Phosphorus-modified ruthenium-based catalyst as well as preparation method and application thereof
By introducing phosphorus elements into the ruthenium-based catalyst, the Ru-P-O covalent interface structure is constructed, and the stability and high-temperature activity decay of the ruthenium-based catalyst is solved, and the efficient 3-methylpiperidine dehydrogenation reaction is achieved, which improves the performance and life of the catalyst.
Patent Information
- Application Number
- CN202510281805.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-07-04
AI Technical Summary
The existing ruthenium-based catalysts have problems of poor stability and decay of high-temperature catalytic activity in the dehydrogenation reaction, especially in complex organic reactions, which have high cost and low activity.
By introducing phosphorus elements into ruthenium-based catalysts, the Ru-P-O covalent interface structure is constructed in the ruthenium metal lattice by in situ phosphating technology, the thermal migration behavior of phosphorus elements is regulated by gradient temperature control reduction technology, so that phosphorus atoms selectively occupy the octahedral gap site of the ruthenium lattice, forming chemical bonds with P→Ru charge transfer characteristics, improving the dispersion of ruthenium metal and inhibiting sintering.
It significantly improves the stability and catalytic performance of the catalyst, improves the conversion rate and reaction stability of the 3-methylpiperidine dehydrogenation reaction, and the preparation method is simple and low cost, and has high industrial application value.
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Figure CN120243075A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to catalysts and their preparation methods and applications, and specifically relates to a phosphorus-modified ruthenium-based catalyst and its preparation method and application. Background Art
[0002] In the chemical industry, dehydrogenation reactions, as an important class of catalytic reactions, are widely used in organic chemical synthesis, petrochemical industry, and the production of fine chemicals. Especially in the dehydrogenation reaction of amino compounds, ruthenium-based catalysts have become one of the research hotspots due to their excellent catalytic performance and high stability. Ruthenium has high catalytic activity and is particularly suitable for the development of catalysts in dehydrogenation reactions. However, ruthenium-based catalysts are prone to particle aggregation or sintering during the reaction process, resulting in a decrease in their catalytic activity and even failure, which is particularly significant under high-temperature or long-term reaction conditions.
[0003] To solve the stability problem of ruthenium-based catalysts in dehydrogenation reactions, researchers have proposed various methods to modify ruthenium catalysts, such as through the selection of carriers, the control of the morphology of ruthenium, and the addition of other elements. However, despite this, the ruthenium-based catalysts in the prior art still face problems such as high cost, poor stability, and low activity, especially in complex organic reaction processes.
[0004] In the prior art, ruthenium-based catalysts have problems such as activity decline and poor stability in high-temperature dehydrogenation reactions. Summary of the Invention
[0005] Object of the Invention: In order to overcome the deficiencies in the prior art, the object of the present invention is to provide a preparation method of a phosphorus-modified ruthenium-based catalyst with good stability and good catalytic performance. Another object of the present invention is to provide a simple, convenient, and low-cost phosphorus-modified ruthenium-based catalyst. Still another object of the present invention is to provide an application of the phosphorus-modified ruthenium-based catalyst in the dehydrogenation of 3-methylpiperidine to prepare 3-methylpyridine.
[0006] Technical Solution: The preparation method of a phosphorus-modified ruthenium-based catalyst according to the present invention includes the following steps:
[0007] Step 1: Add a ruthenium source and a carrier to a solvent, stir evenly, evaporate the solvent, and dry to obtain a precursor of the ruthenium-based catalyst;
[0008] Step 2: Grind the precursor of the ruthenium-based catalyst to obtain a ruthenium-based catalyst powder;
[0009] Step 3: Mix the ruthenium-based catalyst powder with NaH2PO2 at a mass ratio of 1:5 to 50, heat it to 500 to 550 °C in an argon atmosphere and keep it for 2 to 3 hours to ensure that phosphorus elements are evenly distributed on the surface of the catalyst;
[0010] Step 4: Wash the product obtained in Step 3 and dry it under vacuum.
[0011] Step 5: Anneal the product obtained in Step 4 at 550 - 600 °C under an argon atmosphere to ensure the tight binding of phosphorus and ruthenium metal and improve the stability of the catalyst.
[0012] Further, in Step 1, the ruthenium source is triruthenium dodecacarbonyl. The carrier is SBA - 15. The mass ratio of the ruthenium source to the carrier is 3 - 10:200. The solvent is any one of acetone, ethanol, ethyl acetate, acetonitrile, and methanol.
[0013] Further, in Step 2, after grinding, pass through a 200 - 400 mesh sieve.
[0014] Further, in Step 3, the heating rate is 3 - 5 °C / min.
[0015] Further, in Step 4, the washing is carried out using deionized water and absolute ethanol, and the temperature for vacuum drying is 70 - 80 °C, and the time is 12 - 15 h.
[0016] Further, in Step 5, the annealing time is 1 - 3 hours.
[0017] For the phosphorus - modified ruthenium - based catalyst obtained by the preparation method of the phosphorus - modified ruthenium - based catalyst described in the present invention, the mass percentage of ruthenium element is 0.5 - 10 wt%.
[0018] Application of the phosphorus - modified ruthenium - based catalyst described in the present invention in the dehydrogenation of 3 - methylpiperidine to prepare 3 - methylpyridine.
[0019] Further, the mass ratio of the ruthenium - based catalyst to 3 - methylpiperidine is 1:6000. The dehydrogenation is carried out at a reaction temperature of 250 - 320 °C, a pressure of 0.1 - 2 MPa, and in an argon or nitrogen atmosphere. Preferably, under the conditions of a reaction temperature of 320 °C, a reaction gas flow rate of 20 mL / min, and a reaction pressure of 0.5 MPa in an argon atmosphere, the catalyst can achieve efficient dehydrogenation reaction, and the performance of the catalyst does not show significant decline during long - term use.
[0020] Preparation principle: By means of in - situ phosphidation process, phosphorus element is accurately introduced into the ruthenium metal lattice to construct a Ru - P - O covalent interface structure, realizing the electronic state regulation and spatial confinement of ruthenium active centers at the atomic scale. Different from traditional physical doping or surface coating methods, the present invention adopts a gradient temperature - controlled reduction technology to regulate the thermal migration behavior of phosphorus element in stages in the range of 550 - 650 °C, promoting phosphorus atoms to selectively occupy the octahedral interstitial sites of the ruthenium lattice. It is confirmed by XPS depth profiling that this process forms a Ru δ+ -P δ-Chemical bonds effectively reduce the Ru d-band center and significantly optimize the adsorption / desorption of hydrogen intermediates (Ru-H * ). Microstructural characterization (HAADF-STEM) shows that the introduction of phosphorus elements keeps the Ru species in a monodispersed state. By introducing phosphorus elements, the dispersion of Ru metal is improved, the sintering of Ru metal is inhibited, and thus the stability and catalytic performance of the catalyst are enhanced.
[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant features:
[0022] 1. By introducing phosphorus elements into the ruthenium-based catalyst, the problems of poor stability and high-temperature catalytic activity decline of the existing ruthenium-based catalysts are solved, the performance and lifespan of the catalyst are significantly improved, and the preparation method is simple and the cost is relatively low, having high industrial application value;
[0023] 2. The catalyst prepared by the present invention shows high conversion rate and long reaction stability in the dehydrogenation reaction of 3-methylpiperidine, having good catalytic activity and excellent long-term reaction stability. Brief description of the drawings
[0024] Figure 1 is the electron microscope image of the catalyst obtained in Example 1 of the present invention. Among them, (a) is the HAADF-STEM image of the P-modified Ru-based catalyst, (b) is the EDS-Mapping image of P, and (c) is the EDS-Mapping image of Ru;
[0025] Figure 2 The electron microscope image of the Ru-based catalyst without P modification. Detailed description of the invention
[0026] In the following examples, the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels. The experimental methods without specific conditions noted in the examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer.
[0027] Example 1
[0028] A preparation method of a phosphorus-modified ruthenium-based catalyst includes the following steps:
[0029] (1) Add 4 mg of triruthenium dodecacarbonyl (Ru3(CO) 12 ) and 200 mg of the support SBA-15 to 10 mL of acetone solution. After stirring evenly, evaporate the solvent. After sufficient drying, obtain the precursor of the ruthenium catalyst.
[0030] (2) After grinding the precursor of the ruthenium-based catalyst, sieve it through 300 meshes to obtain the ruthenium-based catalyst powder.
[0031] (3) Mix the ruthenium-based catalyst powder with NaH₂PO₂ at a mass ratio of 1:20, uniformly mix them, place them in a tubular furnace, and under an argon atmosphere, heat them to 500 °C at a heating rate of 5 °C / min for calcination and hold for 2 hours.
[0032] (4) Wash the obtained powder with deionized water and absolute ethanol, and dry it at 80 °C for 12 h.
[0033] (5) Under an argon atmosphere, anneal at 550 °C for 2 hours to finally obtain the P 20 -Ru / SBA-15 catalyst, denoted as Catalyst 1.
[0034] Example 2
[0035] A preparation method of a phosphorus-modified ruthenium-based catalyst includes the following steps:
[0036] (1) Add 4 mg of dodecacarbonyltriruthenium (Ru₃(CO) 12 ) and 200 mg of the support SBA-15 to 10 mL of acetone solution, stir well, evaporate the solvent, and after sufficient drying, obtain the precursor of the ruthenium catalyst.
[0037] (2) Grind the precursor of the ruthenium-based catalyst, and pass through a 200-mesh sieve to obtain the ruthenium-based catalyst powder.
[0038] (3) Mix the ruthenium-based catalyst powder with NaH₂PO₂ at a mass ratio of 1:5, uniformly mix them, place them in a tubular furnace, and under an argon atmosphere, heat them to 500 °C at a heating rate of 5 °C / min for calcination and hold for 2 hours.
[0039] (4) Wash the obtained powder with deionized water and absolute ethanol, and dry it at 80 °C for 12 h.
[0040] (5) Under an argon atmosphere, anneal at 550 °C for 2 hours to finally obtain the P5-Ru / SBA-15 catalyst, denoted as Catalyst 2.
[0041] Example 3
[0042] A preparation method of a phosphorus-modified ruthenium-based catalyst includes the following steps:
[0043] (1) Add 4 mg of dodecacarbonyltriruthenium (Ru₃(CO) 12 ) and 200 mg of the support SBA-15 to 10 mL of acetone solution, stir well, evaporate the solvent, and after sufficient drying, obtain the precursor of the ruthenium catalyst.
[0044] (2) Grind the precursor of the ruthenium-based catalyst, and pass through a 200-mesh sieve to obtain the ruthenium-based catalyst powder.
[0045] (3) Mix the ruthenium-based catalyst powder with NaH₂PO₂ at a mass ratio of 1:10, mix evenly, place it in a tubular furnace, and under an argon atmosphere, heat it to 500 °C at a heating rate of 5 °C / min, calcine it, and keep it warm for 2 hours.
[0046] (4) Wash the obtained powder with deionized water and absolute ethanol, and dry it at 80 °C for 12 h.
[0047] (5) Anneal it at 550 °C for 2 hours under an argon atmosphere to finally obtain the P 10 -Ru / SBA-15 catalyst, denoted as catalyst 3.
[0048] Example 4
[0049] A preparation method of a phosphorus-modified ruthenium-based catalyst, comprising the following steps:
[0050] (1) Add 4 mg of triruthenium dodecacarbonyl (Ru₃(CO) 12 ) and 200 mg of the support SBA-15 to 10 mL of acetone solution, stir well, evaporate the solvent, and after sufficient drying, obtain the precursor of the ruthenium catalyst.
[0051] (2) Grind the precursor of the ruthenium-based catalyst, and pass it through a 200-mesh sieve to obtain the ruthenium-based catalyst powder.
[0052] (3) Mix the ruthenium-based catalyst powder with NaH₂PO₂ at a mass ratio of 1:50, mix evenly, place it in a tubular furnace, and under an argon atmosphere, heat it to 500 °C at a heating rate of 5 °C / min, calcine it, and keep it warm for 2 hours.
[0053] (4) Wash the obtained powder with deionized water and absolute ethanol, and dry it at 80 °C for 12 h.
[0054] (5) Anneal it at 550 °C for 2 hours under an argon atmosphere to finally obtain the P 50 -Ru / SBA-15 catalyst, denoted as catalyst 4.
[0055] Example 5
[0056] A preparation method of a phosphorus-modified ruthenium-based catalyst, comprising the following steps:
[0057] (1) Add 3 mg of triruthenium dodecacarbonyl and 200 mg of the support SBA-15 to 10 mL of ethanol solution, stir well, evaporate the solvent, and after sufficient drying, obtain the precursor of the ruthenium catalyst.
[0058] (2) Grind the precursor of the ruthenium-based catalyst, and pass it through a 300-mesh sieve to obtain the ruthenium-based catalyst powder.
[0059] (3) The ruthenium-based catalyst powder and NaH2PO2 in a mass ratio of 1:5 were uniformly mixed and placed in a tubular furnace. Under an argon atmosphere, the temperature was increased to 550°C at a heating rate of 3°C / min and calcined for 3 hours.
[0060] (4) The obtained powder was washed with deionized water and anhydrous ethanol and dried at 70°C for 15 h.
[0061] (5) The catalyst was annealed at 600 °C for 1 hour under an argon atmosphere to obtain a phosphorus-modified ruthenium-based catalyst.
[0062] Example 6
[0063] A method for preparing a phosphorus-modified ruthenium-based catalyst comprises the following steps:
[0064] (1) 10 mg of triruthenium dodecacarbonyl and 200 mg of carrier SBA-15 are added to 10 mL of ethyl acetate solution, stirred thoroughly, and then the solvent is evaporated. After being fully dried, a precursor of a ruthenium catalyst is obtained.
[0065] (2) The precursor of the ruthenium-based catalyst is ground and passed through a 400-mesh filter to obtain a ruthenium-based catalyst powder.
[0066] (3) The ruthenium-based catalyst powder and NaH2PO2 with a mass ratio of 1:50 were uniformly mixed and placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 520°C at a heating rate of 4°C / min, and the mixture was calcined and kept at this temperature for 2.5 hours.
[0067] (4) The obtained powder was washed with deionized water and anhydrous ethanol and dried at 75°C for 13 h.
[0068] (5) Under an argon atmosphere, the catalyst was annealed at 580 °C for 2 h to obtain a phosphorus-modified ruthenium-based catalyst.
[0069] Comparative Example 1
[0070] The remaining steps of this comparative example are the same as those of Example 1, except that the carrier SBA-15 in step (1) is replaced by CeO2. 20 -Ru / CeO2 catalyst is recorded as catalyst 5.
[0071] Comparative Example 2
[0072] The remaining steps of this comparative example are the same as those of Example 1, except that the carrier SBA-15 in step (1) is replaced by TiO2. 20 -Ru / TiO2 catalyst is recorded as catalyst 6.
[0073] Comparative Example 3
[0074] The remaining steps of this comparative example are the same as those of Example 1, and the only difference is that: the support SBA-15 in step (1) is replaced with MgO. The obtained P 20 -Ru / MgO catalyst is denoted as catalyst 7.
[0075] Comparative Example 4
[0076] The remaining steps of this comparative example are the same as those of Example 1, and the only difference is that: the support SBA-15 in step (1) is replaced with ZnO. The obtained P 20 -Ru / ZnO catalyst is denoted as catalyst 8.
[0077] Comparative Example 5
[0078] The remaining steps of this comparative example are the same as those of Example 1, and the only difference is that: the support SBA-15 in step (1) is replaced with Al2O3. The obtained P 20 -Ru / Al2O3 catalyst is denoted as catalyst 9.
[0079] Comparative Example 6
[0080] The remaining steps of this comparative example are the same as those of Example 1, and the only difference is that: the support SBA-15 in step (1) is replaced with Ga2O3. The obtained P 20 -Ru / Ga2O3 catalyst is denoted as catalyst 10.
[0081] Comparative Example 7
[0082] The remaining steps of this comparative example are the same as those of Example 1, and the only difference is that: the support SBA-15 in step (1) is replaced with MCM-41. The obtained P 20 -Ru / MCM-41 catalyst is denoted as catalyst 11.
[0083] Comparative Example 8
[0084] The remaining steps of this comparative example are the same as those of Example 1, and the only difference is that: the support SBA-15 in step (1) is replaced with KIT-6. The obtained P 20 -Ru / KIT-61 catalyst is denoted as catalyst 12.
[0085] Comparative Example 9
[0086] The remaining steps of this comparative example are the same as those of Example 1, and the only difference is that: the 4 mg of dodecacarbonyltriruthenium (Ru3(CO) 12 ) in step (1) is replaced with 6 mg of ruthenium chloride (RuCl3), and finally P 20 -Ru rc / SBA-15 catalyst is denoted as catalyst 13.
[0087] Comparative Example 10
[0088] The remaining steps of this comparative example are the same as those of Example 1, except that: 4 mg of dodecacarbonyltriruthenium (Ru3(CO) 12 ) in step (1) was replaced with 6 mg of ruthenium acetylacetonate (Ru(acac)3), and finally P 20 -Ru rp / SBA-15 catalyst was obtained, denoted as catalyst 14.
[0089] Comparative Example 11
[0090] The remaining steps of this comparative example are the same as those of Example 1, except that: the step of mixing the ruthenium-based catalyst powder with NaH2PO2 in step (3) was omitted, and directly under an argon atmosphere, it was heated to 500 °C at a heating rate of 5 °C / min and calcined for 2 hours.
[0091] The catalysts obtained in Example 1 and Comparative Example 11 were respectively photographed by electron microscopy, as Figures 1 - 2 , it can be seen that: the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image shows that the phosphorus-modified ruthenium catalyst is anchored on the carrier surface in an atomically dispersed form (isolated single atoms and sub-nanometer clusters with uniform brightness), and no obvious ruthenium particle aggregation phenomenon was observed. The ruthenium single-atom sites can be clearly identified by EDS-Mapping energy spectrum, and the phosphorus element (purple signal, Figure 1 b) and ruthenium (green signal, Figure 1 c) showed a highly spatially co-distributed feature, confirming that phosphorus was uniformly modified around the ruthenium active sites with atomic-level precision. Figure 2 In the TEM image of , obvious growth of ruthenium metal particles was found in the unmodified ruthenium-based catalyst, and the average particle size was 3.8 ± 1.2 nm.
[0092] Application Example
[0093] 200 mg of the phosphorus-modified ruthenium-based catalysts obtained in Examples 1 to 4 and Comparative Examples 1 to 10 were respectively loaded into a fixed-bed reactor, and the reaction gas was a mixed gas of 3-methylpiperidine and argon, where 3-methylpiperidine was 1.2 kg. First, start the argon flow (20 mL / min) and raise the reaction temperature to 320 °C, and set the reaction pressure to 0.5 MPa. The injection amount of 3-methylpiperidine was 0.1 mL / min, and the gas flow rate was kept stable. After the reaction started, the conversion rate of 3-methylpiperidine and the selectivity of 3-picoline in the reaction products were regularly analyzed by gas chromatography (GC). The experiment lasted for 200 hours, and samples were taken every 4 hours during the reaction process to monitor the performance changes of the catalyst.
[0094]
[0095] As can be seen from Table 1, the catalytic performances of Examples 1 to 4 are significantly superior to those of the catalysts of Comparative Examples 1 to 10, and the yield and stability are significantly improved. Here, the stability is the retention time of the highest yield and selectivity during the continuous reaction process under the reaction conditions. Among them, Example 1 is the optimal example. By introducing phosphorus element, the present invention significantly improves the dispersion of ruthenium metal and inhibits the sintering phenomenon of ruthenium particles at high temperature, thereby effectively improving the stability and catalytic activity of the catalyst. The preparation method is simple and feasible, and can efficiently synthesize catalysts with excellent performance under conventional experimental conditions. The experimental results show that when the catalyst of the present invention is used for the gas-phase dehydrogenation reaction of 3-methylpiperidine, the catalyst exhibits high conversion and selectivity, and there is no significant catalyst deactivation or structural change during the long-term reaction, showing good long-term stability and reliability. In addition, the catalyst of the present invention can maintain high catalytic activity under the reaction conditions and maintain stable performance under different reaction conditions, having strong adaptability and broad application prospects.
[0096] Table 1 Reaction results of the catalysts obtained in Examples 1 to 4 and Comparative Examples 1 to 10
[0097] Number Catalyst Selectivity (%) Yield (%) Stability (h) Example 1 Catalyst 1 99.99 99.01 200 Example 2 Catalyst 2 99.99 98.72 121 Example 3 Catalyst 3 99.99 99.10 156 Example 4 Catalyst 4 99.99 93.41 200 Comparative Example 1 Catalyst 5 99.99 52.42 67 Comparative Example 2 Catalyst 6 99.99 41.87 45 Comparative Example 3 Catalyst 7 99.99 76.12 120 Comparative Example 4 Catalyst 8 99.99 56.71 45 Comparative Example 5 Catalyst 9 99.99 59.61 12 Comparative Example 6 Catalyst 10 99.99 70.21 90 Comparative Example 7 Catalyst 11 99.99 21.04 76 Comparative Example 8 Catalyst 12 99.99 80.01 144 Comparative Example 9 Catalyst 13 99.99 69.90 200 Comparative Example 10 Catalyst 14 99.99 71.10 200
Claims
1. A method for preparing a phosphorus-modified ruthenium-based catalyst, characterized in that, It includes the following steps: Step 1: Add a ruthenium source and a support to a solvent. After stirring evenly, evaporate the solvent and dry to obtain a precursor of the ruthenium-based catalyst; Step 2: Grind the precursor of the ruthenium-based catalyst to obtain ruthenium-based catalyst powder; Step 3: Mix the ruthenium-based catalyst powder with NaH2PO2 at a mass ratio of 1:5 to 50, heat it to 500 - 550 °C in an argon atmosphere and maintain for 2 - 3 hours; Step 4: Wash the product obtained in Step 3 and dry it under vacuum; Step 5: Anneal the product obtained in Step 4 at 550 - 600 °C in an argon atmosphere.
2. The preparation method of a phosphorus-modified ruthenium-based catalyst according to claim 1, characterized in that: In the said Step 1, the ruthenium source is triruthenium dodecacarbonyl.
3. The preparation method of a phosphorus-modified ruthenium-based catalyst according to claim 1, characterized in that: In the said Step 1, the support is SBA-15.
4. The preparation method of a phosphorus-modified ruthenium-based catalyst according to claim 1, characterized in that: In the said Step 1, the mass ratio of the ruthenium source to the support is 3 - 10:
200.
5. The preparation method of a phosphorus-modified ruthenium-based catalyst according to claim 1, characterized in that: In the said Step 1, the solvent is any one of acetone, ethanol, ethyl acetate, acetonitrile, and methanol.
6. The preparation method of a phosphorus-modified ruthenium-based catalyst according to claim 1, characterized in that: In the said Step 3, the heating rate is 3 - 5 °C / min.
7. The preparation method of a phosphorus-modified ruthenium-based catalyst according to claim 1, characterized in that: In the said Step 4, the washing is carried out using deionized water and absolute ethanol, and the temperature of vacuum drying is 70 - 80 °C and the time is 12 - 15 h.
8. The preparation method of a phosphorus-modified ruthenium-based catalyst according to claim 1, characterized in that: In the said Step 5, the annealing time is 1 - 3 hours.
9. The phosphorus-modified ruthenium-based catalyst obtained by the preparation method of the phosphorus-modified ruthenium-based catalyst according to any one of claims 1 to 7, characterized in that: The mass percentage of ruthenium element is 0.5 - 10 wt%.
10. Use of the phosphorus-modified ruthenium-based catalyst according to claim 9 in the dehydrogenation of 3-methylpiperidine to prepare 3-methylpyridine.