Method for realizing metal-free catalytic hydrogenation by using black phosphorus-based catalyst
The preparation and application of black phosphorus-based catalysts have solved the problems of high cost and easy poisoning of metal-based catalysts in catalytic hydrogenation reactions, achieving efficient and stable catalytic hydrogenation reactions suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2026-04-14
AI Technical Summary
Existing metal-based catalysts suffer from high cost, susceptibility to poisoning, and over-hydrogenation in catalytic hydrogenation reactions, resulting in low selectivity for target products and making large-scale industrial application difficult.
Using a black phosphorus-based catalyst, unsaturated compounds and the black phosphorus-based catalyst are heated and reacted in a high-pressure reactor through a specific preparation method. Hydrogen is then used for catalytic hydrogenation, and post-processing yields a reusable black phosphorus-based catalyst for the catalytic hydrogenation of various unsaturated compounds.
It achieves efficient and low-cost catalytic hydrogenation reaction. The catalyst has good activity and stability, is suitable for large-scale industrial production, and solves the defects of metal-based catalysts.
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Figure CN121850820A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal-free catalysis technology, specifically relating to a method for achieving metal-free catalytic hydrogenation using a recyclable black phosphorus-based catalyst. Background Technology
[0002] Catalytic hydrogenation is a reaction in which hydrogen molecules add to unsaturated groups of organic compounds under the action of a catalyst. As an important organic reaction, it plays an irreplaceable role in many fields such as petrochemicals and fine chemical synthesis. Because catalytic hydrogenation uses inexpensive and readily available hydrogen as a reducing agent, it has good atom economy, and theoretically, the only byproduct is water, making it considered the cleanest reduction method. Furthermore, catalytic hydrogenation is easy to control, and the resulting products have high purity and yield, leading to its wide application in industry.
[0003] In the field of catalytic hydrogenation technology, three main catalytic systems exist: homogeneous liquid-phase coordination catalysis, gas-solid phase contact catalysis, and gas-solid-liquid heterogeneous catalysis. In homogeneous liquid-phase coordination catalysis, the catalyst is uniformly dispersed in the reaction medium, achieving highly efficient and selective conversion. However, this process presents challenges in product separation and catalyst recycling. Conversely, gas-solid phase contact catalysis involves mixing substrate-containing vapor with hydrogen, achieving conversion through a catalyst fixed to a solid surface. This method requires the substrate to have a certain degree of volatility and good thermal stability, limiting its application. Gas-solid-liquid heterogeneous catalytic hydrogenation combines the adsorption of gaseous hydrogen with liquid or solvent-dissolved solid substrates on the surface of a solid catalyst to achieve the hydrogenation reaction. This technology has been widely used in industrial production due to its high activity, wide applicability, simple catalyst recovery, easy product purification, and relatively low environmental impact.
[0004] Currently, metal-based catalysts are widely used in gas-solid-liquid heterogeneous catalysis, among which palladium, platinum, rhodium, and Raney nickel catalysts exhibit good catalytic hydrogenation activity. However, these catalysts have some inherent drawbacks. First, these metals are limited in reserves and expensive, hindering large-scale industrial use. Second, these catalysts are generally susceptible to poisoning; for example, platinum (Pt) and Raney nickel are very easily poisoned by CO. Furthermore, because these metal catalysts exhibit hydrogenation activity for multiple functional groups, they often lead to over-hydrogenation, resulting in low selectivity for the target product.
[0005] Black phosphorus-based materials, as a novel type of material, possess a wrinkled honeycomb structure. This unique structure endows them with many excellent properties, showing promising application prospects in numerous fields. Especially in the field of catalysis, black phosphorus-based materials, due to their high specific surface area, easily tunable electronic properties, and high charge mobility, are considered promising metal-free catalysts. Furthermore, the applications of black phosphorus-based catalysts are mainly concentrated in photocatalysis and electrocatalysis. Compared to photocatalysis and electrocatalysis, thermocatalysis, especially catalytic hydrogenation, involves a wider range and is relatively easier to implement on a large industrial scale; however, these catalysts have not yet been applied in catalytic hydrogenation. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for achieving metal-free catalytic hydrogenation using a black phosphorus-based catalyst.
[0007] The technical solution of this invention is summarized as follows:
[0008] A method for achieving metal-free catalytic hydrogenation using a black phosphorus-based catalyst includes the following steps:
[0009] Unsaturated compounds and black phosphorus-based catalysts were added to a high-pressure reactor along with a solvent. The reactor was then tightly sealed, hydrogen gas was introduced, and the air inside was purged. Hydrogen gas was then introduced at 2-4 MPa, and the reactor was heated to 140-180°C. The reaction was carried out for 6-10 hours with stirring. The reactor was then cooled to room temperature, the pressure was released, and the solid and liquid were separated by filtration. The solid was washed successively with water and anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst for reuse. The liquid contained the target product.
[0010] The ratio of the black phosphorus-based catalyst, unsaturated compound, and solvent is 30 mg: 40-80 mg: 2-4 mL.
[0011] The unsaturated compound is nitrobenzene, p-chloronitrobenzene, o-chloronitrobenzene, m-chloronitrobenzene, p-nitrophenol, o-nitrophenol, m-nitrophenol, p-nitroanisole, p-nitrophenylacetonitrile, dimethyl sulfoxide, diphenyl sulfoxide, ethylene, propylene, styrene, acetylene, propyne, benzaldehyde, acetophenone, acrolein, vanillin, crotonaldehyde, or cinnamaldehyde.
[0012] The solvent is ethanol, tetrahydrofuran, 1,4-dioxane, n-hexane, toluene, cyclohexane, or an aqueous solution of ethanol.
[0013] The black phosphorus-based catalyst is prepared by the following steps:
[0014] (1) Disperse 2-4g of red phosphorus in 60mL of deionized water according to the proportion, sonicate for 30 minutes, then transfer to 100mL of hydrothermal reactor, tighten the seal, transfer to a forced-air drying oven, react at 180℃ for 10 hours, cool to room temperature, filter to remove the supernatant, and vacuum dry to obtain red phosphorus precursor with oxide layer removed;
[0015] (2) Disperse 1-2g of the red phosphorus precursor for removing the oxide layer in 60-70mL of ethylenediamine according to the proportion, stir at room temperature for 1 hour to obtain a mixture;
[0016] (3) Transfer the mixture to a hydrothermal reactor, tighten the seal, transfer it to a forced-air drying oven, react at 140-180℃ for 6-12 hours, and after cooling to room temperature, wash it by centrifugation with deionized water and anhydrous ethanol in sequence, and dry it under vacuum at 50℃ for 6 hours to obtain the black phosphorus-based catalyst.
[0017] Beneficial effects: The method of this invention is the first to apply black phosphorus-based catalyst as a metal-free catalyst in the field of catalytic hydrogenation, successfully realizing the catalytic hydrogenation of a variety of unsaturated compounds. It has high catalytic activity and can fundamentally solve the inherent defects of metal-based catalysts such as high cost and easy poisoning and deactivation. In addition, the catalyst used in this invention has low preparation cost and mild conditions, making it suitable for large-scale industrial production. Attached Figure Description
[0018] Figure 1 SEM images of the red phosphorus precursor and black phosphorus-based catalyst prepared in Example 2.
[0019] Figure 2 This is a TEM image of the black phosphorus-based catalyst prepared in Example 2.
[0020] Figure 3 XRD patterns of black phosphorus-based catalysts prepared as red phosphorus precursors and at different reaction temperatures.
[0021] Figure 4 The cyclic performance diagram of the black phosphorus-based catalyst prepared in Example 2 when applied in Example 9. Detailed Implementation
[0022] The present invention will be further described below through specific embodiments.
[0023] The following embodiments will enable those skilled in the art to better understand the present invention. However, the descriptions in the embodiments are for illustrative purposes only and are not intended to limit the scope of the invention in any way.
[0024] Example 1
[0025] The preparation method of black phosphorus-based catalyst includes the following steps:
[0026] (1) Disperse 2g of red phosphorus (RP) in 60mL of deionized water, sonicate for 30 minutes, then transfer to 100mL of hydrothermal reactor, tighten the seal, transfer to a forced-air drying oven, and continue to react at 180℃ for 10 hours. After cooling to room temperature, filter to remove the supernatant, and vacuum dry to obtain red phosphorus precursor with oxide layer removed.
[0027] (2) Disperse 1g of the red phosphorus precursor obtained above in 60mL of ethylenediamine and stir magnetically for 1 hour at room temperature to obtain a mixture;
[0028] (3) The mixture was transferred to a hydrothermal reactor, sealed tightly, and then transferred to a forced-air drying oven. The mixture was reacted at 140°C for 12 hours. After cooling to room temperature, it was washed three times by centrifugation with deionized water and anhydrous ethanol, and then vacuum dried at 50°C for 6 hours to obtain a black product, which is the black phosphorus-based catalyst, denoted as BP / RP-140.
[0029] Replace 140℃ in step (3) of this embodiment with 120℃, and keep the other conditions the same as in this embodiment to obtain a black phosphorus-based catalyst, denoted as BP / RP-120.
[0030] Example 2
[0031] The preparation method of black phosphorus-based catalyst includes the following steps:
[0032] (1) Disperse 3g of red phosphorus in 60mL of deionized water, sonicate for 30 minutes, then transfer to 100mL of hydrothermal reactor, tighten the seal, transfer to a forced-air drying oven, and continue to react at 180℃ for 10 hours. After cooling to room temperature, filter to remove the supernatant, and vacuum dry to obtain red phosphorus precursor with oxide layer removed.
[0033] (2) Disperse 1.5g of the red phosphorus precursor obtained above in 65mL of ethylenediamine and stir magnetically for 1 hour at room temperature to obtain a mixture;
[0034] (3) The mixture was transferred to a hydrothermal reactor, sealed tightly, and then transferred to a forced-air drying oven. It was reacted at 160°C for 9 hours. After cooling to room temperature, it was washed three times by centrifugation with deionized water and anhydrous ethanol, and then vacuum dried at 50°C for 6 hours to obtain a black product, which is the black phosphorus-based catalyst, denoted as BP / RP-160.
[0035] The black phosphorus-based catalyst obtained in Example 2 was characterized in a series of ways.
[0036] Figure 1 a and b are SEM images of the prepared red phosphorus precursor. The particles have smooth surfaces and exhibit a microporous structure, indicating that the oxide layer on the surface of the red phosphorus was successfully removed after hydrothermal treatment. Figure 1c and d are SEM images of the black phosphorus-based catalyst. As can be seen from the images, there are many wrinkles on the surface of the material, presenting an irregular "cauliflower" shaped structure.
[0037] Figure 2 The image shows a TEM image of the black phosphorus-based catalyst. The image reveals a distinct layered stacked structure. High-magnification transmission electron microscopy reveals lattice fringes with a width of 0.56 nm, corresponding to the (020) crystal plane of black phosphorus, indicating the successful synthesis of black phosphorus nanosheets with a layered structure. Furthermore, amorphous red phosphorus particles are observed tightly connected next to the black phosphorus lattice, indicating the formation of a black phosphorus / red phosphorus heterostructure with good interfacial contact.
[0038] Example 3
[0039] A method for preparing a black phosphorus-based catalyst includes the following steps:
[0040] (1) Disperse 4g of red phosphorus in 60mL of deionized water, sonicate for 30 minutes, then transfer to 100mL of hydrothermal reactor, tighten the seal, transfer to a forced-air drying oven, and continue to react at 180℃ for 10 hours. After cooling to room temperature, filter to remove the supernatant, and vacuum dry to obtain red phosphorus precursor with oxide layer removed.
[0041] (2) Disperse 2g of the red phosphorus precursor obtained above in 70mL of ethylenediamine and stir magnetically for 1 hour at room temperature to obtain a mixture;
[0042] (3) The mixture was transferred to a hydrothermal reactor, sealed tightly, and then transferred to a forced-air drying oven. It was reacted at 180°C for 6 hours. After cooling to room temperature, it was washed three times by centrifugation with deionized water and anhydrous ethanol, and then vacuum dried at 50°C for 6 hours to obtain a black product, which is the black phosphorus-based catalyst, denoted as BP / RP-180.
[0043] Figure 3 The XRD patterns of the red phosphorus precursor and the black phosphorus-based catalyst are shown. The figures show that at a reaction temperature of 120°C, the spectrum of BP / RP-120 is similar to that of RP, indicating that black phosphorus cannot be produced at 120°C. As the reaction temperature increases, the characteristic peak at 15.3° gradually decreases, and new diffraction peaks appear at 16.8°, 26.4°, 34.2°, and 52.3°, gradually becoming sharper. This indicates that with increasing reaction temperature, red phosphorus successfully undergoes a phase transition to produce black phosphorus, and the crystallinity of the black phosphorus increases.
[0044] Example 4
[0045] A method for preparing aniline by metal-free catalytic hydrogenation of nitrobenzene using a black phosphorus-based catalyst (prepared in Example 1) includes the following steps:
[0046] 30 mg of the black phosphorus-based catalyst prepared in Example 1 and 60 mg of nitrobenzene were added to a high-pressure reactor, along with 3 mL of ethanol (or 4 mL of a 40% (v / v) aqueous ethanol solution). The reactor was tightly sealed, and hydrogen gas was repeatedly introduced to purge the air from the reactor. Then, 2 MPa of hydrogen gas was introduced, and the reactor was heated to 180°C. The reaction was carried out for 10 hours with stirring. After cooling to room temperature, the pressure was released, and the solid and liquid were separated by filtration. The solid was washed three times with water and anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst for reuse. The liquid was analyzed by gas chromatography, and the yield of the target product was calculated. The analysis showed that the yield of aniline was 100%.
[0047] Example 5
[0048] A method for preparing o-chloroaniline by metal-free catalytic hydrogenation of o-chloronitrobenzene using a black phosphorus-based catalyst (prepared in Example 1) includes the following steps:
[0049] 30 mg of the black phosphorus-based catalyst prepared in Example 1 and 60 mg of o-chloronitrobenzene were added to a high-pressure reactor, followed by 3 mL of tetrahydrofuran. The reactor was tightly sealed, and hydrogen gas was repeatedly introduced to purge the air. Then, 2 MPa of hydrogen gas was introduced, and the reactor was heated to 180°C and reacted continuously for 10 hours with stirring. After cooling to room temperature, the pressure was released, and the solid and liquid were separated by filtration. The solid was washed three times with water and anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst for reuse. The liquid was analyzed by gas chromatography, and the yield of the target product was calculated. Analysis showed that the yield of o-chloroaniline was 100%.
[0050] Example 6
[0051] A method for preparing p-aminophenol by metal-free catalytic hydrogenation of p-nitrophenol using a black phosphorus-based catalyst (prepared in Example 3) includes the following steps:
[0052] 30 mg of the black phosphorus-based catalyst prepared in Example 3 and 40 mg of p-nitrophenol were added to a high-pressure reactor, followed by 2 mL of 1,4-dioxane. The reactor was tightly sealed, and hydrogen gas was repeatedly introduced to purge the air. Then, hydrogen gas was introduced at 3 MPa, and the reactor was heated to 160°C and reacted continuously for 8 hours with stirring. After cooling to room temperature, the pressure was released, and the solid and liquid were separated by filtration. The solid was washed three times with water and anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst for reuse. The liquid was analyzed by gas chromatography, and the yield of the target product was calculated. The yield of p-aminophenol was 88%.
[0053] Example 7
[0054] A method for preparing p-benzyl alcohol by metal-free catalytic hydrogenation of benzaldehyde using a black phosphorus-based catalyst (prepared in Example 3) includes the following steps:
[0055] 30 mg of the black phosphorus-based catalyst prepared in Example 3 and 40 mg of benzaldehyde were added to a high-pressure reactor, followed by 2 mL of cyclohexane. The reactor was tightly sealed, and hydrogen gas was repeatedly introduced to purge the air from the reactor. Then, 3 MPa of hydrogen gas was introduced, and the reactor was heated to 160°C and reacted continuously for 8 hours with stirring. After cooling to room temperature, the pressure was released (the pressure inside the reactor was purged), and the solid and liquid were separated by filtration. The solid was washed three times with water and anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst for reuse. The liquid was analyzed by gas chromatography, and the yield of the target product was calculated. The yield of benzyl alcohol was 90%.
[0056] Example 8
[0057] A method for preparing p-aminophenylacetonitrile by metal-free catalytic hydrogenation of p-nitrophenylacetonitrile using a black phosphorus-based catalyst (prepared in Example 2) includes the following steps:
[0058] 30 mg of the black phosphorus-based catalyst prepared in Example 2 and 80 mg of p-nitrophenylacetonitrile were added to a high-pressure reactor, followed by 4 mL of toluene. The reactor was tightly sealed, and hydrogen gas was repeatedly introduced to purge the air. Then, hydrogen gas was introduced at 4 MPa, and the reactor was heated to 140°C and reacted continuously for 6 hours with stirring. After cooling to room temperature, the pressure was released (the pressure inside the reactor was purged), and the solid and liquid were separated by filtration. The solid was washed three times with water and anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst for reuse. The liquid was analyzed by gas chromatography, and the yield of the target product was calculated. The yield of p-aminophenylacetonitrile was 100%.
[0059] Example 9
[0060] A method for preparing diphenyl sulfide by metal-free catalytic hydrogenation of diphenyl sulfoxide using a black phosphorus-based catalyst (prepared in Example 2) includes the following steps:
[0061] 30 mg of the black phosphorus-based catalyst prepared in Example 2 and 80 mg of diphenyl sulfoxide were added to a high-pressure reactor, followed by 4 mL of n-hexane. The reactor was tightly sealed, and hydrogen gas was repeatedly introduced to purge the air from the reactor. Then, hydrogen gas was introduced at 4 MPa, and the reactor was heated to 140°C and reacted continuously for 6 hours with stirring. After cooling to room temperature, the pressure was released (the pressure inside the reactor was purged), and the solid and liquid were separated by filtration. The solid was washed three times with water and three times with anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst, which could be reused (recycled 5 times). The liquid was analyzed by gas chromatography, and the yield of the target product was calculated. The yield of diphenyl sulfide was 99%.
[0062] Experiments have shown that by replacing diphenyl sulfoxide in this example with the following unsaturated compounds (the solvents for each unsaturated compound are in parentheses): p-chloronitrobenzene (ethanol), m-chloronitrobenzene (ethanol), o-nitrophenol (ethanol), m-nitrophenol (ethanol), p-nitroanisole (ethanol), dimethyl sulfoxide (n-hexane), ethylene (tetrahydrofuran), propylene (tetrahydrofuran), styrene (tetrahydrofuran), acetylene (toluene), propyne (toluene), acetophenone (ethanol), acrolein (ethanol), vanillin (ethanol), crotonaldehyde (ethanol), or cinnamaldehyde (ethanol), with n-hexane as the solvent, and other aspects remaining the same as in this example, the corresponding hydrogenation reduction products can be obtained.
[0063] The solid from the reaction in Example 9 was washed and dried to obtain the black phosphorus-based catalyst BP / RP-160, which was recycled 5 times. The recycling performance is shown in the figure. Figure 4 As can be seen from the figure, the yield of diphenyl sulfide did not show a significant performance decline after the black phosphorus-based catalyst BP / RP-160 was reused 5 times, proving that the black phosphorus-based catalyst has good stability.
[0064] In summary, the black phosphorus-based catalyst can achieve the catalytic hydrogenation of a variety of unsaturated compounds, exhibiting excellent catalytic activity. Furthermore, the catalytic performance of this black phosphorus-based catalyst is stable and has good reproducibility.
Claims
1. A method for achieving metal-free catalytic hydrogenation using a black phosphorus-based catalyst, comprising the following steps: Unsaturated compounds and black phosphorus-based catalysts were added to a high-pressure reactor along with a solvent. The reactor was then tightly sealed, hydrogen gas was introduced, and the air inside was purged. Hydrogen gas was then introduced at 2-4 MPa, and the reactor was heated to 140-180°C. The reaction was carried out for 6-10 hours with stirring. The reactor was then cooled to room temperature, the pressure was released, and the solid and liquid were separated by filtration. The solid was washed successively with water and anhydrous ethanol, and dried to obtain the black phosphorus-based catalyst for reuse. The liquid contained the target product.
2. The method according to claim 1, characterized in that: The ratio of the black phosphorus-based catalyst, unsaturated compound, and solvent is 30 mg: 40-80 mg: 2-4 mL.
3. The method according to claim 1 or 2, characterized in that: The unsaturated compound is nitrobenzene, p-chloronitrobenzene, o-chloronitrobenzene, m-chloronitrobenzene, p-nitrophenol, o-nitrophenol, m-nitrophenol, p-nitroanisole, p-nitrophenylacetonitrile, dimethyl sulfoxide, diphenyl sulfoxide, ethylene, propylene, styrene, acetylene, propyne, benzaldehyde, acetophenone, acrolein, vanillin, crotonaldehyde, or cinnamaldehyde.
4. The method according to claim 1 or 2, characterized in that: The solvent is ethanol, tetrahydrofuran, 1,4-dioxane, n-hexane, toluene, cyclohexane, or an aqueous solution of ethanol.
5. The method according to claim 1 or 2, characterized in that: The black phosphorus-based catalyst is prepared by the following steps: (1) Disperse 2-4g of red phosphorus in 60mL of deionized water according to the proportion, sonicate for 30 minutes, then transfer to 100mL of hydrothermal reactor, tighten the seal, transfer to a forced-air drying oven, react at 180℃ for 10 hours, cool to room temperature, filter to remove the supernatant, and vacuum dry to obtain red phosphorus precursor with oxide layer removed; (2) Disperse 1-2g of the red phosphorus precursor for removing the oxide layer in 60-70mL of ethylenediamine according to the proportion, stir at room temperature for 1 hour to obtain a mixture; (3) Transfer the mixture to a hydrothermal reactor, tighten the seal, transfer it to a forced-air drying oven, react at 140-180℃ for 6-12 hours, and after cooling to room temperature, wash it by centrifugation with deionized water and anhydrous ethanol in sequence, and dry it under vacuum at 50℃ for 6 hours to obtain the black phosphorus-based catalyst.