Bimetal oxide derived from metal-organic framework material, and synthesis method and application thereof
By using bimetallic oxide catalysts derived from metal-organic frame materials, the problems of high cost and volatile activity of sodium alkoxide catalysts in the prior art are solved, and efficient and recyclable dimethyl carbonate production is achieved.
Patent Information
- Application Number
- CN202510314180.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-17
- Publication Date
- 2025-06-17
AI Technical Summary
In the existing dimethyl carbonate production process, sodium alkoxide catalysts have problems such as high cost, difficulty in separation, and volatile activity, making it difficult to achieve recyclable efficient catalysis.
The MOF precursor was prepared by solvothermal method using bimetal oxide derived from metal-organic frame materials as catalysts, and converted into a polymetal oxide catalyst through high temperature calcination, and used for transesterification reactions of propylene carbonate and methanol.
The efficient catalytic production of dimethyl carbonate is achieved, and the catalyst is easy to be separated and recycled, which reduces production costs and improves the utilization rate of raw materials.
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Figure CN120155178A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of dimethyl carbonate preparation, and particularly relates to a bimetallic oxide derived from a metal-organic framework material, a synthesis method thereof, and an application thereof. Background Art
[0002] Dimethyl carbonate (DMC) is a chemical raw material with low toxicity, excellent environmental protection performance and wide applications. It is an important organic synthesis intermediate, and its molecular structure contains functional groups such as carbonyl, methyl and methoxy groups, and has various reaction properties. It has the characteristics of safe use, convenience, less pollution and easy transportation in production. Since dimethyl carbonate has relatively low toxicity, it is a "green" chemical product with development prospects. In addition, as one of the raw materials for battery electrolytes with excellent performance, dimethyl carbonate can effectively improve the charge and discharge capacity and capacitance density of the battery, enhance the safety performance and service life of the battery, and is thus widely concerned in the preparation under the promotion of the rapid development of new energy vehicles.
[0003] Currently, in the process of producing dimethyl carbonate by the transesterification method using propylene carbonate and methanol, an alcohol sodium methanol solution is mainly used as the catalyst for the transesterification reaction. However, as a homogeneous catalyst, the alcohol sodium catalyst still has common problems that need to be solved urgently: First, the alcohol sodium raw material needs to be used in the form of a methanol solution and the dosage is very large, which undoubtedly increases the cost; Second, after the reaction, the alcohol sodium catalyst is generally separated by a hydrolysis carbonization process, and the generated sodium carbonate solid will affect the normal operation of the equipment; Moreover, the separation of alcohol sodium not only increases the production process, but also a large amount of propylene glycol material remains in the sodium carbonate solid, resulting in material waste; Most importantly, the alcohol sodium catalyst loses its activity after being converted into sodium carbonate and cannot be reused, which increases the production cost. Therefore, there is an urgent need to find a new recyclable solid catalyst suitable for the production of dimethyl carbonate.
[0004] Metal-organic framework materials (MOFs) are a class of novel crystalline porous materials formed by connecting metal nodes and organic ligands through coordination. Compared with traditional inorganic porous materials, their ultra-high specific surface area and porosity, variable structures, and flexible modifiable and tailorable characteristics have been widely studied in many fields and shown excellent performance. By calcining / pyrolyzing MOFs materials, MOFs derivatives can be obtained, especially porous metal oxides. MOFs-derived metal oxides can inherit the characteristics of high pore structure and high surface area of MOFs materials, which is beneficial to the contact of reaction substrates. Therefore, MOFs derivatives show good application prospects in heterogeneous catalytic reactions. Summary of the Invention
[0005] Based on this, the present invention provides a synthesis of a multi-metal composite oxide catalyst for the preparation of dimethyl carbonate by transesterification using MOFs materials as precursors. The synthesis method of the metal oxide catalyst synthesized in the present invention is simple and can effectively improve the utilization rate of raw materials. To achieve the above object, the present invention discloses the following solutions.
[0006] On the one hand, the present invention provides a synthesis method of a bimetallic oxide derived from a metal-organic framework material, and the specific synthesis steps are as follows:
[0007] Step 1, synthesis of the MOFs precursor: Prepare the Ba / Ce-MOF precursor by the solvothermal method. The preparation method is as follows: First, dissolve the salt solutions of Ce and Ba in a mixed solution of ethanol and water, then add trimesic acid, ultrasonically dissolve it, and place it in a heating device for heating and holding reaction; Separate the obtained precipitate Ba / Ce-MOF precursor, wash it and dry it.
[0008] Step 2, synthesis of the bimetallic composite oxide: Obtained by high-temperature calcination. The specific method is as follows: Calcinate the precursor Ba / Ce-MOF in a specific atmosphere to obtain the product.
[0009] Further, in step 1, the molar ratio of Ba:Ce is 2:1 to 2:4.
[0010] Further, in step 1, the molar amount of the trimesic acid is 0.5-2 times the total metal molar amount to ensure that the metal completely reacts with the trimesic acid.
[0011] Further, in step 1, the metal salts of Ce and Ba are cerium nitrate hexahydrate and barium nitrate respectively. The volume ratio of ethanol to water in the solvent ethanol-aqueous solution is 1:1, and the dosage ratio of the metal salt to the solvent is about 1:30-70 g / ml, preferably 1:50 g / ml.
[0012] Further, in step 1, the heating and holding reaction temperature is controlled at about 80-120 °C to facilitate the reaction to proceed more thoroughly.
[0013] Further, in step 1, the heating and holding reaction time is 10-20 hours to ensure complete reaction.
[0014] Further, in step 2, the calcination heating rate is 2-5 °C / min to facilitate the smooth progress of the calcination reaction.
[0015] Further, in step 2, the calcination gas atmosphere is nitrogen or air.
[0016] Further, in step 2, the calcination temperature is 600-900 °C to facilitate the complete conversion of Ba / Ce-MOF.
[0017] On the other hand, the present invention provides a bimetallic oxide prepared by a synthesis method of a bimetallic oxide derived from the metal-organic framework material described above.
[0018] In yet another aspect, the present invention provides an application of the bimetallic oxide derived from the metal-organic framework material as a catalyst for catalyzing the transesterification reaction of propylene carbonate and methanol.
[0019] In yet another aspect, the present invention provides a method for the transesterification reaction of propylene carbonate and methanol. The catalyst is the bimetallic oxide derived from the metal-organic framework material of the present invention. The method steps are as follows: Add propylene carbonate and methanol into a reaction kettle, and add the bimetallic oxide derived from the metal-organic framework material according to 1.5% of the total feeding amount by mass, and heat and keep warm for reaction.
[0020] Compared with the prior art, the advantages and positive effects of the present invention are as follows:
[0021] 1. The present invention provides a rapid, simple, green and efficient method for synthesizing multi-metal oxides by using metal-organic framework precursors. The reaction raw material metal nitrates of this method are cheap and green and pollution-free; the preparation method itself has simple operating conditions, short synthesis time, energy saving and time saving; the multi-metal oxides prepared by this method show good catalytic activity for the transesterification reaction of propylene carbonate and methanol; at the same time, the multi-metal oxides prepared by this method are easy to separate and can be recycled during the catalytic process.
[0022] 2. The present invention synthesizes a multi-metal composite oxide catalyst based on MOF precursors by a two-step method and uses it for catalyzing the transesterification reaction of propylene carbonate and methanol, showing good catalytic activity, and this catalyst can be recycled five times and still maintain high catalytic activity. This method is simple, efficient, green and does not produce solid waste during the catalytic process, and has important application value in the field of synthesizing dimethyl carbonate by the transesterification method. Description of the Drawings
[0023] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.
[0024] Figure 1 It is the XRD pattern of Ba / Ce-MOF-A-600 in Example 1. It can be seen from the XRD pattern that the crystal phase of Ba / Ce-MOF has changed after calcination. By comparing with the standard XRD card, it can be found that Ba / Ce-MOF-A-600 is mainly composed of the crystal phases of BaO and CeO2;
[0025] Figure 2It is the SEM image of Ba / Ce-MOF-A-600 found in Example 1. It can be seen from the SEM that Ba / Ce-MOF is a regular rod-like structure, and this structure is also maintained in the derivative after calcination, which greatly increases the surface area of the material and improves the catalytic effect of the catalyst. The material prepared by this method is a rod-like crystal with a length of about 4-8 μm and a width of about 0.2-0.6 μm. Detailed implementation manners
[0026] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.
[0027] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof. The present invention will be further described through specific examples.
[0028] The raw materials selected in the present invention mainly include: barium nitrate, cerium nitrate hexahydrate, trimesic acid, ethanol, and pure water. The obtained composite metal oxide catalyst has a good catalytic effect in the process of synthesizing dimethyl carbonate from propylene carbonate and methanol.
[0029] Example 1:
[0030] (1) A Ba-doped Ce-MOF precursor (Ba:Ce = 1:1) was prepared by a solvothermal method. The specific method is as follows: Cerium nitrate hexahydrate and barium nitrate were dissolved in an ethanol-water solution (ethanol:water = 1:1) according to a molar ratio of 1:1. The dosage ratio of the metal salt to the solvent was about 1:50 g / ml. Then, a certain amount of trimesic acid (M:H3BTC = 1:1, M is the total metal molar amount) was added to the solution. The mixed solution was ultrasonically treated for 30 min to completely disperse and dissolve it, and then kept at 90 °C for 12 h for reaction. After the reaction, the solid product was filtered and separated, washed three times with water and ethanol respectively, and dried at 80 °C to obtain the product denoted as Ba / Ce-MOF(1:1).
[0031] A metal oxide catalyst was obtained by high-temperature calcination. The specific method was as follows: The precursor Ba / Ce-MOF (1:1) was calcined in air at 600 °C for 2 h (heating rate 5 °C / min) to obtain a catalyst sample denoted as Ba / Ce-MOF(1:1)-A-600. The purpose of calcination was to convert each MOF precursor into a metal oxide. Unsuitable calcination conditions would result in incomplete conversion or non-conversion of the MOF precursor, and no calcination would lead to no catalytic effect.
[0032] (2) Catalytic effect test of Ba / Ce-MOF(1:1)-A-600: Propylene carbonate and methanol were added to the reaction kettle in a molar ratio of 1:30, and the catalyst Ba / Ce-MOF(1:1)-A-600 was added at 1.5% of the total feed mass. It was heated to 70 °C and kept warm for 4 h. After the reaction, the catalyst was recovered to obtain dimethyl carbonate and 1,2-propanediol. Through gas chromatography analysis, the single-pass yield of dimethyl carbonate was 95.47%.
[0033] Example 2:
[0034] (1) A Ba-doped Ce-MOF precursor (Ba:Ce = 1:2) was prepared by the solvothermal method. The specific method was as follows: Cerium nitrate hexahydrate and barium nitrate were dissolved in an ethanol-aqueous solution (ethanol:water = 1:1) at a molar ratio of 2:1. The dosage ratio of metal salt to solvent was about 1:50 g / ml. Then, a certain amount of trimesic acid (M:H3BTC = 1:1, M was the total metal molar amount) was added to the solution, and the mixed solution was ultrasonically treated for 30 min to completely disperse and dissolve it. After that, it was kept at 90 °C for a reaction of 12 h. After the reaction, the solid product was filtered and separated, washed three times with water and ethanol respectively, and dried at 80 °C to obtain the product denoted as Ba / Ce-MOF(2:1).
[0035] A metal oxide catalyst was obtained by high-temperature calcination. The specific method was as follows: The precursor Ba / Ce-MOF(2:1) was calcined in air at 600 °C for 2 h (heating rate 5 °C / min) to obtain a catalyst sample denoted as Ba / Ce-MOF(2:1)-A-600.
[0036] (2) Catalytic effect test of Ba / Ce-MOF(2:1)-A-600: Propylene carbonate and methanol were added to the reaction kettle in a molar ratio of 1:30, and the catalyst Ba / Ce-MOF(2:1)-A-600 was added at 1.5% of the total feed mass. It was heated to 70 °C and kept warm for 4 h. After the reaction, the catalyst was recovered to obtain dimethyl carbonate and 1,2-propanediol. Through gas chromatography analysis, the single-pass yield of dimethyl carbonate was 89.42%.
[0037] Example 3:
[0038] (1) A Ba-doped Ce-MOF precursor (Ba:Ce = 2:1) was prepared by a solvothermal method. The specific method was as follows: Cerium nitrate hexahydrate and barium nitrate were dissolved in an ethanol-aqueous solution (ethanol:water = 1:1) according to a molar ratio of 1:2. The dosage ratio of metal salts to the solvent was approximately 1:50 g / ml. Then, a certain amount of trimesic acid (M:H3BTC = 1:1, M was the total molar amount of metals) was added to the solution. The mixed solution was ultrasonicated for 30 min to completely disperse and dissolve it. After that, it was kept at 90 °C for 12 h for reaction. After the reaction, the solid product was separated by filtration, washed three times with water and ethanol respectively, and dried at 80 °C to obtain the product denoted as Ba / Ce-MOF(1:2).
[0039] The metal oxide catalyst was obtained by high-temperature calcination. The specific method was as follows: The precursor Ba / Ce-MOF(1:2) was calcined in air at 600 °C for 2 h (heating rate 5 °C / min) to obtain the catalyst sample denoted as Ba / Ce-MOF(1:2)-A-600.
[0040] (2) Catalytic effect test of Ba / Ce-MOF(1:2)-A-600: Propylene carbonate and methanol were added to the reaction kettle according to a molar ratio of 1:30. The catalyst Ba / Ce-MOF(1:2)-A-600 was added according to 1.5% of the total feed mass. It was heated to 70 °C and kept for 4 h. After the reaction, the catalyst was recovered to obtain dimethyl carbonate and 1,2-propanediol. Through gas chromatography analysis, the single-pass yield of dimethyl carbonate was 88.39%.
[0041] Example 4:
[0042] (1) A Ba-doped Ce-MOF precursor (Ba:Ce = 1:1) was prepared by a solvothermal method. The specific method was as follows: Cerium nitrate hexahydrate and barium nitrate were dissolved in an ethanol-aqueous solution (ethanol:water = 1:1) according to a molar ratio of 1:1. The dosage ratio of metal salts to the solvent was approximately 1:50 g / ml. Then, a certain amount of trimesic acid (M:H3BTC = 1:1, M was the total molar amount of metals) was added to the solution. The mixed solution was ultrasonicated for 30 min to completely disperse and dissolve it. After that, it was kept at 90 °C for 12 h for reaction. After the reaction, the solid product was separated by filtration, washed three times with water and ethanol respectively, and dried at 80 °C to obtain the product denoted as Ba / Ce-MOF(1:1).
[0043] A metal oxide catalyst was obtained by high-temperature calcination. The specific method was as follows: The precursor Ba / Ce-MOF (1:1) was calcined in air at 700 °C for 2 h (heating rate 5 °C / min) to obtain a catalyst sample, denoted as Ba / Ce-MOF(1:1)-A-700.
[0044] (2) Catalytic effect test of Ba / Ce-MOF(1:1)-A-700: Propylene carbonate and methanol were added to the reaction kettle in a molar ratio of 1:30, and the catalyst Ba / Ce-MOF(1:1)-A-700 was added at 1.5% of the total feed mass. It was heated to 70 °C and kept warm for 4 h. After the reaction ended, the catalyst was recovered to obtain dimethyl carbonate and 1,2-propanediol. Through gas chromatography analysis, the single-pass yield of dimethyl carbonate was 96.61%.
[0045] Example 5:
[0046] (1) A Ba-doped Ce-MOF precursor (Ba:Ce = 1:1) was prepared by the solvothermal method. The specific method was as follows: Cerium nitrate hexahydrate and barium nitrate were dissolved in an ethanol-aqueous solution (ethanol:water = 1:1) in a molar ratio of 1:1. The dosage ratio of metal salts to the solvent was about 1:50 g / ml. Then, a certain amount of trimesic acid (M:H3BTC = 1:1, M was the total metal molar amount) was added to the solution, and the mixed solution was ultrasonicated for 30 min to completely disperse and dissolve it. After that, it was kept warm and reacted at 90 °C for 12 h. After the reaction ended, the solid product was filtered and separated, washed three times with water and ethanol respectively, and dried at 80 °C to obtain the product denoted as Ba / Ce-MOF(1:1).
[0047] A metal oxide catalyst was obtained by high-temperature calcination. The specific method was as follows: The precursor Ba / Ce-MOF (1:1) was calcined in air at 800 °C for 2 h (heating rate 5 °C / min) to obtain a catalyst sample, denoted as Ba / Ce-MOF(1:1)-A-800.
[0048] (2) Catalytic effect test of Ba / Ce-MOF(1:1)-A-800: Propylene carbonate and methanol were added to the reaction kettle in a molar ratio of 1:30, and the catalyst Ba / Ce-MOF(1:1)-A-800 was added at 1.5% of the total feed mass. It was heated to 70 °C and kept warm for 4 h. After the reaction ended, the catalyst was recovered to obtain dimethyl carbonate and 1,2-propanediol. Through gas chromatography analysis, the single-pass yield of dimethyl carbonate was 95.84%.
[0049] Example 6:
[0050] (1) The Ba-doped Ce-MOF precursor (Ba:Ce = 1:1) was prepared by a solvothermal method. The specific method was as follows: Cerium nitrate hexahydrate and barium nitrate were dissolved in an ethanol-aqueous solution (ethanol:water = 1:1) according to a molar ratio of 1:1. The dosage ratio of the metal salt to the solvent was about 1:50 g / ml. Then, a certain amount of trimesic acid (M:H3BTC = 1:1, M was the total molar amount of the metal) was added to the solution. The mixed solution was ultrasonicated for 30 min to completely disperse and dissolve it, and then kept at 90 °C for 12 h for reaction. After the reaction was completed, the solid product was filtered and separated, washed three times with water and ethanol respectively, and dried at 80 °C to obtain the product denoted as Ba / Ce-MOF(1:1).
[0051] The metal oxide catalyst was obtained by high-temperature calcination. The specific method was as follows: The precursor Ba / Ce-MOF(1:1) was calcined in air at 900 °C for 2 h (heating rate 5 °C / min) to obtain the catalyst sample denoted as Ba / Ce-MOF(1:1)-A-900.
[0052] (2) Catalytic effect test of Ba / Ce-MOF(1:1)-A-900: Propylene carbonate and methanol were added to the reaction kettle according to a molar ratio of 1:30. The catalyst Ba / Ce-MOF(1:1)-A-900 was added according to 1.5% of the total feed mass. It was heated to 70 °C and kept for 4 h. After the reaction was completed, the catalyst was recovered to obtain dimethyl carbonate and 1,2-propanediol. Through gas chromatography analysis, the single-pass yield of dimethyl carbonate was 96.83%.
[0053] To verify the cyclic stability of the catalyst, the cyclic stability experiment was carried out with the catalyst obtained in Example 1. The specific experimental scheme was as follows: After each catalytic effect test, the reaction substrate and reaction products were distilled out by vacuum distillation, and then the catalyst was washed twice with methanol and placed in a vacuum drying oven to dry at 80 °C for 12 h, and then the next catalytic effect test was carried out. Five cyclic tests were carried out according to this test method. According to the test results, it can be seen that the cyclic stability of this catalyst was good, and it could still maintain a DMC yield of 88.06% after five cycles. The specific test results were as follows:
[0054] Number of recycling times Once Twice Thrice Four times Five times Yield of DMC 95.47 94.24 92.84 92.05 88.06
[0055] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for synthesizing a bimetallic oxide derived from a metal-organic framework material, characterized in that: The synthesis steps are as follows: Step 1, synthesis of MOFs precursor: Ba / Ce-MOF precursor is prepared by solvothermal method, and the preparation method is as follows: firstly, a salt solution of Ce and Ba is dissolved in a mixed solution of ethanol and water, and then trimesic acid is added, dissolved by ultrasound, and placed in a heating device for heating and heat preservation reaction; the obtained precipitate Ba / Ce-MOF precursor is separated, washed and dried; Step 2, synthesis of bimetallic composite oxide: obtain by high temperature calcination, specifically, calcining the precursor Ba / Ce-MOF in a specific atmosphere to obtain the product.
2. The method for synthesizing a bimetallic oxide derived from a metal-organic framework material according to claim 1, characterized in that: In step 1, the molar ratio of Ba:Ce is 2:1 to 2:
4.
3. The method for synthesizing a bimetallic oxide derived from a metal-organic framework material according to claim 1, characterized in that: In step 1, the molar amount of trimesic acid is 0.5-2 times the molar amount of the total metal.
4. The method for synthesizing a bimetallic oxide derived from a metal-organic framework material according to claim 1, characterized in that: In step 1, the heating and insulation reaction temperature is controlled at 80-120° C.; the heating and insulation reaction time is 10-20 hours.
5. The method for synthesizing a bimetallic oxide derived from a metal-organic framework material according to claim 1, characterized in that: In step 2, the calcination heating rate is 2-5°C / min.
6. The method for synthesizing bimetallic oxides derived from metal-organic framework materials according to claim 1, characterized in that: In step 2, the calcination gas atmosphere is nitrogen or air.
7. The method for synthesizing a bimetallic oxide derived from a metal-organic framework material according to claim 1, characterized in that: In step 2, the calcination temperature is 600-900°C.
8. A bimetallic oxide prepared by the method for synthesizing a bimetallic oxide derived from a metal-organic framework material according to any one of claims 1 to 7.
9. Use of the bimetallic oxide derived from the metal-organic framework material of claim 8 as a catalyst for catalyzing the transesterification reaction of propylene carbonate and methanol.
10. A method for transesterification of propylene carbonate and methanol, characterized in that: The catalyst is a bimetallic oxide derived from a metal-organic framework material as described in any one of claims 1 to 8, and the method steps are: adding propylene carbonate and methanol into a reaction kettle, adding the bimetallic oxide derived from the metal-organic framework material according to 1.5% of the total feed weight, and heating and keeping warm for reaction.