A guanidine compound, a preparation method and application thereof

Abstract

The present application provides a guanidine compound and a preparation method and application thereof, the guanidine compound is a zirconium-based MOF based on guanidine group functionalization, including a zirconium-based MOF matrix and a plurality of alkyl carboxylic acids with guanidine group functional groups and amino groups, the carboxyl group of each alkyl carboxylic acid is directly coordinated with Zr on the zirconium-based MOF matrix, the guanidine compound includes a unit shown in formula 1: [Zr6O6(R1) (6‑x) (R2) x ] Formula 1; wherein R1 includes a functional group having the structural formula of formula 2; R2 is selected from one of the functional groups having the structural formula of formula 3 to formula 6; 0<=x<=3. The guanidine compound provided by the present application has the advantages of high adsorption capacity, low regeneration temperature, non-corrosive and the like as a carbon dioxide adsorbent.

Description

Technical Field

[0001] This invention relates to a guanidine compound, and more particularly to a guanidine compound, its preparation method, and its application, belonging to the field of gas adsorption and separation. Background Technology

[0002] Currently, carbon dioxide mainly comes from the combustion of fossil fuels and carbon emissions from various industrial waste gases. Therefore, current research focuses on how to achieve carbon capture in industrial settings.

[0003] Currently, the more mature carbon capture technologies include post-combustion chemical absorption and pre-combustion physical absorption. These technologies are mainly based on solution-phase adsorption systems. Through the gas-liquid two-phase contact between flue gas and the reaction liquid, the alkali or amine in the solution reacts with carbon dioxide, capturing the carbon dioxide in the solution, thereby achieving carbon dioxide capture. Although this type of capture technology has a high adsorption efficiency for carbon dioxide, it still has problems such as high energy consumption, corrosion of reaction equipment by the solution, and harsh regeneration conditions.

[0004] Therefore, there is an urgent need to develop a solid carbon dioxide adsorbent with high adsorption capacity, low regeneration temperature, and no corrosiveness. Summary of the Invention

[0005] This invention provides a guanidine compound that, when applied as a carbon dioxide adsorbent, has advantages such as high adsorption capacity, low regeneration temperature, and non-corrosiveness.

[0006] This invention provides a method for preparing guanidine compounds, which can produce guanidine compounds with high adsorption capacity, low regeneration temperature and non-corrosiveness. The method also has the advantages of readily available raw materials, simple process, low equipment requirements and environmental friendliness.

[0007] This invention provides a carbon dioxide adsorbent with high adsorption capacity, low regeneration temperature, and environmental friendliness.

[0008] This invention provides a method for adsorbing carbon dioxide, which enables rapid adsorption of carbon dioxide.

[0009] This invention provides a guanidine compound, wherein the guanidine compound is a zirconium-based MOF functionalized with a guanidine group, comprising a zirconium-based MOF matrix and a plurality of alkyl carboxylic acids having a guanidine functional group and an amino group, wherein the carboxyl group of each alkyl carboxylic acid is directly coordinated to Zr on the zirconium-based MOF matrix, and the guanidine compound comprises the unit shown in Formula 1:

[0010] [Zr6O6(R1) (6-x) (R2) x Formula 1;

[0011] Wherein, R1 includes functional groups with the structure of Equation 2; R2 is selected from functional groups with the structures of Equations 3-6; 0≤x≤3;

[0012]

[0013] The guanidine compounds described above are obtained by a preparation method comprising the following process:

[0014] The guanidine compounds are obtained by reflux reaction of a raw material system comprising a carboxyl compound containing guanidine and an amino group, a dicarboxyl compound, and a zirconium salt.

[0015] This invention provides a method for preparing the guanidine compound as described above, comprising the following steps:

[0016] The guanidine compounds are obtained by reflux reaction of a raw material system comprising a carboxyl compound containing guanidine and an amino group, a dicarboxyl compound, and a zirconium salt.

[0017] The method for preparing guanidine compounds as described above, wherein the carboxyl compound containing a guanidine group and an amino group comprises at least one compound having a structural formula of formula 7-10:

[0018]

[0019]

[0020] The method for preparing guanidine compounds as described above, wherein the dicarboxylic acid compound includes aspartic acid;

[0021] And / or, the zirconium salt includes at least one of zirconium tetrachloride, zirconium oxychloride octahydrate, zirconium oxynitrate hydrate, and zirconium acetylacetonate.

[0022] In the preparation method of the guanidine compound as described above, the molar ratio of the carboxyl compound containing guanidine and R1, the dicarboxyl compound and the zirconium salt is (10-5):(8-2):(8-12).

[0023] In the method for preparing guanidine compounds as described above, the reflux reaction is carried out at a temperature of 80-120°C for a time of 12-90 h.

[0024] The method for preparing guanidine compounds as described above, wherein the raw material system further includes acetic acid, and the mass percentage of acetic acid in the raw material system is 5%-50%.

[0025] The present invention provides a carbon dioxide adsorbent comprising guanidine compounds as described above.

[0026] The present invention provides a method for adsorbing carbon dioxide, wherein the carbon dioxide adsorbent described above is used to adsorb carbon dioxide.

[0027] The guanidine compounds provided by this invention have a specific chemical structure. The guanidinyl and amino groups in these compounds can work synergistically, allowing carbon dioxide to bind better with either the guanidinyl or amino group, thereby achieving carbon dioxide adsorption. Furthermore, the guanidinyl and amino groups are located in the pores of the MOF structure, enabling good contact with carbon dioxide and providing suitable space for the binding products, thus improving the adsorption capacity of the guanidine compounds. Moreover, the binding effect is relatively weak, allowing the guanidine compounds to exhibit low-temperature regeneration properties. In addition, the guanidine compounds are solid, which avoids corrosion problems to reaction equipment and facilitates recycling.

[0028] The method for preparing guanidine compounds provided by this invention can prepare guanidine compounds with guanidine groups and amino groups in one step through hydrolysis reaction. The obtained guanidine compounds have high adsorption capacity, low regeneration temperature and non-corrosiveness. Moreover, the preparation method has high efficiency, simple process, low equipment requirements and few types of raw materials.

[0029] The carbon dioxide adsorbent provided by this invention is prepared based on the above-mentioned guanidine compounds and has the advantages of high adsorption capacity and low regeneration temperature.

[0030] The carbon dioxide adsorption method provided by this invention enables rapid adsorption of carbon dioxide. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a guanidine compound in a specific embodiment of the present invention;

[0032] Figure 2 SEM image of the guanidine compound provided in Example 1;

[0033] Figure 3 The XRD pattern of the guanidine compound provided in Example 1;

[0034] Figure 4 The carbon dioxide adsorption-desorption curves for Example 1 and Comparative Examples 1 and 2 at 25°C are shown. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] This invention provides a guanidine compound, which is a zirconium-based MOF based on guanidine functionalization, comprising a zirconium-based MOF matrix and a plurality of alkyl carboxylic acids with guanidine functional groups and amino groups, wherein the carboxyl group of each alkyl carboxylic acid is directly coordinated to Zr on the zirconium-based MOF matrix, and the guanidine compound comprises the unit shown in Formula 1:

[0037] [Zr6O6(R1) (6-x) (R2) x Formula 1;

[0038] Wherein, R1 includes functional groups with the structure of Equation 2; R2 is selected from functional groups with the structures of Equations 3-6; 0≤x≤3;

[0039]

[0040]

[0041] The guanidine compounds of this invention comprise a zirconium-based MOF matrix and several alkyl carboxylic acids containing guanidinium functional groups and amino groups. The zirconium-based MOF matrix refers to a MOF matrix with zirconium ions as the metal ion. The carboxyl group of each alkyl carboxylic acid is directly coordinated with Zr on the zirconium-based MOF matrix, i.e., the oxygen in the carboxyl group coordinates with Zr. In this invention, 0 ≤ x ≤ 3 represents the number of alkyl carboxylic acids containing guanidinium and amino groups doped within a single cell.

[0042] According to the above-described scheme provided by the present invention, the guanidine compound is used as a solid carbon dioxide adsorbent, which exhibits high adsorption capacity, low regeneration temperature, and non-corrosiveness. The inventors analyzed the principle behind this and believe the reason may be that, on the one hand, both the guanidine group and the amino group of the guanidine compound can provide adsorption active sites for carbon dioxide, and the guanidine group can synergistically interact with both intramolecular and intermolecular amino groups, enabling carbon dioxide to better bind to these sites. Figure 1 As shown (taking arginine as an example), this gives the guanidine compound a high adsorption capacity. On the other hand, the guanidine compound has a MOF structure, with the guanidine group and amino group present in the pores of the MOF structure, enabling good contact with carbon dioxide. Simultaneously, due to the pore size limitation, the guanidine compound exists in a relatively folded conformation within the pores, further promoting the interaction between the guanidine group and the amino group, thereby further improving the adsorption capacity of the guanidine compound. Furthermore, due to the guanidine-CO3-(H2O)... x The structure and the relatively weak binding of amino groups with carbon dioxide result in a low regeneration temperature for this guanidine compound. Furthermore, the guanidine compound is in a solid state, which avoids corrosion problems to reaction equipment during application and makes it easy to recycle.

[0043] Specifically, the chemical structures of the guanidine compounds of the present invention were obtained by XRD testing.

[0044] In one specific embodiment, the guanidine compound is obtained by a preparation method comprising the following process:

[0045] Guanidine compounds were obtained by reflux reaction of a raw material system including carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds, and zirconium salts.

[0046] Specifically, a carboxyl compound containing guanidine and amino groups, a dicarboxyl compound, and a zirconium salt are mixed in a solvent to obtain a raw material system. The raw material system is then refluxed to obtain guanidine compounds.

[0047] This invention does not limit the specific selection of carboxyl compounds containing guanidine and amino groups; the selection can be made according to actual needs, such as arginine.

[0048] This invention does not limit the specific selection of dicarboxylic acid compounds, but can select them according to actual needs, such as aspartic acid.

[0049] This invention does not limit the specific selection of zirconium salts; they can be selected according to actual needs, such as zirconium tetrachloride.

[0050] This invention does not limit the specific choice of solvent in the raw material system, as long as it can form a raw material system including carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds and zirconium salts.

[0051] The raw material system of the present invention may also include substances such as hydrochloric acid or acetic acid, which can be selected according to actual needs.

[0052] This invention does not limit the mixing method of carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds, and zirconium salts, as long as a homogeneous and stable raw material system can be formed.

[0053] This invention does not limit the specific parameters of the reflux reaction; they can be selected according to actual needs.

[0054] The present invention prepares guanidine compounds with the above-described structure by means of the above-described preparation method. These guanidine compounds can be used as carbon dioxide adsorbents, have high adsorption capacity, and can be regenerated at low temperatures, which is beneficial to the wide application of these guanidine compounds.

[0055] This invention provides a method for preparing the guanidine compound as described above, comprising the following steps:

[0056] A raw material system comprising carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds, and zirconium salts is subjected to reflux reaction to obtain guanidine compounds.

[0057] Specifically, a carboxyl compound containing guanidine and amino groups, a dicarboxyl compound, and a zirconium salt are mixed in a solvent to obtain a raw material system. The raw material system is then refluxed. After the reaction is completed, solid-liquid separation is performed, followed by washing and drying to obtain guanidine compounds.

[0058] This invention does not limit the specific selection of carboxyl compounds, dicarboxyl compounds, or zirconium salts containing guanidine and amino groups; selection can be made according to actual needs.

[0059] This invention does not limit the specific choice of solvent in the raw material system, as long as it can form a raw material system including carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds and zirconium salts.

[0060] The raw material system of the present invention may also include substances such as hydrochloric acid or acetic acid, which can be selected according to actual needs.

[0061] This invention does not limit the mixing method of carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds, and zirconium salts, as long as a homogeneous and stable raw material system can be formed.

[0062] This invention does not limit the specific parameters of the reflux reaction; they can be selected according to actual needs.

[0063] This invention does not impose any special limitations on the method of solid-liquid separation; for example, filtration, precipitation, and other methods may be used.

[0064] This invention does not limit the specific parameters for cleaning and drying treatments; they can be selected according to actual needs. For example, hot water or ethanol can be used for cleaning, followed by air drying to obtain guanidine compounds.

[0065] This invention prepares guanidine compounds using the above-described preparation method, which involves hydrolyzing carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds, and zirconium salts. The guanidine compounds prepared by this method exhibit uniform distribution of guanidine and amino groups, enabling effective carbon dioxide adsorption. Furthermore, this method allows for the one-step synthesis of guanidine compounds with high efficiency. Additionally, the method utilizes few and readily available raw materials, facilitating industrial application.

[0066] In one specific embodiment, the carboxyl compound containing a guanidine group and an amino group includes at least one compound having a structural formula from Formula 7 to Formula 10:

[0067]

[0068] When the above-mentioned compounds are used as carboxyl compounds containing guanidine and amino groups, guanidine compounds with the structure of Formula 1 can be prepared, and the generation of other by-products during the preparation process can be avoided, thereby ensuring the high purity of the guanidine compounds. At the same time, the guanidine compounds prepared have a high content of guanidine and amino groups, which can make the adsorption capacity of the guanidine compounds higher. In addition, the above-mentioned compounds are environmentally friendly and can avoid environmental pollution during the preparation process.

[0069] In one specific embodiment, the dicarboxylic acid compound includes aspartic acid. When the above compound is selected as the dicarboxylic acid compound, guanidine compounds having the structure of Formula 1 can be prepared, and the dicarboxylic acid compound is environmentally friendly, which can reduce the environmental pollution during the production of guanidine compounds and is conducive to the large-scale production of guanidine compounds.

[0070] In one specific embodiment, the zirconium salt includes at least one of zirconium tetrachloride, zirconium oxychloride octahydrate, zirconium oxynitrate hydrate, and zirconium acetylacetonate. When the zirconium salt is selected from the above compounds, it can react with carboxyl compounds containing guanidine and amino groups, as well as dicarboxyl compounds, to generate guanidine compounds. Furthermore, the zirconium salt is readily available, laying the foundation for the large-scale production of guanidine compounds.

[0071] In one specific embodiment, the molar ratio of the carboxyl compound containing guanidine and amino groups, the dicarboxyl compound, and the zirconium salt is (10⁻⁵):(8⁻²):(8⁻¹²), for example, molar ratios of 10:8:8, 9:8:8, 8:8:8, 7:8:8, 6:8:8, 5:8:8, 10:2:8, 9:2:8, 8:2:8, 7:2:8, 6:2:8, 5:2:8, 10:5:9, 10:5:10, 10:5:11, 10:5:12, etc. When the molar ratio of the carboxyl compound containing guanidine and amino groups, the dicarboxyl compound, and the zirconium salt is within the above range, the carboxyl compound containing guanidine and amino groups, the dicarboxyl compound, and the zirconium salt can undergo better hydrolysis reactions, avoiding the generation of side reactions and the waste of raw materials, thereby obtaining guanidine compounds with high adsorption capacity while saving raw material costs.

[0072] In one specific embodiment, the reflux reaction temperature is 80-120°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, or 120°C, and the reaction time is 12-90 hours, for example, 12 hours, 15 hours, 20 hours, 30 hours, 40 hours, 50 hours, 60 hours, 70 hours, 80 hours, or 90 hours. When the reflux reaction temperature and reaction time are within the above ranges, carboxyl compounds containing guanidine and amino groups, dicarboxyl compounds, and zirconium salts can undergo sufficient hydrolysis to generate guanidine compounds, and side reactions can be avoided, reducing the formation of byproducts.

[0073] In one specific embodiment, the raw material system also includes acetic acid, with the acetic acid content in the raw material system ranging from 5% to 50% by mass, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. When the raw material system also includes acetic acid, and the mass concentration of acetic acid is within the above range, it can increase the solubility of carboxyl compounds containing guanidine and amino groups, as well as dicarboxyl compounds, in the solvent, and can improve the crystallinity of guanidine compounds, making the guanidine compounds more stable. This allows the guanidine compounds to more stably adsorb carbon dioxide, and can also largely avoid deactivation after regeneration treatment, which would prevent them from being reused, further reducing the process cost of carbon dioxide adsorption.

[0074] This invention provides a carbon dioxide adsorbent comprising the aforementioned guanidine compounds. The carbon dioxide adsorbent provided by this invention, comprising the aforementioned guanidine compounds, exhibits high adsorption capacity, low regeneration temperature, and is environmentally friendly and non-corrosive.

[0075] This invention provides a method for adsorbing carbon dioxide, using the carbon dioxide adsorbent described above. The carbon dioxide adsorption method provided by this invention enables rapid adsorption of carbon dioxide.

[0076] In one specific embodiment, the carbon dioxide adsorbent undergoes an activation treatment before adsorption: the adsorbent is heated at 60°C for 2 hours, then raised to 100°C and heated for 12 hours, with a heating rate of 1°C / min. Specifically, the activation treatment includes the following steps: first, the carbon dioxide adsorbent is heated to 60°C at a heating rate of 1°C / min for 2 hours, then raised to 100°C at a heating rate of 1°C / min and heated for 12 hours. This activation treatment removes moisture and impurities from the pores of the carbon dioxide adsorbent, ensuring sufficient exposure of the carbon dioxide adsorption sites, thereby ensuring the full utilization of the adsorption capacity and achieving rapid adsorption of carbon dioxide.

[0077] The present invention will be further described in detail below through specific embodiments.

[0078] Example 1

[0079] The preparation process of guanidine compounds provided in this embodiment includes the following steps:

[0080] 100 mmol arginine, 20 mmol DL-aspartic acid, and 100 mmol ZrCl4 were dispersed in 100 mL of aqueous solution, followed by the addition of 20 mL acetic acid. The mixture was allowed to stand until the solution became clear and transparent, and then refluxed at 100 °C for 40 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with hot water / ethanol at room temperature, and air-dried to obtain guanidine compounds.

[0081] The NMR analysis of guanidine compounds included the following steps: 40 mg of the guanidine compound was placed in a 1M deuterium aqueous solution of NaOH and allowed to stand for 24 hours. The guanidine compound decomposed, and the solution was filtered through a 220-micron filter. The resulting solution was then analyzed using a proton NMR spectrometer. Based on the NMR results, the guanidine compound [Zr6O6(R1)]... 5.46 (R2) 0.54 The guanidine content is 10% (compared to aspartic acid).

[0082] The preparation processes of the guanidine compounds provided in Examples 2-18 and Comparative Examples 1-2 are basically the same as those in Example 1, with some preparation parameters adjusted, as detailed in Table 1.

[0083] Test case

[0084] The guanidine compounds from Example 1 were subjected to SEM and XRD tests, and the results are shown in the figures below. Figure 2 and Figure 3 .Depend on Figure 2 It is known that guanidine compounds are particulate, with a particle size ranging from 35 to 110 nm. Figure 3 It is evident that the guanidinium-doped MOF possesses excellent crystallinity. Its ultra-small nanoscale particle size facilitates the diffusion of carbon dioxide into the material interior during capture.

[0085] The guanidine compounds of Examples 1-18 and Comparative Examples 1-2 were activated by the following steps: the carbon dioxide adsorbent was heated to 60°C at a heating rate of 1°C / min and heated for 2 hours, and then heated to 100°C at a heating rate of 1°C / min and heated for 12 hours.

[0086] Subsequently, with an exhaust rate of less than 2 μbar / hr, the guanidine compounds from Examples 1-18 and Comparative Examples 1-3 were backfilled into carbon dioxide and then transferred to the analysis port. A vacuum treatment was then performed for at least 240 min before analysis began. After 1 h of carbon dioxide adsorption, a BET test was performed to obtain the carbon dioxide adsorption capacity C1. The carbon dioxide adsorbent was then desorbed at 100°C, 120°C, and 140°C, respectively, and carbon dioxide adsorption was continued for 1 h before the carbon dioxide adsorption capacity C1 was tested using a BET test. 100 C 120 C140 If C 100 C 120 C 140 The temperature at which C1 does not decrease significantly is the regeneration temperature of the carbon dioxide adsorbent. Specific test results are shown in Table 1. The carbon dioxide adsorption capacity refers to the saturated adsorption capacity at 25℃ and 100Kpa.

[0087] in, Figure 4 The carbon dioxide adsorption-desorption curves for Example 1 and Comparative Examples 1 and 2 at 25°C are shown.

[0088] Table 1

[0089]

[0090]

[0091]

[0092] As shown in Table 1, the guanidine compounds provided in Examples 1-18 of this invention have excellent carbon dioxide adsorption capacity, with an adsorption capacity of not less than 1.3 mmol / g. Moreover, the regeneration temperature is relatively low, and regeneration can be achieved under relatively mild conditions, thereby realizing the full utilization of guanidine compounds, which is of great significance for carbon capture.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A guanidine compound, characterized in that, The guanidine compound is a zirconium-based MOF functionalized with a guanidine group, comprising a zirconium-based MOF matrix and several alkyl carboxylic acids with guanidine functional groups and amino groups. The carboxyl group of each alkyl carboxylic acid is directly coordinated with Zr on the zirconium-based MOF matrix. The guanidine compound comprises the unit shown in Formula 1: [Zr6O6(R1) (6-x) (R2) x Formula 1; Wherein, R1 includes functional groups with the structure of Equation 2; R2 is selected from functional groups with the structures of Equations 3-6; 0≤x≤3; 2. The guanidine compound according to claim 1, characterized in that, The guanidine compounds are obtained by a preparation method comprising the following steps: The guanidine compounds are obtained by reflux reaction of a raw material system comprising a carboxyl compound containing guanidine and an amino group, a dicarboxyl compound, and a zirconium salt.

3. A method for preparing the guanidine compound according to claim 1 or 2, characterized in that, Includes the following steps: The guanidine compounds are obtained by reflux reaction of a raw material system comprising a carboxyl compound containing guanidine and an amino group, a dicarboxyl compound, and a zirconium salt.

4. The method for preparing guanidine compounds according to claim 3, characterized in that, The carboxyl compounds containing guanidine and amino groups include at least one compound having a structural formula from Formula 7 to Formula 10:

5. The method for preparing guanidine compounds according to claim 3 or 4, characterized in that, The dicarboxylic acid compound is aspartic acid; And / or, the zirconium salt includes at least one of zirconium tetrachloride, zirconium oxychloride octahydrate, zirconium oxynitrate hydrate, and zirconium acetylacetonate.

6. The method for preparing guanidine compounds according to any one of claims 3-5, characterized in that, The molar ratio of the carboxyl compound containing guanidine and amino groups, the dicarboxyl compound, and the zirconium salt is (10-5):(8-2):(8-12).

7. The method for preparing guanidine compounds according to any one of claims 3-6, characterized in that, The reflux reaction is carried out at a temperature of 80-120℃ for 12-90 hours.

8. The method for preparing guanidine compounds according to any one of claims 3-7, characterized in that, The raw material system also includes acetic acid, and the acetic acid content in the raw material system is 5%-50% by mass.

9. A carbon dioxide adsorbent, characterized in that, The carbon dioxide adsorbent includes the guanidine compound as described in claim 1 or 2.

10. A method for adsorbing carbon dioxide, characterized in that, Use the carbon dioxide adsorbent according to claim 9 to adsorb carbon dioxide.

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