Atomically dispersed catalysts, methods of making and using the same, and methods of olefin hydroformylation

Abstract

The present application relates to the field of heterogeneous catalysts, and discloses an atomic dispersion catalyst, a preparation method and application thereof, and an olefin hydroformylation method. The preparation method of the atomic dispersion catalyst comprises the following steps: a carrier is impregnated with a first active metal or a precursor thereof and a second active metal or a precursor thereof in steps, and then the atomic dispersion catalyst is obtained through multi-temperature interval step-by-step continuous calcination under an inert atmosphere, wherein the average particle size of the carrier is less than 100 μm, and the specific surface area is greater than 50 m 2 / g. The preparation method of the atomic dispersion catalyst according to the present application has simple steps, low cost, and extremely excellent air and water stability and high-temperature stability.

Description

Technical Field

[0001] This invention relates to the field of heterogeneous catalysts, specifically to an atomically dispersed catalyst, its preparation method and application, and a method for hydroformylation of olefins. Background Technology

[0002] Hydroformylation is a carbonylation process in which olefins react with syngas (CO / H2) to form aldehydes. The aldehyde group generated by hydroformylation can be further converted into imines, amines, hemiacetals, acetals, acetal amines, carboxyl groups, hydroxyl groups, etc. Aldehydes produced by hydroformylation are widely used in the synthesis of plasticizers, surfactants, pharmaceuticals, pesticides, flavorings, and other fine chemicals. The increasing demand for aldehydes and alcohols in the chemical industry, coupled with the abundant supply of inexpensive olefins from the petroleum industry, has driven the rapid development of hydroformylation.

[0003] Currently, hydroformylation reactions in my country still primarily utilize homogeneous catalysts, mainly rhodium-phosphine complexes. While these catalysts exhibit high activity and selectivity, their subsequent separation and processing are challenging and costly, particularly in long-chain olefin reactions. Furthermore, the high price and water sensitivity of phosphine-containing ligands themselves also hinder the industrial development of hydroformylation reactions. Compared to homogeneous hydroformylation catalysts, heterogeneous hydroformylation catalysts offer the advantage of easy separation, but they also suffer from low space-time yields, failing to meet industrial demands. Therefore, achieving efficient heterogeneous catalytic hydroformylation reactions is currently a research hotspot in this field.

[0004] CN104707660A provides a solid heterogeneous catalyst with a metal component supported on an organic ligand polymer. The metal component is one or more of Rh, Ir, or Co. The organic ligand polymer is a polymer with a large specific surface area and hierarchical porous structure produced by solvothermal polymerization of organic ligand monomers containing P, olefin groups, and optionally N. The metal component forms coordinate bonds with P atoms or N atoms in the porous organic polymer backbone and exists in a single-atom dispersed state. This heterogeneous catalyst exhibits excellent catalytic activity and stability in the hydroformylation of ethylene in a fixed-bed reactor. CN104710288A provides the same porous organic polymer-supported heterogeneous catalyst as CN104707660A, but extends its application to the hydroformylation of C6-C20 high-carbon olefins. However, its catalytic performance is somewhat lower compared to its performance in the hydroformylation of low-carbon olefins. Although this heterogeneous catalyst achieves a single-atom-level distribution of metal active centers and exhibits good catalytic performance, it still cannot overcome the limitations imposed by phosphorus ligands. The preparation process is complex, requires an oxygen-free environment, and is costly. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of complex processes and high costs in the existing technology, and to provide an atomically dispersed catalyst, its preparation method and application, as well as a method for hydroformylation of olefins. The preparation method of this atomically dispersed catalyst is simple and low in cost, and the obtained catalyst has extremely excellent catalytic activity.

[0006] Through in-depth research, the inventors of this invention discovered that by using a support with a specific particle size and specific surface area, and by employing a stepwise continuous calcination method in multiple temperature ranges during catalyst preparation, it is possible to prepare atomically dispersed catalysts with extremely excellent catalytic activity in a simple and low-cost manner, thus completing this invention.

[0007] To achieve the above objectives, the present invention provides a method for preparing an atomically dispersed catalyst. This method includes the following steps: impregnating a support with a first active metal or its precursor and a second active metal or its precursor in a stepwise manner, followed by continuous stepwise calcination in an inert atmosphere at multiple temperature ranges to obtain an atomically dispersed catalyst. The support has an average particle size of less than 100 μm and a specific surface area greater than 50 m². 2 / g.

[0008] Preferably, the continuous calcination is at least a two-step continuous calcination in two temperature ranges; more preferably, the continuous calcination is a two-step continuous calcination in two temperature ranges, a three-step continuous calcination in three temperature ranges, a four-step continuous calcination in four temperature ranges, or a five-step continuous calcination in five temperature ranges.

[0009] Preferably, the method includes the following steps:

[0010] 1) The step of first impregnating the dispersion containing the carrier with the first active metal or its precursor, and then performing a first solid-liquid separation to obtain the first metal-loaded product.

[0011] 2) The step of preparing a dispersion containing the first metal-loaded product;

[0012] 3) The step of subjecting the dispersion containing the first metal-loaded product to a second impregnation with the second active metal or its precursor, followed by a second solid-liquid separation to obtain the second metal-loaded product.

[0013] 4) The second metal-supported product is subjected to a stepwise continuous calcination process in multiple temperature ranges under an inert atmosphere.

[0014] The continuous calcination refers to either a two-step continuous calcination in two temperature ranges or a three-step continuous calcination in three temperature ranges.

[0015] The two-step continuous calcination in the two temperature ranges includes: heating to 50-200℃ and holding for 1-5 hours under an inert atmosphere, heating to 400-1000℃ and holding for 1-5 hours, with a heating rate of 1-10℃ / min.

[0016] The three-temperature-range three-step continuous calcination includes: heating to 50-200℃ and holding for 1-5 hours under an inert atmosphere, heating to 200-400℃ and holding for 1-5 hours, and heating to 400-1000℃ and holding for 1-5 hours, with a heating rate of 1-10℃ / min.

[0017] Preferably, in step 1), the support is selected from at least one of porous activated carbon materials, molecular sieve materials, MOF materials, and metal oxide materials;

[0018] Preferably, the average particle size of the carrier is 0.02-50 μm, and the specific surface area is 50-2000 m². 2 / g.

[0019] Preferably, the first active metal is selected from at least one of Rh, Pd, Ir and Ru, and is preferably Rh metal.

[0020] Preferably, the precursor of the first active metal is selected from at least one of RhCl3, RhCl3·xH2O, RhCl3·3H2O, Rh(CO)2(C5H7O2), [(C6H5)3P]3RhCl, PdCl2, RuCl·3H O and IrCl4·xH2O.

[0021] Preferably, the carrier content in the dispersion containing the carrier is 0.1-20% by weight, more preferably 0.2-10% by weight.

[0022] Preferably, the amount of the first active metal is such that its concentration in the dispersion containing the carrier is 0.01-2 mmol / L, more preferably 0.02-1 mmol / L.

[0023] Preferably, the conditions for the first impregnation include: an impregnation temperature of 10-100°C and an impregnation time of more than 1 hour; more preferably, the conditions for the first impregnation include: an impregnation temperature of 25-50°C and an impregnation time of 2-48 hours.

[0024] Preferably, the second active metal is selected from at least one of Co, Fe, Zn, Al, Mg, Ce, Cs, Li, Na and K, and is preferably Co.

[0025] Preferably, the precursor of the second active metal is selected from at least one of Co(NO3)2, Co(NO3)2·6H2O, CoSO4, CoSO4·7H2O, CoCl2, CoCl2·6H2O, MgSO4, KSO4, FeCl3, FeCl2, Zn(NO3)2·6H2O, Ce(NO3)3, CsCl, LiCl, NaCl, and KCl.

[0026] Preferably, the content of the first metal-loaded product in the dispersion containing the first metal-loaded product is 0.1-20% by weight, more preferably 0.2-10% by weight.

[0027] Preferably, the amount of the second active metal is such that its concentration in the dispersion containing the first metal-loaded product is 1-50 mmol / L, more preferably 3-30 mmol / L.

[0028] Preferably, the conditions for the second impregnation include: an impregnation temperature of 10-100°C and an impregnation time of more than 1 hour; more preferably, the conditions for the second impregnation include: an impregnation temperature of 25-50°C and an impregnation time of 2-48 hours.

[0029] Preferably, the two-step continuous calcination in two temperature ranges includes: heating to 100-150℃ and holding for 1-2 hours in an inert atmosphere, heating to 400-500℃ and holding for 1-3 hours, with a heating rate of 2-10℃ / min.

[0030] Preferably, the three-step continuous calcination in three temperature ranges includes: heating to 100-150℃ and holding for 1-2 hours under an inert atmosphere, heating to 300-400℃ and holding for 1-3 hours, and heating to 400-500℃ and holding for 1-3 hours, wherein the heating rate is 2-10℃ / min.

[0031] Preferably, the solvent in the dispersion containing the carrier is at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide.

[0032] Preferably, the solvent in the dispersion of the first metal-loaded product is at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide.

[0033] Preferably, the method further includes a step of cooling the calcined product.

[0034] Preferably, the cooling is natural cooling or cooling at a rate of 1-10°C / min.

[0035] Preferably, the temperature is cooled to 10-40°C.

[0036] According to a second aspect of the present invention, an atomically dispersed catalyst prepared by the method for preparing the atomically dispersed catalyst described in the first aspect of the present invention is provided.

[0037] According to a third aspect of the present invention, a method for hydroformylation of an olefin is provided, wherein the method includes a step of contacting an olefin with a mixture of carbon monoxide and hydrogen in the presence of a catalyst and an organic solvent, wherein the catalyst is an atomically dispersed catalyst prepared by the method for preparing an atomically dispersed catalyst according to the first aspect of the present invention or an atomically dispersed catalyst according to the second aspect of the present invention.

[0038] Preferably, the olefin is at least one of C2-C16 straight-chain or branched olefins.

[0039] Preferably, the organic solvent is at least one selected from toluene, hexane, aldehyde, and alcohol.

[0040] Preferably, the amount of olefin used is 20-90% by volume, based on the total volume of the solvent and the olefin.

[0041] Preferably, the volume ratio of carbon monoxide to hydrogen in the mixed gas is 1:1-3.

[0042] According to a fourth aspect of the present invention, the application of an atomically dispersed catalyst prepared by the method for preparing an atomically dispersed catalyst according to the first aspect of the present invention or the atomically dispersed catalyst according to the second aspect of the present invention in heterogeneous catalytic reactions is provided.

[0043] According to the present invention, an atomically dispersed solid heterogeneous catalyst was prepared by stepwise impregnation and loading followed by continuous calcination in multiple temperature ranges. Compared with existing atomically dispersed heterogeneous catalysts, the catalyst preparation method is simple. In addition, the atomically dispersed heterogeneous catalyst of the present invention uses only solid support and metal salt as raw materials, which eliminates the limitation of expensive phosphorus-containing organic ligands, significantly reducing the preparation cost. Furthermore, the catalyst obtained by the method of the present invention has extremely excellent catalytic activity.

[0044] The atomic-level heterogeneous catalyst of the present invention exhibits excellent catalytic performance for the hydroformylation of olefins, especially the hydroformylation of high-carbon olefins. Furthermore, the catalyst preparation process does not require the isolation of air, and the impregnation solution can be an aqueous solution. Therefore, it has broad industrial prospects in the field of heterogeneous catalysis for the hydroformylation of olefins, especially the hydroformylation of high-carbon olefins. Attached Figure Description

[0045] Figure 1 This is a spherical aberration electron microscope image of the catalyst prepared in Example 1. Detailed Implementation

[0046] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0047] According to a first aspect of the present invention, a method for preparing an atomically dispersed catalyst is provided, wherein the method includes the following steps: impregnating a support with a first active metal or its precursor and a second active metal or its precursor in a stepwise manner, followed by stepwise continuous calcination in an inert atmosphere at multiple temperature ranges to obtain an atomically dispersed catalyst, wherein the average particle size of the support is less than 100 μm and the specific surface area is greater than 50 m². 2 / g.

[0048] According to the present invention, the continuous calcination is at least a two-step continuous calcination in two temperature ranges; preferably, the continuous calcination is a two-step continuous calcination in two temperature ranges, a three-step continuous calcination in three temperature ranges, a four-step continuous calcination in four temperature ranges, or a five-step continuous calcination in five temperature ranges; more preferably, the continuous calcination is a two-step continuous calcination in two temperature ranges or a three-step continuous calcination in three temperature ranges.

[0049] When the continuous calcination is a two-step continuous calcination in two temperature ranges, the calcination conditions may include: under an inert atmosphere, heating to 50-200℃ and holding for 1-5 hours, heating to 400-1000℃ and holding for 1-5 hours, and the heating rate is 1-10℃ / min; preferably, the two-step continuous calcination in two temperature ranges includes: under an inert atmosphere, heating to 100-150℃ and holding for 1-2 hours, heating to 400-500℃ and holding for 1-3 hours, and the heating rate is 2-10℃ / min.

[0050] When the continuous calcination is a three-step continuous calcination in three temperature ranges, the calcination conditions may include: under an inert atmosphere, heating to 50-200℃ and holding for 1-5 hours, heating to 200-400℃ and holding for 1-5 hours, heating to 400-1000℃ and holding for 1-5 hours, and the heating rate is 1-10℃ / min; preferably, the three-step continuous calcination in three temperature ranges includes: under an inert atmosphere, heating to 100-150℃ and holding for 1-2 hours, heating to 300-400℃ and holding for 1-3 hours, heating to 400-500℃ and holding for 1-3 hours, and the heating rate is 2-10℃ / min.

[0051] In a preferred embodiment of the present invention, the method includes the following steps:

[0052] 1) After impregnating the dispersion containing the carrier with the first active metal or its precursor, a first solid-liquid separation is performed to obtain the first metal-loaded product.

[0053] 2) The step of preparing a dispersion containing the first metal-loaded product;

[0054] 3) The step of subjecting the dispersion containing the first metal-loaded product to a second impregnation with the second active metal or its precursor, followed by a second solid-liquid separation to obtain the second metal-loaded product.

[0055] 4) The second metal-supported product is subjected to a stepwise continuous calcination process in multiple temperature ranges under an inert atmosphere.

[0056] The continuous calcination refers to either a two-step continuous calcination in two temperature ranges or a three-step continuous calcination in three temperature ranges.

[0057] The two-step continuous calcination in the two temperature ranges includes: heating to 50-200℃ and holding for 1-5 hours under an inert atmosphere, heating to 400-1000℃ and holding for 1-5 hours, with a heating rate of 1-10℃ / min.

[0058] The three-temperature-range three-step continuous calcination includes: heating to 50-200℃ and holding for 1-5 hours under an inert atmosphere, heating to 200-400℃ and holding for 1-5 hours, and heating to 400-1000℃ and holding for 1-5 hours, with a heating rate of 1-10℃ / min.

[0059] In this invention, considering the ability to achieve higher loading and more uniform dispersion of active metals on the support, preferably, the support has an average particle size of 0.02-50 μm and a specific surface area of ​​50-2000 m². 2 / g; more preferably, the average particle size of the carrier is 0.02-25μm, and the specific surface area is 50-1000m². 2 / g; More preferably, the average particle size of the carrier is 0.02-5μm, and the specific surface area is 50-800m². 2 / g; More preferably, the average particle size of the carrier is 0.05-5μm, and the specific surface area is 150-400m². 2 / g.

[0060] Specific examples of the average particle size of the carrier include: 0.02 μm, 0.03 μm, 0.05 μm, 0.08 μm, 0.1 μm, 0.3 μm, 0.5 μm, 0.7 μm, 0.9 μm, 1 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm. 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, etc., as well as the range formed by any two of the above values.

[0061] As a specific example of the specific surface area of ​​the carrier, one could give an example of 50 m². 2 / g、60m 2 / g、70m 2 / g、80m 2 / g、90m 2 / g, 100m 2 / g、110m 2 / g, 120m 2 / g, 130m 2 / g, 140m 2 / g, 150m 2 / g, 160m 2 / g、170m 2 / g、180m 2 / g、190m 2 / g、200m 2 / g、210m 2 / g、220m 2 / g、230m 2 / g、240m 2 / g、250m 2 / g、260m 2 / g、270m 2 / g、280m 2 / g、290m 2 / g、300m 2 / g、310m 2 / g、320m 2 / g、330m 2 / g、340m 2 / g, 350m2 / g、360m 2 / g、370m 2 / g、380m 2 / g、390m 2 / g、400m 2 / g、500m 2 / g、600m 2 / g、700m 2 / g、800m 2 / g、900m 2 / g, 1000m 2 / g、1200m 2 / g, 1400m 2 / g, 1600m 2 / g、1800m 2 / g、2000m 2 / g, etc., and the range formed by any two of the above values.

[0062] In this invention, the nitrogen adsorption method was used to determine the specific surface area using a specific surface area analyzer (model Tristar II 3020-M, purchased from Micromeritics). The average particle size of the carrier was determined using a Masters Sizer 2000 particle size analyzer (manufactured by Malvern Instruments Ltd).

[0063] The aforementioned support can be any of the various supports commonly used in the art for preparing heterogeneous catalysts. Preferably, the support is selected from at least one of porous activated carbon materials, molecular sieve materials, MOFs materials, and metal oxide materials.

[0064] Examples of porous activated carbon materials include at least one of coal-based activated carbon, fruit shell activated carbon, and stone tar activated carbon.

[0065] Examples of molecular sieve materials mentioned above include SBA-15 and ZSM-35.

[0066] Examples of MOF materials mentioned above include at least one of MIL-101(Cr), MIL-101(Fe), and HKUST-1.

[0067] Examples of the aforementioned metal oxide materials include at least one of aluminum oxide, iron oxide, and zinc oxide.

[0068] According to the present invention, preferably, the first active metal is selected from at least one of Rh, Pd, Ir and Ru; more preferably, the first active metal is Rh metal.

[0069] According to the present invention, preferably, the precursor of the first active metal is selected from at least one of RhCl3, RhCl3·xH2O, RhCl3·3H2O, Rh(CO)2(C5H7O2), [(C6H5)3P]3RhCl, PdCl2, RuCl·3H O and IrCl4·xH2O; more preferably, the precursor of the first active metal is selected from at least one of RhCl3, RhCl3·xH2O, RhCl3·3H2O, Rh(CO)2(C5H7O2) and [(C6H5)3P]3RhCl.

[0070] In this invention, the dispersion containing the carrier can be obtained by dispersing the carrier in a solvent.

[0071] The solvent can be at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide. That is, the solvent in the dispersion containing the carrier is at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide.

[0072] There are no particular limitations on the above dispersion conditions, as long as sufficient dispersion is achieved. For example, the carrier can be dispersed uniformly by stirring at a temperature of 10-100°C for 0.5-5 hours, and preferably by stirring at a temperature of 25-50°C for 1-4 hours.

[0073] According to the present invention, preferably, the carrier content in the dispersion containing the carrier is 0.1-20% by weight; more preferably, the carrier content in the dispersion containing the carrier is 0.2-10% by weight.

[0074] Specific examples of the carrier content in the dispersion containing the carrier include: 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, etc., as well as any range of any two of the above values.

[0075] According to the present invention, preferably, the amount of the first active metal is such that its concentration in the dispersion containing the carrier is 0.01-2 mmol / L; more preferably, the amount of the first active metal is such that its concentration in the dispersion containing the carrier is 0.02-1 mmol / L.

[0076] According to the present invention, preferably, the conditions for the first impregnation include: an impregnation temperature of 10-100°C and an impregnation time of more than 1 hour; more preferably, the conditions for the first impregnation include: an impregnation temperature of 25-50°C and an impregnation time of 2-48 hours.

[0077] According to the present invention, in step 1), the solid-liquid separation can be performed using methods commonly used in the art for solid-liquid separation, such as filtration and centrifugation.

[0078] Preferably, after the above solid-liquid separation, the separated solid phase is dried to obtain the first metal-supported product. The drying method is not particularly limited; for example, it can be dried at 20-100°C for 2-24 hours.

[0079] According to the present invention, preferably, the second active metal is selected from at least one of Co, Fe, Zn, Al, Mg, Ce, Cs, Li, Na and K; more preferably, the second active metal is Co metal.

[0080] According to the present invention, preferably, the precursor of the second active metal is selected from at least one of Co(NO3)2, Co(NO3)2·6H2O, CoSO4, CoSO4·7H2O, CoCl2, CoCl2·6H2O, MgSO4, KSO4, FeCl3, FeCl2, Zn(NO3)2·6H2O, Ce(NO3)3, CsCl, LiCl, NaCl, and KCl; more preferably, the precursor of the second active metal is selected from at least one of Co(NO3)2, Co(NO3)2·6H2O, CoSO4, CoSO4·7H2O, CoCl2, and CoCl2·6H2O.

[0081] In this invention, the dispersion containing the first metal-loaded product can be obtained by dispersing the first metal-loaded product in a solvent.

[0082] The solvent can be at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide. That is, the solvent in the dispersion containing the first metal-supported product is at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide.

[0083] There are no particular limitations on the above dispersion conditions, as long as sufficient dispersion is achieved. For example, the carrier can be dispersed uniformly by stirring at a temperature of 10-100°C for 0.5-5 hours, and preferably by stirring at a temperature of 25-50°C for 1-4 hours.

[0084] According to the present invention, preferably, the content of the first metal-loaded product in the dispersion containing the first metal-loaded product is 0.1-20% by weight; more preferably, the content of the first metal-loaded product in the dispersion containing the first metal-loaded product is 0.2-10% by weight.

[0085] Specific examples of the content of the first metal-loaded product in the dispersion containing the first metal-loaded product include, for example, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, etc., as well as any range consisting of any two of the above values.

[0086] According to the present invention, preferably, the amount of the second active metal is such that its concentration in the dispersion containing the first metal-loaded product is 1-50 mmol / L; more preferably, the amount of the second active metal is such that its concentration in the dispersion containing the first metal-loaded product is 3-30 mmol / L.

[0087] According to the present invention, preferably, the conditions for the second impregnation include: an impregnation temperature of 10-100°C and an impregnation time of more than 1 hour; more preferably, the conditions for the second impregnation include: an impregnation temperature of 25-50°C and an impregnation time of 2-48 hours.

[0088] According to the present invention, in step 3), the solid-liquid separation can be performed using methods commonly used in the art for solid-liquid separation, such as filtration and centrifugation.

[0089] Preferably, after the above solid-liquid separation, the separated solid phase is dried to obtain the second metal-supported product. The drying method is not particularly limited; for example, it can be dried at 20-100°C for 2-24 hours.

[0090] According to the present invention, from the perspective of further improving the dispersion of the active metal on the support and obtaining a catalyst with better catalytic performance, preferably, the two-step continuous calcination in two temperature ranges includes: heating to 100-150°C and holding for 1-2 hours under an inert atmosphere, heating to 400-500°C and holding for 1-3 hours, and the heating rate is 2-10°C / min.

[0091] According to the present invention, from the perspective of further improving the dispersion of the active metal on the support and obtaining a catalyst with better catalytic performance, preferably, the three-step continuous calcination in three temperature ranges includes: heating to 100-150°C and holding for 1-2 hours under an inert atmosphere, heating to 300-400°C and holding for 1-3 hours, and heating to 400-500°C and holding for 1-3 hours, wherein the heating rate is 2-10°C / min.

[0092] According to the present invention, the inert atmosphere can be implemented by introducing an inert gas, which can be argon, nitrogen, or other inert gases commonly used in the art.

[0093] According to the present invention, preferably, the method further includes the step of cooling the calcined product.

[0094] Preferably, the cooling is natural cooling or cooling at a rate of 1-10°C / min.

[0095] In addition, the temperature to which it is cooled can be room temperature, for example, 10-40°C.

[0096] According to a second aspect of the present invention, an atomically dispersed catalyst prepared by the method for preparing the atomically dispersed catalyst described in the first aspect of the present invention is provided.

[0097] According to a third aspect of the present invention, a method for hydroformylation of an olefin is provided, wherein the method includes a step of contacting an olefin with a mixture of carbon monoxide and hydrogen in the presence of a catalyst and an organic solvent, wherein the catalyst is an atomically dispersed catalyst prepared by the method for preparing an atomically dispersed catalyst according to the first aspect of the present invention or an atomically dispersed catalyst according to the second aspect of the present invention.

[0098] According to the present invention, the olefin is at least one of C2-C16 straight-chain or branched olefins. Examples of such olefins include at least one of ethylene, 1-butene, 1,3-butadiene, 1-hexene, 1-octene, 2,4,4-trimethylpentene, 1-dodecene, isododecene, and 1-hexadecene.

[0099] According to the present invention, preferably, the organic solvent is at least one selected from toluene, hexane, aldehyde, and alcohol.

[0100] Examples of aldehydes mentioned above include: pentanal, nonanal, isononal, tridecanal, etc.

[0101] Examples of alcohols mentioned above include ethanol, propanol, butanol, hexanol, tridecanol, etc.

[0102] According to the present invention, preferably, the amount of the olefin used is 20-90% by volume, based on the total volume of the solvent and the olefin.

[0103] According to the present invention, preferably, the volume ratio of carbon monoxide to hydrogen in the mixed gas is 1:1-3, and particularly preferably 1:1.

[0104] According to a fourth aspect of the present invention, the application of an atomically dispersed catalyst prepared by the method for preparing an atomically dispersed catalyst according to the first aspect of the present invention or the atomically dispersed catalyst according to the second aspect of the present invention in heterogeneous catalytic reactions is provided.

[0105] The present invention will be described in detail below through embodiments, but the present invention is not limited to the following embodiments.

[0106] Unless otherwise specified, all materials used in the following examples and comparative examples are commercially available products.

[0107] In the following examples and comparative examples, room temperature refers to 25±3℃.

[0108] In the following examples and comparative examples, the specific surface area was determined using nitrogen adsorption on a specific surface area analyzer (model Tristar II 3020-M, purchased from Micromeritics); the average particle size of the carrier was determined using a Masters Sizer 2000 particle size analyzer (manufactured by Malvern Instruments Ltd); and the spherical aberration electron microscopy images were obtained using a JEOL TEM / STEM ARM 200CF (equipped with an Oxford X-max 100TLE windowless X-ray detector) at a probe convergence angle of 22 mrad and a detector angle within 90 mrad.

[0109] Example 1

[0110] 10g of activated carbon (average particle size 0.5μm, specific surface area 200m²) was used. 2 / g) was dispersed in 3L of water, and 500mL of 2.0mmol / L RhCl3 aqueous solution was added under stirring. The mixture was then stirred at 30℃ for 10h. The mixture was then filtered and separated. The resulting solid was transferred to a drying oven and vacuum dried at 60℃ for 24h. The solid was then weighed to obtain the first-step loaded product.

[0111] 10g of the first step loading product was evenly dispersed in 2L of water. 500mL of 50mmol / L Co(NO3)2 aqueous solution was added while stirring. The mixture was then stirred at 40℃ for 16h. The mixture was then filtered and separated. The obtained solid was transferred to a drying oven and dried under vacuum at 60℃ for 24h. The solid was then weighed to obtain the second step loading product.

[0112] The second-step loaded product obtained above was transferred to a tube furnace. Nitrogen gas was introduced to completely purge the air from the furnace. Under a nitrogen atmosphere, the temperature was increased to 100°C at a rate of 5°C / min and held for 1 hour. Then, the temperature was increased to 300°C at a rate of 5°C / min and held for 2 hours. Finally, the temperature was increased to 400°C at a rate of 5°C / min and held for 3 hours. After the isothermal process, the heating was turned off, and the furnace was allowed to cool naturally to room temperature to obtain catalyst A1 (Rh and Co loadings were 0.35 wt% and 0.5 wt%, respectively). High-resolution aberration electron microscopy (HMI) analysis of catalyst A1 was performed, and the results are shown below. Figure 1 ,pass Figure 1 It can be seen that the active metal in catalyst A1 is uniformly dispersed, and the metal particle size is about 0.3 nm, which is close to the atomic diameter of Rh and Co, proving that this example obtained an atomically dispersed catalyst.

[0113] Example 2

[0114] 10g of activated carbon (average particle size 0.05μm, specific surface area 200m²) was used. 2 / g) was dispersed in 3L of water, and 500mL of 3.0mmol / L RhCl3 aqueous solution was added under stirring. The mixture was then stirred at 50℃ for 16h. The mixture was then filtered and separated, and the resulting solid was transferred to a drying oven and vacuum dried at 60℃ for 24h. The solid was then weighed to obtain the first-step loaded product.

[0115] 10g of the first step loading product was evenly dispersed in 3L of water. 500mL of 50mmol / L Co(NO3)2 aqueous solution was added while stirring. The mixture was then stirred at 40℃ for 16h. The mixture was then filtered and separated. The resulting solid was transferred to a drying oven and vacuum dried at 60℃ for 24h. The solid was then weighed to obtain the second step loading product.

[0116] The second-step loaded product obtained above was transferred to a tube furnace. After completely replacing and purging the air in the tube furnace with nitrogen, the temperature was increased to 100°C at a rate of 5°C / min under a nitrogen atmosphere and held at that temperature for 2 hours. Then, the temperature was increased to 400°C at a rate of 5°C / min and held at that temperature for 2 hours. Finally, the temperature was increased to 500°C at a rate of 5°C / min and held at that temperature for 2 hours. After the isothermal process, the heating was turned off and the furnace was allowed to cool naturally to room temperature to obtain catalyst A2 (with Rh and Co loadings of 0.45 wt% and 0.53 wt%, respectively). High-resolution aberration electron microscopy (HREM) analysis of catalyst A2 showed that the active metals in catalyst A2 were uniformly dispersed, with a metal particle size of approximately 0.3 nm, close to the atomic diameter of Rh and Co, proving that this example yielded an atomically dispersed catalyst.

[0117] Example 3

[0118] 10g of activated carbon (average particle size 0.02μm, specific surface area 250m²) was used. 2 / g) was dispersed in 3L of water, and 500mL of 2mmol / L RhCl3 aqueous solution was added under stirring. The mixture was then stirred at 30℃ for 10h. The mixture was then filtered and separated, and the resulting solid was transferred to a drying oven and vacuum dried at 60℃ for 24h. The solid was then weighed to obtain the first-step loaded product.

[0119] 10g of the first step loading product was evenly dispersed in 3L of water. 500mL of 50mmol / L Co(NO3)2 aqueous solution was added while stirring. The mixture was then stirred at 40℃ for 16h. The mixture was then filtered and separated. The resulting solid was transferred to a drying oven and vacuum dried at 60℃ for 24h. The solid was then weighed to obtain the second step loading product.

[0120] The second-step loaded product obtained above was transferred to a tube furnace. After completely replacing and purging the air in the tube furnace with nitrogen, the temperature was increased to 150°C at a rate of 2°C / min under a nitrogen atmosphere and held at that temperature for 1 hour. Then, the temperature was increased to 400°C at a rate of 5°C / min and held at that temperature for 1 hour. Finally, the temperature was increased to 500°C at a rate of 5°C / min and held at that temperature for 3 hours. After the isothermal process, the heating was turned off and the furnace was allowed to cool naturally to room temperature to obtain catalyst A3 (with Rh and Co loadings of 0.43 wt% and 0.61 wt%, respectively). High-resolution aberration-corrected electron microscopy (HREM) analysis of catalyst A3 showed that the active metals in catalyst A3 were uniformly dispersed, with a metal particle size of approximately 0.3 nm, close to the atomic diameter of Rh and Co, proving that this example yielded an atomically dispersed catalyst.

[0121] Example 4

[0122] The method of Example 1 was followed, except that the heating rate during calcination was changed from 5°C / min to 10°C / min, and catalyst A4 was obtained in the same manner (Rh and Co loadings were 0.35 wt% and 0.5 wt%, respectively). High-resolution aberration-corrected electron microscopy (HREM) analysis of catalyst A4 showed that the active metals in catalyst A4 were uniformly dispersed, with a metal particle size of approximately 0.3 nm, which is close to the atomic diameter of Rh and Co, proving that this example yielded an atomically dispersed catalyst.

[0123] Example 5

[0124] The method of Example 1 was followed, except that the calcination process was changed to heating to 100°C at a rate of 5°C / min under a nitrogen atmosphere and holding at that temperature for 1 hour, followed by heating to 400°C at a rate of 5°C / min and holding at that temperature for 3 hours, thus obtaining catalyst A5 (with Rh and Co loadings of 0.35 wt% and 0.5 wt%, respectively). High-resolution aberration-corrected electron microscopy (HREM) analysis of catalyst A5 showed that the active metals were uniformly dispersed in the catalyst, with a metal particle size of approximately 0.3 nm, which is close to the atomic diameter of Rh and Co, proving that this example yielded an atomically dispersed catalyst.

[0125] Example 6

[0126] The method of Example 1 was followed, except that the calcination process was changed to heating to 150°C at a rate of 10°C / min under a nitrogen atmosphere and holding at that temperature for 2 hours, followed by heating to 500°C at a rate of 10°C / min and holding at that temperature for 3 hours, thus obtaining catalyst A6 (with Rh and Co loadings of 0.35 wt% and 0.51 wt%, respectively). High-resolution aberration-corrected electron microscopy (HREM) analysis of catalyst A5 showed that the active metals were uniformly dispersed in the catalyst, with a metal particle size of approximately 0.3 nm, which is close to the atomic diameter of Rh and Co, proving that this example yielded an atomically dispersed catalyst.

[0127] Example 7

[0128] The procedure was carried out according to Example 1, except that the activated carbon was replaced with alumina (average particle size of 0.05 μm, specific surface area of ​​230 m²). 2 Similarly, catalyst A7 (with Rh and Co loadings of 0.3 wt% and 0.6 wt%, respectively) was obtained. High-resolution aberration electron microscopy (HEM) analysis of catalyst A7 revealed that the active metals were uniformly dispersed, with a particle size of approximately 0.3 nm, which is close to the atomic diameter of Rh and Co, confirming that this example yielded an atomically dispersed catalyst.

[0129] Example 8

[0130] The procedure was carried out according to Example 1, except that the activated carbon was changed to SBA-15 (average particle size 1.0 μm, specific surface area 700 m²). 2 Similarly, catalyst A8 (with Rh and Co loadings of 0.4 wt% and 0.6 wt%, respectively) was obtained. High-resolution aberration-corrected electron microscopy (HEM) analysis of catalyst A8 revealed that the active metals were uniformly dispersed with a particle size of approximately 0.3 nm, which is close to the atomic diameter of Rh and Co, confirming that this example yielded an atomically dispersed catalyst.

[0131] Example 9

[0132] The procedure was carried out according to Example 1, except that the activated carbon was changed to ZSM-35 (average particle size 3.0 μm, specific surface area 350 m²). 2 Similarly, catalyst A9 (with Rh and Co loadings of 0.41 wt% and 0.55 wt%, respectively) was obtained. High-resolution aberration electron microscopy (HEM) analysis of catalyst A9 revealed that the active metals were uniformly dispersed, with a particle size of approximately 0.3 nm, which is close to the atomic diameter of Rh and Co, confirming that this example yielded an atomically dispersed catalyst.

[0133] Comparative Example 1

[0134] The method of Example 1 was followed, except that the heating rate during calcination was changed from 5°C / min to 12°C / min, and catalyst D1 was obtained in the same manner. High-resolution aberration-corrected electron microscopy (HRM) analysis of catalyst D1 revealed that the active metal agglomerated on the support surface, and no atomically dispersed catalyst was obtained.

[0135] Comparative Example 2

[0136] The procedure was carried out according to Example 1, except that the catalyst calcination process was changed to directly heating to 500°C and then holding at that temperature for 3 hours, resulting in catalyst D2. High-resolution aberration-corrected electron microscopy (HRM) analysis of catalyst D2 revealed that some active metals had agglomerated, and a completely atomically dispersed catalyst was not obtained.

[0137] Comparative Example 3

[0138] The procedure was carried out according to Example 1, except that the activated carbon was replaced with ordinary zinc oxide (average particle size 80 μm, specific surface area 5 m²). 2 Catalyst D3 was obtained by reacting / g) with the same method. High-resolution aberration-corrected electron microscopy (HEM) analysis of catalyst D3 revealed that the active metal agglomerated on the support surface, and no atomically dispersed catalyst was obtained.

[0139] Comparative Example 4

[0140] The procedure was carried out according to Example 1, except that the activated carbon was replaced with large-particle alumina (average particle size of 110 μm and specific surface area of ​​50 m²). 2 Catalyst D4 was obtained by reacting the active metals with the support surface (g) in the same manner. High-resolution aberration-corrected electron microscopy (HEM) analysis of catalyst D4 revealed that the active metals agglomerated on the support surface, and no atomically dispersed catalyst was obtained.

[0141] Test Example 1

[0142] 100 mg of the catalyst from the above examples and comparative examples was mixed with 10 mL of 2,4,4-trimethylpentene and 30 mL of toluene, and then transferred to a high-pressure reactor. A CO / H2 mixture (CO:H2 volume ratio of 1:1) was introduced into the reactor to displace the air. The pressure was increased to 6 MPa, stirring was started, and the reaction was carried out at a constant temperature of 90 °C for 9 hours. After that, the heating was turned off and the mixture was allowed to cool naturally to room temperature. A small amount of the reaction mixture was placed in a centrifuge tube, and after centrifugation, the supernatant was used for qualitative analysis by LC-MS and quantitative analysis by an Agilent 7890B gas chromatograph. The specific chromatographic analysis conditions were as follows: injector temperature 300 °C, detector temperature 300 °C, Agilent HP-5 capillary column (30 m × 0.32 mm × 0.25 m). The temperature program was as follows: initial temperature 35 °C, held for 6 min, then increased to 250 °C at a rate of 10 °C / min. The reaction results are listed in Table 1.

[0143] Table 1

[0144] Example 1 90.3％ 97.9％ Example 2 91.6％ 98.0％ Example 3 91.5％ 97.9％ Example 4 91.4％ 98.0％ Example 5 89.2％ 97.9％ Example 6 89.3％ 98.0％ Example 7 89.2％ 98.2％ Example 8 88.9％ 97.8％ Example 9 89.3％ 98.0％ Comparative Example 1 75.3％ 96.1％ Comparative Example 2 85.7％ 95.9％ Comparative Example 3 62.1％ 94.1％ Comparative Example 4 62.9％ 94.9％

[0145] As can be seen from Examples 1-9, Comparative Examples 1-4, and Table 1, the method for preparing the atomically dispersed catalyst of the present invention can yield an atomically dispersed catalyst with excellent conversion rate and aldehyde selectivity. In contrast, Comparative Example 1, where the heating rate during calcination is outside the range of the present invention, cannot yield an atomically dispersed catalyst, and has poor conversion rate and aldehyde selectivity; Comparative Example 2, which involves one-step calcination, also cannot yield an atomically dispersed catalyst, and has poor conversion rate and aldehyde selectivity; Comparative Example 3, where the specific surface area of ​​the support is outside the range of the present invention, also cannot yield an atomically dispersed catalyst, and has poor conversion rate and aldehyde selectivity; Comparative Example 4, where the average particle size of the support is outside the range of the present invention, also cannot yield an atomically dispersed catalyst, and has poor conversion rate and aldehyde selectivity.

[0146] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing an atomically dispersed catalyst, characterized in that, The method includes the following steps: impregnating a support with a first active metal or its precursor and a second active metal or its precursor in stages, followed by stepwise continuous calcination in an inert atmosphere at multiple temperature ranges to obtain an atomically dispersed catalyst. The support has an average particle size of less than 100 µm and a specific surface area greater than 50 m². 2 / g, The continuous calcination refers to either a two-step continuous calcination in two temperature ranges or a three-step continuous calcination in three temperature ranges. The two-step continuous calcination in the two temperature ranges includes: heating to 50-200℃ and holding for 1-5 hours under an inert atmosphere, heating to 400-1000℃ and holding for 1-5 hours, with a heating rate of 1-10℃ / min. The three-temperature-range three-step continuous calcination includes: heating to 50-200℃ and holding for 1-5 hours under an inert atmosphere, heating to 200-400℃ and holding for 1-5 hours, and heating to 400-1000℃ and holding for 1-5 hours, with a heating rate of 1-10℃ / min.

2. The method according to claim 1, wherein, This method Includes the following steps, 1) The step of first impregnating the dispersion containing the carrier with the first active metal or its precursor, and then performing a first solid-liquid separation to obtain the first metal-loaded product. 2) The step of preparing a dispersion containing the first metal-loaded product; 3) The step of subjecting the dispersion containing the first metal-loaded product to a second impregnation with the second active metal or its precursor, followed by a second solid-liquid separation to obtain the second metal-loaded product. 4) The second metal-loaded product is subjected to stepwise continuous calcination in multiple temperature ranges under an inert atmosphere.

3. The method according to claim 1 or 2, wherein, The carrier is selected from at least one of porous activated carbon materials, molecular sieve materials, MOF materials, and metal oxide materials.

4. The method according to claim 3, wherein, The carrier has an average particle size of 0.02-50µm and a specific surface area of ​​50-2000m². 2 / g.

5. The method according to claim 4, wherein, The carrier has an average particle size of 0.02-25µm and a specific surface area of ​​50-1000m². 2 / g.

6. The method according to claim 5, wherein, The carrier has an average particle size of 0.02-5µm and a specific surface area of ​​50-800m². 2 / g.

7. The method according to claim 6, wherein, The carrier has an average particle size of 0.05-5µm and a specific surface area of ​​150-400m². 2 / g.

8. The method according to claim 1 or 2, wherein, The first active metal is selected from at least one of Rh, Pd, Ir and Ru.

9. The method according to claim 8, wherein, The first active metal is Rh metal.

10. The method according to claim 1 or 2, wherein, The precursor of the first active metal is selected from RhCl3 and RhCl3. At least one of xH2O, Rh(CO)2(C5H7O2), [(C6H5)3P]3RhCl, PdCl2, RuCl3·3H2O and IrCl4·xH2O.

11. The method according to claim 1 or 2, wherein, The precursor of the first active metal is RhCl3 3H2O.

12. The method according to claim 2, wherein, The carrier-containing dispersion contains 0.1-20% by weight of the carrier.

13. The method according to claim 12, wherein, The carrier-containing dispersion contains 0.2-10% by weight of the carrier.

14. The method according to claim 2, wherein, The amount of the first active metal used is such that its concentration in the dispersion containing the carrier is 0.01-2 mmol / L.

15. The method according to claim 14, wherein, The amount of the first active metal used is such that its concentration in the dispersion containing the carrier is 0.02-1 mmol / L.

16. The method of claim 14, wherein, The conditions for the first impregnation include: an impregnation temperature of 10-100℃ and an impregnation time of more than 1 hour.

17. The method according to claim 16, wherein, The conditions for the first impregnation include: an impregnation temperature of 25-50°C and an impregnation time of 2-48 hours.

18. The method according to claim 1 or 2, wherein, The second active metal is selected from at least one of Co, Fe, Zn, Al, Mg, Ce, Cs, Li, Na and K.

19. The method according to claim 18, wherein, The second active metal is Co.

20. The method according to claim 1 or 2, wherein, The precursor of the second active metal is selected from Co(NO3)2 and Co(NO3)2. 6H2O, CoSO4, CoSO4 7H2O, CoCl2, CoCl2 6H2O, MgSO4, K2SO4, FeCl3, FeCl2, Zn(NO3)2 At least one of 6H2O, Ce(NO3)3, CsCl, LiCl, NaCl, and KCl.

21. The method according to claim 2, wherein, The content of the first metal-loaded product in the dispersion containing the first metal-loaded product is 0.1-20% by weight.

22. The method according to claim 21, wherein, The content of the first metal-loaded product in the dispersion containing the first metal-loaded product is 0.2-10% by weight.

23. The method according to claim 21, wherein, The amount of the second active metal used is such that its concentration in the dispersion containing the first metal-loaded product is 1-50 mmol / L.

24. The method according to claim 23, wherein, The amount of the second active metal used is such that its concentration in the dispersion containing the first metal-loaded product is 3-30 mmol / L.

25. The method according to claim 2, wherein, The conditions for the second impregnation include: an impregnation temperature of 10-100℃ and an impregnation time of more than 1 hour.

26. The method according to claim 25, wherein, The conditions for the second impregnation include: an impregnation temperature of 25-50°C and an impregnation time of 2-48 hours.

27. The method according to claim 1, wherein, The two-step continuous calcination in two temperature ranges includes: heating to 100-150℃ and holding for 1-2 hours under an inert atmosphere, and heating to 400-500℃ and holding for 1-3 hours, with a heating rate of 2-10℃ / min.

28. The method according to claim 1, wherein, The three-temperature-range three-step continuous calcination includes: heating to 100-150℃ and holding for 1-2 hours under an inert atmosphere, heating to 300-400℃ and holding for 1-3 hours, and heating to 400-500℃ and holding for 1-3 hours, wherein the heating rate is 2-10℃ / min.

29. The method according to claim 2, wherein, The solvent in the dispersion containing the carrier is at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide.

30. The method according to claim 2, wherein, The solvent in the dispersion of the first metal-loaded product is at least one of water, ethanol, methanol, n-hexane, and N,N-dimethylformamide.

31. The method according to claim 1 or 2, wherein, The method also includes the step of cooling the calcined product.

32. The method according to claim 31, wherein, The cooling is either natural cooling or cooling at a rate of 1-10℃ / min.

33. The method according to claim 32, wherein, Cool to a temperature of 10-40℃.

34. The atomically dispersed catalyst prepared by the method of any one of claims 1-33.

35. A method for hydroformylation of an olefin, characterized in that, The method includes the step of contacting an olefin with a mixture of carbon monoxide and hydrogen in the presence of a catalyst and an organic solvent, wherein the catalyst is an atomically dispersed catalyst prepared by the method for preparing an atomically dispersed catalyst according to any one of claims 1-33 or an atomically dispersed catalyst according to claim 34.

36. The method according to claim 35, wherein, The olefin is at least one of C2-C16 straight-chain or branched olefins.

37. The method of claim 35, wherein, The organic solvent is at least one of toluene, hexane, aldehyde, and alcohol.

38. The method according to claim 35, wherein, The amount of olefin used is 20-90 vol based on the total volume of the organic solvent and the olefin.

39. The method according to claim 35, wherein, In the mixed gas, the volume ratio of carbon monoxide to hydrogen is 1:1-3.

40. The application of an atomically dispersed catalyst prepared by any one of the methods described in claims 1-33 or the atomically dispersed catalyst described in claim 34 in heterogeneous catalytic reactions.

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