Monatomic rh polymer catalyst, its preparation method and application

Abstract

The application discloses a single-atom Rh polymer catalyst and 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 a rhodium metal, the carrier is a phosphine ligand-containing polymer, and the catalyst is of a microporous structure. The single-atom Rh polymer catalyst can realize efficient conversion of common olefin compounds under relatively mild conditions, has high activity and high aldehyde formation 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, the selectivity of terminal silane products is generated, and the single-atom Rh polymer catalyst is an effective method for preparing organosilicon reagents. The application solves the problems of poor stability and activity of existing heterogeneous catalysts.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a single-atom Rh polymer catalyst, its preparation method, and its application. Background Technology

[0002] Hydroformylation of olefins is considered one of the most important and efficient methods for producing aldehydes, which are key intermediates in the synthesis of esters, alcohols, carboxylic acids, aliphatic amines, and various other fine chemicals. Furthermore, hydrosilylation of olefins is an effective method for synthesizing organosilicon reagents, a class of compounds widely used in the production of consumer and commercial chemicals. The functionalization of olefins using homogeneous noble metal catalysts is a highly effective strategy for producing value-added products. Rhodium-based homogeneous catalysts, renowned for their excellent catalytic activity and chemoselectivity, have been successfully applied in processes such as hydroformylation and hydrosilylation, achieving significant progress. However, separating Rh catalysts from products by distillation is energy-intensive and carries the risk of catalyst decomposition. Therefore, designing novel Rh-based heterogeneous catalysts to improve their stability and recyclability is crucial.

[0003] Rh-based heterogeneous catalysts possess advantages such as high metal loading rates and convenient separation and recovery. Currently, heterogeneous supports for Rh-based catalysts are broadly classified into inorganic and organic supports. Heterogeneous Rh catalysts supported on inorganic solids, such as carbon materials, SiO2, g-C3N4, and molecular sieves, are simple to synthesize and separate. However, these catalysts suffer from low activity and poor stability, necessitating further improvements in the utilization efficiency of precious metals and the stability of the catalysts. In recent years, supporting Rh catalysts on organic supports such as metal-organic frameworks, covalent organic frameworks, and porous organic polymers has attracted widespread attention. Firstly, these materials possess large surface areas and porosities, which are conducive to the presence of more Rh active sites. Secondly, the robust framework structure of organic materials can improve the rhodium metal leaching problem. In particular, porous organic polymers with covalent bonds are widely used as supporting materials for metal catalysts due to their high surface area and porosity, diverse synthesis methods, customizable structures, robust stability, ease of separation, and recyclability. Furthermore, achieving single-atom dispersion of Rh can significantly improve the atomic utilization of noble metals. Therefore, it is crucial to develop novel rhodium-based single-atom catalysts with robust polymer frameworks to enhance catalyst stability and activity. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a single-atom Rh polymer catalyst, its preparation method, and its application, thereby solving the problems of poor stability and activity of existing heterogeneous catalysts.

[0005] The technical scheme for solving the above technical problems is as follows: a monatomic Rh polymer catalyst is provided, the catalyst comprising an active component and a carrier, the active component being a rhodium metal, and the carrier being a phosphine ligand-containing polymer, coordination existing between the phosphine ligand-containing polymer and the rhodium metal, and the catalyst being a microporous structure.

[0006] On the basis of the above technical scheme, the application can also be improved as follows:

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

[0008] Further, the content of the rhodium metal in the catalyst is 2.3wt%.

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

[0010] The application also provides a preparation method of the above monatomic Rh polymer catalyst, comprising the following steps:

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

[0012] (2) sequentially performing freezing, degassing and thawing on the mixed solution prepared in step (1), under vacuum, heating to room temperature, and then standing at 100-130℃, and then sequentially performing filtering, washing, purifying and vacuum drying to prepare a polymer carrier;

[0013] (3) dissolving the polymer carrier prepared in step (2) and a rhodium precursor in an organic solvent, and reacting under the conditions of an inert gas and 35-45℃ for 15-20h, and then sequentially performing filtering, washing and drying to prepare Rh@POP, i.e. the monatomic Rh polymer catalyst.

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

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

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

[0017] Further, 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'-diphenyl diacetonitrile or 4-cyanophenylacetonitrile.

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

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

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

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

[0022] Further, in step (1), the alkali is potassium tert-butoxide, sodium hydroxide, potassium hydroxide, cesium carbonate or 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0023] Further, in step (1), the ultrasonic treatment is performed for 8-12 min.

[0024] Further, in step (1), the ultrasonic treatment is performed for 10 min.

[0025] Further, in step (2), the freeze, degassing and thawing cycle operation is performed for 3 times.

[0026] Further, in step (2), the tube is sealed by using a pyrex tube to obtain a vacuum condition.

[0027] Further, in step (2), the standing is performed at 120°C.

[0028] Further, in step (2), the standing is performed for 2-4 days.

[0029] Further, in step (2), the standing is performed for 3 days.

[0030] Further, in step (2), the washing is performed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence.

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

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

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

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

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

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

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

[0038] Further, 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] Further, in step (3), the reaction is carried out under inert gas and at 40℃ for 18 h.

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

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

[0042] Further, in step (3), the washing is carried out with dimethylformamide, water, tetrahydrofuran and ethanol in sequence.

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

[0044] The present application also provides the use of the monatomic Rh polymer catalyst as described above in the catalysis of olefin hydroformylation or olefin hydrosilication.

[0045] Further, the olefin hydroformylation comprises the following steps: mixing olefin, monatomic Rh polymer catalyst and organic solvent, and reacting under 2-4 MPa of synthesis gas atmosphere at 40-120℃ for 2-6 h, and filtering to obtain filtrate product and monatomic Rh polymer catalyst.

[0046] Further, the molar volume ratio of the olefin and the monatomic Rh polymer catalyst is 2000-15000: 1.

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

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

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

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

[0051] Further, the olefin hydrosilylation reaction comprises the following steps: mixing the olefin, the monatomic Rh polymer catalyst and the hydrosilylation raw material, reacting under a nitrogen atmosphere at 75-85°C for 10-15h, filtering to obtain a filtrate product and the monatomic Rh polymer catalyst.

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

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

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

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

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

[0057] 1. The monatomic Rh polymer catalyst prepared by the present application has high activity and high selectivity, and the structure is stable, and the catalyst structure and catalytic performance do not change significantly after 5 cycles.

[0058] 2. The monatomic Rh polymer catalyst prepared by the present application is a heterogeneous catalyst, since the catalyst is a solid powder, and the reaction raw material and product are both liquid or gas, which can be separated by simple centrifugal filtration, greatly reducing the separation cost of the catalyst, and improving the separation efficiency of the catalyst.

[0059] 3. The carrier of the monatomic Rh polymer catalyst of the present application is synthesized by Knoevenagel condensation reaction of formyl-functionalized PPh3 and diethyl cyanide under the catalysis of a base, and the high-surface-area porous phosphine ligand polymer has strong coordination with the metal Rh, and can realize high-content Rh atom dispersion.

[0060] 4. This single-atom Rh polymer catalyst can achieve efficient conversion of common olefin compounds under relatively mild conditions. It exhibits high reactivity for terminal olefins, aromatic olefins, and cyclic olefins, and demonstrates excellent catalytic performance in heterogeneous hydroformylation and hydrosilylation of olefins. In the hydroformylation reaction, it exhibits high activity and high aldehyde-forming selectivity, and can be stably cycled more than 5 times, effectively solving the problems of catalyst separation and recovery. In the hydrosilylation reaction, it selectively generates terminal silane products, providing an effective method for preparing organosilicon reagents. Attached Figure Description

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

[0062] Figure 2 Aberration-corrected electron microscopy image of the single-atom Rh polymer catalyst prepared in Example 1;

[0063] Figure 3 The image shows the infrared spectrum of the single-atom Rh polymer catalyst prepared in Example 1. Detailed Implementation

[0064] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

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

[0066]

[0067] The structural formula of the cyano ligand is:

[0068]

[0069] Example 1:

[0070] A method for preparing a single-atom Rh polymer catalyst includes the following steps: (reaction formulas are shown in the figure) Figure 1 )

[0071] (1) In a Pyrex tube, a phosphine-containing ligand (tris(4-formylphenyl)phosphine) and a cyano-containing ligand (1,3,5-tris(4-cyanomethylphenyl)benzene) were dissolved in an organic solvent (a mixture of o-dichlorobenzene and n-butanol with a volume ratio of 3:1), and a base solution (1,8-diazabicyclo[5.4.0]undec-7-ene) with a concentration of 3 mol / L 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-containing ligand, the organic solvent and the base solution was 1 mol: 1 mol: 4 mL: 0.4 mL;

[0072] (2) The mixed solution prepared in step (1) was sequentially subjected to freezing, degassing and thawing, and the cycle operation was performed for 3 times, and the tube was sealed for treatment, and the vacuum condition was obtained, and after being warmed to room temperature, the test tube was placed in an oven at 120℃, and was allowed to stand for 3 days, and then the precipitate was collected by filtration, and was sequentially washed with dimethylformamide, water, tetrahydrofuran and ethanol, and the washing was performed for 3 times, and the obtained precipitate was Soxhlet extracted in tetrahydrofuran for 12 h to complete the purification process, and then vacuum drying was performed to obtain a yellow powder-shaped polymer support (POP);

[0073] (3) The polymer support and a rhodium precursor (Rh(acac)(CO)2) obtained in step (2) were dissolved in an organic solvent (tetrahydrofuran), and were allowed to react under the conditions of inert gas nitrogen and 40℃ for 18 h, and then the precipitate was collected by filtration, and was sequentially washed with dimethylformamide, water, tetrahydrofuran and ethanol, and the washing was performed for 3 times, and then vacuum drying was performed to obtain Rh@POP, i.e. a monatomic Rh polymer catalyst (the content of rhodium metal was 2.3 wt%, measured by inductively coupled plasma emission spectrometer); wherein the molar volume ratio of the polymer support, the rhodium precursor and the organic solvent was 5 mol: 1 mol: 15 mL.

[0074] Example 2:

[0075] A preparation method of a monatomic Rh polymer catalyst, comprising the following steps:

[0076] (1) In a Pyrex tube, a phosphine-containing ligand (tris(4-formylphenyl)phosphine) and a cyano-containing ligand (1,3,5-tris(4-cyanomethylphenyl)benzene) were dissolved in an organic solvent (a mixture of o-dichlorobenzene and n-butanol with a volume ratio of 2:1), and a base solution (sodium hydroxide) with a concentration of 4 mol / L 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-containing ligand, the organic solvent and the base solution was 1 mol: 1.5 mol: 4 mL: 0.5 mL;

[0077] (2) The mixed solution prepared in step (1) is subjected to freezing, degassing and thawing in sequence, and the cycle operation is performed 3 times, and the tube is sealed for treatment, vacuum conditions are obtained, and after being warmed to room temperature, the test tube is placed in an oven at 120°C, and is left to stand for 3d, then the precipitate is collected by filtration, and is washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence, and the washing is performed 3 times, the obtained precipitate is Soxhlet extracted in tetrahydrofuran for 12h, the purification process is completed, and then vacuum drying is performed, to obtain a yellow powder-shaped polymer support (POP);

[0078] (3) The polymer support and the rhodium precursor ([Rh(cod)Cl]2) obtained in step (2) are dissolved in an organic solvent (tetrahydrofuran), and are reacted under the conditions of inert gas nitrogen and 40°C for 18h, then the precipitate is collected by filtration, and is washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence, and the washing is performed 3 times, and then vacuum drying is performed, to obtain Rh@POP, that is, a monatomic Rh polymer catalyst (the content of rhodium metal is 1.2wt%, measured by inductively coupled plasma emission spectrometer); wherein the molar volume ratio of the polymer support, the rhodium precursor and the organic solvent is 10mol:1mol:15mL.

[0079] Example 3:

[0080] A preparation method of a monatomic Rh polymer catalyst, comprising the following steps:

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

[0082] (2) The mixed solution prepared in step (1) is subjected to freezing, degassing and thawing in sequence, and the cycle operation is performed 3 times, and the tube is sealed for treatment, vacuum conditions are obtained, and after being warmed to room temperature, the test tube is placed in an oven at 120°C, and is left to stand for 3d, then the precipitate is collected by filtration, and is washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence, and the washing is performed 3 times, the obtained precipitate is Soxhlet extracted in tetrahydrofuran for 12h, the purification process is completed, and then vacuum drying is performed, to obtain a yellow powder-shaped polymer support (POP));

[0083] (3) The polymer support and rhodium precursor (Rh(acac)(CO)2) obtained in step (2) are dissolved in an organic solvent (tetrahydrofuran), and reacted under the conditions of inert gas nitrogen and 40℃ for 18h, and then the precipitate is collected by filtration, washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence, washed for 3 times, and vacuum dried to prepare Rh@POP, i.e. a monatomic Rh polymer catalyst (the content of rhodium metal is 0.7wt%, measured by inductively coupled plasma emission spectrometer); wherein the molar volume ratio of the polymer support, the rhodium precursor and the organic solvent is 20mol:1mol:15mL.

[0084] Example 4:

[0085] A preparation method of a monatomic Rh polymer catalyst, comprising the following steps:

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

[0087] (2) The mixed solution prepared in step (1) is sequentially subjected to freezing, degassing and thawing, and the cycle operation is performed for 3 times, and the tube is sealed and treated under vacuum conditions, and after being warmed to room temperature, the test tube is placed in an oven under the condition of 100℃, and is placed for 4d, and then the precipitate is collected by filtration, and is washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence, and washed for 2 times, and the obtained precipitate is Soxhlet extracted in tetrahydrofuran for 10h to complete the purification process, and then vacuum dried to prepare a yellow powder-shaped polymer support (POP);

[0088] (3) The polymer support and rhodium precursor (HRh(CO)(TPP)3) obtained in step (2) are dissolved in an organic solvent (1,4-dioxane), and reacted under the conditions of inert gas nitrogen and 35℃ for 20h, and then the precipitate is collected by filtration, and is washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence, and washed for 2 times, and vacuum dried to prepare Rh@POP, i.e. a monatomic Rh polymer catalyst (the content of rhodium metal is 4.3wt%, measured by inductively coupled plasma emission spectrometer); wherein the molar volume ratio of the polymer support, the rhodium precursor and the organic solvent is 2mol:1mol:10mL.

[0089] Example 5:

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

[0091] (1) In a Pyrex tube, the phosphine ligand (tris(4-formylphenyl)phosphine) and cyano ligand (1,3,5-tris(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 (potassium hydroxide) was added. The mixture was sonicated for 12 min to obtain a mixed solution. The molar volume ratio of the phosphine ligand, cyano ligand, organic solvent and alkaline solution was 1 mol: 1.2 mol: 5 mL: 0.4 mL.

[0092] (2) The mixed solution obtained in step (1) was frozen, degassed and thawed in sequence, and the cycle was repeated 3 times. The tube was sealed to obtain vacuum conditions. After the temperature was raised to room temperature, the tube was placed in an oven at 130°C and left to stand for 2 days. Then the precipitate was collected by filtration and washed with dimethylformamide, water, tetrahydrofuran and ethanol in sequence. The washing was repeated 4 times. The precipitate was extracted with tetrahydrofuran by Soxhlet extraction for 12 hours to complete the purification process. Then it was dried under vacuum to obtain a yellow powdered polymer carrier (POP).

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

[0094] Comparative Example 1:

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

[0096] Test case

[0097] I. The single-atom Rh polymer catalyst prepared in Example 1 was subjected to spherical aberration electron microscopy and infrared spectroscopy, respectively. The results are shown in the figure. Figures 2-3 .

[0098] Depend on Figure 2 As can be seen, many bright atomic spots appear in the spherical aberration electron microscopy image, which indicates that the individual Rh atoms have 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 bond, cyano group and rhodium carbonyl group in the infrared spectrum characterize the specific structure of the monatomic Rh catalyst.

[0100] II. Catalytic performance

[0101] The monatomic Rh polymer catalyst prepared in Example 1-3 and the commercially available 10% Rh / C catalyst of Comparative Example 1 were subjected to a hydroformylation reaction of 1-octene, and the reaction included the following steps:

[0102] 4 mmol of 1-octene, 4 mg of the monatomic Rh polymer catalyst and 4 mL of toluene were added to a high-pressure reaction kettle with magnetic stirring, the air in the kettle was replaced with synthesis gas (a mixed gas of CO and H2 in a volume ratio of 1:1) for 3 times, and then 4 MPa of synthesis gas was filled, and the reaction was carried out at 100°C for 4 h, and the reaction equation was as follows:

[0103]

[0104] After the reaction, the mixture was centrifuged and filtered, and the filtrate was detected by gas chromatography (GC) for the conversion rate of olefins and the yield of aldehydes, and the results are shown in Table 1.

[0105] Table 1 Test results of catalyst performance

[0106] Catalyst Conversion (%) Aldehyde yield (%) 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 monometallic active sites Rh supported) / reaction time.

[0108] III. Recycling performance

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

[0110] S1: 8 mmol of olefins, 8 mg of the monatomic Rh polymer catalyst and 4 mL of toluene were added to a high-pressure reaction kettle with magnetic stirring, the air in the kettle was replaced with synthesis gas (a mixed gas of CO and H2 in a volume ratio of 1:1) for 3 times, and then 3 MPa of synthesis gas was filled, and the reaction was carried out at 80°C for 6 h.

[0111] After the reaction, the mixture was centrifuged and filtered, and the filtrate was detected by gas chromatography (GC) for the conversion rate of olefins and the yield of aldehydes.

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

[0113] The results are shown in Table 2.

[0114] Table 2 Test results of the catalysts' cycle performance

[0115]

[0116]

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

[0118] Four, Hydroformylation of different olefins

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

[0120] 4 mmol of olefin, 4 mg of monatomic Rh polymer catalyst and 4 mL of toluene were added to a high-pressure reactor with magnetic stirring, the reactor was replaced with synthetic gas (a mixture of CO and H2 with a volume ratio of 1:1) for 3 times, and then filled with 4 MPa of synthetic gas, and reacted at 90°C for 5 h, and the reaction equation was as follows:

[0121]

[0122] After the reaction, the mixture was centrifuged and filtered, and the filtrate was detected by gas chromatography (GC) for the conversion of olefins and the yield of aldehyde, and the results were shown in Table 3.

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

[0124] Olefin Conversion (%) Aldehyde yield (%) 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 single metal active sites Rh supported) / reaction time.

[0126] Five, Hydrosilylation of different olefins

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

[0128] 0.6 mmol of olefin, 4 mg of monatomic Rh polymer catalyst and 2 mL of dimethyl(phenyl)silane were added to a Schlenk tube, the tube was replaced with nitrogen for 3 times and filled with nitrogen, and reacted at 80°C for 12 h, and the reaction equation was as follows:

[0129]

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

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

[0132] Olefin Conversion (%) Yield (%) 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 = moles of product / (moles of single metal active sites Rh loaded) / reaction time.

[0134] In summary, according to Tables 1-4, the single-atom Rh polymer catalyst of the present application 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 decrease in performance after 5 cycles of catalysis.

[0135] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A single-atom Rh polymer catalyst, characterized in that, The catalyst comprises an active component and a support, wherein the active component is rhodium metal, the support is a polymer containing phosphine ligands, there is coordination between the polymer containing phosphine ligands and the rhodium metal, and the catalyst has a microporous structure; The method for preparing the single-atom Rh polymer catalyst includes the following steps: (1) Dissolve the phosphine-containing ligand and the cyano ligand in an organic solvent, add an alkaline solution, and sonicate to obtain a mixed solution; (2) The mixed solution obtained in step (1) is frozen, degassed and thawed in sequence. Under vacuum conditions, the temperature is raised to room temperature and then allowed to stand at 100-130°C. Then it is filtered, washed, purified and vacuum dried in sequence to obtain the polymer carrier. (3) Dissolve the polymer support and rhodium precursor obtained in step (2) in an organic solvent and react them under an inert gas and at 35-45°C for 15-20 h. Then filter, wash and dry them in sequence to obtain Rh@POP, i.e., single-atom Rh polymer catalyst. In step (1), the phosphine-containing ligand is tris(3-formylphenyl)phosphine or tris(2-formylphenyl)phosphine; 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-cyanophenylacetonitrile; 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 1,5-cyclooctadiene.

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

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

4. The use of the single-atom Rh polymer catalyst according to any one of claims 1-3 in the catalysis of olefin hydroformylation or olefin hydrosilylation.

5. The application of the single-atom Rh polymer catalyst according to claim 4 in the catalysis of olefin hydroformylation or olefin hydrosilylation, characterized in that, The olefin hydroformylation reaction The process includes the following steps: mixing olefins, a single-atom Rh polymer catalyst, and an organic solvent, reacting them at 40-120°C for 2-6 hours under a syngas atmosphere of 2-4 MPa, filtering, and obtaining the filtrate product and the single-atom Rh polymer catalyst.

6. The application of the single-atom Rh polymer catalyst according to claim 4 in the catalysis of olefin hydroformylation or olefin hydrosilylation, characterized in that, The olefin hydrosilanization reaction The process includes the following steps: mixing olefins, a single-atom Rh polymer catalyst, and hydrosilylation feedstock, reacting them under a nitrogen atmosphere at 75-85°C for 10-15 hours, filtering, and obtaining the filtrate product and the single-atom Rh polymer catalyst.

Images