An aminozirconium cluster metal-organic framework composite material, its preparation method and application

Abstract

This invention discloses an aminozirconium cluster metal-organic framework composite material, its preparation method, and its applications. The aminozirconium cluster metal-organic framework composite material is obtained by hydrothermal reaction of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid in a solvent; the mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid is 100–500:0.7–7:200–300; the solvent includes acetic acid and N,N-dimethylformamide. The aminozirconium cluster metal-organic framework composite material prepared by this invention exhibits excellent catalytic performance in the catalytic CO2 cycloaddition reaction. Furthermore, the material has a stable and reliable structure and can be repeatedly recycled in the reaction system without frequent replacement, which helps reduce production costs and improves the economic efficiency and sustainability of the catalytic CO2 cycloaddition process.

Description

Technical Field

[0001] This invention relates to the field of catalytic material preparation and application, and more specifically, to an aminozirconium cluster metal-organic framework composite material, its preparation method, and its application. Background Technology

[0002] In recent decades, carbon dioxide (CO2) has become one of the largest emitters of greenhouse gases, and its excessive emissions have led to severe greenhouse effects and global warming. Therefore, there is an urgent need to reduce the ever-increasing atmospheric CO2 levels through CO2 capture and conversion. However, due to the thermodynamic stability and kinetic inertia of CO2, achieving its efficient conversion and resource utilization presents new challenges.

[0003] Among various CO2 conversion pathways, the cycloaddition reaction of CO2 with epoxides to form cyclic carbonates is considered an ideal strategy for CO2 conversion due to its 100% atom utilization rate. This method has enormous potential and has become a focus of research. Furthermore, the cyclic carbonates produced by this reaction are stable, non-toxic, and harmless, making them valuable as green solvents, lithium battery electrolytes, and important intermediates for the synthesis of polymers and chemicals.

[0004] Currently, many homogeneous catalysts have been used for the cycloaddition reaction of CO2, including ionic liquids, quaternary ammonium salts, transition metal complexes, and alkali metal halides. However, a major limitation of homogeneous catalysts is their easy dissolution in the reaction system, leading to difficulties in separation from the reaction phase, low catalyst recovery efficiency, and consequently, resource waste. Therefore, developing efficient and recyclable heterogeneous catalysts for CO2 conversion is particularly important. These catalysts can be separated and recovered after the reaction by simple filtration or precipitation, although their catalytic activity may be lower than that of homogeneous catalysts.

[0005] Metal-organic frameworks (MOFs), as porous materials with remarkable properties, have attracted widespread attention due to their tunable porous structure, high specific surface area, excellent porosity, and strong adsorption capacity. These properties enable MOFs to perform well in various applications such as gas storage and separation, chemical sensing, heterogeneous catalysis, and drug delivery. In recent years, various MOF materials have been studied as heterogeneous catalysts for the cycloaddition reaction of CO2 with epoxides, exhibiting good catalytic performance and recyclability potential. For example, Chinese patent CN110305330A discloses a three-dimensional porous metal-organic framework material self-assembled from iron clusters and the organic ligand 4,4-dicarboxylic acid diphenyl ether through a solvothermal reaction, which exhibits good water stability; Chinese patent CN112280052A develops an environmentally friendly amphoteric surfactant (3-sulfopropyltetradecyl dimethyl betaine). Based on the hydroxyl bimetallic salt ((Zn,Zn)-HDS) and using an amphoteric surfactant as a structure-directing agent, a hierarchical porous ZIF-8 material with microporous, mesoporous, and macroporous pore structures can be synthesized under mild conditions, effectively improving its catalytic activity for CO2 cycloaddition reactions. The ZIF-8 / CeO2 material developed in Chinese patent CN112844486A possesses high specific surface area and porosity, as well as high stability, exhibiting good catalytic activity and reusability in CO2 cycloaddition reactions. However, most of these catalysts can only achieve ideal catalytic effects under organic salt co-catalysis or high-pressure conditions, limiting their application in CO2 cycloaddition reactions. Therefore, this patent develops a novel composite catalyst with excellent catalytic performance under mild conditions, and its synthesis steps are simple and its effects are stable, showing great promise for industrial applications. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an aminozirconium cluster metal-organic framework composite material, its preparation method, and its application. The aminozirconium cluster metal-organic framework composite material is prepared using zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid as raw materials. It exhibits excellent catalytic performance in the catalytic CO2 cycloaddition reaction, and the material has a stable and reliable structure, allowing for multiple cycles within the reaction system without frequent replacement. This reduces production costs and improves the economic efficiency and sustainability of the catalytic CO2 cycloaddition process.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides an aminozirconium cluster metal-organic framework composite material, which is obtained by hydrothermal reaction of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid in a solvent;

[0009] The mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid is 100–500: 0.7–7: 200–300;

[0010] The solvents include acetic acid and N,N-dimethylformamide.

[0011] Preferably, the total mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid to the volume ratio of N,N-dimethylformamide is 0.3–0.81 g: 30–55 mL.

[0012] Preferably, the volume ratio of acetic acid to N,N-dimethylformamide is 5-10:30-45.

[0013] The second aspect of the present invention provides a method for preparing an aminozirconium cluster metal-organic framework composite material, wherein zirconium tetrachloride, palladium dichloride, 2-aminoterephthalic acid, N,N-dimethylformamide, and acetic acid are mixed, stirred evenly at room temperature, and then ultrasonically treated. After that, the mixture is transferred to a stainless steel high-pressure reactor and subjected to hydrothermal reaction in an oven. After the hydrothermal reaction product is naturally cooled, it is washed and dried to obtain the aminozirconium cluster metal-organic framework composite material.

[0014] Preferably, the mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid is 100-500:0.7-7:200-300.

[0015] The ratio of the total mass of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid to the amount of N,N-dimethylformamide is 0.3–0.8 g: 35–55 mL.

[0016] The volume ratio of the acetic acid to the organic solvent is 5-10:30-45.

[0017] Preferably, the stirring time is 20-40 min and the ultrasonic treatment time is 20-30 min;

[0018] The stainless steel high-pressure reactor is lined with polytetrafluoroethylene.

[0019] During the hydrothermal reaction process, the oven temperature is 100–120°C, and the hydrothermal reaction time is 20–24 hours.

[0020] Preferably, the washing involves centrifuging and washing the hydrothermal reaction products with N,N-dimethylformamide and methanol, respectively.

[0021] The drying process is performed in a vacuum oven at a temperature of 60–80°C.

[0022] A third aspect of the present invention provides the application of the aminozirconium cluster metal-organic framework composite material as described in the first aspect of the present invention in the photocatalytic CO2 cycloaddition reaction.

[0023] Preferably, the aminozirconium cluster metal-organic framework composite material is activated in a vacuum environment;

[0024] The activated aminozirconium cluster metal-organic framework composite material was added to a reactor containing epichlorohydrin and tetrabutylammonium bromide, CO2 was introduced, and a xenon lamp was used as the light source to carry out a CO2 cycloaddition reaction.

[0025] The beneficial effects of this invention are as follows:

[0026] The aminozirconium cluster metal-organic framework composite material prepared by this invention exhibits excellent catalytic performance under mild conditions, has a simple synthesis procedure, and can save a significant amount of energy, showing promising application prospects in industrial applications. The aminozirconium cluster metal-organic framework composite material has a stable and reliable structure, and even after five reaction cycles, its catalytic activity remains above 80%, maintaining its high efficiency and stability. This characteristic is crucial for industrial applications because it means that the catalyst can be recycled multiple times in the reaction system without frequent replacement, which helps reduce production costs and improves the economic efficiency and sustainability of the entire process. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the preparation method of the aminozirconium cluster metal-organic framework composite material of the present invention;

[0028] Figure 2 The images show SEM images of the aminozirconium cluster metal-organic framework composite material synthesized in Example 1 of this invention before and after the CO2 cycloaddition reaction; (a) is the SEM image of 0.5 wt% PdUN before the CO2 cycloaddition reaction; (b) is the SEM image of 0.5 wt% PdUN before the CO2 cycloaddition reaction.

[0029] Figure 3 The following are EDS distribution diagrams of 0.5 wt% PdUN in Embodiment 1 of the present invention: (a) is the overall EDS distribution diagram of 0.5 wt% PdUN; (b) is the EDS distribution diagram of Zr; (c) is the EDS distribution diagram of C; (d) is the EDS distribution diagram of N; and (e) is the EDS distribution diagram of Pd.

[0030] Figure 4 The image shows the XRD patterns of 0.5 wt% PdUN in Example 1 of this invention before and after the CO2 cycloaddition reaction. Detailed Implementation

[0031] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] The aminozirconium cluster metal-organic framework composite material of the present invention is obtained by hydrothermal reaction of zirconium tetrachloride, palladium dichloride and 2-aminoterephthalic acid in a solvent; the mass ratio of zirconium tetrachloride, palladium dichloride and 2-aminoterephthalic acid is 100-500:0.7-7:200-300; the solvent includes acetic acid and N,N-dimethylformamide.

[0033] The ratio of the total mass of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid to the amount of N,N-dimethylformamide is 0.3–0.81 g: 30–55 mL.

[0034] The volume ratio of acetic acid to N,N-dimethylformamide is 5–10:30–45.

[0035] Combination Figure 1 As shown, the preparation method of aminozirconium cluster metal-organic framework composite material includes the following steps:

[0036] (1) Zirconium tetrachloride, palladium dichloride, 2-aminoterephthalic acid, N,N-dimethylformamide, and acetic acid were mixed, stirred evenly at room temperature, and then ultrasonically treated. After that, the mixture was transferred to a stainless steel high-pressure reactor and hydrothermal reaction was carried out in an oven.

[0037] In this step, zirconium tetrachloride, palladium dichloride, 2-aminoterephthalic acid, N,N-dimethylformamide, and acetic acid are mixed and stirred at room temperature for 20–40 min. After thorough mixing, the mixture is ultrasonically treated for 20–30 min, then transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene (PTFE), and subjected to a hydrothermal reaction at 100–120°C in an oven for 20–24 h. The mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid is 100–500:0.7–7:200–300; the total mass of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid to the amount of N,N-dimethylformamide is 0.3–0.8 g:35–55 mL; and the volume ratio of acetic acid to organic solvent is 5–10:30–45.

[0038] The hydrothermal reaction principle is as follows: Hydrothermal synthesis is carried out in a specially designed closed reaction vessel using a specific solvent as the reaction medium. The vessel is heated to create a high-temperature, high-pressure reaction environment, allowing normally insoluble or poorly soluble substances to dissolve and recrystallize, thus enabling inorganic synthesis and material processing. The main advantages of this method are its simplicity, low cost, and ability to synthesize nanocrystals with unique morphologies and excellent properties. During the hydrothermal reaction, 2-aminoterephthalic acid, acting as an organic ligand, coordinates with the Zr metal ions in zirconium tetrachloride to form a crystal structure, resulting in the final product.

[0039] (2) After the hydrothermal reaction products are naturally cooled, they are washed and dried to obtain aminozirconium cluster metal-organic framework composite materials.

[0040] In this step, after the hydrothermal reaction product cools naturally to room temperature, the hydrothermal reaction product is washed with N,N-dimethylformamide and methanol to obtain the target product. Specifically, the product is stirred with N,N-dimethylformamide for 30-40 minutes, centrifuged and washed, and then fresh N,N-dimethylformamide is added and centrifuged and washed once more in the same manner. Subsequently, the hydrothermal reaction product is transferred and centrifuged and washed with methanol for 1-2 hours, and then stirred with fresh methanol for 12-16 hours. The material obtained by centrifugation and washing is placed in a vacuum oven and dried at 60-80°C to obtain an aminozirconium cluster metal-organic framework composite material.

[0041] This invention also provides an application of an aminozirconium cluster metal-organic framework composite material in the photocatalytic CO2 cycloaddition reaction, the method of which is as follows:

[0042] (1) Before the CO2 cycloaddition reaction, the aminozirconium cluster metal-organic framework composite material was activated in a vacuum environment at 150℃±10℃.

[0043] (2) 10-30 mg of activated aminozirconium cluster metal-organic framework composite material was added to a reactor containing 10-20 mmol of epichlorohydrin and 160-180 mg of tetrabutylammonium bromide (co-catalyst), CO2 was introduced, and a xenon lamp was used as the light source to carry out the CO2 cycloaddition reaction (the actual current, pressure, etc. during the reaction can be determined according to the actual situation). After the reaction, the yield of cyclic carbonate reached more than 80%.

[0044] The principle of the photocatalytic CO2 cycloaddition reaction described above is as follows: The oxygen atom of the epoxide (such as epichlorohydrin) combines with the metal ions of the aminozirconium cluster metal-organic framework composite material, thereby being activated. The activated epoxide is then attacked by nucleophilic ions (usually halide anions) provided by a co-catalyst (such as tetrabutylammonium bromide, TBAB), which attack the less sterically hindered carbon atoms, leading to ring opening of the epoxide and the formation of an alkoxy intermediate. The para-cation in the co-catalyst helps maintain the stability of the alkoxy intermediate and prevents it from re-closing. Next, CO2 inserts an electrophilic carbon atom into the negatively charged oxygen atom in the alkoxy intermediate to form an open-chain carbonate intermediate; this step is crucial in the conversion process because it directly involves the insertion and activation of CO2. Subsequently, the open-chain carbonate intermediate undergoes an intramolecular ring elimination process to form a five-membered cyclic carbonate; in this process, the halide anion eventually leaves, the catalyst is regenerated, and it can continue to participate in the next round of reaction cycle.

[0045] The preparation method of the aminozirconium cluster metal-organic framework composite material of the present invention is further described below with reference to specific embodiments. The dosage error of the materials prepared in the following embodiments and comparative examples is controlled within one-thousandth, and the final yield of cyclic carbonate is the average value of multiple experiments.

[0046] Example 1

[0047] A method for preparing an aminozirconium cluster metal-organic framework composite material, the specific steps of which are as follows:

[0048] (1) Mix 0.3g, 1.3mmol zirconium tetrachloride, 3.5mg, 0.5wt% palladium dichloride, 0.236g, 1.3mmol 2-aminoterephthalic acid, 40mL N,N-dimethylformamide and 8mL acetic acid, stir at room temperature for 30min, sonicate for 20min after stirring, transfer to the liner of a polytetrafluoroethylene stainless steel high pressure reactor, and hydrothermally heat at 120℃ for 24h in an oven.

[0049] (2) After naturally cooling to room temperature, the obtained material was washed with N,N-dimethylformamide and methanol to obtain the target product. Specifically, the material was stirred with N,N-dimethylformamide for 30 min, centrifuged and washed, and then fresh N,N-dimethylformamide was added and centrifuged and washed once in the same manner. Subsequently, the product was transferred and centrifuged and washed with methanol for 1-2 h, and then stirred with fresh methanol for 12 h. The material obtained by centrifugation and washing was placed in a vacuum oven at 60°C and dried to obtain aminozirconium cluster metal-organic framework composite material, denoted as 0.5wt%PdUN.

[0050] Figure 2 SEM images of 0.5 wt% PdUN before and after the CO2 cycloaddition reaction are shown. As can be seen from the images, the crystal particles of the material did not change significantly before and after the CO2 cycloaddition reaction, and the structure was stable.

[0051] Figure 3 The figure shows the EDS curve of 0.5 wt% PdUN. As can be seen from the figure, this embodiment successfully synthesized an aminozirconium cluster metal-organic framework composite material with a relatively low Pd element loading.

[0052] Figure 4 The XRD patterns of 0.5 wt% PdUN before and after the CO2 cycloaddition reaction are shown. Figure 4 The XRD patterns of the material did not change significantly before and after the CO2 cycloaddition reaction, demonstrating its structural stability.

[0053] Application of aminozirconium cluster metal-organic framework composite material in photocatalytic CO2 cycloaddition reaction: In a reactor containing 10 mmol epichlorohydrin and 161 mg and 0.5 mmol tetrabutylammonium bromide (co-catalyst), 20 mg of the aminozirconium cluster metal-organic framework material prepared above was added as a catalyst, CO2 was introduced, a xenon lamp was used as the light source, the actual current was 18 A, 0.1 MPa, the mixture was stirred, and the reaction was carried out for 4 h. The yield of cyclic carbonate was detected and calculated by GC-MS and was greater than 98.8%.

[0054] Example 2

[0055] (1) Same as in Example 1, except that the palladium dichloride used in step (1) was changed to 0.7 mg and 0.1 wt%, and other conditions remained unchanged. The yield of cyclic carbonate was 81.39%.

[0056] (2) Same as in Example 1, except that the palladium dichloride used in step (1) was replaced with 2.1 mg and 0.3 wt%, and other conditions remained unchanged. The yield of cyclic carbonate was 87.68%.

[0057] (3) Same as Example 1, except that the palladium dichloride used in step (1) was changed to 4.9 mg, 0.7 wt%, and other conditions remained unchanged. The yield of cyclic carbonate was 86.03%.

[0058] (4) Same as Example 1, except that the palladium dichloride used in step (1) was replaced with 7 mg, 1 wt%, and other conditions remained unchanged, and the yield of cyclic carbonate was 84.36%.

[0059] Example 3

[0060] (1) Same as in Example 1, except that the dosage of aminozirconium cluster metal-organic framework composite material (catalyst) was changed to 10 mg, and other conditions remained unchanged, the yield of cyclic carbonate was 81.49%.

[0061] (2) Same as in Example 1, except that the dosage of aminozirconium cluster metal-organic framework composite material (catalyst) was changed to 15 mg, and other conditions remained unchanged, the yield of cyclic carbonate was 91.94%.

[0062] (3) Same as in Example 1, except that the dosage of aminozirconium cluster metal-organic framework composite material (catalyst) was changed to 25 mg, and other conditions remained unchanged, the yield of cyclic carbonate was 93.80%.

[0063] (4) Same as in Example 1, except that the dosage of aminozirconium cluster metal-organic framework composite material (catalyst) was changed to 30 mg, and other conditions remained unchanged, the yield of cyclic carbonate was 91.56%.

[0064] Example 4

[0065] (1) Same as in Example 1, when the aminozirconium cluster metal-organic framework composite material (catalyst) was recycled for the second time, the cyclic carbonate yield was 92.94% under the same conditions.

[0066] (2) Same as in Example 1, when the aminozirconium cluster metal-organic framework composite material (catalyst) was recycled for the third time, the cyclic carbonate yield was 90.30% under the same conditions.

[0067] (3) Same as in Example 1, when the aminozirconium cluster metal-organic framework composite material (catalyst) was recycled for the fourth time, the cyclic carbonate yield was 85.43% under the same conditions.

[0068] (4) Same as in Example 1, when the aminozirconium cluster metal-organic framework composite material (catalyst) was recycled for the 5th time, the cyclic carbonate yield was 82.80% under the same conditions.

[0069] Example 5

[0070] Same as in Example 1, in step (1), the amount of zirconium tetrachloride is 0.1 g; the amount of 2-aminoterephthalic acid is 0.2 g; the amount of N,N-dimethylformamide is 30 mL; and the amount of acetic acid is 5 mL. Under the same conditions, the yield of cyclic carbonate is 89.26%.

[0071] Example 6

[0072] Same as in Example 1, in step (1), the amount of zirconium tetrachloride is 0.5g; the amount of 2-aminoterephthalic acid is 0.3g; the amount of N,N-dimethylformamide is 45mL; and the amount of acetic acid is 10mL. Under the same conditions, the yield of cyclic carbonate is 88.57%.

[0073] Comparative Example 1

[0074] Same as Example 1, but without the addition of palladium dichloride, and with other conditions unchanged, the yield of cyclic carbonates was 60.6%-62.4%.

[0075] Comparative Example 2

[0076] (1) Same as in Example 1, except that the dosage of tetrabutylammonium bromide (co-catalyst) was changed to 96.7 mg and 0.3 mmol, and other conditions remained unchanged, the yield of cyclic carbonate was 45.54%.

[0077] (2) Same as in Example 1, except that the dosage of tetrabutylammonium bromide (co-catalyst) was changed to 225.7 mg and 0.7 mmol, and other conditions remained unchanged. The yield of cyclic carbonate was 74.90%.

[0078] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. An aminozirconium cluster metal-organic framework composite material, characterized in that, It is obtained by hydrothermal reaction of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid in a solvent; The mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid is 100–500: 0.7–7: 200–300; The solvents include acetic acid and N,N-dimethylformamide.

2. The aminozirconium cluster metal-organic framework composite material according to claim 1, characterized in that: The total mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid to the volume ratio of N,N-dimethylformamide is 0.3–0.81 g: 30–55 mL.

3. The aminozirconium cluster metal-organic framework composite material according to claim 1 or 2, characterized in that: The volume ratio of acetic acid to N,N-dimethylformamide is 5–10:30–45.

4. A method for preparing an aminozirconium cluster metal-organic framework composite material, characterized in that: Zirconium tetrachloride, palladium dichloride, 2-aminoterephthalic acid, N,N-dimethylformamide, and acetic acid were mixed, stirred evenly at room temperature, and then ultrasonically treated. The mixture was then transferred to a stainless steel high-pressure reactor and subjected to hydrothermal reaction in an oven. After the hydrothermal reaction product cooled naturally, it was washed and dried to obtain an aminozirconium cluster metal-organic framework composite material.

5. The method for preparing the aminozirconium cluster metal-organic framework composite material according to claim 4, characterized in that: The mass ratio of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid is 100–500: 0.7–7: 200–300; The ratio of the total mass of zirconium tetrachloride, palladium dichloride, and 2-aminoterephthalic acid to the amount of N,N-dimethylformamide is 0.3–0.8 g: 35–55 mL. The volume ratio of the acetic acid to the organic solvent is 5-10:30-45.

6. The method for preparing the aminozirconium cluster metal-organic framework composite material according to claim 4, characterized in that: The stirring time is 20-40 min, and the ultrasonic treatment time is 20-30 min; The stainless steel high-pressure reactor is lined with polytetrafluoroethylene. During the hydrothermal reaction process, the oven temperature is 100–120°C, and the hydrothermal reaction time is 20–24 hours.

7. The method for preparing the aminozirconium cluster metal-organic framework composite material according to claim 4, characterized in that: The washing process involves centrifuging and washing the hydrothermal reaction products with N,N-dimethylformamide and methanol, respectively. The drying process is performed in a vacuum oven at a temperature of 60–80°C.

8. The application of an aminozirconium cluster metal-organic framework composite material as described in claims 1 to 3 in the photocatalytic CO2 cycloaddition reaction.

9. The application according to claim 8, characterized in that, The aminozirconium cluster metal-organic framework composite material was activated in a vacuum environment; The activated aminozirconium cluster metal-organic framework composite material was added to a reactor containing epichlorohydrin and tetrabutylammonium bromide, CO2 was introduced, and a xenon lamp was used as the light source to carry out a CO2 cycloaddition reaction.

Images