A CO2 scavenger and its preparation method
By loading amine derivatives onto β-cyclodextrin to form a solid adsorbent material, the problems of easy degradation and poor thermal stability of liquid amine materials under high humidity are solved, achieving efficient low-concentration carbon dioxide capture, which is suitable for large-scale industrial applications.
Patent Information
- Application Number
- CN202610523050.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-20
- Publication Date
- 2026-07-31
AI Technical Summary
Existing liquid amine adsorbents suffer from problems such as easy degradation, high regeneration energy consumption, easy corrosion of equipment, and poor thermal stability when used for low-concentration carbon dioxide capture under high humidity conditions, which limits their large-scale application.
A CO2 scavenger was prepared by using a solid adsorbent material with β-cyclodextrin loaded with amine derivatives through a specific synthesis method, including steps such as reaction, filtration, washing, and vacuum distillation under a nitrogen atmosphere to form an amine-cyclodextrin mixture, which was then activated in a vacuum to enhance the stability and adsorption capacity of the material.
The stability of solid amine adsorbent materials and their ability to capture low-concentration carbon dioxide are improved under high humidity conditions, while reducing regeneration losses, making them suitable for large-scale production.
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Figure CN122479722A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a CO2 capture agent for capturing low-concentration carbon dioxide under high humidity conditions and its preparation method, belonging to the field of gas adsorption technology. Background Technology
[0002] Direct air capture (DAC) of carbon dioxide is considered a key mitigation strategy for offsetting carbon dioxide emissions from industries with difficult-to-reduce emissions and addressing legacy emissions. When implemented in conjunction with other mitigation strategies, DAC can help prevent the most severe impacts of human-induced climate change. To meet this need, DACs must be deployed to remove billions of tons of carbon dioxide annually. Due to the extremely low concentration of CO2 in the air (approximately 420 ppm), the materials used in this process must have high mass adsorption capacity for CO2, rapid adsorption kinetics, and stability against humid, oxygen-enriched airflows.
[0003] Liquid amine adsorbents, currently the core adsorbents in industrialized CO2 capture technology globally, offer advantages such as high adsorption efficiency and low cost. However, they also suffer from drawbacks including easy degradation, high regeneration energy consumption, and easy corrosion of equipment, which undoubtedly increases the cost of CO2 capture. Solid amine adsorbents have been proven to be effective at chemically adsorbing large amounts of CO2 in humid environments. Compared to traditional liquid amine adsorbents, solid amine adsorbents are not only less prone to degradation but also non-corrosive to equipment, and their regeneration temperature is lower than that of liquid amine materials, effectively reducing adsorption costs. However, their poor thermal stability leads to easy sublimation during regeneration, causing unnecessary losses and limiting their large-scale application. Therefore, it is necessary to improve materials and methods to enhance their thermal stability in order to synthesize solid amine adsorbents on a large scale for capturing low-concentration CO2 in humid environments. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a CO2 capture agent for capturing low-concentration carbon dioxide under high humidity conditions and its preparation method.
[0005] This invention is achieved through the following technical solution: A CO2 scavenger comprises β-cyclodextrin and an amino derivative supported on the β-cyclodextrin, the amino derivative having the general molecular formula Ar-(CH2NH2). n In this context, Ar is phenyl, triphenyl, 1,3,5-triphenylbenzene, or 1,2,4,5-tetraphenylbenzene, and n is 2, 3, or 4.
[0006] As a preferred embodiment, the structural formula of the amine derivative includes: A method for preparing a CO2 scavenger as described above includes the following steps: In a nitrogen atmosphere, an anhydrous tetrahydrofuran solution containing a cyano precursor was mixed with an anhydrous tetrahydrofuran solution of LiAlH4. After reacting at 40℃~60℃, sodium hydroxide solution and aqueous solution were added, filtered, the residue was collected, and washed with tetrahydrofuran solution to obtain a washing liquid. The solvent in the washing solution is removed under vacuum, the residue is dissolved in an organic solvent and washed with water, and the corresponding amine derivative is obtained by evaporating the organic layer. The amino derivative was mixed with β-cyclodextrin and dissolved in water. The solvent was removed by vacuum distillation to obtain a gel-like mixture. The gel-like mixture was activated in a vacuum at 90°C to 110°C to obtain the CO2 scavenger.
[0007] As a preferred embodiment, the cyano precursor includes at least one of phenyl-1,2,4,5-tetracarboxynitrile, 5'-(4-cyanophenyl)-[1,1':3',1''-terphenyl]-4,4''-dicarboxynitrile, 1,4-dicyanophenyl, 4',5'-bis(4-cyanophenyl)-[1,1':2',1''-terphenyl]-4,4''-dicarboxynitrile, [1,1':4',1''-terphenyl]-4,4''-dicarboxynitrile, and 1,3,5-benzentrionitrile.
[0008] As a preferred embodiment, the NaOH solution has a mass fraction of 10% to 20%.
[0009] As a preferred embodiment, the organic solvent is at least one of dichloromethane or ethyl acetate.
[0010] As a preferred embodiment, the amino derivative is selected from one of the following: benzene-1,3,5-trimethyltrimethylamine, 5'-[4-(aminomethyl)phenyl]-[1,1':3',1''-terphenyl]-4,4''-dimethylamine, 1,2,4,5-benzylamine, p-xylenediamine, [1,1':4',1''-terphenyl]-4,4''-dimethylamine, and (4-[2,4,5-tris[4-(aminomethyl)phenyl]phenyl)phenyl)methylamine.
[0011] As a preferred embodiment, the mass ratio of the amino derivative to β-cyclodextrin is (5~15):1.
[0012] Compared with the prior art, the present invention has the following beneficial effects: This invention prepares a series of solid amine adsorbents by improving materials and synthesis methods. By loading them into β-cyclodextrin, the loaded amine-cyclodextrin mixture retains its ability to capture low concentrations of carbon dioxide under high humidity conditions. At the same time, it enhances the stability of the solid amine adsorbent, overcomes the problem of easy sublimation during the regeneration of previous solid amine adsorbents, avoids unnecessary consumption, and can be put into large-scale factory production. Attached Figure Description
[0013] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a low-concentration CO2 breakthrough experiment of the CO2 scavenger amine-cyclodextrin-A prepared in Example 1 of the present invention under humid and high air velocity ratio conditions; Figure 2 These are the cycling performance results of the CO2 scavenger amine-cyclodextrin-A prepared in Example 1 of this invention; Figure 3 The CO2 capture agents amine-cyclodextrin-B, amine-cyclodextrin-C, amine-cyclodextrin-D, amine-cyclodextrin-E, and amine-cyclodextrin-F prepared in Examples 2-6 of this invention were subjected to low-concentration CO2 breakthrough experiments under humid and high air velocity ratio conditions. Detailed Implementation The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.
[0014] The reagents used in this invention are as follows: 1,3,5-benzotrionitrile (GR, 98%, Shanghai Haohong Biomedical Technology Co., Ltd.), LiAlH4 (AR, ≥99%, Adamas), sodium hydroxide (99.00%, Sinopharm Chemical Reagent Co., Ltd.), ultra-dry tetrahydrofuran (99.00%, Beijing Bailingwei Technology Co., Ltd.), and β-cyclodextrin (GR, 98%, Shanghai Haohong Biomedical Technology Co., Ltd.).
[0015] All reagents were commercially available and used without further purification. The reagents were prepared using PU... + The purification system (VWR) supplies ultrapure water.
[0016] Example 1 This embodiment provides a method for preparing a CO2 scavenger (in which the amino derivative is benzene-1,3,5-trimethyltrimethylamine), specifically including the following steps: (1) Dissolve 1,3,5-benzentrionitrile (8 mmol) in anhydrous THF (50 mL), and add 2.5 M LiAlH4 solution (solvent is anhydrous tetrahydrofuran (THF) (18.9 mL)) to the mixture under a nitrogen atmosphere, and react at 50 °C for 24 hours; (2) Quench the reaction with water (2 mL), add 15wt% NaOH aqueous solution (2 mL) and water (2 mL) and filter the mixture, wash the mixture with THF (100 mL), and evaporate the resulting solution to remove the solvent; (3) The residue was dissolved in DCM and washed with water, and then the DCM was evaporated to remove it, yielding benzene-1,3,5-trimethyltrimethylamine; (4) Mix benzene-1,3,5-trimethyltrimethylamine and β-cyclodextrin in a mass ratio of 10:1 and dissolve in water. Then evaporate under reduced pressure to remove the solvent and obtain a gel-like mixture. (5) The obtained gel-like mixture was activated at 100°C for 2 hours to obtain a CO2 scavenger, denoted as amine-cyclodextrin-A.
[0017] The amine-cyclodextrin-A material prepared in this embodiment was characterized. When the amine-cyclodextrin-A material prepared in this embodiment was used to separate CO2 from a simulated humid air gas (CO2 concentration 700 ppm, RH 100%, flow rate 20 mL / min, mass of amine-cyclodextrin-A 0.1558 g) at room temperature, the breakthrough curve was as follows: Figure 1 As shown, amine-cyclodextrin-A can effectively separate CO2 from the mixture in a humid air simulated atmosphere, demonstrating its excellent CO2 adsorption capacity. Furthermore, we tested the cycling performance of amine-cyclodextrin-A. After activating the adsorbed saturated amine-cyclodextrin-A material by vacuum heating at 100℃ for 2 hours, a breakthrough experiment was conducted again, and the cycling performance was as follows: Figure 2 As shown.
[0018] Example 2 This embodiment provides a method for preparing a CO2 scavenger (in which the amino derivative is 5'-[4-(aminomethyl)phenyl]-[1,1':3',1''-terphenyl]-4,4''-dimethylamine), specifically including the following steps: (1) Dissolve 1,3,5-tris(p-cyanophenyl)benzene (8 mmol) in anhydrous THF (50 mL), and add 2.5 M LiAlH4 solution (anhydrous tetrahydrofuran (THF) (18.9 mL)) to the mixture under a nitrogen atmosphere. React at 50 °C for 24 hours. Quench the reaction with water (2 mL), add 15 wt% NaOH aqueous solution (2 mL) and water (2 mL) and filter the mixture. Wash the mixture with THF (100 mL) and evaporate the solvent from the resulting solution. Dissolve the residue with DCM and wash with water. Then evaporate the DCM to obtain 5'-[4-(aminomethyl)phenyl]-[1,1':3',1''-terphenyl]-4,4''-dimethylamine.
[0019] (2) 5'-[4-(aminomethyl)phenyl]-[1,1':3',1''-terphenyl]-4,4''-dimethylamine and β-cyclodextrin were mixed in a mass ratio of 10:1 and dissolved in water. The solvent was then removed by vacuum evaporation to obtain a gel-like mixture. The gel-like mixture was activated at 100°C for 2 hours to obtain a CO2 scavenger, denoted as amine-cyclodextrin-B.
[0020] Example 3 This embodiment provides a method for preparing a CO2 scavenger (in which the amino derivative is 1,2,4,5-benzylamine), specifically including the following steps: (1) Benzene-1,2,4,5-tetracarboxynitrile (8 mmol) was dissolved in anhydrous THF (50 mL). Under a nitrogen atmosphere, 2.5 M LiAlH4 solution (anhydrous tetrahydrofuran (THF) (18.9 mL)) was added to the mixture and reacted at 50 °C for 24 hours. The reaction was quenched with water (2 mL), and 15 wt% NaOH aqueous solution (2 mL) and water (2 mL) were added and the mixture was filtered. The mixture was washed with THF (100 mL), and the solvent was removed by evaporation of the resulting solution. The residue was dissolved with DCM and washed with water. Then the DCM was removed by evaporation to obtain 1,2,4,5-benzylamine.
[0021] (2) Mix 1,2,4,5-benzylamine and β-cyclodextrin in a mass ratio of 10:1 and dissolve them in water. Then evaporate the solvent under reduced pressure to obtain a gel-like mixture. Activate the gel-like mixture at 100°C for 2 hours to obtain a CO2 scavenger, denoted as amine-cyclodextrin-C.
[0022] Example 4 This embodiment provides a method for preparing a CO2 scavenger (in which the amino derivative is p-xylenediamine), specifically including the following steps: (1) Dissolve 1,4-dicyanobenzene (8 mmol) in anhydrous THF (50 mL), and add 2.5 M LiAlH4 solution (anhydrous tetrahydrofuran (THF) (18.9 mL)) to the mixture under a nitrogen atmosphere. React at 50 °C for 24 hours. Quench the reaction with water (2 mL), add 15 wt% NaOH aqueous solution (2 mL) and water (2 mL) and filter the mixture. Wash the mixture with THF (100 mL) and evaporate the solvent from the resulting solution. Dissolve the residue with DCM and wash with water. Then evaporate the DCM to obtain p-xylenediamine.
[0023] (2) Mix p-xylenediamine and β-cyclodextrin in a mass ratio of 10:1 and dissolve them in water. Then evaporate the solvent under reduced pressure to obtain a gel-like mixture. Activate the obtained gel-like mixture at 100°C for 2 hours to obtain a CO2 scavenger, denoted as amine-cyclodextrin-D.
[0024] Example 5 This embodiment provides a method for preparing a CO2 scavenger (in which the amino derivative is [1, 1': 4', 1''-terphenyl]-4, 4''-dimethylamine), specifically including the following steps: (1) Dissolve [1,1':4',1''-terphenyl]-4,4''-dimethylamine (8 mmol) in anhydrous THF (50 mL). Under a nitrogen atmosphere, add 2.5 M LiAlH4 solution (anhydrous tetrahydrofuran (THF) (18.9 mL)) to the mixture and react at 50 °C for 24 hours. Quench the reaction with water (2 mL), add 15 wt% NaOH aqueous solution (2 mL) and water (2 mL) and filter the mixture. Wash the mixture with THF (100 mL) and evaporate the solvent from the resulting solution. Dissolve the residue with DCM and wash with water. Then evaporate the DCM to obtain [1,1':4',1''-terphenyl]-4,4''-dimethylamine.
[0025] (2) [1, 1': 4', 1''-terphenyl]-4,4''-dimethylamine and β-cyclodextrin were mixed in a mass ratio of 10:1 and dissolved in water. The solvent was then removed by vacuum evaporation to obtain a gel-like mixture. The gel-like mixture was activated at 100°C for 2 hours to obtain a CO2 scavenger, denoted as amine-cyclodextrin-E.
[0026] Example 6 This embodiment provides a method for preparing a CO2 scavenger (in which the amino derivative is (4-[2,4,5-tris[4-(aminomethyl)phenyl]phenyl)phenyl)methylamine), specifically including the following steps: (1) 4',5'-bis(4-cyanophenyl)[1,1':2',1''-terphenyl]-4,4''-dicarboxynitrile (8 mmol) was dissolved in anhydrous THF (50 mL). Under a nitrogen atmosphere, 2.5 M LiAlH4 solution (anhydrous tetrahydrofuran (THF) (18.9 mL)) was added to the mixture, and the reaction was carried out at 50 °C for 24 hours. The reaction was quenched with water (2 mL), and 15% NaOH aqueous solution (2 mL) and water (2 mL) were added and the mixture was filtered. The mixture was washed with THF (100 mL), and the solvent was removed by evaporation of the resulting solution. The residue was dissolved with DCM and washed with water, and then the DCM was removed by evaporation to obtain (4-[2,4,5-tris[4-(aminomethyl)phenyl]phenyl)phenyl)methylamine.
[0027] (2) Mix (4-[2,4,5-tris[4-(aminomethyl)phenyl]phenyl)phenyl)methylamine and β-cyclodextrin in a mass ratio of 10:1 and dissolve in water. Then evaporate under reduced pressure to remove the solvent and obtain a gel-like mixture. Activate the obtained gel-like mixture at 100°C for 2 hours to obtain a CO2 scavenger, denoted as amine-cyclodextrin-F.
[0028] The amine-cyclodextrin-B~F materials obtained in Examples 2-6 were subjected to a humid air simulated gas breakthrough experiment at room temperature (CO2 concentration of 700 ppm, RH of 100%, flow rate of 20 mL / min). The experimental results are as follows: Figure 3 As shown in the figure, the experimental data indicate that the adsorption effect is greater than that of amine-cyclodextrin-A, amine-cyclodextrin-C, amine-cyclodextrin-B, amine-cyclodextrin-F, amine-cyclodextrin-D, and amine-cyclodextrin-E.
[0029] Comparative Example 1 Compared to Example 1, the only difference in this comparative example is that the mass ratio of the amino derivative to β-cyclodextrin was adjusted to 3:1 during the preparation process. Breakthrough experiments showed that the CO2 adsorption capacity of the material obtained under these conditions was lower than that of the material with a mass ratio of amino derivative to β-cyclodextrin of 10:1, which may be due to the reduced content of the amino derivative.
[0030] Comparative Example 2 Compared to Example 1, the only difference in this comparative example is that the mass ratio of amine derivative to β-cyclodextrin was adjusted to 20:1 during the preparation process. Cyclic test results show that the CO2 adsorption capacity of the regenerated material obtained under these conditions is lower than that before regeneration, and its cyclic stability is poor. This may be due to the reduced β-cyclodextrin content, leading to the loss of some amine derivatives during the regeneration process.
[0031] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.
Claims
1. A CO2 capture agent, characterized by, Comprise β-cyclodextrin and amine group derivative loaded into the β-cyclodextrin, the molecular general formula of the amine group derivative is: Ar-(CH2NH2) n Wherein, Ar is phenyl, triphenyl, 1,3,5-triphenylbenzene or 1,2,4,5-tetraphenylbenzene, and n is 2, 3 or 4.
2. The CO2 capture agent of claim 1, wherein, The structural formulas of the amino derivatives include:
3. A method for producing the CO2 capturing agent as claimed in claim 1 or 2, characterized by, Includes the following steps: In a nitrogen atmosphere, an anhydrous tetrahydrofuran solution containing a cyano precursor was mixed with an anhydrous tetrahydrofuran solution of LiAlH4. After reacting at 40℃~60℃, sodium hydroxide solution and aqueous solution were added, filtered, the residue was collected, and washed with tetrahydrofuran solution to obtain a washing liquid. The solvent in the washing solution is removed under vacuum, the residue is dissolved in an organic solvent and washed with water, and the corresponding amine derivative is obtained by evaporating the organic layer. The amino derivative was mixed with β-cyclodextrin and dissolved in water. The solvent was removed by vacuum distillation to obtain a gel-like mixture. The gel-like mixture was activated in a vacuum at 90°C to 110°C to obtain the CO2 scavenger.
4. The method of claim 3, wherein the CO2 capture agent is prepared by the process of: The cyano precursor includes at least one of phenyl-1,2,4,5-tetracarboxynitrile, 5'-(4-cyanophenyl)-[1,1':3',1''-terphenyl]-4,4''-dicarboxynitrile, 1,4-dicyanophenyl, 4',5'-bis(4-cyanophenyl)-[1,1':2',1''-terphenyl]-4,4''-dicarboxynitrile, [1,1':4',1''-terphenyl]-4,4''-dicarboxynitrile, and 1,3,5-benzentrionitrile.
5. The method for preparing the CO2 scavenger as described in claim 3, characterized in that, The NaOH solution has a mass fraction of 10% to 20%.
6. The method for preparing the CO2 scavenger as described in claim 3, characterized in that, The organic solvent is at least one of dichloromethane or ethyl acetate.
7. The method for preparing the CO2 scavenger as described in claim 3, characterized in that, The amino derivative is selected from one of the following: benzene-1,3,5-trimethyltrimethylamine, 5'-[4-(aminomethyl)phenyl]-[1,1':3',1''-terphenyl]-4,4''-dimethylamine, 1,2,4,5-benzylamine, p-xylenediamine, [1,1':4',1''-terphenyl]-4,4''-dimethylamine, and (4-[2,4,5-tris[4-(aminomethyl)phenyl]phenyl)phenyl)methylamine.
8. The method for preparing the CO2 scavenger as described in claim 3, characterized in that, The mass ratio of the amino derivative to β-cyclodextrin is (5~15):1.