Monatomic Rh polymer catalyst as well as preparation method and application thereof

Abstract

The invention discloses a monatomic Rh polymer catalyst as well as a preparation method and application thereof, and relates to the technical field of catalyst preparation. The catalyst comprises an active component and a carrier, the active component is rhodium metal, the carrier is a polymer containing a phosphine ligand, and the catalyst is of a microporous structure. The monatomic Rh polymer catalyst can realize efficient conversion of common olefin compounds under relatively mild conditions, has high activity and high aldehyde forming selectivity in a hydroformylation reaction, can be stably circulated for more than 5 times, and effectively solves the problems of catalyst separation and recovery. In a hydrosilylation reaction, a terminal silane product is selectively generated, and the method is an effective method for preparing an organosilicon reagent. The invention solves the problem of poor stability and activity of the existing heterogeneous catalyst.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst preparation, and in particular to a single-atom Rh polymer catalyst and a preparation method and application thereof. Background Art

[0002] The hydroformylation of olefins is considered one of the most important and efficient processes for the production of aldehydes, which are key intermediates in the synthesis of esters, alcohols, carboxylic acids, aliphatic amines, and various other fine chemicals. In addition, the hydrosilylation of olefins is an efficient method for the synthesis of organosilicon reagents, a class of compounds widely used in the production of consumer products and commercial chemicals. The functionalization of olefins using homogeneous precious metal catalysts is a very effective strategy for the production of value-added products. Rhodium-based homogeneous catalysts, known for their excellent catalytic activity and chemoselectivity, have been successfully applied to processes such as hydroformylation and hydrosilylation, and have achieved significant progress. However, the separation of Rh catalysts from the products by distillation is energy-consuming and there is a risk of catalyst decomposition. Therefore, it is important to design new Rh-based heterogeneous catalysts to improve their stability and recyclability.

[0003] Rh-based heterogeneous catalysts have the advantages of high metal loading rate, convenient separation and recovery. At present, Rh-based catalyst heterogeneous carriers include two major categories: inorganic carriers and organic carriers. Heterogeneous Rh catalysts loaded on inorganic solids, such as carbon materials, SiO2, g-C3N4 and molecular sieves, are simple to synthesize and separate. However, these catalysts have the problems of low activity and poor stability, and it is necessary to further improve the utilization efficiency of precious metals and the stability of catalysts. In recent years, loading Rh catalysts on organic carriers such as metal organic frameworks, covalent organic frameworks and porous organic polymers has attracted widespread attention from scholars. First, these materials have large surface area and porosity, which is conducive to the presence of more Rh active sites. Secondly, the strong framework structure of organic materials can improve the problem of rhodium metal leaching. In particular, porous organic polymers with covalent bonds are widely used as supporting materials for metal catalysts because of their high surface area and porosity, diversified synthesis methods, customizable structure, strong stability, easy separation and recyclability. In addition, achieving single-atom dispersion of Rh can significantly improve the atomic utilization of precious metals, so it is crucial to develop new Rh-based single-atom catalysts with a strong polymer framework to enhance catalyst stability and activity. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a single-atom Rh polymer catalyst and a preparation method and application thereof, so as to solve the problems of poor stability and activity of existing multiphase catalysts.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: a single-atom Rh polymer catalyst is provided, the catalyst includes an active component and a carrier, the active component is rhodium metal, the carrier is a polymer containing a phosphine ligand, there is coordination between the polymer containing the phosphine ligand and the rhodium metal, and the catalyst has a microporous structure.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows:

[0007] Furthermore, the content of rhodium metal in the catalyst is 0.7-4.3 wt%.

[0008] Furthermore, the content of rhodium metal in the catalyst was 2.3 wt%.

[0009] Furthermore, the main pore size of the microporous structure is 0.62-1.42 nm, and the pore volume is 0.65-0.87 cm 3 / g, specific surface area is 582-683m 2 / g.

[0010] The present invention also provides a method for preparing the above-mentioned single-atom Rh polymer catalyst, comprising the following steps:

[0011] (1) dissolving a phosphine-containing ligand and a cyano ligand in an organic solvent, adding an alkaline solution, and ultrasonically treating to obtain a mixed solution;

[0012] (2) freezing, degassing and thawing the mixed solution obtained in step (1) in sequence, heating it to room temperature under vacuum, standing it at 100-130° C., and then filtering, washing, purifying and vacuum drying it in sequence to obtain a polymer carrier;

[0013] (3) dissolving the polymer support and rhodium precursor obtained in step (2) in an organic solvent, reacting for 15-20 hours under an inert gas and 35-45° C., and then filtering, washing and drying in sequence to obtain Rh@POP, i.e., a single-atom Rh polymer catalyst.

[0014] Furthermore, in step (1), the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution is 1 mol: 1-1.5 mol: 3-5 mL: 0.2-0.5 mL.

[0015] Furthermore, in step (1), the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution is 1 mol: 1 mol: 4 mL: 0.4 mL.

[0016] Furthermore, in step (1), the phosphine-containing ligand is tri(4-formylphenyl)phosphine, tri(3-formylphenyl)phosphine or tri(2-formylphenyl)phosphine.

[0017] Furthermore, in step (1), the cyano ligand is 1,3,5-tris(4-cyanomethylphenyl)benzene, 2,2'-([1,1':4',1"-triphenyl]-4,4'-diyl)diacetonitrile, 4,4'-biphenyldiacetonitrile or 4-cyanobenzeneacetonitrile.

[0018] Furthermore, in step (1), the organic solvent is a mixed solution of o-dichlorobenzene and n-butanol.

[0019] Furthermore, the volume ratio of o-dichlorobenzene to n-butanol in the organic solvent is 1-5:1.

[0020] Furthermore, the volume ratio of o-dichlorobenzene to n-butanol in the organic solvent is 3:1.

[0021] Furthermore, in step (1), the concentration of the alkaline solution is 0.1-4 mol / L.

[0022] Furthermore, in step (1), the base is potassium tert-butyl alcohol, sodium hydroxide, potassium hydroxide, cesium carbonate or 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0023] Furthermore, in step (1), ultrasonication is performed for 8-12 minutes.

[0024] Furthermore, in step (1), ultrasonication is performed for 10 minutes.

[0025] Furthermore, in step (2), the freezing, degassing and thawing cycles are performed three times.

[0026] Furthermore, in step (2), a Pyrex tube is used for sealing to obtain vacuum conditions.

[0027] Furthermore, in step (2), the mixture is allowed to stand at 120°C.

[0028] Further, in step (2), the mixture is allowed to stand for 2-4 days.

[0029] Furthermore, in step (2), the mixture is allowed to stand for 3 days.

[0030] Furthermore, in step (2), dimethylformamide, water, tetrahydrofuran and ethanol are used for washing in sequence.

[0031] Further, in step (2), washing is performed 2-4 times.

[0032] Furthermore, in step (2), Soxhlet extraction is performed in tetrahydrofuran for 10-15 hours to complete the purification process.

[0033] Furthermore, in step (2), Soxhlet extraction is performed in tetrahydrofuran for 12 hours to complete the purification process.

[0034] Furthermore, in step (3), the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 1-20 mol: 1 mol: 10-25 mL.

[0035] Furthermore, in step (3), the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 5 mol:1 mol:15 mL.

[0036] Furthermore, in step (3), the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 10 mol: 1 mol: 15 mL.

[0037] Furthermore, in step (3), the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 20 mol:1 mol:15 mL.

[0038] Furthermore, in step (3), the rhodium precursor is HRh(CO)(TPP)3, [Rh(cod)Cl]2, [RhCl(CH2=CH2)2]2, Rh(acac)(CO)2, Rh(acac)(CH2=CH2)2 or [Rh(Cp*)Cl2]2, wherein acac is acetylacetone, Cp* is pentamethylcyclopentadiene, and cod is 1,4-cyclooctadiene.

[0039] Furthermore, in step (3), the reaction is carried out under inert gas and 40° C. for 18 h.

[0040] Furthermore, in step (3), the inert gas is argon or nitrogen.

[0041] Furthermore, in step (3), the organic solvent is tetrahydrofuran, 1,4-dioxane or ethanol.

[0042] Furthermore, in step (3), dimethylformamide, water, tetrahydrofuran and ethanol are used for washing in sequence.

[0043] Further, in step (3), washing is performed 2-4 times.

[0044] The present invention also provides the use of the single-atom Rh polymer catalyst in catalysis of olefin hydroformylation reaction or olefin hydrosilylation reaction.

[0045] Furthermore, the olefin hydroformylation reaction includes the following steps: mixing the olefin, the single-atom Rh polymer catalyst and the organic solvent, reacting at 40-120° C. for 2-6 hours in a 2-4 MPa synthesis gas atmosphere, filtering, and obtaining a filtrate product and the single-atom Rh polymer catalyst.

[0046] Furthermore, the molar volume ratio of olefin to single-atom Rh polymer catalyst is 2000-15000:1.

[0047] Furthermore, the olefin is at least one of a terminal olefin, an aromatic olefin and a cyclic olefin.

[0048] Furthermore, the organic solvent is at least one of toluene, chloroform, tetrahydrofuran, 1,4-dioxane, diethyl ether, xylene, trimethylbenzene and acetonitrile.

[0049] Furthermore, the synthesis gas is a mixed gas of CO and H2 in a volume ratio of 1-3:1-5.

[0050] Furthermore, the synthesis gas is a mixed gas of CO and H2 in a volume ratio of 1:1.

[0051] Furthermore, the olefin hydrosilylation reaction includes the following steps: mixing the olefin, the single-atom Rh polymer catalyst and the hydrosilylation raw material, reacting at 75-85° C. for 10-15 hours under a nitrogen atmosphere, filtering, and obtaining a filtrate product and the single-atom Rh polymer catalyst.

[0052] Further, the reaction was carried out at 80°C for 12h.

[0053] Furthermore, the molar ratio of olefin to single-atom Rh polymer catalyst is 200-1000:1.

[0054] Furthermore, the olefin is at least one of a terminal olefin, an aromatic olefin and a cyclic olefin.

[0055] Furthermore, the hydrosilylation raw material is at least one of dimethyl(phenyl)silane, diphenylmethylsilane and triethoxysilane.

[0056] The present invention has the following beneficial effects:

[0057] 1. The single-atom Rh polymer catalyst prepared by the present invention has high activity and high selectivity; and its structure is stable. After 5 cycles, there is no obvious change in the catalyst structure and catalytic performance.

[0058] 2. The single-atom Rh polymer catalyst prepared by the present invention is a heterogeneous catalyst. Since the catalyst is a solid powder, and the reaction raw materials and products are liquid or gas, they can be separated by simple centrifugal filtration, which greatly reduces the separation cost of the catalyst and improves the catalyst separation efficiency.

[0059] 3. The carrier of the single-atom Rh polymer catalyst of the present invention is synthesized by Knoevenagel condensation reaction of formyl-functionalized PPh3 and diacetonitrile under base catalysis. This high-surface-area porous structure phosphine ligand polymer has a strong coordination effect with metal Rh, and can achieve high-content Rh atomic dispersion.

[0060] 4. The single-atom Rh polymer catalyst can achieve efficient conversion of common olefin compounds under relatively mild conditions. It has high reactivity for chain-end olefins, aromatic olefins and cyclic olefins, and exhibits excellent catalytic performance in heterogeneous catalytic hydroformylation and hydrosilylation of olefins. In the hydroformylation reaction, it has high activity and high selectivity for aldehyde formation, and can be stably cycled for more than 5 times, effectively solving the problem of catalyst separation and recovery. In the hydrosilylation reaction, the terminal silane product is selectively generated, which is an effective method for preparing organosilicon reagents. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The preparation process of the single-atom Rh polymer catalyst prepared in Example 1;

[0062] Figure 2 This is a spherical aberration electron microscope image of the single-atom Rh polymer catalyst prepared in Example 1;

[0063] Figure 3 This is the infrared spectrum of the single-atom Rh polymer catalyst prepared in Example 1. DETAILED DESCRIPTION

[0064] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0065] The structural formula of the phosphine-containing ligand is:

[0066]

[0067] The structural formula of cyano ligand is:

[0068]

[0069] Embodiment 1:

[0070] A method for preparing a single-atom Rh polymer catalyst comprises the following steps: (reaction formula see Figure 1 )

[0071] (1) In a Pyrex tube, a phosphine-containing ligand (tri(4-formylphenyl)phosphine) and a cyano ligand (1,3,5-tri(4-cyanomethylphenyl)benzene) were dissolved in an organic solvent (a mixed solution of o-dichlorobenzene and n-butanol in a volume ratio of 3:1), and a 3 mol / L alkaline solution (1,8-diazabicyclo[5.4.0]undec-7-ene) was added, and ultrasonic treatment was performed for 10 min to obtain a mixed solution; wherein the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution was 1 mol: 1 mol: 4 mL: 0.4 mL;

[0072] (2) The mixed solution obtained in step (1) was sequentially frozen, degassed and thawed, and the operation was repeated three times, and the tube was sealed to obtain a vacuum condition. After the temperature was raised to room temperature, the test tube was placed in an oven at 120° C. and allowed to stand for 3 days. The precipitate was then collected by filtration and washed with dimethylformamide, water, tetrahydrofuran and ethanol in turn for three times. The obtained precipitate was subjected to Soxhlet extraction in tetrahydrofuran for 12 hours to complete the purification process, and then vacuum dried to obtain a yellow powdery polymer carrier (POP);

[0073] (3) The polymer carrier and rhodium precursor (Rh(acac)(CO)2) obtained in step (2) are dissolved in an organic solvent (tetrahydrofuran), reacted under an inert gas nitrogen atmosphere at 40°C for 18 hours, and then filtered to collect the precipitate, washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence for 3 times, and then vacuum dried to obtain Rh@POP, i.e., a single-atom Rh polymer catalyst (the content of rhodium metal is 2.3wt%, measured by inductively coupled plasma emission spectrometry); wherein the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 5mol:1mol:15mL.

[0074] Embodiment 2:

[0075] A method for preparing a single-atom Rh polymer catalyst comprises the following steps:

[0076] (1) In a Pyrex tube, a phosphine-containing ligand (tri(4-formylphenyl)phosphine) and a cyano ligand (1,3,5-tri(4-cyanomethylphenyl)benzene) are dissolved in an organic solvent (a mixed solution of o-dichlorobenzene and n-butanol in a volume ratio of 2:1), and a 4 mol / L alkaline solution (sodium hydroxide) is added, and ultrasonic treatment is performed for 10 min to obtain a mixed solution; wherein the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution is 1 mol: 1.5 mol: 4 mL: 0.5 mL;

[0077] (2) The mixed solution obtained in step (1) was sequentially frozen, degassed and thawed, and the operation was repeated three times, and the tube was sealed to obtain a vacuum condition. After the temperature was raised to room temperature, the test tube was placed in an oven at 120° C. and allowed to stand for 3 days. The precipitate was then collected by filtration and washed with dimethylformamide, water, tetrahydrofuran and ethanol in turn for three times. The obtained precipitate was subjected to Soxhlet extraction in tetrahydrofuran for 12 hours to complete the purification process, and then vacuum dried to obtain a yellow powdery polymer carrier (POP);

[0078] (3) The polymer carrier obtained in step (2) and the rhodium precursor ([Rh(cod)Cl]2) are dissolved in an organic solvent (tetrahydrofuran), reacted under an inert gas nitrogen atmosphere at 40°C for 18 hours, and then filtered to collect the precipitate, washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence for 3 times, and then vacuum dried to obtain Rh@POP, i.e., a single-atom Rh polymer catalyst (the content of rhodium metal is 1.2wt%, measured by inductively coupled plasma emission spectrometry); wherein the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 10mol:1mol:15mL.

[0079] Embodiment 3:

[0080] A method for preparing a single-atom Rh polymer catalyst comprises the following steps:

[0081] (1) In a Pyrex tube, a phosphine-containing ligand (tri(3-formylphenyl)phosphine) and a cyano ligand (4-cyanobenzeneacetonitrile) are dissolved in an organic solvent (a mixed solution of o-dichlorobenzene and n-butanol in a volume ratio of 4:1), and an alkaline solution (cesium carbonate) with a concentration of 0.1 mol / L is added, and ultrasonic treatment is performed for 10 min to obtain a mixed solution; wherein the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution is 1 mol:1.5 mol:4 mL:0.2 mL;

[0082] (2) The mixed solution obtained in step (1) was sequentially frozen, degassed and thawed, and the operation was repeated three times, and the tube was sealed to obtain a vacuum condition. After the temperature was raised to room temperature, the test tube was placed in an oven at 120° C. and allowed to stand for 3 days. The precipitate was then collected by filtration and washed with dimethylformamide, water, tetrahydrofuran and ethanol in turn for three times. The obtained precipitate was subjected to Soxhlet extraction in tetrahydrofuran for 12 hours to complete the purification process, and then vacuum dried to obtain a yellow powdery polymer carrier (POP);

[0083] (3) The polymer carrier obtained in step (2) and the rhodium precursor (Rh(acac)(CO)2) are dissolved in an organic solvent (tetrahydrofuran), reacted under an inert gas nitrogen atmosphere at 40°C for 18 hours, and then filtered to collect the precipitate, washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence for 3 times, and then vacuum dried to obtain Rh@POP, i.e., a single-atom Rh polymer catalyst (the content of rhodium metal is 0.7wt%, measured by inductively coupled plasma emission spectrometry); wherein the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 20mol:1mol:15mL.

[0084] Embodiment 4:

[0085] A method for preparing a single-atom Rh polymer catalyst comprises the following steps:

[0086] (1) In a Pyrex tube, a phosphine-containing ligand (tri(2-formylphenyl)phosphine) and a cyano ligand (2,2'-([1,1':4',1"-triphenyl]-4,4'-diyl)diacetonitrile) were dissolved in an organic solvent (a mixed solution of o-dichlorobenzene and n-butanol in a volume ratio of 1:1), and an alkaline solution (potassium tert-butyl alcohol) with a concentration of 0.1 mol / L was added, and ultrasonic treatment was performed for 8 min to obtain a mixed solution; wherein the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution was 1 mol:1.5 mol:3 mL:0.2 mL;

[0087] (2) The mixed solution obtained in step (1) is sequentially frozen, degassed and thawed, and the operation is repeated three times, and the tube is sealed to obtain a vacuum condition. After the temperature is raised to room temperature, the test tube is placed in an oven at 100° C. and allowed to stand for 4 days. The precipitate is then collected by filtration and washed with dimethylformamide, water, tetrahydrofuran and ethanol in turn for two times. The obtained precipitate is subjected to Soxhlet extraction in tetrahydrofuran for 10 hours to complete the purification process, and then vacuum dried to obtain a yellow powdery polymer carrier (POP);

[0088] (3) The polymer carrier and rhodium precursor (HRh(CO)(TPP)3) obtained in step (2) are dissolved in an organic solvent (1,4-dioxane), reacted under an inert gas nitrogen atmosphere at 35°C for 20 hours, and then filtered to collect the precipitate, washed with dimethylformamide, water, tetrahydrofuran and ethanol in turn, washed twice, and then vacuum dried to obtain Rh@POP, i.e., a single-atom Rh polymer catalyst (the content of rhodium metal is 4.3wt%, measured by inductively coupled plasma emission spectrometry); wherein the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 2mol:1mol:10mL.

[0089] Embodiment 5:

[0090] A method for preparing a single-atom Rh polymer catalyst comprises the following steps:

[0091] (1) In a Pyrex tube, a phosphine-containing ligand (tri(4-formylphenyl)phosphine) and a cyano ligand (1,3,5-tri(4-cyanomethylphenyl)benzene) are dissolved in an organic solvent (a mixed solution of o-dichlorobenzene and n-butanol in a volume ratio of 3:1), and a 3 mol / L alkaline solution (potassium hydroxide) is added, and ultrasonic treatment is performed for 12 min to obtain a mixed solution; wherein the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution is 1 mol: 1.2 mol: 5 mL: 0.4 mL;

[0092] (2) The mixed solution obtained in step (1) was sequentially frozen, degassed and thawed, and the operation was repeated for 3 times, and the tube was sealed to obtain a vacuum condition. After the temperature was raised to room temperature, the test tube was placed in an oven at 130° C. and allowed to stand for 2 days. The precipitate was then collected by filtration and washed with dimethylformamide, water, tetrahydrofuran and ethanol in turn for 4 times. The obtained precipitate was Soxhlet extracted in tetrahydrofuran for 12 hours to complete the purification process, and then vacuum dried to obtain a yellow powdery polymer carrier (POP);

[0093] (3) The polymer carrier obtained in step (2) and the rhodium precursor ([Rh(cod)Cl]2) are dissolved in an organic solvent (ethanol), reacted under an inert gas nitrogen atmosphere at 45°C for 15 hours, and then the precipitate is collected by filtration, washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence for 4 times, and then vacuum dried to obtain Rh@POP, i.e., a single-atom Rh polymer catalyst (the content of rhodium metal is 0.8wt%, measured by inductively coupled plasma emission spectrometry); wherein the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 20mol:1mol:25mL.

[0094] Comparative Example 1:

[0095] Commercially available 10% Rh / C catalyst.

[0096] Test example

[0097] 1. The single-atom Rh polymer catalyst prepared in Example 1 was tested by spherical aberration electron microscopy and infrared spectroscopy. The results are shown in Figure 2-3 .

[0098] Depend on Figure 2 It can be seen that many bright atomic dots appear in the spherical aberration electron microscopy image, which shows that the single Rh atom has good dispersion on the polymer network, indicating the successful synthesis of the single atom Rh catalyst.

[0099] Depend on Figure 3It can be seen that the characteristic peaks of carbon-carbon double bonds, cyanide and rhodium carbonyl groups in the infrared spectrum characterize the specific structure of the single-atom Rh catalyst.

[0100] 2. Catalytic performance

[0101] The single-atom Rh polymer catalysts prepared in Examples 1-3 and the commercially available 10% Rh / C catalyst in Comparative Example 1 were respectively used to carry out the hydroformylation reaction of 1-octene, and the reaction comprises the following steps:

[0102] 4mmol 1-octene, 4mg single-atom Rh polymer catalyst and 4mL toluene were added to a high-pressure reactor with magnetic stirring, and the air in the reactor was replaced with synthesis gas (a mixture of CO and H2 with a volume ratio of 1:1). The replacement was repeated 3 times, and then 4MPa of synthesis gas was filled in. The reaction was carried out at 100℃ for 4h. The reaction equation is as follows:

[0103]

[0104] After the reaction, the mixture was centrifuged and filtered, and the filtrate was tested for olefin conversion and aldehyde yield by gas chromatography (GC). The results are shown in Table 1.

[0105] Table 1 Catalyst performance test results

[0106] catalyst Conversion rate (%) Formaldehyde rate (%) <![CDATA[TOF(h -1 )]]> Example 1 99 96 716 Example 2 99 89 355 Example 3 99 60 1470 Comparative Example 1 99 54 93

[0107] TOF = moles of aldehyde / (moles of Rh loaded on single metal active sites) / reaction time.

[0108] 3. Cycle Performance

[0109] The single-atom Rh polymer catalyst prepared in Example 1 was subjected to a hydroformylation reaction of 1-octene, and a cyclic test was performed. The reaction included the following steps:

[0110] S1: 8 mmol of olefin, 8 mg of single-atom Rh polymer catalyst and 4 mL of toluene were added to a high-pressure reactor with magnetic stirring, and the air in the reactor was replaced with synthesis gas (a mixture of CO and H2 in a volume ratio of 1:1). The replacement was repeated 3 times, and then 3 MPa of synthesis gas was filled in and reacted at 80°C for 6 h.

[0111] After the reaction, the mixture was centrifuged and filtered, and the filtrate was measured for olefin conversion and aldehyde yield by gas chromatography (GC).

[0112] S2: The filter cake obtained in step S1 is washed with ethanol for 3 times, and then used as a catalyst for a new round, and step S1 is repeated until it is repeated 4 times.

[0113] The results are shown in Table 2.

[0114] Table 2 Cyclic performance test results of catalysts

[0115]

[0116]

[0117] TOF = moles of aldehyde / (moles of Rh loaded on single metal active sites) / reaction time.

[0118] 4. Hydroformylation of different olefins

[0119] The single-atom Rh polymer catalyst prepared in Example 1 was subjected to hydroformylation reactions of different olefins, and the reactions included the following steps:

[0120] 4 mmol of olefin, 4 mg of single-atom Rh polymer catalyst and 4 mL of toluene were added to a high-pressure reactor with magnetic stirring, and the air in the reactor was replaced with synthesis gas (a mixture of CO and H2 with a volume ratio of 1:1). The replacement was repeated 3 times, and then 4 MPa of synthesis gas was filled in. The reaction was carried out at 90 ° C for 5 h. The reaction equation is as follows:

[0121]

[0122] After the reaction, the mixture was centrifuged and filtered, and the filtrate was used to detect the conversion rate of olefins and the yield of aldehydes by gas chromatography (GC). The results are shown in Table 3.

[0123] Table 3 Test results of catalyst performance of different substrates

[0124] Olefins Conversion rate (%) Formaldehyde rate (%) <![CDATA[TOF(h -1 )]]> 1-Hexene 99 96 716 1-Octene 99 96 716 Styrene 99 99 738 p-Methoxystyrene 99 85 634 Cyclohexene 99 99 738

[0125] TOF = moles of aldehyde / (moles of Rh loaded on single metal active sites) / reaction time.

[0126] 5. Hydrosilylation of different olefins

[0127] The single-atom Rh polymer catalyst prepared in Example 1 was subjected to hydrosilylation reaction of different olefins, and the reaction included the following steps:

[0128] 0.6 mmol olefin, 4 mg single atom Rh polymer catalyst and 2 mL dimethyl (phenyl) silane were added to the Schlenk tube, and the air in the tube was replaced with nitrogen. The replacement was repeated 3 times and nitrogen was filled in. The reaction was carried out at 80 ° C for 12 h. The reaction equation is as follows:

[0129]

[0130] After the reaction, the mixture was briefly centrifuged and filtered. The conversion rate of olefins and the yield of terminal silane were detected by gas chromatography (GC). The results are shown in Table 4.

[0131] Table 4 Performance test results of different substrate catalysts

[0132] Olefins Conversion rate (%) Yield (%) <![CDATA[TOF(h -1 )]]> 1-Hexene 90 87 104 1-Octene 91 88 105 1-Decene 89 81 97 1-Dodecene 84 77 92 Styrene 90 68 81 p-Methoxystyrene 85 57 68

[0133] TOF = number of moles of product / (number of moles of Rh loaded on single metal active sites) / reaction time.

[0134] In summary, it can be seen from Tables 1-4 that the single-atom Rh polymer catalyst of the present invention has high catalytic activity and yield for chain-end olefins, aromatic olefins and cyclic olefins, is easy to separate and recover, and has no significant performance degradation after 5 catalytic cycles.

[0135] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A single-atom Rh polymer catalyst, characterized in that: The catalyst comprises an active component and a carrier, wherein the active component is rhodium metal, the carrier is a polymer containing a phosphine ligand, coordination exists between the polymer containing the phosphine ligand and the rhodium metal, and the catalyst is a microporous structure.

2. The method for preparing the single-atom Rh polymer catalyst according to claim 1, characterized in that: The following steps are involved: (1) dissolving a phosphine-containing ligand and a cyano ligand in an organic solvent, adding an alkaline solution, and ultrasonically treating to obtain a mixed solution; (2) freezing, degassing and thawing the mixed solution obtained in step (1) in sequence, heating it to room temperature under vacuum, standing it at 100-130° C., and then filtering, washing, purifying and vacuum drying it in sequence to obtain a polymer carrier; (3) dissolving the polymer support and rhodium precursor obtained in step (2) in an organic solvent, reacting for 15-20 hours under an inert gas and 35-45° C., and then filtering, washing and drying in sequence to obtain Rh@POP, i.e., a single-atom Rh polymer catalyst.

3. The method for preparing the single-atom Rh polymer catalyst according to claim 2, characterized in that: In step (1), the molar volume ratio of the phosphine-containing ligand, the cyano ligand, the organic solvent and the alkaline solution is 1 mol: 1-1.5 mol: 3-5 mL: 0.2-0.5 mL.

4. The method for preparing the single-atom Rh polymer catalyst according to claim 2, characterized in that: In step (1), the phosphine-containing ligand is tri(4-formylphenyl)phosphine, tri(3-formylphenyl)phosphine or tri(2-formylphenyl)phosphine.

5. The method for preparing the single-atom Rh polymer catalyst according to claim 2, characterized in that: In step (1), the cyano ligand is 1,3,5-tris(4-cyanomethylphenyl)benzene, 2,2'-([1,1':4',1"-triphenyl]-4,4'-diyl)diacetonitrile, 4,4'-biphenyldiacetonitrile or 4-cyanobenzeneacetonitrile.

6. The method for preparing the single-atom Rh polymer catalyst according to claim 2, characterized in that: In step (3), the molar volume ratio of the polymer carrier, the rhodium precursor and the organic solvent is 1-20 mol: 1 mol: 10-25 mL.

7. The method for preparing the single-atom Rh polymer catalyst according to claim 2, characterized in that: In step (3), the rhodium precursor is HRh(CO)(TPP)3, [Rh(cod)Cl]2, [RhCl(CH2=CH2)2]2, Rh(acac)(CO)2, Rh(acac)(CH2=CH2)2 or [Rh(Cp*)Cl2]2, wherein acac is acetylacetone, Cp* is pentamethylcyclopentadiene, and cod is 1,4-cyclooctadiene.

8. Use of the single-atom Rh polymer catalyst according to claim 1 in catalysis of olefin hydroformylation reaction or olefin hydrosilylation reaction.

9. Use of the single-atom Rh polymer catalyst according to claim 8 in catalysis of olefin hydroformylation reaction or olefin hydrosilylation reaction, characterized in that: The olefin hydroformylation reaction The method comprises the following steps: mixing olefin, single-atom Rh polymer catalyst and organic solvent, reacting at 40-120° C. for 2-6 hours in a 2-4 MPa synthesis gas atmosphere, filtering, and obtaining a filtrate product and a single-atom Rh polymer catalyst.

10. Use of the single-atom Rh polymer catalyst according to claim 8 in catalysis of olefin hydroformylation reaction or olefin hydrosilylation reaction, characterized in that: The olefin hydrosilylation reaction The method comprises the following steps: mixing olefin, single-atom Rh polymer catalyst and hydrosilylation raw material, reacting for 10-15 hours at 75-85° C. under nitrogen atmosphere, filtering and obtaining filtrate product and single-atom Rh polymer catalyst.

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