen at the same time. The C1-C8 alkyl group is optionally substituted with 1, 2, or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; the C3-C8 cycloalkane is optionally substituted with 1, 2, or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; the C5-C8 heteroaryl group is optionally substituted with 1, 2, or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; the C5-C8 aryl group is optionally substituted with 1, 2, or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; the heteroatom in the heteroaryl or heterocycloalkane is selected from N.

[0011] Optionally, R1, R2, and R3 can be independently selected as hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, phenyl, benzyl, phenoxymethyl, phenoxyethyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, aminomethyl, aminoethyl, aminopropyl, fluoromethyl, fluoroethyl, chloromethyl, chloroethyl, bromomethyl, bromoethyl, difluoromethyl, trifluoromethyl, aryl, or heteroaryl, and R1, R2, and R3 cannot all be hydrogen.

[0012] Optionally, where R 1、 R 2、 R3 is independently selected from hydrogen or C1-C3 alkyl, and R1, R 2、 R3 is not simultaneously hydrogen, and the C1-C3 alkyl group is optionally substituted with hydroxyl or methoxy groups.

[0013] Optionally, R1 is hydrogen, R 2、 R3 is selected from hydrogen or C1-C3 alkyl, and R 2、 R3 is not simultaneously hydrogen; the C1-C3 alkyl group is optionally substituted with a hydroxyl or methoxy group.

[0014] Optionally, the organic amine is at least one of primary amines, secondary amines, tertiary amines, and aromatic amines.

[0015] The primary amine refers to an organic amine formed by replacing one hydrogen atom in an ammonia (NH3) molecule with a hydrocarbon group, and its general formula is R-NH2. The primary amine is selected from ethylamine, n-propylamine, n-butylamine, butanediamine, monoethanolamine, p-phenylenediamine, or isobutanolamine.

[0016] The secondary amine refers to an organic amine formed by replacing two hydrogen atoms in an ammonia molecule with a hydrocarbon group, and its general formula is R2-NH (the two hydrocarbon groups may be the same or different). Optionally, the secondary amine is selected from alkyl straight-chain secondary amines, alkyl branched-chain secondary amines, or cyclic secondary amines; preferably, the secondary amine is selected from diethylamine, diethanolamine, dibutylamine, diisopropanolamine, diisopropylamine, N-isopropylmethylamine, N-methylaniline, piperidine, or pyrrolidine.

[0017] The tertiary amine refers to an organic amine in which all three hydrogen atoms in the ammonia molecule are replaced by hydrocarbon groups, with the general formula R3N (the three hydrocarbon groups can be the same or different), and there are no hydrogen atoms on the nitrogen atom. Examples include triethanolamine (TEA), N-methyldiethanolamine, trimethylamine, triethylamine, or N,N-dimethylaniline.

[0018] The aromatic amine refers to an organic amine in which the amino group is directly attached to an aromatic ring (such as a benzene ring). Examples include N-methylaniline, N,N-dimethylaniline, aniline, or diphenylamine.

[0019] Optionally, the organic amine complexing agent is at least one selected from diethanolamine, diethylamine, ethylene glycolamine, butanediamine, triethanolamine, N-methylaniline, p-phenylenediamine, piperidine, and pyrrolidine.

[0020] Optionally, the molar ratio of carbon dioxide to organic amine is (0.20~0.80):1; for example, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1; preferably, the molar ratio is (0.3~0.6):1.

[0021] Optionally, the content of the second component is 10-30% of the content of the first component. For example, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or 30%.

[0022] In another aspect of this disclosure, a method for separating carbon isotopes is proposed, the method comprising: Carbon dioxide and a complexing agent are introduced into the complexing tower. The carbon dioxide contains... 12 CO2 complexes with organic amines to form... 12 C-amine complex; the complexing agent is the complexing agent described above; The 12 The C-amine complex flows into an exchange tower, and carbon dioxide gas is introduced into the exchange tower. The carbon dioxide contains... 13 CO2 and the above 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex; The 13C-amine complexes are pyrolyzed by heating in a pyrolysis tower into pyrolysis products and... 13 CO2; The pyrolysis products form organic amines and impurities in the impurity removal tower.

[0023] Optionally, the temperature of the complexing tower is 25-35℃; it can be selected from 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34℃ or 35℃.

[0024] Optionally, the temperature of the exchange tower is 10-60℃; it can be selected from 10℃, 12℃, 14℃, 16℃, 18℃, 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 38℃, 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃ or 60℃.

[0025] Optionally, the heating and pyrolysis temperature of the pyrolysis tower is 100-250℃; it can be selected from 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃ or 250℃.

[0026] Optionally, the pyrolysis products are subjected to vacuum distillation or azeotropic distillation to form an organic amine complexing agent and impurities. The purity of the organic amine complexing agent is sufficient for use as a complexing agent, preferably 99% or higher.

[0027] In another aspect, this disclosure provides a 13 The C isotope is prepared by the aforementioned separation method. 13 C isotope abundance is above 99.00%.

[0028] This disclosure proposes a complexing agent, separation device, and separation method for carbon isotopes. The complexing agent comprises a first component and a second component; wherein the first component is an organic amine; and the second component is any one of a small molecule hydrocarbon, a small molecule ether, or a small molecule ketone. The second component of this disclosure acts as a viscosity modifier, capable of disrupting hydrogen bonds between amine molecules. Furthermore, based on the fact that the second component is a small molecule organic compound, it inserts into the intermolecule gaps of the amine through a molecular dilution effect, physically separating the molecules and further reducing the viscosity of the organic amine liquid. Thus, in the exchange reaction, the diffusion rate of the ¹³C-amine complex in the liquid phase is increased, the isotope exchange time is shortened, and energy consumption is reduced. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a carbon isotope separation device according to a specific embodiment of this disclosure; Figure 2This is a flowchart illustrating a carbon isotope separation method according to a specific embodiment of this disclosure. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0031] In one aspect of this disclosure, a complexing agent for carbon isotope separation is proposed, the complexing agent comprising a first component and a second component; wherein the first component is an organic amine; and the second component is any one of a small molecule hydrocarbon, a small molecule ether, or a small molecule ketone.

[0032] It should be noted that the first component in this embodiment is added during the complexation stage, and the second component is added during the complexation stage or the exchange stage. In other words, it is sufficient to ensure that the second component is added when the exchange reaction occurs.

[0033] It should be understood that when organic amines are used alone, the high viscosity is due to the intermolecular hydrogen bond network, and this high viscosity leads to... 13 C-amine complexes diffuse slowly, resulting in incomplete isotope exchange reactions, high resistance to pump delivery and gas flow, and high circulation energy consumption. Furthermore, their poor flowability can lead to fouling and reduced efficiency of the amine solution. Therefore, in this embodiment, by combining the second component with the first component, the hydrogen bonds between amine molecules are broken. Additionally, based on the fact that the second component is a small-molecule organic compound, it is inserted into the intermolecule gaps of the amine through a molecular dilution effect, physically separating the molecules and further reducing the viscosity of the organic amine solution. Thus, during the exchange reaction, the diffusion rate of the ¹³C-amine complex in the liquid phase is increased, the isotope exchange time is shortened, and energy consumption is reduced.

[0034] In some preferred embodiments, the small molecule hydrocarbon is preferably C5-C. 10 Halogenated hydrocarbons, such as chloroalkanes, include 1-chloropentane, chlorobutane, 1,2-dichloropentane, 1-chlorohexane, 1-chlorooctane, dichlorocyclohexane, chlorocyclopentane, etc.

[0035] These small-molecule hydrocarbons are widely available, inexpensive, contain no polar groups, do not react chemically with CO2 or organic amines, and do not affect... 13 The stability of C-amine complexes ensures that isotope separation efficiency is not affected. Simultaneously, these small molecule hydrocarbons have extremely low viscosity, and their addition to organic amines can significantly reduce the system viscosity. Furthermore, these small molecule hydrocarbons can be separated from organic amines with high recovery rates and without affecting the product.

[0036] In some other preferred embodiments, the small molecule ether is C5-C. 10 Ethers, such as diisopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, di-n-propyl ether, etc., and of course, other ethers can be selected, without specific limitations.

[0037] These small-molecule ethers form weak hydrogen bonds with the -NH2 group of amine molecules through the polar oxygen atom of the ether bond, competing for strong hydrogen bond sites between amine molecules, weakening the original hydrogen bond network, and reducing viscosity. Simultaneously, they physically separate amine molecules based on the nonpolar portion of the alkyl chain, reducing the frequency of intermolecular contact, further reducing cohesion and viscosity. Furthermore, ethers can reduce the surface tension of amine solutions, making it easier for the liquid to spread into a uniform liquid film on the packing surface, increasing the gas-liquid contact area and indirectly improving mass transfer efficiency.

[0038] In some other preferred embodiments, the small molecule ketone is C5-C. 10 Ketones, such as cyclohexanone, methyl isobutyl ketone, cyclopentanone, n-heptanone, etc.

[0039] These small ketone carbonyl oxygens (C=O) possess strong electronegativity and can form weak hydrogen bonds with the amino groups of amines (-NH2 / -NHR), competing for the strong hydrogen bonds between amine molecules. The original continuous hydrogen bond network breaks down into localized weak interactions of "amine-ketone-amine," reducing intermolecular sliding resistance and significantly decreasing viscosity. Secondly, C5-C... 10 Ketones have a molecular size similar to that of organic amines, allowing them to disperse uniformly between amine molecules, physically separating them and reducing internal frictional resistance. Furthermore, ketones and amines are completely miscible, eliminating the risk of stratification.

[0040] It should be noted that this embodiment does not specifically limit the second component, which can be any of the above-mentioned small molecule alkanes, small molecule ethers or small molecule ketones, or a combination of multiple components.

[0041] In some other preferred embodiments, the organic amine is at least one of primary amine, secondary amine, tertiary amine, and aromatic amine. For example, the secondary amine is an alkyl branched secondary amine, such as N-methylaniline; the primary amine is monoethanolamine; the tertiary amine is triethanolamine; and the aromatic amine is N,N-dimethylaniline.

[0042] As a further preferred option, the organic amine is selected from diethanolamine, butanediamine, triethanolamine, ethylene glycolamine, N-methylaniline, p-phenylenediamine, piperidine, or pyrrolidine.

[0043] In some other preferred embodiments, the content of the second component is 10-30% of the content of the first component.

[0044] like Figure 1As shown, in another aspect of this disclosure, a carbon isotope separation device 100 is provided, comprising: a complexing tower 110, an exchange tower 120, a pyrolysis tower 130, and a purification tower 140 connected in sequence; wherein, the bottom of the complexing tower 110 is provided with a first gas inlet for introducing carbon dioxide and a gas outlet for discharging carbon dioxide. 12 The first outlet of the C-amine complex has a first inlet at the top. The complexing agent here is the complexing agent described above, which includes a first component and a second component. The first component is an organic amine, and the second component includes any one of small molecule hydrocarbons, small molecule ethers, and small molecule ketones. In this complexing tower 110, carbon dioxide... 12 C complexes with organic amines to form 12C-amine complexes; the bottom of the exchange tower 120 is equipped with a second gas inlet for introducing carbon dioxide gas and a outlet for discharging gas. 13 The second outlet of the C-amine complex has a second inlet connected to the first outlet at its top and a discharge port for discharging. 12 The first CO2 gas outlet allows the 12C-amine complex to enter the exchange tower 120 via the first outlet and the second inlet. In this exchange tower 120, the introduced carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, 12 CO2 is discharged through the first gas outlet. 13 The C-amine complex is discharged into the cracking tower through the second outlet. The cracking tower 130 has a third outlet at the bottom for discharging the cracking products, and a third inlet connected to the second outlet at the top, as well as a discharge outlet. 13 The second gas outlet for CO2, thus... 13 The C-amine complex enters the cracking tower 130 through the second outlet and the third inlet. 13 C-amine complexes undergo thermal pyrolysis to produce pyrolysis products and 13 CO2, 13 CO2 is discharged through the second gas outlet, and the pyrolysis products are discharged through the third outlet to the impurity removal tower. The bottom of the impurity removal tower 140 is provided with a fourth inlet connected to the third outlet, and the top is provided with a fourth outlet for discharging organic amines. In this impurity removal tower 140, the pyrolysis products form organic amines and impurities, of which the impurities remain at the bottom of the tower and the organic amines are discharged through the fourth outlet.

[0045] It should be noted that the organic amine in the complexing agent is added through the first inlet, while the second component in the complexing agent can be directly mixed with the organic amine and added to the complexing tower through the first inlet, or the second component can be added separately through other inlets in the exchange tower. In other words, the second component can be added before the exchange reaction, and the order of addition is not specifically limited. It should be understood that when the second component is added to the exchange tower, the exchange tower should also be equipped with other inlets for adding the second component.

[0046] It should be noted that the low-boiling-point solvent here is not limited to being added at the first inlet; it can also be added in the cracking tower. When the low-boiling-point solvent is added in the cracking tower, the cracking tower should also be equipped with a separate inlet for the low-boiling-point solvent.

[0047] It should be noted that this embodiment does not specifically limit the complexing tower, exchange tower, pyrolysis tower and impurity removal tower included in the device. They can be selected according to actual needs. For details, please refer to the following description.

[0048] Specifically, since carbon dioxide gas participates in the complexation reaction, its weak chemical bonds can generally proceed in two steps when reacting with organic amines. That is, the complexation tower can include a pre-synthesis tower and a synthesis tower. The pre-synthesis tower can be an atmospheric pressure tower, and the synthesis tower can be an atmospheric pressure tower or a pressurized tower. In the pre-synthesis tower, under low temperature and high amine concentration conditions, ¹²C is rapidly captured to generate an intermediate. In the synthesis tower, under gas-liquid countercurrent conditions, the activated amine liquid reacts countercurrently with CO2 in the packed tower. The catalytic effect of the gas phase chemicals is used to increase the complexation reaction rate and convert it into a stable complex.

[0049] In some preferred embodiments, the temperature of the complexation tower is set to 25-40°C. At this temperature, the forward reaction is promoted, the reverse reaction is suppressed, the decomposition of the complex is avoided, and the ¹²C separation efficiency is improved.

[0050] In this embodiment, by using organic amines to selectively adsorb carbon dioxide in the complexation tower, low-purity carbon dioxide feedstock can be directly processed. Combined with subsequent exchange and pyrolysis processes, the abundance of carbon isotopes can be effectively increased, thus broadening the sources of raw materials for carbon isotope separation.

[0051] Furthermore, the exchange tower can be a packed tower or a plate tower. For example, when using a packed tower, the gas-liquid contact area is 2–3 times that of a plate tower due to the highly efficient and well-structured packing, which can significantly improve the isotope exchange efficiency. ¹²C-amine complexes are sprayed from the top distributor, forming a continuous liquid film on the packing surface. CO2 gas containing ¹³C enters from the bottom of the tower, flows upward through the gaps in the packing, and comes into countercurrent contact with the liquid film. At the gas-liquid interface, the ¹³C in CO2 undergoes a reversible exchange reaction with the ¹²C-amine complex in the liquid film. For example, ¹³CO2 (gas phase) + ¹²C-amine complex (liquid phase). The reaction is ¹²CO₂ (gas phase) + ¹³C-amine complex (liquid phase). The ¹³C-amine complex is more stable than the ¹²C-amine complex, shifting the equilibrium towards its formation. The large contact area provided by the packing material ensures a sufficient exchange reaction. Simultaneously, due to the second component, the effective mass transfer area per unit volume of packing increases, leading to a higher contact frequency between ¹³C and the ¹²C-amine complex. ¹³C continues to accumulate in the liquid phase, and the reduced viscosity further enhances the diffusion coefficient of the ¹³C-amine complex within the liquid film, shortening the isotope exchange reaction time and ensuring complete exchange within the limited height of the packed tower, thus improving isotope conversion efficiency. Furthermore, the low-viscosity amine liquid has uniform flowability, allowing it to evenly cover the packing surface after passing through the distributor in the packing layer, thereby increasing the fractionation coefficient.

[0052] In some preferred embodiments, the temperature of the exchange tower is set to 40-60°C, at which temperature the isotope exchange equilibrium constant K is optimized. 13 C migrates into the liquid phase.

[0053] The packed tower in this embodiment provides an efficient mass transfer environment for isotope exchange of ¹³C and ¹²C-amine complexes through the synergistic effect of high specific surface area packing, gas-liquid countercurrent, and fine distribution. Its low pressure drop characteristics reduce gas transport and circulation energy consumption, resulting in high mass transfer efficiency.

[0054] Furthermore, the cracking tower can be a plate tower. In the cracking tower, the liquid phase is violently agitated by rising bubbles on the tower plate. The ¹³C-amine complex undergoes reversible decomposition at high temperature, generating a regenerated amine liquid phase and a ¹³CO2 gas phase. The ¹³CO2 in the bubbles flows upward and enters the separation section, while the regenerated amine flows downward along the downcomer, collects in the tower bottom, and is pumped to the impurity removal tower for purification and recycling.

[0055] This embodiment 13 C-amine complexes decompose upon heating into organic amines and 13 The thermal decomposition temperature of CO2 is 100-250℃. High temperatures promote the reverse reaction, resulting in the targeted release of high-purity CO2. 13 CO2, avoid 13 C loss.

[0056] Furthermore, the impurity removal tower can be a vacuum distillation tower or an azeotropic distillation tower.

[0057] For example, when the impurity removal tower is a vacuum distillation tower, the cracking products are converted into organic amines and impurities by vacuum distillation. This method mainly utilizes the difference in boiling points of each component to achieve separation. Under vacuum conditions, organic amines have a higher boiling point and do not decompose, but still exist in molecular form. They are collected as high-boiling-point components from the fourth outlet of the vacuum distillation tower. Other by-products, such as amine polymers produced by the oxidation, condensation or cross-linking reaction of organic amines, undergo partial depolymerization under vacuum distillation conditions or remain at the bottom of the tower.

[0058] For example, when the impurity removal tower is an azeotropic distillation tower, the cracking products are azeotropically distilled to form organic amines and impurities. Most organic amines form the lowest azeotrope with water, and after condensation and separation, an aqueous phase and an amine phase are obtained. The amine phase is discharged through the fourth outlet, while some other oligomeric impurities have larger molecular weights and boiling points higher than pure amines, do not participate in the azeotrope, and remain at the bottom of the tower.

[0059] It should also be understood that the fourth outlet of the impurity removal tower can be connected to the first inlet to allow the recovered organic amines to participate in further reactions, be recycled, and reduce costs.

[0060] As shown in Figure 2, another aspect of this disclosure provides a method S200 for separating carbon isotopes, specifically including the following steps S210~S240: S210. Carbon dioxide and a complexing agent are introduced into the complexing tower. The complexing agent here is the complexing agent described above, which includes a first component and a second component. The first component is an organic amine, specifically a primary amine. The second component includes any one of small molecule hydrocarbons, small molecule ethers, or small molecule ketones. Thus, the carbon dioxide... 12 C complexes with organic amines to form 12 C-amine complexes, taking secondary amines as an example, have the following reaction process: 12 CO2 + RNH2 RNH 12 COOH ( 12 C-amine complex).

[0061] The temperature of the complexation tower in step S210 is set to 25-35℃. At this temperature, the forward reaction is promoted, the reverse reaction is inhibited, the decomposition of the complex is avoided, and the ¹²C separation efficiency is improved.

[0062] It should be noted that the second component in the complexing agent in this embodiment can be added in step S110 to mix with the organic amine and then added in the complexing tower, or the second component can be added in the exchange tower in step S220. That is to say, the second component can be added before the exchange reaction, and there is no specific limitation on the order of addition.

[0063] S220, 12The C-amine complex flows into the exchange tower, and carbon dioxide gas is introduced into the exchange tower, so that the carbon dioxide in the exchange tower... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, thus forming 12 CO2 is directly discharged from the exchange tower and collected. 13 The C-amine complex further flows into the cracking tower, where the reaction process is as follows: 13 CO2+RNH 12 COOH ( 12 C-amine complex) 12 CO2+ RNH 13 COOH ( 13 C-amine complex).

[0064] In step S220, the temperature of the exchange tower is set to 10-60℃. At this temperature, the isotope exchange equilibrium constant K is optimized to make... 13 C migrates into the liquid phase. Simultaneously, due to the second component, the effective mass transfer area per unit volume of packing increases, and the contact frequency between ¹³CO₂ and ¹²C-amine complex increases. 13 C continuously accumulates in the liquid phase, and the reduced viscosity also increases the diffusion coefficient of the ¹³C-amine complex within the liquid film, shortening the isotope exchange reaction time and ensuring sufficient exchange within the limited height of the packed tower, thus improving isotope conversion efficiency. Furthermore, the low-viscosity amine liquid has uniform flowability, and after passing through the distributor of the packing layer, it can uniformly cover the surface of the packing, increasing the fractionation coefficient.

[0065] S230 13 C-amine complexes are pyrolyzed by heating in a pyrolysis tower into pyrolysis products and... 13 CO2, at this time 13 CO2 is directly discharged from the cracking tower and collected to separate carbon isotopes, while the cracking products further flow into the impurity removal tower. The reaction process is as follows: RNH 13 COOH ( 13 C-amine complex) RNH2+13CO2.

[0066] The heating and pyrolysis temperature of the S230 pyrolysis tower is 100-250℃. High temperature promotes the reverse reaction and directionally releases high-purity [product / material]. 13 CO2, avoid 13 C loss.

[0067] S240, the cracking products form organic amines and impurities in the impurity removal tower.

[0068] It should be noted that in step S240, the pyrolysis products can be purified by vacuum distillation or azeotropic distillation, and there is no specific limitation on which method is used.

[0069] Exemplarily, the cracking products are subjected to vacuum distillation to form organic amines and impurities. Under these conditions, the impurity removal column is a vacuum distillation column. This method mainly utilizes the difference in boiling points of the components to achieve separation. Under vacuum conditions, the organic amines, with their higher boiling points, do not decompose and remain in molecular form, being collected as the high-boiling-point component from the fourth outlet of the vacuum distillation column. Other byproducts, such as amine polymers produced by the oxidation, condensation, or cross-linking reactions of organic amines, undergo partial depolymerization under vacuum distillation conditions or remain at the bottom of the column. In the final impurity removal stage of this disclosure, the complexing agent and the low-viscosity solvent require two distillation columns for impurity removal. First, the low-viscosity solvent is distilled off, and then the complexing agent is distilled off for impurity removal.

[0070] For example, the cracking products are azeotropically distilled to form organic amines and impurities. Under these conditions, the impurity removal tower is an azeotropic distillation tower. Most organic amines form the lowest azeotrope with water. After condensation and separation, an aqueous phase and an amine phase are obtained. The amine phase is discharged through the fourth outlet, while some other oligomeric impurities have larger molecular weights and boiling points higher than pure amines. They do not participate in the azeotrope and remain at the bottom of the tower.

[0071] The separation method disclosed herein is simple. It is based on adding a second component to the exchange reaction, which effectively reduces the viscosity of organic amines, increases mass transfer efficiency, thereby improving separation efficiency, reducing energy consumption, and increasing carbon isotope abundance.

[0072] The carbon dioxide gas introduced into the complexation tower and exchange tower disclosed herein has a natural abundance of approximately 1.1%¹³C and approximately 98.89%¹²C.

[0073] The method for separating carbon isotopes will be further explained below with reference to specific embodiments: Example 1: The organic amine is a secondary amine, and the second component is a small molecule alkane. This example illustrates a method for separating carbon isotopes, with the following reaction process: 12 CO2 + R2NH R2NH + 12 COO - 13 CO2 + R2NH + 12 COO - 12 CO2 + R2NH +13 COO - R2NH +13 COO- R2NH+ 13 CO2.

[0074] Where R=(HOCH2CH2)2- The specific methods include the following: S1. Carbon dioxide and a complexing agent are introduced into the complexing tower. The complexing agent comprises a first component, an organic amine, and a second component, a small molecule alkane. The organic amine is diethanolamine, and the small molecule alkane is chlorohexane, with the chlorohexane content being 20% ​​of the organic amine. Chlorohexane reduces the viscosity of diethanolamine. The molar ratio of carbon dioxide to organic amine is 0.35:1. At 30°C, the carbon dioxide... 12 CO2 complexes with diethanolamine to form... 13 CO2-amine complex, at this point the amine complex flows into the exchange tower.

[0075] S2, R2NH + 12 COO - The complex flows into the exchange tower from the top, and carbon dioxide gas is introduced into the exchange tower from the bottom. At 35°C, the gas in the carbon dioxide... 13 CO2 molecules and liquid R2NH + 12 COO - The complex undergoes an exchange reaction to produce 12 CO2 gas molecules and liquid R2NH + 13 COO - Complex molecules, enriched with carbon-12 isotopes 12 CO2 is removed from the exchange tower, and R2NH enriched with carbon-13 isotopes isotopes is collected. + 13 COO - The complex further enters the pyrolysis tower.

[0076] S3, R2NH + 13 COO - The complex was decomposed in a cracking tower at 105°C into a diethanolamine complexing agent and 13 CO2, at this point, the diethanolamine complexing agent further enters the impurity removal tower. 13 CO2 is discharged from the cracking tower.

[0077] S4, the diethanolamine complexing agent, is separated by distillation in the impurity removal tower to remove impurities, becoming regenerated diethanolamine. The diethanolamine then recycles into the complexing tower to participate in the reaction, while small molecule alkanes and other impurities remain at the bottom of the impurity removal tower and are periodically discharged.

[0078] Detection method: Inductively coupled plasma mass spectrometry After analysis and testing 12 CO2 abundance: 0.73 ,%13 The abundance of CO2 was 99.27%. Specifically, under reduced pressure, the organic amine complexing agent, which has a high boiling point, does not decompose and remains in molecular form. It is collected as a high-boiling-point component from the fourth outlet of the reduced pressure distillation column. Other by-products, such as amine polymers produced by the oxidation, condensation, or cross-linking reactions of organic amines, undergo partial depolymerization under reduced pressure distillation conditions or remain at the bottom of the column.

[0079] Example 2: The second component is a small molecule ether: diisopropyl ether. S1. Carbon dioxide and a complexing agent are introduced into the complexing tower. The complexing agent comprises a first component, an organic amine, and a second component, a small molecule ether. The organic amine is diethanolamine, and the small molecule ether is diisopropyl ether. The content of diisopropyl ether is 20% of the organic amine. Diisopropyl ether reduces the viscosity of diethanolamine. The molar ratio of carbon dioxide to organic amine is 0.45:1. At 25°C, the carbon dioxide... 12 CO2 complexes with diethanolamine to form... 13 CO2-amine complex, at this point the amine complex flows into the exchange tower.

[0080] S2, R2NH + 12 COO - The complex flows into the exchange tower from the top, and carbon dioxide gas is introduced into the exchange tower from the bottom. At 40°C, the gas in the carbon dioxide... 13 CO2 molecules and liquid R2NH + 12 COO - The complex undergoes an exchange reaction to produce 12 CO2 gas molecules and liquid R2NH + 13 COO - Complex molecules, enriched with carbon-12 isotopes 12 CO2 is removed from the exchange tower, and R2NH enriched with carbon-13 isotopes isotopes is collected. + 13 COO - The complex further enters the pyrolysis tower.

[0081] S3, R2NH + 13 COO - The complex was decomposed in a cracking tower at 120°C into a diethanolamine complexing agent and 13 CO2, at this point, the diethanolamine complexing agent further enters the impurity removal tower. 13 CO2 is discharged from the cracking tower.

[0082] S4, the diethanolamine complexing agent, is separated by distillation in the impurity removal tower to remove impurities, becoming the regenerated diethanolamine complexing agent. The diethanolamine then further recycles into the complexing tower to participate in the reaction, while the impurities remain at the bottom of the impurity removal tower and are periodically discharged.

[0083] After analysis and testing 12 CO2 abundance: 0.66 ,% 13 The abundance of CO2 was 99.34%. Specifically, under reduced pressure, the organic amine complexing agent, which has a high boiling point, does not decompose and remains in molecular form. It is collected as a high-boiling-point component from the fourth outlet of the reduced pressure distillation column. Other by-products, such as amine polymers produced by the oxidation, condensation, or cross-linking reactions of organic amines, undergo partial depolymerization under reduced pressure distillation conditions or remain at the bottom of the column.

[0084] Example 3: The second component is a small molecule ketone: n-Heptanone S1. Carbon dioxide and a complexing agent are introduced into the complexing tower. The complexing agent comprises a first component, an organic amine, and a second component, a small molecule ketone. The organic amine is diethanolamine, and the small molecule ketone is n-heptanone, with the n-heptanone content being 20% ​​of the organic amine. The n-heptanone reduces the viscosity of the diethanolamine. The molar ratio of carbon dioxide to organic amine is 0.5:1. At 27°C under ether conditions, the carbon dioxide... 12 CO2 complexes with diethanolamine to form... 13 CO2-amine complex, at this point the amine complex flows into the exchange tower.

[0085] S2, R2NH + 12 COO - The complex flows into the exchange tower from the top, and carbon dioxide gas is introduced into the exchange tower from the bottom. At 44°C, the gas in the carbon dioxide... 13 CO2 molecules and liquid R2NH + 12 COO - The complex undergoes an exchange reaction to produce 12 CO2 gas molecules and liquid R2NH + 13 COO - Complex molecules, enriched with carbon-12 isotopes 12 CO2 is removed from the exchange tower, and R2NH enriched with carbon-13 isotopes isotopes is collected. + 13 COO - The complex further enters the pyrolysis tower.

[0086] S3, R2NH + 13 COO - The complex was decomposed in a cracking tower at 140°C into a diethanolamine complexing agent and 13 CO2, at this point, the diethanolamine complexing agent further enters the impurity removal tower. 13 CO2 is discharged from the cracking tower.

[0087] S4, the diethanolamine complexing agent, is separated by distillation in the impurity removal tower to remove impurities, becoming the regenerated diethanolamine complexing agent. The diethanolamine then further recycles into the complexing tower to participate in the reaction, while the impurities remain at the bottom of the impurity removal tower and are periodically discharged.

[0088] After analysis and testing 12 The abundance of CO2 was 0.62%. 13 The abundance of CO2 was 99.38%.

[0089] Specifically, under reduced pressure, the organic amine complexing agent, which has a high boiling point, does not decompose and remains in molecular form. It is collected as a high-boiling-point component from the fourth outlet of the reduced pressure distillation column. Other by-products, such as amine polymers produced by the oxidation, condensation, or cross-linking reactions of organic amines, undergo partial depolymerization under reduced pressure distillation conditions or remain at the bottom of the column.

[0090] Example 4: The organic amine is a primary amine, and the second component is a small molecule ether. This example illustrates a method for separating carbon isotopes, with the following reaction process: 12 CO2 + RNH2 RNH2 + 12 COO - 13 CO2 + RNH2 + 12 COO - 12 CO2 + RNH2 + 13 COO - RNH2 +132 COO - RNH2+ 13 CO2.

[0091] R=HO-CH2-CH2- The specific methods include the following: S1. Carbon dioxide and a complexing agent are introduced into the complexing tower. The complexing agent comprises a first component, an organic amine, and a second component, a small molecule ether. The organic amine is ethylene glycol amine, and the small molecule ether is ethyl tert-butyl ether, with the ethyl tert-butyl ether content being 20% ​​of the organic amine. The ethyl tert-butyl ether reduces the viscosity of the ethylene glycol amine. Carbon dioxide and ethylene glycol amine are introduced into the complexing tower at a molar ratio of 0.45:1. At 32°C, the carbon dioxide gas... 13 CO2 molecules complex with ethylene glycolamine to generate RNH2. + 12 COO - The complex then enters the exchange tower.

[0092] S2, RNH2 + 12 COO - The complex flows into the exchange tower from the top, and carbon dioxide gas is introduced into the exchange tower from the bottom. At 50°C, the gas in the carbon dioxide... 13 CO2 molecules and liquid RNH2 +12 COO - The complex undergoes an exchange reaction to produce 12 CO2 gas molecules and liquid RNH2 +13 COO - Complex molecules, enriched with carbon-12 isotopes 12 CO2 is removed from the exchange tower, and RNH2 enriched with carbon-13 isotopes isotopes is collected. +13 COO - The complex further enters the pyrolysis tower.

[0093] S3, RNH2 +13 COO - The complex was decomposed in a cracking tower at 150°C into an ethylene glycol amine complexing agent and 13 CO2, at this point, the ethylene glycol amine complexing agent further enters the impurity removal tower. 13 CO2 is discharged from the cracking tower.

[0094] S4, the ethylene glycol amine complexing agent, is separated by distillation in the impurity removal tower to remove impurities, becoming the regenerated ethylene glycol amine complexing agent. The ethylene glycol amine then further recycles into the complexing tower to participate in the reaction, while the impurities remain at the bottom of the impurity removal tower and are periodically discharged.

[0095] Specifically, under the decomposition conditions of the cracking tower, only carbon dioxide gas is released. The organic amine complexing agent, with its high boiling point, does not decompose or boil and remains in liquid molecule form. After entering the impurity removal tower, it is collected as a high-boiling-point component from the fourth outlet of the vacuum distillation tower. Other by-products, such as amine polymers produced by the oxidation, condensation, or cross-linking reactions of organic amines, undergo partial depolymerization under vacuum distillation conditions or remain at the bottom of the tower.

[0096] After analysis and testing 12 CO2 abundance was 0.52%. ， 13 The abundance of CO2 was 99.48%.

[0097] Example 5: The organic amine is a tertiary amine, and the second component is a small molecule ketone. This example illustrates a method for separating carbon isotopes, with the following reaction: 12 CO2 + H2O + R3N R3NH + H¹²CO3 - 13 CO2 + R3NH + H¹²CO3 - 12 CO2+ R3NH + H 13 CO3 -

[0098] R3NH + H 13 CO3 - R3N+ 13 CO2 + H2O Where R=(HOCH2CH2)3- Specific methods include S1. Carbon dioxide, water, and a complexing agent are introduced into the complexing tower. The complexing agent comprises a first component, an organic amine, and a second component, a small molecule ketone. The organic amine is triethanolamine, and the small molecule ketone is cyclohexanone, with the cyclohexanone content being 20% ​​of the organic amine. Cyclohexanone reduces the viscosity of triethanolamine. The molar ratio of carbon dioxide to triethanolamine is 0.55:1. At 32°C, the carbon dioxide gas... 13 CO2 molecules complex with triethanolamine to form R3N. 12 The COOH complex then enters the exchange tower.

[0099] S2, R3N 12 The COOH complex flows into the exchange tower from the top, and carbon dioxide gas is introduced into the exchange tower from the bottom. At 54°C, the carbon dioxide gas... 13 CO2 molecules and liquid R3N 12 The COOH complex undergoes an exchange reaction to generate... 12 CO2 gas molecules and liquid R3N 13 COOH complex molecules, enriched with carbon-12 isotopes 12 CO2 is removed from the exchange tower, and R3N, enriched with carbon-13 isotopes, is collected. 13 The COOH complex further enters the cracking tower.

[0100] S3, R3N 13 The COOH complex was decomposed in a cracking tower at 180°C into a triethanolamine complexing agent and... 13 CO2, at this point, the triethanolamine complexing agent further enters the impurity removal tower. 13 CO2 is discharged from the cracking tower.

[0101] S4, the triethanolamine complexing agent is purified by distillation in the impurity removal tower to remove impurities, becoming the regenerated triethanolamine complexing agent. The triethanolamine then recycles into the complexing tower to participate in the reaction, while the impurities remain at the bottom of the impurity removal tower and are periodically discharged.

[0102] After analysis and testing 12 The abundance of CO2 was 0.58%. 13 The abundance of CO2 was 99.42%.

[0103] Example 6: The organic amine is N-methylaniline, and the second component is a small molecule alkane. This example illustrates a method for separating carbon isotopes, including the following steps: S1. Carbon dioxide and a complexing agent are introduced into the complexing tower. The complexing agent comprises a first component, an organic amine, and a second component, a small molecule alkyl group. The organic amine is N-methylaniline, and the small molecule alkane is dichlorocyclohexane, with the dichlorocyclohexane content being 20% ​​of the organic amine. Dichlorocyclohexane reduces the viscosity of N-methylaniline. The molar ratio of carbon dioxide to N-methylaniline is 0.6:1. At 35°C, the carbon dioxide gas... 13 CO2 molecules complex with N-methylaniline to form the corresponding... 12 C complex, at this point the complex enters the exchange tower.

[0104] S2, 12 The C complex flows into the exchange tower from the top, and carbon dioxide gas is introduced into the exchange tower from the bottom. At 50°C, the carbon dioxide gas... 13 CO2 molecules and liquid 12 The C complex undergoes an exchange reaction to generate... 12 CO2 gas molecules and liquid 13 C-complex molecules, enriched with carbon-12 isotopes 12 CO2 is removed from the exchange tower, enriching carbon-13 isotopes. 13 The C complex further enters the pyrolysis tower.

[0105] S3 13 The C complex was decomposed in a cracking tower at 200°C into N-methylaniline complexing agent and 13 CO2, at this point, the N-methylaniline complexing agent further enters the impurity removal tower. 13 CO2 is discharged from the cracking tower.

[0106] The S4 and N-methylaniline complexing agents are separated by distillation in a purification tower to remove impurities, becoming a regenerated piperidine complexing agent. N-methylaniline then recycles into the complexing tower to participate in the reaction, while impurities remain at the bottom of the purification tower and are periodically discharged.

[0107] After analysis and testing 12The abundance of CO2 was 0.75%. 13 The abundance of CO2 was 99.25%.

[0108] The test case added viscosity modifier to the 13 Effect of CO2 abundance Comparative Example 1: Example 1 did not contain the second component, small molecule alkane; otherwise, it was the same as Example 1.

[0109] In Comparative Example 2, there was no second component, small molecule ether, and other conditions were the same as in Example 2.

[0110] Comparative Example 3: No second component, small molecule ketone, was included in Example 3. Other conditions were the same as in Example 3.

[0111] The results are shown in Table 1 below: Table 1

[0112] Conclusion: It can be seen that increasing the concentration of small molecule alkanes, small molecule ethers, and small molecule ketones can reduce the viscosity of organic amines and significantly improve their viscosity. 13 The abundance of CO2 reached over 99%.

[0113] Experiment Example 2: Screening Test for the Dosage of Component 2 Following the method of Example 1, the amount of viscosity modifier used is shown in Table 2 below: Table 2

[0114] Results: In the 5%→10% stage, the abundance increased by 2.63 percentage points (from 96.62% to 99.25%), a very significant improvement. In the 10%→30% stage, the abundance continued to climb steadily to 99.57%, but the marginal benefit decreased (each 10% increase in dosage only resulted in an increase of about 0.1~0.2 percentage points). Therefore, there is an optimal addition window for viscosity modifiers (10%~30%).

[0115] In summary, this disclosure presents a complexing agent, separation apparatus, and separation method for carbon isotopes, which have the following advantages over the prior art: First, this disclosure combines the second component with the first component. Based on the fact that the second component can break the hydrogen bonds between amine molecules and that the second component is a small molecule organic compound, it inserts into the gaps between amine molecules through the molecular dilution effect, physically separating the molecules, thereby further reducing the viscosity of the organic amine liquid, increasing the diffusion rate of the ¹³C-amine complex in the liquid phase, shortening the isotope exchange time, and reducing energy consumption.

[0116] Second, the first component of this disclosure is an organic amine, whose amino group forms a reversible carbamate complex with CO2. It has high selectivity for carbon dioxide, fast complexation reaction rate, high fractionation coefficient, large single-stage enrichment factor, and excellent thermal stability and resistance to high-temperature degradation.

[0117] Third, this public announcement is adopted. 12 C has a stronger complexing ability with organic amines than 13 The characteristic of C is that it preferentially complexes in the complexation tower. 12 C, generating 12 C-amine complex, making the gas phase 13 C abundance was initially increased; then, through gas-liquid countercurrent contact... 13 C transfers from the gas phase to the liquid phase, increasing its abundance again; further high-temperature pyrolysis promotes the reverse reaction, further increasing its abundance. 13 C abundance.

[0118] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A complexing agent for carbon isotope separation, characterized in that, The complexing agent comprises a first component and a second component; wherein... The first component is an organic amine; The second component is any one of a small molecule hydrocarbon, a small molecule ether, or a small molecule ketone; The organic amine is selected from compounds of Formula 1 below: R1, R2, and R3 can each be independently selected as one of hydrogen, C1-C8 alkyl, C5-C8 heteroaryl, C3-C8 cycloalkyl, C5-C8 aryl, or C3-C8 heterocyclic, and R1, R2, and R3 cannot all be hydrogen at the same time. The C1-C8 alkyl group is substituted with one, two or three substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen or hydroxyl; The C3-C8 cycloalkyl group is substituted with one, two, or three substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; The C5-C8 heteroaryl group is substituted with 1, 2 or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, hydroxyl; The C5-C8 aryl group is substituted with 1, 2 or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, hydroxyl; The heteroatom in the heteroaryl or heterocyclic alkane is selected from N.

2. The complexing agent according to claim 1, characterized in that, The small molecule hydrocarbon is selected from C5-C6. 10 Alkanes, C5-C 10 Cycloalkanes, C5-C 10 Aromatic hydrocarbons, C5-C 10 heteroaromatics or C5-C 10 Olefins; the C5-C 10 The alkane is substituted with one, two, or three halogens; the C5-C 10 The cycloalkanes are substituted with one, two, or three halogens; the C5-C 10 The aryl hydrocarbon is substituted with one, two, or three halogens; the C5-C 10 The heteroaromatic hydrocarbons are substituted with one, two, or three halogens; the C5-C 10 The olefin is substituted with one, two or three halogens; said halogens include one or more of fluorine, chlorine and bromine.

3. The complexing agent according to claim 1, characterized in that, The small molecule hydrocarbon is one of 1-chloropentane, 1,2-dichloropentane, 1-chlorohexane, n-heptane, 1-chlorooctane, dichlorocyclohexane, and chlorocyclopentane.

4. The complexing agent according to claim 1, characterized in that, The small molecule ether is represented by the general formula R1OR2, wherein R1 and R2 are independently selected from C1-C1. 10 Alkyl, C3-C 10 cycloalkyl or C5-C 10 One of the aryl groups, the C1-C 10 The alkyl group is substituted with one or more of the C1-C3 alkyl groups, wherein the C5-C 10 The aryl group is substituted by one or more of C1-C3 alkyl groups; the C3-C 10 The cycloalkyl group is substituted by one or more of the C1-C3 alkyl groups; R1 and R2 are independently selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, phenyl, and benzyl.

5. The complexing agent according to claim 1, characterized in that, The small molecule ether is selected from one of diisopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, or di-n-propyl ether.

6. The complexing agent according to claim 1, characterized in that, The small molecule ketone is represented by the following general formula R1(C=O)R2, wherein R1 and R2 are independently selected from C1-C2. 10 Alkyl, C3-C 10 cycloalkyl, C5-C 10 Aryl groups or R1, R2 form cyclic ketones with C=O, wherein the C1-C 10 The alkyl group is substituted with one or more of the C1-C3 alkyl groups, wherein the C5-C 10 The aryl group may be optionally substituted with one or more of a C1-C3 alkyl group, wherein the C3-C 10 The cycloalkyl group is substituted with one or more of the C1-C3 alkyl groups; the cycloketone is substituted with one or more of the C1-C3 alkyl groups; R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, phenyl, benzyl, or R1 and R2 form a C4-C8 cycloketone with C=O.

7. The complexing agent according to claim 1, characterized in that, The small molecule ketone is selected from one of cyclopentanone, cyclohexanone, methylcyclopentanone, methylcyclohexanone, and methyl isobutyl ketone.

8. The complexing agent according to claim 1, characterized in that, R1, R2, and R3 can each be independently selected from one of the following: hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, phenyl, benzyl, phenoxymethyl, phenoxyethyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, aminomethyl, aminoethyl, aminopropyl, fluoromethyl, fluoroethyl, chloromethyl, chloroethyl, bromomethyl, bromoethyl, difluoromethyl, trifluoromethyl, aryl, or heteroaryl, and R1, R2, and R3 cannot all be hydrogen.

9. The complexing agent according to claim 1, characterized in that, The organic amine is at least one of primary amines, secondary amines, tertiary amines, and aromatic amines.

10. The complexing agent according to claim 1, characterized in that, The content of the second component is 10-30% of the content of the first component.

11. A method for separating carbon isotopes, characterized in that, The separation method includes: Carbon dioxide and a complexing agent are introduced into the complexing tower. The carbon dioxide contains... 12 CO2 complexes with organic amines to form... 12 C-amine complex; the complexing agent is the complexing agent according to any one of claims 1-10; The 12 The C-amine complex flows into an exchange tower, and carbon dioxide gas is introduced into the exchange tower. The carbon dioxide contains... 13 CO2 and the above 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex; The 13 C-amine complexes are pyrolyzed by heating in a pyrolysis tower into pyrolysis products and... 13 CO2; The pyrolysis products form organic amines and impurities in the impurity removal tower.

Images