Vegetable oil-based carbon dioxide absorbent as well as preparation method and antibacterial application thereof

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a vegetable oil-based carbon dioxide absorbent as well as a preparation method and antibacterial application thereof. According to the invention, a vegetable oleic acid chain or a cyclonitrided vegetable oleic acid chain is introduced to a typical amine absorbent polyethyleneimine molecule, and a non-polar long-carbon-chain fatty acid structure can obviously weaken a polyethyleneimine intermolecular hydrogen bond and reduce an intermolecular force, so that more amino groups are exposed to be combined with carbon dioxide; and high-efficiency, high-capacity and low-energy-consumption absorption of carbon dioxide is realized. According to the invention, by carrying out cyclic nitridation modification on unsaturated carbon-carbon double bonds on vegetable oleic acid chains, more secondary amines are introduced, and the absorption amount of carbon dioxide is further improved. And after carbon dioxide is absorbed, tertiary amine in the molecular structure is converted into quaternary ammonium salt ions, so that the quaternary ammonium salt has excellent antibacterial performance, shows an excellent antibacterial effect on staphylococcus aureus and escherichia coli, and can be used as an antibacterial agent.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a vegetable oil-based carbon dioxide absorbent, a preparation method thereof and antibacterial application thereof. Background Art

[0002] Against the backdrop of global climate change, the continued growth of carbon dioxide (CO2) emissions as one of the main greenhouse gases has become a hot topic of global concern. According to the International Energy Agency, global annual CO2 emissions have exceeded 30 billion tons. Excessive carbon emissions will not only put tremendous pressure on the global climate environment, but also affect human survival and development. Therefore, how to reduce CO2 emissions is a key issue that needs to be addressed. At present, carbon capture, utilization and storage is one of the most effective and direct methods to deal with carbon emissions. Among them, how to achieve high-efficiency, low-energy consumption and high-capacity absorption of CO2 by absorbents is a problem that needs to be solved urgently.

[0003] Polyethyleneimine is a commonly used amine absorbent. The molecules of this material have strong intermolecular forces, which makes it difficult for CO2 to diffuse into the material. As a result, after the material surface absorbs CO2, the reaction between the internal amino groups and CO2 is very slow, which greatly reduces the CO2 absorption efficiency. Therefore, it is necessary to modify polyethyleneimine to overcome the problems of "low efficiency, low capacity, and high regeneration energy consumption" of traditional amine absorbents. Summary of the invention

[0004] The first object of the present invention is to provide a method for preparing a plant oil-based carbon dioxide absorber. The second object of the present invention is to provide a plant oil-based carbon dioxide absorber obtained by the preparation method. The third object of the present invention is to provide an application of the plant oil-based carbon dioxide absorber.

[0005] According to a first aspect of the present invention, there is provided a method for preparing a vegetable oil-based carbon dioxide absorbent, comprising the following steps: (1) Mixing the first vegetable oleic acid or cyclic nitrogen vegetable oleic acid and dichloromethane, then cooling to below 0°C, adding thionyl chloride, first reacting at below 0°C for 15-35 minutes, then stirring and reacting at 50-70°C for 3-5 hours to obtain vegetable oleic acid chloride or cyclic nitrogen vegetable oleic acid chloride; (2) Disperse polyethyleneimine in tetrahydrofuran, cool to below 0°C, add the vegetable oil acid chloride or cyclonitrile vegetable oil acid chloride obtained in step (1), and then react at 15-35°C for 4-8h, using the acid chloride to react with the amino group to generate amide and hydrogen chloride, and after the reaction, add an extractant to remove excess reactants and product impurities, and finally perform rotary evaporation to obtain a vegetable oil-based carbon dioxide absorbent.

[0006] In some embodiments, the method for preparing cyclic nitrogen plant oleic acid comprises the following steps: Mix anhydrous cupric chloride, 1,10-phenanthroline and hexafluoroisopropanol, stir for 30-60 min, and then cool to below 0°C. Subsequently, add the second vegetable oleic acid, hydroxylamine-o-sulfonic acid and cesium hydroxide aqueous solution, first react below 0°C for 15-30 min, and then stir at 15-35°C for 16-32 h to activate the unsaturated carbon-carbon double bonds in the second vegetable oleic acid and form a ring nitrogen structure to obtain the product.

[0007] In some embodiments, in parts by mass, the amount of anhydrous cupric chloride is 0.1-1 part, the amount of 1,10-phenanthroline is 0.1-1 part, the amount of hexafluoroisopropanol is 100-200 parts, the amount of the second vegetable oil acid is 5-20 parts, the amount of hydroxylamine-o-sulfonic acid is 3-10 parts, and the amount of cesium hydroxide aqueous solution is 5-20 parts, wherein the concentration of cesium hydroxide in the cesium hydroxide aqueous solution is 40-60 wt%.

[0008] In some embodiments, the second vegetable oil acid is selected from at least one of oleic acid, linoleic acid, linolenic acid, ricinoleic acid, and eleostearic acid.

[0009] In some embodiments, the first vegetable oil acid is selected from at least one of oleic acid, linoleic acid, linolenic acid, ricinoleic acid, and eleostearic acid.

[0010] In some embodiments, the extractant is a mixture of saturated brine and n-hexane in a volume ratio of 1: (1-3).

[0011] In some embodiments, when preparing vegetable oleic acid chloride or cyclic nitrogen vegetable oleic acid chloride, the amount of the first vegetable oleic acid or cyclic nitrogen vegetable oleic acid is 5-20 parts, the amount of dichloromethane is 30-80 parts, and the amount of thionyl chloride is 10-30 parts by weight; When preparing the vegetable oil-based carbon dioxide absorbent, the amount of polyethyleneimine used is 1-5 parts, the amount of tetrahydrofuran used is 10-50 parts, and the amount of vegetable oil acid chloride or cyclonitrogen vegetable oil acid chloride is 1-10 parts by weight.

[0012] According to a second aspect of the present invention, there is provided a vegetable oil-based carbon dioxide absorbent prepared by the above preparation method.

[0013] According to a third aspect of the present invention, there is provided a use of the above-mentioned vegetable oil-based carbon dioxide absorbent in the preparation of an adsorbent for capturing carbon dioxide.

[0014] According to a fourth aspect of the present invention, there is provided use of the above-mentioned plant oil-based carbon dioxide absorbent in the preparation of an antibacterial agent.

[0015] The beneficial effects of the present invention include: (1) The present invention introduces a vegetable oil acid chain or a ring-nitrogenated vegetable oil acid chain into the typical amine absorbent polyethyleneimine molecule. The unique non-polar long carbon chain fatty acid structure can significantly weaken the hydrogen bonds between polyethyleneimine molecules, reduce the intermolecular forces, and expose more amino groups to combine with carbon dioxide, thereby achieving high-efficiency, high-capacity, low-energy absorption of carbon dioxide, and shortening the time to saturation. In addition, the long carbon chain fatty acid structure can give the vegetable oil-based carbon dioxide absorbent of the present invention good hydrophobic properties, overcome the limitation of amine absorbents being easily hygroscopic, and expand its practical application scenarios.

[0016] (2) It takes more energy to destroy the interaction between primary amine and carbon dioxide. The present invention uses fatty acid chains with different grafting degrees to reduce the proportion of primary amine in polyethyleneimine, so that the regeneration energy consumption of the vegetable oil-based carbon dioxide absorber of the present invention after absorbing carbon dioxide is greatly reduced. (3) The present invention obtains a cyclonitrogenated plant oleic acid chain by cyclonitrogenating the unsaturated carbon-carbon double bonds on the plant oleic acid chain, thereby introducing more secondary amines, further increasing the carbon dioxide absorption, which can reach 7.53 mmol / g. Moreover, after absorbing carbon dioxide, the tertiary amine in the molecular structure is converted into a quaternary ammonium salt ion, which has excellent antibacterial properties, and exhibits excellent antibacterial effects against Staphylococcus aureus and Escherichia coli, and can be used as an antibacterial agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the Fourier transform infrared spectrum of the polyethyleneimine and vegetable oil-based carbon dioxide absorbent of Example 1 of the present invention.

[0018] Figure 2 This is the reaction scheme of the vegetable oil-based carbon dioxide absorbent of Example 2 of the present invention.

[0019] Figure 3 It is a Fourier transform infrared spectrum of cyclonitrooleic acid, cyclonitrooleic acid chloride, and vegetable oil-based carbon dioxide absorbent of Example 2 of the present invention.

[0020] Figure 4 It is a graph showing the change in carbon dioxide pressure in a closed reactor containing the carbon dioxide absorbents of Examples 1-2 and Comparative Example 1.

[0021] Figure 5 Graph showing the carbon dioxide absorption capacity of the carbon dioxide absorbents of Examples 1-2 of the present invention and Comparative Example 1.

[0022] Figure 6 It is a graph showing the desorption of carbon dioxide by the carbon dioxide absorbents of Examples 1-2 of the present invention and Comparative Example 1.

[0023] Figure 7 It is an infrared image of carbon dioxide desorption by the carbon dioxide absorbent of Examples 1-2 of the present invention and Comparative Example 1.

[0024] Figure 8 It is a graph showing the antibacterial results of the carbon dioxide absorbents of Examples 1-2 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific examples, but the embodiments of the present invention are not limited thereto. The materials involved in the following examples can all be obtained from commercial channels.

[0026] In the following examples, the stirring speed is 200-400 rpm, below 0°C refers to 0 to -10°C, and room temperature refers to 15-35°C.

[0027] Oleic acid is derived from soybean oil.

[0028] The extractant was obtained by mixing 150 mL of saturated saline and 150 mL of n-hexane.

[0029] In the following examples and comparative examples, the molecular weight of polyethyleneimine is 7000 and the structure is branched.

[0030] Example 1 The preparation method of the vegetable oil-based carbon dioxide absorbent of this embodiment comprises the following steps: (1) Place 10 g of oleic acid and 50 mL of dichloromethane in a double-necked flask. Open the cold trap in advance to cool to below 0 °C. Then install the double-necked flask in the cold trap. Slowly drop 20 g of thionyl chloride into the double-necked flask. First, react at below 0 °C for 30 min. Then, stir and react at 60 °C for 4 h to obtain vegetable oleic acid chloride.

[0031] (2) Weigh 3 g of polyethyleneimine and disperse it in 30 mL of tetrahydrofuran. Then put it into another clean double-necked flask. Open the cold trap in advance to cool it to below 0 °C. Install the double-necked flask into the cold trap. Then, in a cold trap environment below 0 °C, slowly drop 5.22 g of the vegetable oleic acid chloride obtained in step (1) into the double-necked flask. Then, take the double-necked flask out of the cold trap, react at room temperature for 6 h, then add an extractant to extract 3 times, and finally rotary evaporate to obtain a vegetable oil-based carbon dioxide absorbent (abbreviated as PEI-OA).

[0032] The Fourier transform infrared spectra of the polyethyleneimine and vegetable oil-based carbon dioxide absorbent of this embodiment are shown in FIG. Figure 1 As shown in the figure, the raw material is polyethyleneimine (denoted as PEI) and the product is a vegetable oil-based carbon dioxide absorbent (denoted as PEI-OA).

[0033] from Figure 1 It can be seen that compared with pure PEI, PEI-OA has a -1 There is an obvious stretching vibration peak at 1652 cm-1, which corresponds to the stretching vibration peak of C=O on the amide generated by the reaction of amino group and acyl chloride, which proves that PEI reacts with oleic acid (OA) and generates the corresponding amide group. In addition, it is worth noting that PEI-OA has a peak at 1652 cm-1. -1 An obvious stretching vibration peak appeared at , corresponding to the unsaturated double bond on the oleic acid chain, which further proved that OA had been successfully grafted onto the structure of PEI.

[0034] Example 2 The preparation method of the vegetable oil-based carbon dioxide absorbent of this embodiment comprises the following steps: (1) 0.48 g of anhydrous copper chloride, 0.64 g of 1,10-phenanthroline and 160 g of hexafluoroisopropanol were added to a round-bottom flask in sequence. After the flask was covered with a glass stopper and stirred for 30 min, the flask was placed in a cold trap until the system temperature was below 0 °C. Subsequently, 10 g of oleic acid was slowly added dropwise, followed by 5.86 g of hydroxylamine-o-sulfonic acid and then 8.78 g of cesium hydroxide aqueous solution (cesium hydroxide concentration was 50 wt%). The flask was reacted at below 0 °C for 30 min and then mechanically stirred at room temperature for 24 h to obtain cyclonitrogen plant oleic acid.

[0035] (2) 10 g of the cyclonitrobenzene vegetable oil acid obtained in step (1) and 50 mL of dichloromethane were placed in a double-necked flask. The cold trap was opened in advance to cool to below 0°C. Then, the double-necked flask was installed in the cold trap. 20 g of thionyl chloride was slowly added dropwise to the double-necked flask. The mixture was first reacted at below 0°C for 30 min, and then stirred at 60°C for 4 h to obtain cyclonitrobenzene vegetable oil acid chloride.

[0036] (3) Weigh 3 g of polyethyleneimine and disperse it in 30 mL of tetrahydrofuran. Then put it into another clean double-necked flask. Open the cold trap in advance to cool to below 0 °C. Install the double-necked flask into the cold trap. Then, in a cold trap environment below 0 °C, slowly drop 5.22 g of the cyclonitrile plant oil acid chloride obtained in step (2) into the double-necked flask. Then, take the double-necked flask out of the cold trap, react at room temperature for 6 h, then add an extractant to extract 3 times, and finally perform rotary evaporation to obtain a plant oil-based carbon dioxide absorbent (abbreviated as PEI-N-OA).

[0037] The reaction route of the vegetable oil-based carbon dioxide absorbent of this embodiment is as follows Figure 2 shown.

[0038] The Fourier transform infrared spectra of the cyclic nitrogen plant oil acid, the cyclic nitrogen plant oil acid chloride, and the plant oil-based carbon dioxide absorbent of this embodiment are as follows: Figure 3As shown in the figure, the cyclic nitrogen plant oil acid is recorded as N-OA, the cyclic nitrogen plant oil acid chloride is recorded as N-OA-Cl, and the plant oil-based carbon dioxide absorbent is recorded as PEI-N-OA.

[0039] from Figure 3 As can be seen from the left figure, compared with pure N-OA, the N-OA-Cl after acyl chlorination has a peak at 1823 cm -1 There is an obvious stretching vibration peak at , which corresponds to the stretching vibration peak of C-Cl on the acyl chloride, which proves that N-OA reacts with thionyl chloride and generates the corresponding acyl chloride group. Figure 3 As can be seen from the right figure, PEI-N-OA has a peak at 1823 cm -1 The stretching vibration peak of C-Cl on the acyl chloride at 60° obviously disappeared, indicating that the acyl chloride reacted with the amino group, indicating that N-OA had been successfully grafted onto the structure of polyethyleneimine (PEI).

[0040] Comparative Example 1 Take the typical amine carbon dioxide absorber polyethyleneimine (PEI for short) as a comparison case.

[0041] In order to illustrate the comprehensive performance of the plant oil-based carbon dioxide absorber prepared by the present invention, the following performance tests were performed on the plant oil-based carbon dioxide absorber (PEI-OA) prepared in Example 1, the plant oil-based carbon dioxide absorber (PEI-N-OA) prepared in Example 2, and the amine carbon dioxide absorber polyethyleneimine (PEI) of Comparative Example 1.

[0042] (1) Carbon dioxide absorption test 3 MPa carbon dioxide was introduced into the closed reactors containing carbon dioxide absorbents, and the pressure changes in the closed reactors were monitored. The carbon dioxide pressure changes in the closed reactors containing the carbon dioxide absorbents of Examples 1-2 and Comparative Example 1 are shown in the figure below. Figure 4 As shown, the carbon dioxide absorption capacity of the carbon dioxide absorbents of Examples 1-2 and Comparative Example 1 is shown in FIG. Figure 5 shown.

[0043] from Figure 4It can be seen that with the passage of time, the carbon dioxide pressure in the reactor decreases accordingly. Compared with pure polyethyleneimine (PEI), the pressure in the closed reactor of PEI-OA grafted with vegetable oil acid chains and PEI-N-OA grafted with cyclonitrided vegetable oil acid chains drops faster, and the time to reach the adsorption saturation state (pressure remains unchanged, no longer absorbing carbon dioxide) is shorter. This shows that the absorption efficiency of carbon dioxide is improved after grafting vegetable oil acid chains or cyclonitrided vegetable oil acid chains on PEI, and the carbon dioxide absorption efficiency is higher after grafting cyclonitrided vegetable oil acid chains. Then, by observing the pressure of the remaining carbon dioxide in the closed reactor, it can be found that when pure PEI reaches adsorption saturation (pressure remains unchanged, no longer absorbing carbon dioxide), the remaining carbon dioxide pressure in the reactor is higher, while when PEI-OA grafted with vegetable oleic acid chains and PEI-N-OA grafted with cyclonitrogenated vegetable oleic acid chains reach adsorption saturation, the remaining carbon dioxide pressure in the reactor is lower, indicating that the carbon dioxide absorption capacity of PEI-OA grafted with vegetable oleic acid chains and PEI-N-OA grafted with cyclonitrogenated vegetable oleic acid chains has been improved, and the carbon dioxide absorption capacity of PEI-N-OA grafted with cyclonitrogenated vegetable oleic acid chains is greater. Figure 5 It can be seen that the carbon dioxide absorption capacity of PEI, PEI-OA and PEI-N-OA are 4.82 mmol / g, 6.61 mmol / g and 7.53 mmol / g, respectively.

[0044] (2) Carbon dioxide desorption test The carbon dioxide desorption test was performed on the carbon dioxide absorbents PEI, PEI-OA, and PEI-N-OA that reached the saturated adsorption state. The carbon dioxide desorption of PEI, PEI-OA, and PEI-N-OA at 80° C. was monitored. The carbon dioxide desorption of the carbon dioxide absorbents of Examples 1-2 and Comparative Example 1 is shown in the figure. Figure 6 As shown. Figure 6It can be seen that after PEI desorbs carbon dioxide at 80°C, there is still 50%~55% residual carbon dioxide. This may be because the hydrogen bond force inside becomes larger after carbon dioxide combines with amino groups, and 80°C is not enough to destroy the interaction between them, resulting in some carbon dioxide remaining in PEI without being released. After PEI-OA desorbs carbon dioxide at 80°C, there is still 35%~40% residual carbon dioxide. Compared with pure PEI, the residual carbon dioxide content of PEI-OA is reduced. This may be because the addition of vegetable oil acid chains opens the hydrogen bonds in PEI, weakens the interaction between molecules, and reduces the energy required during the desorption process. Therefore, under the same condition of 80°C, PEI-OA has less residual carbon dioxide content than PEI. After PEI-N-OA desorbs carbon dioxide at 80°C, there is still about 10% residual carbon dioxide. Compared with PEI and PEI-OA, the residual carbon dioxide content of PEI-N-OA is lower. This may be because the addition of the ring-nitrogenated plant oil acid chain opens the hydrogen bonds in PEI and weakens the intermolecular forces, resulting in a reduction in the energy required for the desorption process. On the other hand, the introduced secondary amine further enhances the binding sites of carbon dioxide. Therefore, under the same condition of 80°C, PEI-N-OA has less residual carbon dioxide content than PEI-OA and PEI, and has a greater absorption capacity.

[0045] (3) Desorption of carbon dioxide infrared test The desorption of carbon dioxide by PEI, PEI-OA and PEI-N-OA at 80° C. was monitored by infrared. The infrared images of the carbon dioxide absorbents of Examples 1-2 and Comparative Example 1 for desorption of carbon dioxide are as follows: Figure 7 As shown. Figure 7 It can be seen that the amount of carbon dioxide released in the early stage of PEI desorption at 80°C is relatively small, so the signal peak of carbon dioxide is relatively weak; compared with PEI, the infrared spectrum of PEI-OA has more carbon dioxide released in the early stage, and the signal peak is more obvious, which further verifies that the addition of vegetable oil acid chains opens the hydrogen bonds in PEI, weakens the intermolecular forces, and results in less energy required in the desorption process. Therefore, PEI-OA releases carbon dioxide earlier than PEI. From the infrared spectrum of PEI-N-OA, it can be found that the amount of carbon dioxide released in the early stage is more, and the signal peak is more obvious. This is because the addition of ring-nitrogenated vegetable oil acid chains opens the hydrogen bonds in PEI, weakens the intermolecular forces, and results in less energy required in the desorption process. On the other hand, the introduced secondary amine further increases the binding site of carbon dioxide, resulting in more absorption capacity.

[0046] (4) Antibacterial test The carbon dioxide absorbers PEI, PEI-OA, and PEI-N-OA that had reached the saturated adsorption state were irradiated under ultraviolet light for 30 minutes, and then soaked in a PBS solution with a pH of 7 for 30 minutes for use; the carbon dioxide absorber samples soaked in PBS solution were co-cultured with 1 mL of Staphylococcus aureus culture or Escherichia coli culture (culture concentration was 0.5 McFarland turbidity) for 3.5 hours, respectively, and the samples were filtered, and 30 uL of the co-cultured culture was evenly spread on the agar surface, and the bacterial growth was observed after cultured in a 37°C incubator for 16 hours.

[0047] The antibacterial results of the carbon dioxide absorbents of Examples 1-2 and Comparative Example 1 are as follows: Figure 8 As shown. Figure 8 It can be seen that PEI shows weak antibacterial properties, and a large number of strains appear on its corresponding agar surface. PEI-OA and PEI-N-OA show more excellent antibacterial effects compared to PEI, PEI-OA has the characteristic of resisting Staphylococcus aureus, and PEI-N-OA shows good antibacterial properties and shows excellent antibacterial effects to Staphylococcus aureus and Escherichia coli. This is related to the molecular structure of carbon dioxide absorbent. Compared to PEI and PEI-OA, PEI-N-OA has more tertiary amine groups on the molecule, and more quaternary ammonium salt ions are formed after absorbing carbon dioxide, thus having stronger antibacterial properties. This shows that the vegetable oil-based carbon dioxide absorbent of the present invention can be used as an antibacterial agent after absorbing carbon dioxide.

[0048] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing a vegetable oil-based carbon dioxide absorbent, characterized in that: The steps include: (1) Mixing the first vegetable oleic acid or cyclic nitrogen vegetable oleic acid and dichloromethane, then cooling to below 0°C, adding thionyl chloride, first reacting at below 0°C for 15-35 minutes, then stirring and reacting at 50-70°C for 3-5 hours to obtain vegetable oleic acid chloride or cyclic nitrogen vegetable oleic acid chloride; (2) Disperse polyethyleneimine in tetrahydrofuran, cool to below 0°C, add the vegetable oil acid chloride or cyclonitrile vegetable oil acid chloride obtained in step (1), and then react at 15-35°C for 4-8h. After the reaction is completed, add an extractant for extraction, and finally rotary evaporate to obtain a vegetable oil-based carbon dioxide absorbent.

2. The preparation method according to claim 1, characterized in that: The preparation method of the cyclic nitrogen plant oleic acid comprises the following steps: Mix anhydrous cupric chloride, 1,10-phenanthroline and hexafluoroisopropanol, stir for 30-60 min, and then cool to below 0°C. Then add the second vegetable oil acid, hydroxylamine-o-sulfonic acid and cesium hydroxide aqueous solution, first react below 0°C for 15-30 min, and then stir at 15-35°C for 16-32 h to obtain the product.

3. The preparation method according to claim 2, characterized in that: In parts by mass, the amount of anhydrous cupric chloride is 0.1-1 part, the amount of 1,10-phenanthroline is 0.1-1 part, the amount of hexafluoroisopropanol is 100-200 parts, the amount of the second vegetable oil acid is 5-20 parts, the amount of hydroxylamine-o-sulfonic acid is 3-10 parts, and the amount of cesium hydroxide aqueous solution is 5-20 parts, and the concentration of cesium hydroxide in the cesium hydroxide aqueous solution is 40-60 wt%.

4. The preparation method according to claim 2 or 3, characterized in that: The second vegetable oil acid is at least one selected from oleic acid, linoleic acid, linolenic acid, ricinoleic acid, and eleostearic acid.

5. The preparation method according to claim 1 or 2, characterized in that: The first vegetable oil acid is at least one selected from oleic acid, linoleic acid, linolenic acid, ricinoleic acid, and eleostearic acid.

6. The preparation method according to claim 1 or 2, characterized in that: The extractant is obtained by mixing saturated salt water and n-hexane in a volume ratio of 1: (1-3).

7. The preparation method according to claim 1 or 2, characterized in that: When preparing vegetable oleic acid chloride or cyclic nitrogen vegetable oleic acid chloride, the amount of the first vegetable oleic acid or cyclic nitrogen vegetable oleic acid is 5-20 parts, the amount of dichloromethane is 30-80 parts, and the amount of thionyl chloride is 10-30 parts by weight; When preparing the vegetable oil-based carbon dioxide absorbent, the amount of polyethyleneimine used is 1-5 parts, the amount of tetrahydrofuran used is 10-50 parts, and the amount of vegetable oil acid chloride or cyclonitrogen vegetable oil acid chloride is 1-10 parts by weight.

8. The vegetable oil-based carbon dioxide absorbent obtained by the preparation method according to any one of claims 1 to 7.

9. Use of the vegetable oil-based carbon dioxide absorbent according to claim 8 in preparing an adsorbent for capturing carbon dioxide.

10. Use of the vegetable oil-based carbon dioxide absorbent according to claim 8 in the preparation of an antibacterial agent.

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