Bimetallic oxide catalysts, methods of preparation and use
The prepared bimetallic oxide catalyst catalyzes the selective oxidation of styrene to benzaldehyde under low-concentration hydrogen peroxide, solving the safety risks of high-concentration hydrogen peroxide and the environmental pollution problems of traditional methods, and realizing efficient and safe benzaldehyde synthesis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV OF TECH
- Filing Date
- 2024-09-14
- Publication Date
- 2026-05-29
AI Technical Summary
In the existing technology, high-concentration hydrogen peroxide poses safety risks during transportation and use, while low-concentration hydrogen peroxide has the potential to explode during purification. Furthermore, traditional methods for synthesizing benzaldehyde are complex, use expensive raw materials, and pollute the environment, making it difficult to effectively utilize low-concentration hydrogen peroxide for catalytic oxidation to prepare benzaldehyde.
A bimetallic oxide catalyst, comprising a support and an active component A and a promoting component B supported on the support, was prepared by impregnation, drying, and calcination. The catalyst was used to selectively oxidize styrene to benzaldehyde under low-concentration hydrogen peroxide conditions. The catalyst surface state and mesostructure were optimized by using low-concentration hydrogen peroxide as an oxidant and combining the strong synergistic effect of active component A and promoting component B.
This method achieves efficient catalytic oxidation of styrene under low-concentration hydrogen peroxide conditions, avoiding the safety risks associated with high-concentration hydrogen peroxide, simplifying the reaction process, improving process safety, and eliminating the risk of polymerization blockage in the liquid-solid phase reaction, thereby enhancing the selectivity and conversion rate of benzaldehyde.
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Figure CN119075973B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst materials technology, specifically relating to bimetallic oxide catalysts, their preparation methods, and applications. Background Technology
[0002] Benzaldehyde, as an important organic intermediate, has been widely used in the chemical industry, with applications in fragrances, dyes, pharmaceuticals, and agriculture. Traditional methods for preparing benzaldehyde include toluene chlorination and hydrolysis, toluene oxidation, benzyl alcohol oxidation, benzoic acid hydrogenation reduction, and indirect electro-oxidation. However, these methods have many drawbacks, such as complex synthesis processes, expensive raw materials, environmental pollution, and poor reaction efficiency. In recent years, the direct oxidation of styrene to benzaldehyde using hydrogen peroxide, a green oxidant, has attracted widespread attention.
[0003] Hydrogen peroxide, as an environmentally friendly oxidant, has received considerable attention from researchers worldwide. It requires relatively low reaction conditions, the process is simple and harmless to the environment, and it effectively promotes the oxidation of carbon-carbon double bonds. Nevertheless, high-concentration hydrogen peroxide poses safety risks during transportation and production; for example, its irritant and corrosive properties may cause harm to personnel. Currently, the direct production of high-concentration hydrogen peroxide faces technical obstacles, while low-concentration hydrogen peroxide also faces dangers during purification and carries the potential for explosion during transportation and storage. Therefore, exploring how to safely and effectively use low-concentration hydrogen peroxide as an oxidant for the synthesis of fine chemicals has become particularly crucial.
[0004] Currently, low-concentration hydrogen peroxide is widely used in polysaccharide oxidation, gel and pulp bleaching, and medical disinfection. However, in the catalytic oxidation of fine chemicals, such as the production of benzaldehyde from styrene, the standard 30% concentration hydrogen peroxide is still commonly used. Summary of the Invention
[0005] To address the aforementioned problems, the present invention aims to provide a bimetallic oxide catalyst, its preparation method, and its application. Under the catalytic action of this catalyst, styrene can be selectively oxidized to benzaldehyde under low concentration hydrogen peroxide conditions. Furthermore, it features mild reaction conditions and a simple preparation method.
[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0007] A bimetallic oxide catalyst includes a support and a metal oxide of active component A and a metal oxide of promoting component B supported on the support; the support is one of Al2O3, TiO2, and SiO2; the active component A is at least one of silver, vanadium, iron, and copper, preferably vanadium; the promoting component B is selected from at least one of cobalt, cerium, tungsten, and molybdenum, preferably molybdenum.
[0008] Furthermore, the loading amount of the active component A is 0-20% of the carrier mass, preferably 8-12%; the loading amount of the promoting component B is 0-20% of the carrier mass, preferably 8-12%.
[0009] This invention proposes a method for preparing the above-mentioned bimetallic oxide catalyst, comprising the following steps:
[0010] The ammonium salts corresponding to active component A and promoting component B are dissolved in an aqueous solution, impregnated with a support, and after rotary evaporation, the resulting powder is dried in a vacuum drying oven and then calcined in a muffle furnace to obtain the bimetallic oxide catalyst AB / support.
[0011] Furthermore, the loading conditions for the active component A and the promoting component B are mixing and stirring at 60-80°C and impregnation for 9-12 hours.
[0012] Furthermore, the rotary evaporation temperature is 70-80℃, the calcination temperature is 400-600℃, preferably 550℃, and the calcination time is 4-5h.
[0013] In the preparation of the bimetallic oxide catalyst, the molar ratio of active component A to promoting component B is 1:3 to 3:1.
[0014] The present invention also proposes the application of the above-mentioned bimetallic oxide catalyst in the in-situ oxidation of styrene with low-concentration hydrogen peroxide to prepare benzaldehyde. Specifically, under the action of the above-mentioned bimetallic oxide catalyst, low-concentration hydrogen peroxide is used as an oxidant to selectively oxidize styrene to prepare benzaldehyde.
[0015] This invention proposes an in-situ method for preparing benzaldehyde by oxidizing styrene with low-concentration hydrogen peroxide. Under the action of the bimetallic oxide catalyst described above, low-concentration hydrogen peroxide is used as the oxidant to selectively oxidize styrene to prepare benzaldehyde.
[0016] Furthermore, in the above method, the concentration of the low-concentration hydrogen peroxide is 5-10%.
[0017] Furthermore, in the above method, the oxidation temperature of styrene by low-concentration hydrogen peroxide is 50-80℃; the molar ratio of styrene to hydrogen peroxide is 1:2 to 1:3.
[0018] Furthermore, the amount of the bimetallic oxide catalyst was screened to be 6.33 mg per mole of styrene through orthogonal experiments.
[0019] The catalytic reaction principle of the bimetallic oxide catalyst of this invention (taking the Mo-V combination as an example): The vanadium catalyst contains active sites that can react with hydrogen peroxide (H2O2) to form highly active peroxide species. These active peroxide species can selectively oxidize styrene to generate benzaldehyde. Existing literature demonstrates a strong synergistic effect between vanadium and molybdenum. During catalyst preparation, the interaction between the active species and the support can be adjusted through controlled synthesis to optimize the catalyst's surface state, thereby obtaining a high-performance mesoscopic catalyst system. It is speculated that this strong synergistic effect significantly improves the peroxide species formation efficiency, enabling styrene to achieve high catalytic oxidation efficiency even under low-concentration hydrogen peroxide conditions.
[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention relates to a solid bimetallic oxide catalyst, and the process of selectively oxidizing styrene to benzaldehyde with low concentration hydrogen peroxide is a liquid-solid phase reaction. Styrene is in a liquid state under the reaction conditions. The styrene liquid undergoes an oxidation reaction on the surface of the heterogeneous catalyst, eliminating the risk of polymerization blockage. Furthermore, the reaction utilizes low concentration hydrogen peroxide as an oxidant in situ, effectively solving a series of problems existing in the transportation and use of high concentration hydrogen peroxide, and significantly improving the inherent safety of the process. Attached Figure Description
[0021] Figure 1 This is a schematic diagram showing the catalytic performance evaluation results of the catalysts prepared in Examples 1-5 of this invention;
[0022] Figure 2 This is a schematic diagram showing the catalytic performance evaluation results of the catalysts obtained in Examples 6-10 of the present invention;
[0023] Figure 3 This is a schematic diagram showing the catalytic performance evaluation results of the catalysts prepared in Examples 11-14 of this invention. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0025] Example 1
[0026] (1) Preparation of bimetallic oxide catalysts
[0027] 0.4086 g of (NH4)2MoO4 and 0.4592 g of NH4(VO)3 were added to a beaker (molar ratio Mo:V = 10:10), followed by 30 ml of deionized water. The mixture was then ultrasonically washed for 5 min, and 2 g of commercial SiO2 (500 nm) was added. After rotary evaporation at 70–80 °C, the resulting powder was dried overnight at 70 °C in a vacuum drying oven and then calcined in a muffle furnace at 400 °C for 4 hours. The catalyst Mo was obtained. 10 V 10 / SiO2-400, grind to 40-60 mesh for later use.
[0028] (2) Evaluation of catalysts
[0029] The catalytic reaction was carried out in a round-necked flask equipped with a condenser under the following conditions: 17.398 mmol of styrene, 10 ml of acetonitrile, and 110 mg of catalyst were stirred at 70 °C for approximately 10 min. Then, 49.017 mmol of H₂O₂ (10%) was added, and the mixture was heated and stirred for at least 9 h on a heating device equipped with a magnetic stirrer. Samples were collected for qualitative and quantitative analysis of the reaction products using GC-MS. The results are as follows: Figure 1 As shown.
[0030] Examples 2-5
[0031] (1) Preparation of bimetallic oxide catalysts
[0032] 0.4086 g of (NH4)2MoO4 and 0.4592 g of NH4(VO)3 were added to a beaker (molar ratio Mo:V = 10:10), followed by 30 ml of deionized water. The mixture was then ultrasonically washed for 5 min, and 2 g of commercial SiO2 (500 nm) was added. After rotary evaporation at 70–80 °C, the resulting powder was dried overnight at 70 °C in a vacuum drying oven, and then calcined for 4 hours at 450, 500, 550, and 600 °C, respectively. The resulting catalysts, Mo, were obtained. 10 V 10 / SiO2-450, Mo 10 V 10 / SiO2-500, Mo 10 V 10 / SiO2-550、Mo 10 V 10 / SiO2-600, grind to 40-60 mesh for later use.
[0033] (2) Evaluation of catalysts
[0034] The catalyst evaluation methods in Examples 2-5 are the same as those in Example 1, and the results are as follows: Figure 1 Example 6 shown
[0035] (1) Preparation of bimetallic oxide catalysts
[0036] 0.8172 g of (NH4)2MoO4 was added to a beaker (molar ratio Mo:V = 20:0), followed by 30 ml of deionized water. The mixture was then ultrasonically washed for 5 min, and 2 g of commercial SiO2 (500 nm) was added. After rotary evaporation at 70–80 °C, the resulting powder was dried overnight at 70 °C in a vacuum drying oven, and then calcined in a muffle furnace at 550 °C for 4 hours. The catalyst Mo was obtained. 20 / SiO2-550, grind to 40-60 mesh for later use.
[0037] (2) Evaluation of catalysts
[0038] The catalyst evaluation method in Example 6 was the same as that in Example 1, and the results are as follows: Figure 2 As shown.
[0039] Example 7
[0040] (1) Preparation of bimetallic oxide catalysts
[0041] 0.6129 g of (NH4)2MoO4 and 0.2296 g of NH4(VO)3 were added to a beaker (molar ratio Mo:V = 15:5), followed by 30 ml of deionized water. The mixture was ultrasonically washed for 5 min, and then 2 g of commercial SiO2 (500 nm) was added. After rotary evaporation at 70–80 °C, the resulting powder was dried overnight at 70 °C in a vacuum drying oven and then calcined in a muffle furnace at 550 °C for 4 hours. The catalyst Mo was obtained. 15 V5 / SiO2-550, grind to 40-60 mesh for later use.
[0042] (2) Evaluation of catalysts
[0043] The catalyst evaluation method in Example 7 was the same as that in Example 1, and the results are as follows: Figure 2 As shown
[0044] Example 8
[0045] (1) Preparation of bimetallic oxide catalysts
[0046] 0.4086 g of (NH4)2MoO4 and 0.4592 g of NH4(VO)3 were added to a beaker (molar ratio Mo:V = 10:10), followed by 30 ml of deionized water. The mixture was then ultrasonically washed for 5 min, and 2 g of commercial SiO2 (500 nm) was added. After rotary evaporation at 70–80 °C, the resulting powder was dried overnight at 70 °C in a vacuum drying oven and then calcined in a muffle furnace at 550 °C for 4 hours. The catalyst Mo was obtained. 10 V 10 / SiO2-550, grind to 40-60 mesh for later use.
[0047] (2) Evaluation of catalysts
[0048] The catalyst evaluation method in Example 8 was the same as that in Example 1, and the results are as follows: Figure 2 As shown.
[0049] Example 9
[0050] (1) Preparation of bimetallic oxide catalysts
[0051] 0.2043 g of (NH4)2MoO4 and 0.6888 g of NH4(VO)3 were added to a beaker (molar ratio Mo:V = 5:15), followed by 30 ml of deionized water. After ultrasonic washing for 5 min, 2 g of commercial SiO2 (500 nm) was added. The mixture was then rotary evaporated at 70–80 °C. The resulting powder was dried overnight at 70 °C in a vacuum drying oven and calcined in a muffle furnace at 550 °C for 4 hours to obtain the catalyst Mo5V. 15 / SiO2-550, grind to 40-60 mesh for later use.
[0052] (2) Evaluation of catalysts
[0053] The catalyst evaluation method in Example 9 was the same as that in Example 1, and the results are as follows: Figure 2 As shown
[0054] Example 10
[0055] (1) Preparation of bimetallic oxide catalysts
[0056] 0.9184 g of NH4(VO)3 was added to a beaker (molar ratio Mo:V = 0:20), followed by 30 ml of deionized water. The mixture was then ultrasonically washed for 5 min, and 2 g of commercial SiO2 (500 nm) was added. After rotary evaporation at 70–80 °C, the resulting powder was dried overnight at 70 °C in a vacuum drying oven, and then calcined in a muffle furnace at 550 °C for 4 hours. Catalyst V was obtained. 20 / SiO2-550, grind to 40-60 mesh for later use.
[0057] (2) Evaluation of catalysts
[0058] The catalyst evaluation method in Example 10 was the same as that in Example 1, and the results are as follows: Figure 2 As shown
[0059] Examples 11-14
[0060] (1) Preparation of bimetallic oxide catalysts
[0061] The catalyst preparation methods in Examples 11-14 are the same as those in Example 8.
[0062] 2) Evaluation of catalysts
[0063] The catalytic reaction was carried out in a round-necked flask equipped with a condenser under the following conditions: 17.398 mmol of styrene, 10 ml of acetonitrile, and 110 mg of catalyst were stirred at 50, 60, 70, and 80 °C for approximately 10 min each. Then, 49.017 mmol of 10% H₂O₂ was added, and the mixture was heated and stirred for at least 9 h on a heating device equipped with a magnetic stirrer. Samples were collected for qualitative and quantitative analysis of the reaction products using GC-MS. The results are as follows: Figure 3 As shown.
[0064] Examples 15-23
[0065] The substrate range was expanded to include a variety of aromatic olefins. Under the conditions of this catalyst and low-concentration hydrogen peroxide, they were all oxidized to carbonyl-containing compounds, as shown in Table 1 below, where the catalyst used and reaction conditions were similar to those in Example 8.
[0066] Table 1. Conversion rates and carbonyl compound selectivity of extended substrates in Examples 15-23
[0067]
[0068]
[0069] From the above Figure 1-3 As can be seen, the in-situ low-concentration hydrogen peroxide oxidation method for preparing benzaldehyde from styrene of the present invention achieves highly efficient styrene conversion in a laboratory round-neck flask, with a conversion rate of over 70% and a benzaldehyde selectivity of over 80%. The styrene conversion rate and benzaldehyde selectivity can be optimized as needed by adjusting the composition of the active components of the catalyst or by adjusting the calcination temperature and oxidation reaction temperature parameters. Comparing Examples 1-14, Example 8 shows that it represents the optimal catalyst preparation method and optimal reaction parameters, achieving a styrene conversion rate of 96.11% and a benzaldehyde selectivity of 87.82%. Furthermore, as shown in the table above, the catalyst prepared by the present invention is also applicable to some other aromatic olefins.
[0070] Although the present invention has been described in detail through the above preferred embodiments, these descriptions should not be considered as limiting the invention. Those skilled in the art, guided by this specification, should be able to recognize the possibility of making appropriate modifications or adjustments to the invention. Such potential modifications or adjustments, as long as they do not exceed the scope of the claims, should be considered reasonable extensions of the invention.
Claims
1. The application of a bimetallic oxide catalyst in the in-situ oxidation of styrene with low-concentration hydrogen peroxide to prepare benzaldehyde, characterized in that, Under the action of the aforementioned bimetallic oxide catalyst, styrene is selectively oxidized to prepare benzaldehyde using low-concentration hydrogen peroxide as an oxidant. The bimetallic oxide catalyst includes a support and a metal oxide of active component A and a metal oxide of promoting component B supported on the support. The support is SiO2; the active component A is vanadium; the promoting component B is molybdenum; the loading of active component A is 8-12% of the support mass; the loading of promoting component B is 8-12% of the support mass; and the concentration of the low-concentration hydrogen peroxide is 5-10%.
2. The application of the bimetallic oxide catalyst according to claim 1 in the in-situ oxidation of styrene with low-concentration hydrogen peroxide to prepare benzaldehyde, characterized in that, The oxidation temperature of the low-concentration hydrogen peroxide to styrene is 50-80℃; the molar ratio of styrene to hydrogen peroxide is 1:2 to 1:
3.
3. The application of the bimetallic oxide catalyst according to claim 1 in the in-situ oxidation of styrene with low-concentration hydrogen peroxide to prepare benzaldehyde, characterized in that, The preparation method of the bimetallic oxide catalyst includes the following steps: dissolving the ammonium salts corresponding to active component A and promoting component B in an aqueous solution, adding a support for impregnation, and after rotary evaporation, drying the resulting powder in a vacuum drying oven and calcining it in a muffle furnace to obtain the bimetallic oxide catalyst AB / support.
4. The application of the bimetallic oxide catalyst according to claim 3 in the in-situ oxidation of styrene with low-concentration hydrogen peroxide to prepare benzaldehyde, characterized in that, The loading conditions for the active component A and the promoting component B in the preparation method of the bimetallic oxide catalyst are mixing and stirring at 60-80℃ and impregnation for 9-12 hours.
5. The application of the bimetallic oxide catalyst according to claim 3 in the in-situ oxidation of styrene with low-concentration hydrogen peroxide to prepare benzaldehyde, characterized in that, In the preparation method of the bimetallic oxide catalyst, the rotary evaporation temperature is 70-80℃, the calcination temperature is 400-600℃, and the calcination time is 4-5h.
6. The application of the bimetallic oxide catalyst according to claim 3 in the in-situ oxidation of styrene with low-concentration hydrogen peroxide to prepare benzaldehyde, characterized in that, In the preparation method of bimetallic oxide catalyst, the molar ratio of active component A and promoting component B is 1:3 to 3:
1.
7. A method for preparing benzaldehyde in situ using low-concentration hydrogen peroxide through the oxidation of styrene, characterized in that, In the action of the bimetallic oxide catalyst described in claim 1, benzaldehyde is prepared by selective oxidation of styrene using low-concentration hydrogen peroxide as an oxidant.
8. The method for preparing benzaldehyde by in-situ oxidation of styrene with low-concentration hydrogen peroxide according to claim 7, characterized in that, The concentration of the low-concentration hydrogen peroxide is 5-10%; the oxidation temperature of the low-concentration hydrogen peroxide for styrene is 50-80℃; and the molar ratio of styrene to hydrogen peroxide is 1:2 to 1:3.