Catalyst for preparing cyclopentanone through cyclopentanol dehydrogenation and preparation method thereof
By optimizing the porous structure of Sn-Cu-CNT composite materials and carbon nanotubes, the problem of the single active site of Raney nickel catalyst was solved, and the high efficiency conversion of cyclopentanol and the improvement of cyclopentanone selectivity were achieved.
Patent Information
- Application Number
- CN202511009136.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-22
- Publication Date
- 2025-11-21
AI Technical Summary
Existing Raney nickel catalysts with particle sizes of 0.05-0.076 mm have single active sites and low dispersion, resulting in low cyclopentanol conversion rates, which cannot meet the needs of efficient industrial production.
Using Sn-Cu-CNT composite material as a catalyst, a porous structure is formed through electrodeposition and etching. By combining the hydrophobicity of carbon nanotubes and the acidic sites of tin, the electronic state and reaction pathway of nickel are optimized to form a microporous-mesoporous hierarchical network.
It significantly improved the conversion rate of cyclopentanol and the selectivity of cyclopentanone, and the activity and selectivity of the catalyst were significantly enhanced.
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Figure CN120984278A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst technology, and in particular relates to a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone and its preparation method. Background Technology
[0002] In the dehydrogenation of cyclopentanol to cyclopentanone, Raney nickel catalyst is typically used. It is known that when the particle size of the Raney nickel catalyst is greater than 0.076 mm, the reaction is significantly controlled by internal diffusion, resulting in a slow rate. When the catalyst particle size is less than 0.05 mm, the strength of the Raney nickel catalyst decreases, the framework is disrupted, and thus the activity of the Raney nickel catalyst is reduced.
[0003] When the particle size of the Raney nickel catalyst is 0.05-0.076 mm, the conversion rate of cyclopentanol is relatively good. However, the overall cyclopentanol conversion rate still cannot meet the requirements of high-efficiency industrial production. This is mainly because although the microporous structure of Raney nickel (pore size < 2 nm) provides a high specific surface area, when nickel itself is used as a support, both the active component and the support are metallic nickel, resulting in a single active site and low dispersion. The microporous dominant structure of the nickel framework (more than 65% of which are < 2 nm micropores) hinders the diffusion of cyclopentanol molecules, leading to a low cyclopentanol conversion rate. Summary of the Invention
[0004] To address the above problems, this invention proposes a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone and its preparation method, which can effectively improve the conversion rate of cyclopentanol and the selectivity of cyclopentanone.
[0005] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, comprising the following steps:
[0006] S1. Add 120-126g potassium pyrophosphate, 10-13g stannous chloride, 8-10g copper sulfate and 2-3g carbon nanotube powder to 1L of deionized water, and adjust the pH value to 7-8 with ammonia water to obtain the electroplating solution.
[0007] S2. The copper sheet is degreased with acetone, the surface oxide film is removed with dilute hydrochloric acid, and then rinsed with deionized water to obtain a pretreated copper sheet. A PS gel crystal template is then assembled on the pretreated copper sheet to obtain a copper sheet with a PS gel crystal template.
[0008] S3. Using the copper sheet with PS colloidal template obtained in S2 as the cathode and the titanium mesh as the anode, electrodeposition is performed in the electroplating solution obtained in S1. The mixture is then calcined at 500-550℃ for 3-4 hours, peeled off, and ground to obtain the Sn-Cu-CNT composite material.
[0009] S4. The Sn-Cu-CNT composite material obtained in S3 was etched with 10 vol% acetic acid under an ice bath at 0-5℃ for 30-35 min to obtain the etched material. The material was then placed in an ammonia-EDTA mixture at pH 9.5 and shaken at 60℃ for 10 min to obtain the carrier.
[0010] S5. The support obtained in S4 is impregnated with nickel nitrate solution, and after drying and calcination, a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone is obtained.
[0011] Furthermore, the specific operation of S2 is as follows:
[0012] Preparation of S21 PS microspheres: Ethanol and deionized water were mixed and stirred in an oil bath at 70-75℃ for 30-35 min under argon atmosphere. Then, styrene monomer was added to obtain a mixture. Potassium persulfate solution was added dropwise to the mixture to obtain a mixed solution. The mixture was stirred at 70℃ for 20 h and then the reaction was stopped to obtain PS microspheres. The microspheres were washed several times with anhydrous ethanol and deionized water before use.
[0013] S22. Assemble PS microspheres using spin coating: Before coating, roll flatten the copper sheet, clean it with acetone and deionized water, and dry it; dissolve the PS microspheres obtained in S21 in ethanol to obtain a PS microsphere emulsion; before coating, adjust the rotation time and speed of the high and low speed settings of the coating machine, drop the PS microsphere emulsion onto the copper sheet, and when the coating machine rotates at high speed, the PS microsphere emulsion is assembled under the combined action of the viscous force between the liquid and the substrate and the centrifugal force of rotation. This process is accompanied by the evaporation of the solvent ethanol, resulting in a copper sheet with a PS colloidal template.
[0014] Furthermore, in S21, 60-62g of ethanol, 40-43g of deionized water, 5mL of styrene monomer, and potassium persulfate solution are prepared by dissolving 0.1g of potassium persulfate in 20mL of deionized water.
[0015] Furthermore, in S22, the concentration of the PS microsphere emulsion is 0.2-0.23 wt%, the size of the copper sheet is 2 cm × 2 cm, and the amount of PS microsphere emulsion added is 100-120 μL.
[0016] Furthermore, in S22, the low speed gear has a rotation speed of 500-1000 rpm and a rotation time of 3-5 seconds; the high speed gear has a rotation speed of 2000-2500 rpm and a rotation time of 40-50 seconds.
[0017] Furthermore, in S3, at a temperature of 25±1℃ and a current density of 8-10A / dm 2 Deposition for 40 minutes.
[0018] Furthermore, in S5, after drying at 110°C for 2 hours, it is calcined in an air atmosphere at 400-450°C for 3 hours.
[0019] Furthermore, in S5, the concentration of the nickel nitrate solution is 10-12 g / L.
[0020] Secondly, the present invention provides a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, which is prepared by the above-described preparation method.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] 1. Copper (Cu) 0 As an electron donor, it is used to transfer electrons to nickel (Ni). 2+ ) provides electrons to form electron-rich nickel (Niδ) - This significantly reduces the center position of the d-band of nickel. This electron transfer weakens the adsorption strength of nickel for the reaction intermediate, lowers the energy barrier for breaking the C-OH bond, accelerates dehydrogenation, and improves the conversion rate of cyclopentanol.
[0023] Tin (SnO) x Anchoring of copper (Cu) via strong metal-support interaction (SMSI) 0 ), inhibiting its oxidation to Cu 2+ Tin (SnO) x ) Surface oxygen vacancies capture reactive oxygen species, blocking copper (Cu) 0 The oxidation pathway maintains the electron donor function and improves the conversion rate of cyclopentanol.
[0024] 2. The hydrophobic surface of carbon nanotubes preferentially adsorbs cyclopentanol molecules, reducing the excessive adsorption of cyclopentanone at the active site, avoiding its deep dehydrogenation to generate byproducts, and improving the selectivity of cyclopentanone.
[0025] Copper modification of the d-band center of nickel can weaken the adsorption strength of nickel for cyclopentanone products and accelerate their desorption. In addition, the acidic sites of tin selectively adsorb cyclopentanol hydroxyl groups, directionally guiding the dehydrogenation reaction pathway and improving the selectivity of cyclopentanone.
[0026] 3. After etching, the porous structure of the carrier forms a microporous-mesoporous hierarchical network. The micropores provide a high specific surface area to anchor the metal active sites, while the mesopores promote the rapid diffusion of cyclopentanol molecules to the active center, thereby increasing the conversion rate of cyclopentanol. The mesopores can also shorten the residence time of cyclopentanone at the active site, reduce the generation of excessive dehydrogenation byproducts, and improve the selectivity of cyclopentanone.
[0027] Meanwhile, the continuous conductive network of carbon nanotubes, in conjunction with the three-dimensional electron transport pathway of the porous structure, accelerates charge transfer in the dehydrogenation reaction, lowers the reaction energy barrier, and synergistically improves the conversion rate of cyclopentanol and the selectivity of cyclopentanone. Attached Figure Description
[0028] Figure 1 This is a comparative trend chart showing the cyclopentanol conversion rate data when the catalysts prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention are used in the process of cyclopentanol dehydrogenation to cyclopentanone. Detailed Implementation
[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0031] Example 1: A method for preparing a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, comprising the following steps:
[0032] S1. Add 124g potassium pyrophosphate, 12g stannous chloride, 9g copper sulfate and 2.5g carbon nanotube powder to 1L deionized water, stir magnetically at 220rpm for 60min, and then adjust the pH to 7.5 dropwise with 10wt% ammonia water (using a pH meter for real-time monitoring) to obtain the electroplating solution.
[0033] S2. The copper sheet is ultrasonically treated with acetone for 10 minutes to remove oil stains, then soaked in 5wt% dilute hydrochloric acid for 2 minutes to remove the surface oxide film, and then rinsed with deionized water until neutral to obtain a pretreated copper sheet. A PS gel crystal template is then assembled on the pretreated copper sheet to obtain a copper sheet with a PS gel crystal template. The specific operation is as follows:
[0034] Preparation of S21 PS microspheres: 61g of ethanol and 42g of deionized water were mixed and stirred in an oil bath at 72℃ for 32min under argon atmosphere (maintaining oxygen content <5ppm). Then, 5mL of styrene monomer was added to obtain a mixture. 0.1g of potassium persulfate initiator was dissolved in 20mL of deionized water to prepare a potassium persulfate solution. The potassium persulfate solution was added dropwise to the mixture to obtain a mixed solution. The mixture was stirred at 70℃ for 20h and then the reaction was stopped to obtain PS microspheres. The microspheres were washed three times with anhydrous ethanol and deionized water for later use.
[0035] S22. PS microspheres are assembled using a spin coating method: Before coating, a 2cm×2cm copper sheet is rolled flat, cleaned with acetone and deionized water, and dried. The PS microspheres obtained in S21 are dissolved in ethanol to obtain a PS microsphere emulsion with a concentration of 0.21wt%. Before coating, the rotation time and speed of the coating machine are adjusted for high and low speed settings. The low speed setting is 800rpm for 4s, and the high speed setting is 2200rpm for 45s. The PS microsphere emulsion is dropped onto the copper sheet at a volume of 110μL. When the coating machine rotates at high speed, the PS microsphere emulsion is assembled under the combined action of the viscous force between the liquid and the substrate and the centrifugal force of rotation. This process is accompanied by the evaporation of the solvent ethanol, resulting in a copper sheet with a PS colloidal template.
[0036] S3. Using the copper sheet with PS gel crystal template obtained in S2 as the cathode (working electrode) and the titanium mesh as the anode, with an electrode spacing of 3 cm, electrode deposition is performed in the electroplating solution obtained in S1 at a temperature of 25℃ and a current density of 9 A / dm³. 2 The substrate was deposited for 40 minutes, then heated to 520°C at a rate of 5°C / min and calcined at this temperature for 3.5 hours under nitrogen protection, followed by natural cooling to room temperature (approximately 25°C). The 520°C calcination caused differential expansion between the copper substrate and the deposited layer. Upon cooling, shear stress was generated at the interface, leading to the formation of microcracks, which facilitated peeling.
[0037] Using a polytetrafluoroethylene (PTFE) scraper, the deposited layer is cut into the interface gap between the copper sheet and the substrate. The scraper is slowly moved horizontally to gradually lift the deposited layer. When local adhesion is encountered, a small amount of anhydrous ethanol is added to wet the interface, and the adhesion is weakened by capillary action before peeling. Then, the material is ground in an agate mortar and pestle. The ground powder is passed through 100-mesh (150 μm pore size) and 200-mesh (75 μm pore size) standard sieves to collect 75-150 μm particles, thus obtaining the Sn-Cu-CNT composite material.
[0038] S4. The Sn-Cu-CNT composite material obtained in S3 was etched with 10 vol% acetic acid at 2°C for 32 min in an ice bath to increase the pore size and obtain the etched material. The etched material was placed in an ammonia-EDTA mixture with pH=9.5, shaken at 60°C for 10 min, filtered, and dried to obtain the carrier.
[0039] S5. The support obtained in S4 is impregnated with a nickel nitrate solution with a concentration of 11 g / L, then dried at 110 °C for 2 h, and then calcined at 420 °C in air atmosphere (air flow rate 50 mL / min) for 3 h to obtain the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone.
[0040] Example 2: A method for preparing a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, comprising the following steps:
[0041] S1. Add 120g potassium pyrophosphate, 10g stannous chloride, 8g copper sulfate and 2g carbon nanotube powder to 1L of deionized water, and adjust the pH value to 7 with ammonia water to obtain the electroplating solution.
[0042] S2. The copper sheet is degreased with acetone, the surface oxide film is removed with dilute hydrochloric acid, and then rinsed with deionized water to obtain a pretreated copper sheet. A PS gel crystal template is then assembled on the pretreated copper sheet to obtain a copper sheet with a PS gel crystal template. The specific operation is as follows:
[0043] S21. Preparation of PS microspheres: 60g of ethanol and 40g of deionized water were mixed and stirred in an oil bath at 70℃ for 30min under argon atmosphere. Then, 5mL of styrene monomer was added to obtain a mixture. 0.1g of potassium persulfate initiator was dissolved in 20mL of deionized water to prepare a potassium persulfate solution. The potassium persulfate solution was added dropwise to the mixture to obtain a mixed solution. The mixture was stirred at 70℃ for 20h and then the reaction was stopped to obtain PS microspheres. The microspheres were washed three times with anhydrous ethanol and deionized water for later use.
[0044] S22. PS microspheres are assembled using a spin coating method: Before coating, a 2cm×2cm copper sheet is rolled flat, cleaned with acetone and deionized water, and dried. The PS microspheres obtained in S21 are dissolved in ethanol to obtain a PS microsphere emulsion with a concentration of 0.2wt%. Before coating, the rotation time and speed of the coating machine are adjusted for high and low speed settings. The low speed setting is 500rpm for 3s, and the high speed setting is 2000rpm for 40s. The PS microsphere emulsion is dropped onto the copper sheet at a volume of 100μL. When the coating machine rotates at high speed, the PS microsphere emulsion is assembled under the combined action of the viscous force between the liquid and the substrate and the centrifugal force of rotation. This process is accompanied by the evaporation of the solvent ethanol, resulting in a copper sheet with a PS colloidal template.
[0045] S3. Using the copper sheet with PS gel crystal template obtained in S2 as the cathode (working electrode) and the titanium mesh as the anode, with an electrode spacing of 3 cm, electrodeposition is performed in the electroplating solution obtained in S1 using the electrodeposition method at a temperature of 25℃ and a current density of 8 A / dm³. 2 The material was deposited for 40 min, then heated to 500℃ at a rate of 5℃ / min, and calcined at a constant temperature for 3 h under nitrogen protection. After peeling and grinding, the Sn-Cu-CNT composite material was obtained.
[0046] S4. The Sn-Cu-CNT composite material obtained in S3 was etched with 10 vol% acetic acid at 2°C for 30 min in an ice bath to obtain the etched material. The etched material was then placed in an ammonia-EDTA mixture with pH 9.5, shaken at 60°C for 10 min, filtered, and dried to obtain the carrier.
[0047] S5. The support obtained in S4 is impregnated with a nickel nitrate solution with a concentration of 10 g / L, then dried at 110 °C for 2 h, and then calcined in air at 400 °C for 3 h to obtain the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone.
[0048] Example 3: A method for preparing a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, comprising the following steps:
[0049] S1. Add 126g potassium pyrophosphate, 13g stannous chloride, 10g copper sulfate and 3g carbon nanotube powder to 1L of deionized water, and adjust the pH value to 8 with ammonia water to obtain the electroplating solution.
[0050] S2. The copper sheet is degreased with acetone, the surface oxide film is removed with dilute hydrochloric acid, and then rinsed with deionized water to obtain a pretreated copper sheet. A PS gel crystal template is then assembled on the pretreated copper sheet to obtain a copper sheet with a PS gel crystal template. The specific operation is as follows:
[0051] Preparation of S21 PS microspheres: 62g of ethanol and 43g of deionized water were mixed and stirred in an oil bath at 75℃ for 35min under argon atmosphere. Then, 5mL of styrene monomer was added to obtain a mixture. 0.1g of potassium persulfate initiator was dissolved in 20mL of deionized water to prepare a potassium persulfate solution. The potassium persulfate solution was added dropwise to the mixture to obtain a mixed solution. The mixture was stirred at 70℃ for 20h and then the reaction was stopped to obtain PS microspheres. The microspheres were washed three times with anhydrous ethanol and deionized water for later use.
[0052] S22. PS microspheres are assembled using a spin coating method: Before coating, a 2cm×2cm copper sheet is rolled flat, cleaned with acetone and deionized water, and dried. The PS microspheres obtained in S21 are dissolved in ethanol to obtain a PS microsphere emulsion with a concentration of 0.23wt%. Before coating, the rotation time and speed of the coating machine are adjusted for high and low speed settings. The low speed setting is 1000rpm for 5s, and the high speed setting is 2500rpm for 50s. The PS microsphere emulsion is dropped onto the copper sheet at a volume of 120μL. When the coating machine rotates at high speed, the PS microsphere emulsion is assembled under the combined action of the viscous force between the liquid and the substrate and the centrifugal force of rotation. This process is accompanied by the evaporation of the solvent ethanol, resulting in a copper sheet with a PS colloidal template.
[0053] S3. Using the copper sheet with PS gel crystal template obtained in S2 as the cathode (working electrode) and the titanium mesh as the anode, with an electrode spacing of 3 cm, electrode deposition is performed in the electroplating solution obtained in S1 at a temperature of 25℃ and a current density of 9 A / dm³. 2 The material was deposited for 40 min, then heated to 550 °C at a rate of 5 °C / min, and calcined at a constant temperature under nitrogen protection for 4 h. After peeling and grinding, the Sn-Cu-CNT composite material was obtained.
[0054] S4. The Sn-Cu-CNT composite material obtained in S3 was etched with 10 vol% acetic acid at 2°C for 35 min in an ice bath to obtain the etched material. The etched material was then placed in an ammonia-EDTA mixture with pH 9.5, shaken at 60°C for 10 min, filtered, and dried to obtain the carrier.
[0055] S5. The support obtained in S4 is impregnated with a nickel nitrate solution with a concentration of 12 g / L, then dried at 110 °C for 2 h, and then calcined in air at 450 °C for 3 h to obtain the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone.
[0056] Comparative Example 1: In the preparation of the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, no stannous chloride or carbon nanotubes were added, and no etching was performed.
[0057] Specifically, a method for preparing a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone includes the following steps:
[0058] S1. Add 124g of potassium pyrophosphate and 9g of copper sulfate to 1L of deionized water, stir magnetically at 220rpm for 60min, and then adjust the pH to 7.5 dropwise with 10wt% ammonia water (using a pH meter for real-time monitoring) to obtain the electroplating solution.
[0059] S2. The copper sheet is ultrasonically treated with acetone for 10 minutes to remove oil stains, then soaked in 5wt% dilute hydrochloric acid for 2 minutes to remove the surface oxide film, and then rinsed with deionized water until neutral to obtain a pretreated copper sheet. A PS gel crystal template is then assembled on the pretreated copper sheet to obtain a copper sheet with a PS gel crystal template. The specific operation is as follows:
[0060] Preparation of S21 PS microspheres: 61g of ethanol and 42g of deionized water were mixed and stirred in an oil bath at 72℃ for 32min under argon atmosphere (maintaining oxygen content <5ppm). Then, 5mL of styrene monomer was added to obtain a mixture. 0.1g of potassium persulfate initiator was dissolved in 20mL of deionized water to prepare a potassium persulfate solution. The potassium persulfate solution was added dropwise to the mixture to obtain a mixed solution. The mixture was stirred at 70℃ for 20h and then the reaction was stopped to obtain PS microspheres. The microspheres were washed three times with anhydrous ethanol and deionized water for later use.
[0061] S22. PS microspheres are assembled using a spin coating method: Before coating, a 2cm×2cm copper sheet is rolled flat, cleaned with acetone and deionized water, and dried. The PS microspheres obtained in S21 are dissolved in ethanol to obtain a PS microsphere emulsion with a concentration of 0.21wt%. Before coating, the rotation time and speed of the coating machine are adjusted for high and low speed settings. The low speed setting is 800rpm for 4s, and the high speed setting is 2200rpm for 45s. The PS microsphere emulsion is dropped onto the copper sheet at a volume of 110μL. When the coating machine rotates at high speed, the PS microsphere emulsion is assembled under the combined action of the viscous force between the liquid and the substrate and the centrifugal force of rotation. This process is accompanied by the evaporation of the solvent ethanol, resulting in a copper sheet with a PS colloidal template.
[0062] S3. Using the copper sheet with PS gel crystal template obtained in S2 as the cathode (working electrode) and the titanium mesh as the anode, with an electrode spacing of 3 cm, electrode deposition is performed in the electroplating solution obtained in S1 at a temperature of 25℃ and a current density of 9 A / dm³. 2 The material was deposited for 40 min, then heated to 520℃ at a rate of 5℃ / min, and calcined at a constant temperature for 3.5 h under nitrogen protection. After peeling and grinding, the Sn-Cu-CNT composite material was obtained.
[0063] S4. The Sn-Cu-CNT composite material obtained in S3 was impregnated with a nickel nitrate solution with a concentration of 11 g / L, then dried at 110 °C for 2 h, and then calcined at 420 °C in air atmosphere (air flow rate 50 mL / min) for 3 h to obtain the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone.
[0064] Comparative Example 2: In the preparation of the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, no carbon nanotubes were added and no etching was performed.
[0065] In Comparative Example 3, no etching was performed during the preparation of the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone.
[0066] Comparative Example 4: In the preparation of the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, no carbon nanotubes were added.
[0067] Experimental example:
[0068] Table 1. Experimental Data
[0069] Cyclopentanol conversion rate (%) Cyclopentanone selectivity (%) Example 1 80.3 99.8 Example 2 80.1 99.2 Example 3 80.0 99.6 Comparative Example 1 76.5 93.7 Comparative Example 2 77.1 94.5 Comparative Example 3 77.2 96.0 Comparative Example 4 79.4 97.4
[0070] Results Analysis: Combining the data in Table 1 and... Figure 1 Analysis of Examples 1-3 shows that when the catalyst prepared by the present invention (Examples 1-3) is used in the process of dehydrogenation of cyclopentanol to cyclopentanone, the conversion rate of cyclopentanol reaches more than 80.0%, and the selectivity of cyclopentanone is as high as 99.2%.
[0071] Combining the data in Table 1 and Figure 1 Analysis was conducted on Example 1 and Comparative Examples 1-4, specifically comparing Comparative Examples 1 and 2. It was found that, compared to Comparative Example 1, Comparative Example 2 incorporated stannous chloride into the catalyst feedstock, thus introducing tin into the final catalyst. As a result, the cyclopentanol conversion increased from 76.5% (Comparative Example 1) to 77.1% (Comparative Example 2), and the cyclopentanone selectivity increased from 93.7% (Comparative Example 1) to 94.5% (Comparative Example 2). This indicates that introducing tin into the catalyst preparation can improve the cyclopentanol conversion and cyclopentanone selectivity in the cyclopentanol dehydrogenation to cyclopentanone process.
[0072] This is mainly because copper (Cu) 0 As an electron donor, it is used to transfer electrons to nickel (Ni). 2+ ) provides electrons to form electron-rich nickel (Niδ) - The electron transfer significantly reduces the d-band center position of nickel, weakening the adsorption strength of nickel for reaction intermediates, lowering the C-OH bond breaking barrier, accelerating dehydrogenation, and increasing the conversion rate of cyclopentanol; while tin (SnO) x Anchoring of copper (Cu) via strong metal-support interaction (SMSI) 0 ), inhibiting its oxidation to Cu 2+ Tin (SnO) x ) Surface oxygen vacancies capture reactive oxygen species, blocking copper (Cu) 0 The oxidation pathway maintains the electron donor function, thereby improving the conversion rate of cyclopentanol. Additionally, the acidic sites of tin selectively adsorb the cyclopentanol hydroxyl groups, directionally guiding the dehydrogenation reaction pathway and thus improving the selectivity of cyclopentanone.
[0073] Specifically, comparing Comparative Examples 2 and 3, it can be seen that, compared to Comparative Example 2, the addition of carbon nanotubes to the catalyst feedstock in Comparative Example 3 did not significantly change the cyclopentanol conversion rate, but the cyclopentanone selectivity increased from 94.5% (Comparative Example 2) to 96.0% (Comparative Example 3). This indicates that introducing carbon nanotubes into the catalyst preparation can further improve the cyclopentanone selectivity in the cyclopentanol dehydrogenation to cyclopentanone process.
[0074] This is mainly because the hydrophobic surface of carbon nanotubes preferentially adsorbs cyclopentanol molecules, reducing the excessive adsorption of cyclopentanone at the active site and preventing its deep dehydrogenation to generate byproducts such as cyclopentene, thereby improving the selectivity of cyclopentanone.
[0075] Specifically, comparing Comparative Examples 2 and 4, it can be seen that, compared to Comparative Example 2, Comparative Example 4 added an etching step to increase the pore size and form a microporous-mesoporous hierarchical porous structure. As a result, the cyclopentanol conversion rate increased from 77.1% (Comparative Example 2) to 79.4% (Comparative Example 4), and the cyclopentanone selectivity increased from 94.5% (Comparative Example 2) to 97.4% (Comparative Example 4). This indicates that adding an etching step in catalyst preparation can improve the cyclopentanol conversion rate and cyclopentanone selectivity in the cyclopentanol dehydrogenation to cyclopentanone process.
[0076] This is mainly because in the micropore-mesopore hierarchical porous structure, the micropores provide a high specific surface area to anchor the metal active sites, while the mesopores promote the rapid diffusion of cyclopentanol molecules to the active center, thereby increasing the conversion rate of cyclopentanol. The mesopores can also shorten the residence time of cyclopentanone at the active site, reduce the generation of excessive dehydrogenation byproducts, and thus improve the selectivity of cyclopentanone.
[0077] In comparison with Example 1, it can be seen that adding carbon nanotubes and etching steps in the catalyst preparation process can produce a synergistic effect, which can synergistically improve the conversion rate of cyclopentanol and the selectivity of cyclopentanone in the process of dehydrogenation of cyclopentanol to cyclopentanone.
[0078] This is mainly because the continuous conductive network of carbon nanotubes can work in synergy with the three-dimensional electron transport pathway of the micropore-mesopore hierarchical porous structure to accelerate charge transfer in the dehydrogenation reaction, lower the reaction energy barrier, and synergistically improve the conversion rate of cyclopentanol and the selectivity of cyclopentanone.
[0079] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, characterized in that, Includes the following steps: S1. Add 120-126g potassium pyrophosphate, 10-13g stannous chloride, 8-10g copper sulfate and 2-3g carbon nanotube powder to 1L of deionized water, and adjust the pH value to 7-8 with ammonia water to obtain the electroplating solution. S2. The copper sheet is degreased with acetone, the surface oxide film is removed with dilute hydrochloric acid, and then rinsed with deionized water to obtain a pretreated copper sheet. A PS gel crystal template is then assembled on the pretreated copper sheet to obtain a copper sheet with a PS gel crystal template. S3. Using the copper sheet with PS colloidal template obtained in S2 as the cathode and the titanium mesh as the anode, electrodeposition is performed in the electroplating solution obtained in S1. The mixture is then calcined at 500-550℃ for 3-4 hours, peeled off, and ground to obtain the Sn-Cu-CNT composite material. S4. The Sn-Cu-CNT composite material obtained in S3 was etched with 10 vol% acetic acid under an ice bath at 0-5℃ for 30-35 min to obtain the etched material. The material was then placed in an ammonia-EDTA mixture at pH 9.5 and shaken at 60℃ for 10 min to obtain the carrier. S5. The support obtained in S4 is impregnated with nickel nitrate solution, and after drying and calcination, a catalyst for the dehydrogenation of cyclopentanol to cyclopentanone is obtained.
2. The method for preparing the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone according to claim 1, characterized in that, The specific operation of S2 is as follows: Preparation of S21 PS microspheres: Ethanol and deionized water were mixed and stirred in an oil bath at 70-75℃ for 30-35 min under argon atmosphere. Then, styrene monomer was added to obtain a mixture. Potassium persulfate solution was added dropwise to the mixture to obtain a mixed solution. The mixture was stirred at 70℃ for 20 h and then the reaction was stopped to obtain PS microspheres. The microspheres were washed several times with anhydrous ethanol and deionized water before use. S22. Assemble PS microspheres using spin coating: Before coating, roll flatten the copper sheet, clean it with acetone and deionized water, and dry it; dissolve the PS microspheres obtained in S21 in ethanol to obtain a PS microsphere emulsion; before coating, adjust the rotation time and speed of the high and low speed settings of the coating machine, drop the PS microsphere emulsion onto the copper sheet, and when the coating machine rotates at high speed, the PS microsphere emulsion is assembled under the combined action of the viscous force between the liquid and the substrate and the centrifugal force of rotation. This process is accompanied by the evaporation of the solvent ethanol, resulting in a copper sheet with a PS colloidal template.
3. The method for preparing the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone according to claim 2, characterized in that, In S21, ethanol is 60-62g, deionized water is 40-43g, styrene monomer is 5mL, and potassium persulfate solution is prepared by dissolving 0.1g of potassium persulfate in 20mL of deionized water.
4. The method for preparing the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone according to claim 2, characterized in that, In S22, the concentration of PS microsphere emulsion is 0.2-0.23 wt%, the size of the copper sheet is 2 cm × 2 cm, and the amount of PS microsphere emulsion added is 100-120 μL.
5. The method for preparing the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone according to claim 2, characterized in that, In S22, the low speed gear has a rotation speed of 500-1000 rpm and a rotation time of 3-5 seconds; the high speed gear has a rotation speed of 2000-2500 rpm and a rotation time of 40-50 seconds.
6. The method for preparing the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone according to claim 1, characterized in that, In S3, at a temperature of 25±1℃ and a current density of 8-10A / dm 2 Deposition for 40 minutes.
7. The method for preparing the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone according to claim 1, characterized in that, In S5, after drying at 110℃ for 2 hours, it is calcined in air at 400-450℃ for 3 hours.
8. The method for preparing the catalyst for the dehydrogenation of cyclopentanol to cyclopentanone according to claim 1, characterized in that, In S5, the concentration of nickel nitrate solution is 10-12 g / L.
9. A catalyst for the dehydrogenation of cyclopentanol to cyclopentanone, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.