Acid-base dual-functional framework material catalyst and its preparation method and application

Abstract

The present invention relates to an acid-base dual-functional framework material catalyst, a preparation method, and an application thereof, belonging to the technical field of composite materials. The present invention utilizes multiple strong coordination sites on polyazoles, coordinates and grafts them with Zr-based MOFs containing certain defect sites and acidic sites, then combines strongly basic 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with the supported polyazoles to form an alkaline ionic liquid structure, thereby preparing a dual-functional framework material containing acidic and basic sites. The prepared acid-base dual-functional framework material catalyst not only has the characteristics of strong catalytic activity, large specific surface area, and adjustable solid loading, but also, during the reaction process, the acid-base active sites are not neutralized or lost, and has extremely strong catalytic stability. It can be used in the transesterification reaction of dimethyl carbonate and diethyl carbonate to prepare ethyl methyl carbonate.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and in particular relates to an acid-base dual-functional framework material catalyst, a preparation method and an application thereof. Background Art

[0002] Energy is the material foundation for human survival and development and holds a particularly important strategic position in the national economy. Electrochemical energy storage technologies, represented by lithium-ion batteries, are key to my country's energy industry restructuring and achieving carbon neutrality in the new era. With the increasing scarcity of fossil energy and growing awareness of energy conservation and environmental protection, market demand for electric and hybrid vehicles has surged. Lithium batteries, with their unique advantages, have driven the development of the electric vehicle industry, and the demand for lithium battery electrolytes has also continued to grow.

[0003] Ethyl methyl carbonate (EMC) is a highly effective solvent for improving battery safety, energy density, and discharge capacity, extending battery life, due to its excellent solubility for lithium salts, low viscosity, and high dielectric constant. It is the most widely used solvent in lithium-ion battery electrolytes, comprising approximately 30–35% of the electrolyte. Therefore, research into the preparation of EMC is of great economic and social significance for promoting the large-scale utilization of new energy sources. The synthesis of EMC through the transesterification reaction of dimethyl carbonate (DMC) with diethyl carbonate (DEC) offers advantages such as mild reaction conditions, environmental friendliness, and high atom economy. Furthermore, the reactants DMC and DEC also serve as excellent solvents for lithium battery electrolytes, allowing their direct use as electrolyte solvents without further separation. However, studies have shown that the transesterification reaction of DMC with DEC is a reversible reaction with a low equilibrium constant and a long reaction time. In this reaction, acidic and basic catalytic active sites play crucial roles. Acid-base bifunctional framework material catalysts have both acidic and alkaline catalytic active sites. The two can synergistically catalyze to increase reaction rate and product selectivity and extend catalyst life, so they have great development potential.

[0004] In recent years, acid-base dual-functional framework material catalysts have been applied to the process of preparing EMC by transesterification reaction of DMC and DEC, but there are still some problems that need to be solved, (1) the catalyst cost is high; (2) the preparation time is long and the preparation process is complicated; (3) the catalyst is easily deactivated, and there is still a lot of room for improvement. ILs-MOFs composite materials are a new type of functional materials. Among them, ionic liquids have a series of advantages such as diversity, green environmental protection, and controllable anions and cations. Similarly, MOFs materials also have a series of advantages such as rich topological structures and highly adjustable pore structures. ILs-MOFs successfully combine the advantages of both ILs and MOFs materials. The preparation of acid-base dual-functional framework material catalysts with ILs and MOFs as acidic catalytic active sites and alkaline catalytic active sites respectively has a very broad application prospect. Summary of the Invention

[0005] In order to overcome the problems of high cost, long preparation time, complex preparation process and easy deactivation of existing acid-base dual-functional framework material catalysts, the present invention prepares an acid-base dual-functional framework material catalyst with ILs and MOFs as acidic catalytic active sites and alkaline catalytic active sites respectively.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] A catalyst for an acid-base dual-functional framework material and a preparation method thereof: utilizing the multiple strong coordination sites on polyazole, it is coordinated and grafted with Zr-based MOFs containing certain defect sites and acidic sites. Then, the strongly basic 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is combined with the immobilized polyazole to form an alkaline ionic liquid structure, thereby preparing a dual-functional framework material containing acidic sites and basic sites.

[0008] An acid-base dual-functional framework material catalyst and a preparation method thereof, comprising the following specific steps:

[0009] (1) ZrCl4 and an organic ligand in an equimolar ratio are dissolved in a mixed solvent of DMF and water. A certain amount of glacial acetic acid is then added and ultrasonically dissolved for a certain period of time. The reaction solution is then poured into a hydrothermal synthesis reactor and placed in a forced air drying oven at a specific temperature for a certain period of time. The oven is closed and the reactor is naturally cooled to room temperature. The sample is then centrifuged to remove the solvent and washed with DMF and ethanol, respectively. The sample is then dried in a vacuum drying oven at a specific temperature for a certain period of time to obtain a MOF material with defect sites and a central Zr site.

[0010] (2) The MOFs material with Zr as the central site obtained in step (1) and polyazole are dispersed in toluene, placed in an oil bath at a certain temperature for a specific time, centrifuged to remove the solvent, and washed with DMF and ethanol respectively, and dried in a vacuum drying oven at a specific temperature for a specific time to obtain a MOFs framework material with Zr at the central site coordinated and grafted with polyazole;

[0011] (3) The framework material obtained in step (2) is dispersed in toluene, and then a certain amount of DBU is added. After being placed in an oil bath at a specific temperature for a certain period of time, the solvent is removed by centrifugation, and the mixture is washed with DMF and ethanol respectively. After drying in a vacuum drying oven at a specific temperature for a certain period of time, an acid-base bifunctional framework material catalyst is obtained.

[0012] The MOFs material with Zr as the central site in the above step (1) is one of UiO-66, UiO-67, UiO-68 and their derivatives.

[0013] The organic ligand in the above step (1) is one of terephthalic acid (H2BDC), 1,4-naphthalene dicarboxylic acid (H2NDC), 4,4'-biphenyl dicarboxylic acid (H2BPDC), and [1,1':4',1''-triphenyl]-4,4'-dicarboxylic acid (H2TPDC).

[0014] In the above step (1), the mass ratio of glacial acetic acid to ZrCl4 is between 10 and 20.

[0015] In the above step (1), the volume ratio of DMF to glacial acetic acid is between 10 and 15.

[0016] The volume ratio of DMF to water in the mixed solvent in the above step (1) is between 20 and 25.

[0017] The specific time for ultrasonic dissolution in the above step (1) is between 20 and 40 minutes.

[0018] The specific reaction temperature of the blast drying oven in the above step (1) is between 100 and 140 °C.

[0019] The reaction time of the blast drying oven in the above step (1) is between 20 and 28 h.

[0020] The polyazole in the above step (2) is one of imidazole, 2-methylimidazole, benzimidazole, mercaptoimidazole, 2,5-dicarboxyimidazole, 2-ethylimidazole, 1,2,4-triazole, tetrazole, and histidine.

[0021] In the above step (2), the mass ratio of the polyazole to the MOFs material with Zr as the central site is between 0.1 and 2.

[0022] In the above step (3), the molar ratio of DBU to polyazole is between 0.5 and 2.

[0023] The specific drying temperature of the vacuum drying oven in the above steps (1), (2) and (3) is between 80 and 120 °C.

[0024] The drying time in the vacuum drying oven in the above steps (1), (2) and (3) is between 10 and 14 h.

[0025] The specific reaction temperature of the oil bath in the above steps (2) and (3) is between 80 and 100 °C.

[0026] The reaction time of the oil bath in the above steps (2) and (3) is between 10 and 14 h.

[0027] The acid-base dual-functional framework material catalyst prepared by the above method.

[0028] Application: Application of acid-base bifunctional framework material catalyst in the transesterification reaction of dimethyl carbonate and diethyl carbonate to prepare ethyl methyl carbonate.

[0029] The present invention discovered that polyazoles possess multiple strong coordination sites, which can be coordinated and grafted onto Zr-based MOFs containing certain defect sites and acidic sites. Subsequently, the strongly basic 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) can be used to combine with the immobilized polyazoles to form an alkaline ionic liquid structure, thereby preparing an acid-base bifunctional framework material containing both acidic and basic sites. Therefore, the present invention uses a solvothermal method to graft the polyazole-DBU ionic liquid onto a MOF material with a central Zr site, significantly improving the stability of the acid-base bifunctional catalytic material.

[0030] The beneficial effects of the present invention are:

[0031] The number of acidic sites and basic sites in the prepared acid-base bifunctional framework material catalyst can be regulated as needed to prepare acid-base bifunctional framework material catalysts containing different acid strengths and base strengths. The acid-base bifunctional framework material catalyst prepared using this method not only has the characteristics of strong catalytic activity, large specific surface area, and adjustable solid loading, but also has extremely strong catalytic stability during the reaction process, as the acid-base active sites are not neutralized or lost. The acid-base bifunctional framework material catalyst prepared by the present invention can be used in the reaction of preparing ethyl methyl carbonate by ester exchange between dimethyl carbonate and diethyl carbonate, and has good catalytic activity, selectivity, and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 11 is a diagram showing the preparation mechanism and structure of the composite material prepared in Example 1 of the present invention;

[0033] Figure 2 is the X-ray diffraction pattern of the composite materials prepared in Examples 1 and 2;

[0034] Figure 3 is a scanning electron microscope image of the composite material of Example 1;

[0035] from Figure 3 It can be seen that the surface morphology of the catalyst before and after loading with ionic liquid has not changed significantly, and has a typical UiO-66 skeleton structure, indicating that the DBU-IM-UiO-66 acid-base dual-functional material synthesized by immobilized ionic liquid still retains the skeleton structure of the carrier UiO-66.

[0036] Figure 4 2 are the N2 adsorption-desorption isotherms and pore size distribution diagrams of the composite materials prepared in Examples 1 and 2.

[0037] Table 1 shows the specific surface area and pore volume data of the composite materials prepared in Examples 1 and 2. Figure 4 It can be seen that after UiO-66 and UiO-66-NDC were immobilized with alkaline ionic liquid, their specific surface area and pore volume decreased. This may be due to the introduction of alkaline ionic liquid into the UiO-66 and UiO-66-NDC nanocages, which caused partial pore blockage. In addition, the specific surface area and pore volume of UiO-66-NDC are smaller than those of UiO-66. This is because the naphthalene ring of the H2NDC ligand occupies the pore space, resulting in a decrease in specific surface area and pore volume. The above analysis shows that the alkaline ionic liquid was successfully introduced into the pores of the carriers UiO-66 and UiO-66-NDC, and the pores were not completely blocked, and a large specific surface area and pore volume were still retained. Specific implementation methods

[0038] The present invention is further described by the following specific examples, but the protection scope of the present invention is not limited to the following examples.

[0039] Example 1

[0040] (1) Preparation of UiO-66

[0041] 0.28 g ZrCl₄ (1.2 mmol), 0.20 g terephthalic acid (1.2 mmol), and 4 mL glacial acetic acid were dissolved in a mixed solvent containing 48 mL DMF and 2 mL water. The solution was sonicated for 30 minutes. The reaction solution was then poured into a hydrothermal synthesis reactor and placed in a 120°C forced air drying oven for 24 hours. The oven was then closed and the reactor was allowed to cool naturally to room temperature. The sample was then centrifuged to remove the solvent, rinsed three times with DMF and ethanol, and dried in a 100°C vacuum drying oven for 12 hours to obtain a powdered UiO-66 sample.

[0042] (2) Preparation of DBU-IM-UiO-66

[0043] 0.5 g (1.25 mmol) of UiO-66 powder and 0.175 g (2.5 mmol) of imidazole were dispersed in 40 ml of toluene and reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the powdered IM-UiO-66 sample. The obtained sample was then redispersed in 40 ml of toluene, and 0.38 g (2.5 mmol) of DBU was added. The mixture was reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the desired acid-base bifunctional framework catalyst DBU-IM-UiO-66 sample.

[0044] Example 2

[0045] (1) Preparation of UiO-66-NDC

[0046] 0.28 g ZrCl₄ (1.2 mmol), 0.26 g 1,4-naphthalenedicarboxylic acid (1.2 mmol), and 4 mL glacial acetic acid were dissolved in a mixed solvent containing 48 mL DMF and 2 mL water. The solution was sonicated for 30 minutes. The reaction solution was then poured into a hydrothermal synthesis reactor and placed in a 120°C forced air drying oven for 24 hours. The oven was then closed and the reactor was allowed to cool naturally to room temperature. The sample was then centrifuged to remove the solvent, rinsed three times with DMF and ethanol, and dried in a 100°C vacuum drying oven for 12 hours to obtain a powdered UiO-66-NDC sample.

[0047] (2) Preparation of DBU-IM-UiO-66-NDC

[0048] 0.56 g (1.25 mmol) of UiO-66-NDC powder and 0.175 g (2.5 mmol) of imidazole were dispersed in 40 ml of toluene and reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the powdered IM-UiO-66-NDC sample. The obtained sample was then redispersed in 40 ml of toluene, and 0.38 g (2.5 mmol) of DBU was added. The mixture was reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the desired acid-base bifunctional framework catalyst DBU-IM-UiO-66-NDC sample.

[0049] Example 3

[0050] (1) Preparation of UiO-67

[0051] 0.28 g ZrCl₄ (1.2 mmol), 0.29 g 4,4'-diphenyldicarboxylic acid (1.2 mmol), and 4 mL glacial acetic acid were dissolved in a mixed solvent containing 48 mL DMF and 2 mL water. The solution was sonicated for 30 minutes. The reaction solution was then poured into a hydrothermal synthesis reactor and placed in a 120°C forced air drying oven for 24 hours. The oven was then closed and the reactor was allowed to cool naturally to room temperature. The sample was then centrifuged to remove the solvent, rinsed three times with DMF and ethanol, and dried in a 100°C vacuum drying oven for 12 hours to obtain a powdered UiO-67 sample.

[0052] (2) Preparation of DBU-IM-UiO-67

[0053] 0.59 g (1.25 mmol) of UiO-67 powder and 0.175 g (2.5 mmol) of imidazole were dispersed in 40 ml of toluene and reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the powdered IM-UiO-67 sample. The obtained sample was then redispersed in 40 ml of toluene, and 0.38 g (2.5 mmol) of DBU was added. The mixture was reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the desired acid-base bifunctional framework catalyst DBU-IM-UiO-67 sample.

[0054] Example 4

[0055] (1) Preparation of UiO-68

[0056] 0.28 g ZrCl₄ (1.2 mmol), 0.38 g [1,1':4',1''-triphenyl]-4,4'-dicarboxylic acid (1.2 mmol), and 4 mL glacial acetic acid were dissolved in a mixed solvent containing 48 mL DMF and 2 mL water. The solution was sonicated for 30 minutes. The reaction solution was then poured into a hydrothermal synthesis reactor and placed in a 120°C forced air drying oven for 24 hours. The oven was then closed and the reactor was allowed to cool naturally to room temperature. The sample was then centrifuged to remove the solvent, rinsed three times with DMF and ethanol, and dried in a vacuum drying oven at 100°C for 12 hours to obtain a powdered UiO-68 sample.

[0057] (2) Preparation of DBU-IM-UiO-68

[0058] 0.69 g (1.25 mmol) of UiO-68 powder and 0.175 g (2.5 mmol) of imidazole were dispersed in 40 ml of toluene and reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the powdered IM-UiO-68 sample. The obtained sample was then redispersed in 40 ml of toluene, and 0.38 g (2.5 mmol) of DBU was added. The mixture was reacted in an oil bath at 90°C for 12 h. After the reaction, the solvent was removed by centrifugation, and the mixture was washed three times with DMF and ethanol, respectively, and dried in a vacuum oven at 100°C for 12 h to obtain the desired acid-base bifunctional framework catalyst DBU-IM-UiO-68 sample.

[0059] Table 1 Specific surface area and pore volume of DBU-IM-UiO-66 and DBU-IM-UiO-66-NDC(50) composites

[0060]

[0061] Application Example 1

[0062] 0.35 g of the DBU-IM-UiO-66 catalyst prepared in Example 1, 1.5 g of dimethyl carbonate, and 2 g of diethyl carbonate were added to a pressure bottle, and the reaction was incubated at 110 °C with magnetic stirring for 4 h. After the reaction was completed, samples were taken for analysis, and the conversion of dimethyl carbonate was 52.5%, and the yield of ethyl methyl carbonate was 52.2%.

[0063] Under the aforementioned reaction conditions, the reusability of the prepared DBU-IM-UiO-66 catalyst was investigated. After five reuses, the dimethyl carbonate conversion rate and ethyl methyl carbonate yield were shown in Table 2:

[0064] Table 2 Reusability of DBU-IM-UiO-66 in catalyzing the transesterification of dimethyl carbonate and diethyl carbonate to produce ethyl methyl carbonate.

[0065]

[0066] The results in Table 2 show that the activity of the DBU-IM-UiO-66 catalyst only slightly decreased after five reuses, demonstrating its good catalytic stability.

[0067] Application Example 2

[0068] 0.35 g of the DBU-IM-UiO-66-NDC catalyst prepared in Example 2, 1.5 g of dimethyl carbonate, and 2 g of diethyl carbonate were added to a pressure bottle, and the reaction was carried out at a temperature of 110 ° C. and magnetic stirring was performed for 4 h. After the reaction was completed, sampling and analysis showed that the conversion rate of dimethyl carbonate was 53.4%, and the yield of ethyl methyl carbonate was 52.9%.

[0069] Under the aforementioned reaction conditions, the reusability of the prepared DBU-IM-UiO-66-NDC catalyst was investigated. After five reuses, the dimethyl carbonate conversion rate and ethyl methyl carbonate yield were shown in Table 3.

[0070] Table 3 Reusability of DBU-IM-UiO-66-NDC in catalyzing the transesterification of dimethyl carbonate and diethyl carbonate to produce ethyl methyl carbonate.

[0071]

[0072] The results in Table 3 show that the activity of the DBU-IM-UiO-66-NDC catalyst only slightly decreased after five repeated uses, demonstrating its good catalytic stability.

[0073] Application Example 3

[0074] 0.35 g of the DBU-IM-UiO-67 catalyst prepared in Example 3, 1.5 g of dimethyl carbonate, and 2 g of diethyl carbonate were added to a pressure bottle, and the reaction temperature was 110 ° C. and magnetic stirring was performed for 4 h. After the reaction was completed, sampling and analysis showed that the conversion of dimethyl carbonate was 53.6%, and the yield of ethyl methyl carbonate was 53.0%.

[0075] Under the aforementioned reaction conditions, the reusability of the prepared DBU-IM-UiO-67 catalyst was investigated. After five reuses, the dimethyl carbonate conversion rate and the ethyl methyl carbonate yield were shown in Table 4.

[0076] Table 4 Reusability of DBU-IM-UiO-67 in catalyzing the transesterification of dimethyl carbonate and diethyl carbonate to produce ethyl methyl carbonate.

[0077]

[0078] The results in Table 4 show that the activity of the DBU-IM-UiO-67 catalyst only slightly decreased after five reuses, demonstrating its good catalytic stability.

[0079] Application Example 4

[0080] 0.35 g of the DBU-IM-UiO-68 catalyst prepared in Example 4, 1.5 g of dimethyl carbonate, and 2 g of diethyl carbonate were added to a pressure bottle, and the reaction temperature was 110 ° C. and magnetic stirring was performed for 4 h. After the reaction was completed, sampling and analysis showed that the conversion rate of dimethyl carbonate was 53.8%, and the yield of ethyl methyl carbonate was 53.2%.

[0081] Under the aforementioned reaction conditions, the reusability of the prepared DBU-IM-UiO-68 catalyst was investigated. After five reuses, the dimethyl carbonate conversion rate and the ethyl methyl carbonate yield were shown in Table 5.

[0082] Table 5 Reusability of DBU-IM-UiO-68 in catalyzing the transesterification of dimethyl carbonate and diethyl carbonate to produce ethyl methyl carbonate.

[0083]

[0084] The results in Table 5 show that the activity of the DBU-IM-UiO-68 catalyst only slightly decreased after five repeated uses, demonstrating its good catalytic stability.

[0085] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing an acid-base dual-functional framework material catalyst, characterized by: Taking advantage of the multiple strong coordination sites on polyazole, it was coordinated and grafted with Zr-based MOFs containing certain defect sites and acidic sites at 80~100℃. Then, the strongly basic 1,8-diazabicyclo[5.4.0]undec-7-ene DBU was combined with the immobilized polyazole at 80~100℃ to form an alkaline ionic liquid structure, thereby preparing a dual-functional framework material containing acidic sites and basic sites.

2. The method for preparing an acid-base dual-functional framework material catalyst according to claim 1, characterized in that: The specific steps include: (1) ZrCl4 and organic ligands in equal molar ratios are dissolved in a mixed solvent of DMF and water, and then a certain amount of glacial acetic acid is added. The mixture is ultrasonically dissolved for a certain period of time, and then the reaction solution is poured into a hydrothermal synthesis reactor and placed in a blast drying oven at a specific temperature for a certain period of time. The oven is closed, and the reactor is naturally cooled to room temperature. The sample in the reactor is centrifuged to remove the solvent, and then washed with DMF and ethanol respectively. The sample is dried in a vacuum drying oven at a specific temperature for a certain period of time to obtain a MOFs material with defect sites and a central site of Zr; (2) The MOFs material with Zr as the central site obtained in step (1) and polyazole are dispersed in toluene, placed in an oil bath at 80-100°C for a specific reaction time, centrifuged to remove the solvent, and washed with DMF and ethanol respectively, and dried in a vacuum drying oven at a specific temperature for a certain period of time to obtain a MOFs framework material with Zr at the central site coordinated and grafted with polyazole; (3) The framework material obtained in step (2) is dispersed in toluene, and then a certain amount of DBU is added. After being placed in an oil bath at 80-100°C for a certain period of time, the solvent is removed by centrifugation, and the mixture is washed with DMF and ethanol respectively, and dried in a vacuum drying oven at a specific temperature for a certain period of time to obtain an acid-base bifunctional framework material catalyst.

3. The method according to claim 2, wherein: The polyazole is one of imidazole, 2-methylimidazole, benzimidazole, mercaptoimidazole, 2,5-dicarboxyimidazole, 2-ethylimidazole, 1,2,4-triazole, tetrazole, and histidine; the MOFs material with Zr as the central site is one of UiO-66, UiO-67, UiO-68 and its derivatives; the organic ligand is one of terephthalic acid, 1,4-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, and [1,1':4',1''-triphenyl]-4,4'-dicarboxylic acid.

4. The method according to claim 2, wherein: In step (1), the mass ratio of glacial acetic acid to ZrCl4 is between 10 and 20; and the volume ratio of DMF to water in the mixed solvent is between 20 and 25.

5. The method according to claim 2, wherein: The mass ratio of polyazole to MOFs material with Zr as the central site is between 0.1 and 2; the molar ratio of DBU to polyazole is between 0.5 and 2.

6. The method according to claim 2, wherein: The specific reaction temperature of the blast drying oven in step (1) is between 100 and 140° C.; the specific reaction time of the blast drying oven is between 20 and 28 h.

7. The method according to claim 2, wherein: In the steps (1), (2) and (3), the specific drying temperature of the vacuum drying oven is between 80 and 120° C.; and the specific drying time of the vacuum drying oven is between 10 and 14 hours.

8. The method according to claim 2, wherein: The reaction time of the oil bath in steps (2) and (3) is between 10 and 14 hours.

9. An acid-base dual-functional framework material catalyst prepared by the method according to claim 1 or 2.

10. Use of the acid-base bifunctional framework material catalyst as claimed in claim 9 in the reaction of preparing ethyl methyl carbonate by transesterification of dimethyl carbonate and diethyl carbonate.

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