A rhodium complex catalyst containing a polyazoligand, a preparation method and application thereof
By loading a rhodium-based composite catalyst with polynitrogen ligands onto a γ-Al2O3 support, the problem of easy loss of phosphine ligands was solved, and the effect of efficient catalysis of propylene to butyraldehyde was achieved. The catalyst has good stability and low cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIV
- Filing Date
- 2026-05-09
- Publication Date
- 2026-06-09
AI Technical Summary
Among existing olefin hydroformylation catalysts, phosphine ligands are expensive, sensitive to air and water, and easily lost, leading to deactivation of homogeneous processes. As a result, there are almost no applications of heterogeneous catalysts in this reaction.
A novel Rh-N coordination active site is formed by using a multi-nitrogen ligand and a rhodium-based composite catalyst and supporting Rh-N complexes on a γ-Al2O3 support to promote the hydroformylation of olefins. The preparation method is simple, the raw materials are readily available, and the cost is low.
The catalyst achieved highly efficient catalysis to produce butyraldehyde from propylene, with a propylene conversion rate of 69.5% and a butyraldehyde selectivity of approximately 93.7%. The catalyst exhibited good stability, with almost no loss of Rh species, thus avoiding the drawbacks of phosphine ligands.
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Figure CN122164502A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of heterogeneous catalysis technology, and specifically relates to a method for preparing and applying a rhodium-based composite catalyst with multiple nitrogen ligands. Background Technology
[0002] Hydroformylation of olefins is an important industrial process in which olefins react with carbon monoxide and hydrogen to produce aldehydes with one more carbon atom. This process has long been considered the best method for synthesizing aldehydes and alcohols, and these compounds are widely used as intermediates and feedstocks in the production of pharmaceuticals and various commercial chemicals, with a total annual output exceeding 20 million tons. Internationally, over 10 million tons of butyraldehyde, over 1 million tons of propionaldehyde, and as many as 2.4 million tons of other linear aldehydes are produced annually through homogeneous hydroformylation. Therefore, the hydroformylation of propylene to butyraldehyde has a huge production capacity and continues to receive considerable research attention. Homogeneous rhodium catalysts are typically used extensively in these processes. Triphenylphosphine, discovered early on, is the most effective ligand, and since then, polyphosphorus-containing ligands have been continuously developed. To date, phosphine ligands remain the dominant catalyst ligands for olefin hydroformylation reactions. For example, patent CN117399073B reports a hydrolysis-resistant phosphine ligand olefin hydroformylation catalyst, which exhibits high stability and resistance to hydrolysis. Patents such as EP3712126A1, CN102826967, CN114401940A, CN107737609A, CN111333680B, and CN113754615A all use phosphine ligands or modified phosphine ligands as ligands for olefin hydroformylation catalysts. Besides patents, numerous publications have investigated the ligand effect of olefin hydroformylation catalysts. For example, *Journal of Organometallic Chemistry*, 2002, 654, 83-90; *Molecular Catalysis*, 2017, 434, 116–122; and *Angew. Chem. Int. Ed.*, 2019, 58, 2120–2124, all employ different types of phosphine ligands. However, phosphine ligands are typically expensive, sensitive to air and water, and easily lost during the reaction. The changes in phosphine ligands and the aggregation of rhodium species during the reaction inevitably lead to the deactivation of the homogeneous process. Although nitrogen ligands are inferior to phosphine ligands, they are more readily available, cheaper, and less toxic, and therefore have been neglected despite earlier research. Furthermore, despite the numerous advantages of heterogeneous catalysts and gas-solid processes, there are virtually no successful industrial applications for this reaction. Summary of the Invention
[0003] To address the problems of low catalyst activity and easy loss of Rh species in the propylene hydroformylation reaction, this invention aims to provide a method for preparing a multi-nitrogen-coordinated rhodium-based composite catalyst. The raw materials are simple and readily available, the cost is low, and the method is straightforward. This catalyst can catalyze the formation of butyraldehyde from propylene under conventional conditions.
[0004] The specific solution of the present invention is as follows:
[0005] A rhodium-based composite catalyst containing multiple nitrogen ligands, wherein the general formula of the multi-nitrogen ligand-rhodium-based composite catalyst is as follows: xRh-N / γ-Al2O3; where x is the Rh loading, N is different types of nitrogen-containing ligands, and the support is γ-Al2O3;
[0006] The molar ratio of Rh to N ligands ranges from 0 to 35, with the molar ratio based on the molar amount of Rh species. The calculation method is as follows: calculate the mass of Rh species loaded on 1 g of the vector, then convert it to the number of moles of Rh. Then, using the number of moles of Rh species as a baseline, calculate the required number of moles of polynitrogen ligands for each different molar ratio. The ratio of the number of moles of polynitrogen ligands to the number of moles of Rh species is the molar ratio.
[0007] x represents the load quality fraction of Rh, which ranges from 0.05 to 1;
[0008] The loaded mass of Rh is calculated as the mass of Rh atoms;
[0009] Preferably, the rhodium-based composite catalyst containing polynitrogen ligands is 0.05Rh-N / γ-Al2O3, 0.08Rh-N / γ-Al2O3, 0.1Rh-N / γ-Al2O3, 0.21Rh-N / γ-Al2O3, 0.32Rh-N / γ-Al2O3, or 0.72Rh-N / γ-Al2O3.
[0010] Preferably, the Rh is derived from Rh salt, which is selected from rhodium dicarbonyl acetylacetone Rh(acac)(CO)2, rhodium trichloride, and rhodium nitrate.
[0011] The preferred N-ligand is derived from the polynitrogen ligand shown in formula (I).
[0012]
[0013] (I)
[0014] Where R1 represents -CH3, -CH2CH3, and -CH2CH2CH3; and R2 represents -NH2, -CH2CH2NH2, and -CH2CH2NHCH2CH2NH2.
[0015] The preferred polynitrogen ligand has the following structure:
[0016] .
[0017] The preferred rhodium-based composite catalyst is 0.1Rh-N / γ-Al2O3, which consists of γ-Al2O3 as the support, and stepwise loading of 10.7% of a polynitrogen ligand and 0.1% of rhodium.
[0018] The aforementioned catalyst preparation method includes the following steps:
[0019] (1) Dissolve the polynitrogen ligand as shown in formula (I) in anhydrous ethanol;
[0020] (2) Dissolve the Rh salt in acetone;
[0021] (3) Take a certain amount of γ-Al2O3 support, impregnate the polynitrogen ligand dissolved in ethanol onto the surface of the support, let it stand and then dry it in an oven;
[0022] (4) Add the solution obtained in step (2) to the powder obtained in step (3) using the equal volume impregnation method, and let it stand at 80°C. o Dry overnight in an oven at C. Once drying is complete, the xRh-N / γ-Al2O3 catalyst is obtained.
[0023] Preferably, the polynitrogen ligand in step (1) is selected from diethylenetriaminepropyltrimethoxysilane C 10 H 27 N3O3Si;
[0024] Preferably, the Rh salt in step (2) is selected from rhodium dicarbonyl acetylacetone Rh(acac)(CO)2.
[0025] The application of the aforementioned catalyst in the hydroformylation of propylene is preferred.
[0026] Preferably, the application includes the following steps:
[0027] (1) Press the aforementioned catalyst into 20-40 mesh particles and place them in a fixed-bed reactor;
[0028] (2) In a continuous flow fixed bed reactor, a mixture of propylene, CO and H2 is continuously introduced into the reactor, and then the reactor is heated to 110℃~170℃ to obtain the product butyraldehyde and its partial hydrogenation product butanol.
[0029] The preferred step (1) uses a polynitrogen ligand selected from diethylenetriaminepropyltrimethoxysilane C 10 H 27 N3O3Si, γ-aminopropyltriethoxysilane C9H 23NO3Si, N-β-aminoethyl-γ-aminopropyltrimethoxysilane C8H 22 N2O3Si; The Rh salt mentioned in step (2) is selected from rhodium dicarbonyl acetylacetone Rh(acac)(CO)2, rhodium trichloride, and rhodium nitrate.
[0030] Beneficial effects:
[0031] The catalyst of this invention is simple to prepare, uses readily available raw materials, is low in cost, and exhibits excellent performance. At a reaction pressure of 5 MPa, this catalyst achieves a propylene conversion of 69.5% in the hydroformylation of olefins, a selectivity of approximately 93.7% for butyraldehyde, a selectivity of approximately 6.3% for butanol, and a propylene TOF as high as 710 h⁻¹. -1 .
[0032] The coordination of polynitrogen ligands with rhodium sites on γ-Al₂O₃ forms a novel Rh-N coordination, which can uniformly disperse Rh species and promote the physical adsorption and heterolytic dissociation of H₂ on Rh species. This synergistic effect further enhances the catalytic performance of olefin hydroformylation. This study utilizes the coordination of polynitrogen ligands with Rh species to construct novel Rh-N coordination active sites to catalyze the hydroformylation of olefins to butyraldehyde.
[0033] The overall process of this invention is simple, the catalyst exhibits good stability, and there is almost no Rh species loss during the reaction. ICP-MS results show that the Rh loading was 0.106 wt% before the reaction and 0.103 wt% after the reaction, a decrease of 0.37% in Rh content. This demonstrates the excellent stability of the catalyst and the near absence of Rh species loss. There are no issues related to Rh species loss or organophosphorus contamination. Attached Figure Description
[0034] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:
[0035] Figure 1 This is a spherical aberration electron microscope image of the 0.1Rh / γ-Al2O3 catalyst prepared in Example 1 of this invention.
[0036] Figure 2 This is the synchrotron radiation spectrum of the 0.1Rh / γ-Al2O3 catalyst prepared in Example 1 of this invention.
[0037] Figure 3 This is a spherical aberration electron microscope image of the 0.1Rh-NQ62 / γ-Al2O3 catalyst prepared in Example 2 of this invention.
[0038] Figure 4 This is the synchrotron radiation spectrum of the 0.1Rh-NQ62 / γ-Al2O3 catalyst prepared in Example 2 of this invention.
[0039] Figure 5 The results are CO-DRIFT characterization results of the 0.1Rh-NQ62 / γ-Al2O3 catalyst prepared in Example 2 of this invention.
[0040] Figure 6 The above are the XRD results of the 0.1Rh-NQ62 / γ-Al2O3 catalyst prepared in Example 2 of this invention.
[0041] Figure 7 The results are the evaluation results of xRh-NQ62 / γ-Al2O3 catalysts with different Rh loadings prepared in Example 3 of this invention.
[0042] Figure 8 The results are the evaluation results of the 0.1Rh-NQ62 / γ-Al2O3 catalysts with different ligand / Rh molar ratios prepared in Example 4 of this invention.
[0043] Figure 9 These are the evaluation results of 0.1Rh-N / γ-Al2O3 catalysts with different ligand types prepared in Example 5 of this invention.
[0044] Figure 10 The results are the evaluation results of 0.1Rh-NQ62 / γ-Al2O3 catalysts with different support types prepared in Example 6 of this invention.
[0045] Figure 11 These are the evaluation results of different types of precursor 0.1Rh-NQ62 / γ-Al2O3 catalysts prepared in Example 7 of this invention.
[0046] Figure 12 This is a spherical aberration electron microscope image of the catalyst prepared in Example 1 of this invention after reaction.
[0047] Figure 13 This is a spherical aberration electron microscope image of the catalyst prepared in Example 2 of this invention after reaction.
[0048] Figure 14 These are the synchrotron radiation characterization results of the catalysts prepared in Examples 1 and 2 of this invention after reaction. Detailed Implementation
[0049] The invention can be further illustrated by the following examples, which are for illustrative purposes only and not for limiting the invention. Any person skilled in the art will understand that these examples do not limit the invention in any way, and that appropriate modifications and data transformations can be made thereto without departing from the spirit and scope of the invention. Unless otherwise stated, all chemicals were purchased from commercially available products.
[0050] Example 1:
[0051] (1) Dissolve 2.5 mg of rhodium dicarbonyl acetylacetone in 1.2 mL of acetone.
[0052] (2) Weigh 1.0 g of γ-Al2O3 and add the rhodium dicarbonyl acetylacetone solution to the γ-Al2O3 powder using the equal volume impregnation method, stirring while adding, and then place it in 80 o The catalyst was dried in an oven at C to obtain 0.1Rh / γ-Al2O3. The metal loading was determined by ICP-MS.
[0053]
[0054] Figure 1 These are aberration-corrected electron micrographs of the catalyst prepared in Example 1 of this invention. Figure 2 These are the synchrotron radiation characterization results of the catalyst prepared in Example 1 of this invention. Figure 1 As shown, without the addition of polynitrogen ligands, the prepared Rh species aggregated on the support surface, forming small clusters. From Figure 2 The characterization results show that, without the addition of polynitrogen ligands, significant Rh-Rh scattering occurred on the catalyst surface, indicating the formation of rhodium clusters.
[0055] Example 2:
[0056] (1) Dissolve 2.5 mg of rhodium dicarbonyl acetylacetone in 1.2 mL of acetone, and dissolve 71.2 mg of diethylenetriaminepropyltrimethoxysilane in 0.9 mL of anhydrous ethanol.
[0057] (2) Weigh 1.0 g of γ-Al2O3 and add diethylenetriaminepropyltrimethoxysilane solution to γ-Al2O3 powder using the equal volume impregnation method, stirring while adding, and then place it in 80 o Drying in an oven at C yields NQ62 / γ-Al2O3.
[0058] (3) Add the rhodium dicarbonyl acetylacetone solution to NQ62 / γ-Al2O3 while stirring, and then add 80 o The catalyst was dried in an oven at C to obtain 0.1Rh-NQ62 / γ-Al2O3.
[0059] Figure 3 These are aberration-corrected electron micrographs of the catalyst prepared in Example 2 of this invention. Figure 4 This is the synchrotron radiation characterization result of the catalyst prepared in Example 2 of this invention. Figure 3 As shown, with the addition of polynitrogen ligands, the prepared Rh species were uniformly dispersed on the support surface without obvious clusters. Figure 4The characterization results show that after the addition of polynitrogen ligands, the Rh species are uniformly dispersed on the support surface, with no obvious Rh-Rh scattering and only a single Rh-N coordination. This indicates that the Rh species on the support surface only coordinate with polynitrogen ligands.
[0060] x% = W(Rh)\((W(Al2O3)+W(NQ62)+W(Rh salt), where W(Rh) represents the mass of Rh atoms; W(Al2O3) represents the mass of aluminum oxide; W(NQ62) represents the mass of NQ62; and W(Rh salt) represents the mass of rhodium salt.
[0061] Figure 5 These are the CO-DRIFT characterization results of the catalyst prepared in Example 2 of this invention. Figure 5 As shown, the infrared adsorption peak positions of CO are 2021.3 cm⁻¹. -1 and 2084 cm -1 These correspond to the symmetric and asymmetric vibrations of CO on the positively charged Rh atom, respectively. Due to the electron-donating effect of the amino group, the absorption peak of the symmetric vibration of CO on Rh undergoes a red shift, and the vibrational signal of CO is captured at 2021.3 cm⁻¹. This also indicates that the polynitrogen ligand effectively coordinates with the Rh group on the support surface.
[0062] Figure 6 The X-ray diffraction pattern of the catalyst and support prepared in Example 2 of this invention shows that, due to the low metal loading and good dispersion, there are no obvious metal diffraction peaks.
[0063] Example 3:
[0064] (1) Dissolve 2.0 mg / 2.5 mg / 5.25 mg / 8.0 mg / 18 mg of dicarbonyl acetylacetone rhodium in 1.2 mL of acetone, and dissolve 59.69 mg / 71.2 mg / 149.52 mg / 227.84 mg / 512.64 mg of diethylenetriaminopropyltrimethoxysilane in 0.9 mL of anhydrous ethanol.
[0065] (2) Weigh 1.0 g of γ-Al2O3 and add diethylenetriaminepropyltrimethoxysilane solution to γ-Al2O3 powder using the equal volume impregnation method, stirring while adding, and then place it in 80 o Drying in an oven at C yields NQ62 / γ-Al2O3.
[0066] (3) Then, using the equal-volume impregnation method, the dicarbonyl acetylacetone rhodium is dissolved and added to NQ62 / γ-Al2O3 while stirring. Then, 80 o The xRh-N / γ-Al2O3 catalysts with different Rh loadings were obtained by drying in an oven at C.
[0067] Example 4:
[0068] (1) Dissolve 2.5 mg of rhodium dicarbonyl acetylacetone in 1.2 mL of acetone, and dissolve 20.74 mg / 46.70 mg / 71.2 mg / 87.65 mg of diethylenetriaminopropyltrimethoxysilane in 0.9 mL of anhydrous ethanol.
[0069] (2) Weigh 1.0 g of γ-Al2O3 and add diethylenetriaminepropyltrimethoxysilane solution to γ-Al2O3 powder using the equal volume impregnation method, stirring while adding, and then place it in 80 o Drying in an oven at C yields NQ62 / γ-Al2O3.
[0070] (3) Then, using the equal-volume impregnation method, the dicarbonyl acetylacetone rhodium is dissolved and added to NQ62 / γ-Al2O3 while stirring. Then, 80 o Drying in an oven at C20°C yields 0.1Rh-NQ62 / γ-Al2O3 catalysts with different molar ratios of polynitrogen ligands.
[0071] Example 5:
[0072] (1) Dissolve 2.5 mg of rhodium dicarbonyl acetylacetone in 1.2 mL of acetone, and dissolve 71.2 mg of γ-aminopropyltriethoxysilane (KH550) / N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH792) / diethylenetriaminopropyltrimethoxysilane (NQ62) in 0.9 mL of anhydrous ethanol.
[0073] (2) Weigh 1.0 g of γ-Al2O3 and add the solutions of γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, and diethylenetriaminopropyltrimethoxysilane to the γ-Al2O3 powder using the equal volume impregnation method, stirring while adding. Then place it in 80 o Drying in an oven at C yields N / γ-Al2O3.
[0074] (3) Then, using the equal-volume impregnation method, rhodium dicarbonyl acetylacetone was dissolved and added to N / γ-Al2O3 while stirring. Then, 80 °C was added. o The catalysts were dried in an oven at C to obtain Rh-N / γ-Al2O3 catalysts with different ligand types. As shown in the figure, the NQ62-coordinated catalyst exhibits better performance compared to other types of polynitrogen ligands, achieving a TOF of 710 h⁻¹ for propylene. -1 .
[0075] Example 6:
[0076] (1) Dissolve 2.5 mg of rhodium dicarbonyl acetylacetone in 1.2 mL of acetone, and dissolve 71.2 mg of diethylenetriaminopropyltrimethoxysilane (NQ62) in 0.9 mL of anhydrous ethanol.
[0077] (2) Weigh 1.0 g of different types of γ-Al2O3 (commercial Al2O3, 111 crystal facet, 110 crystal facet) and add diethylenetriaminepropyltrimethoxysilane solution to γ-Al2O3 powder using the equal volume impregnation method, stirring while adding. Then place it in 80 o Drying in an oven at C yields NQ62 / γ-Al2O3.
[0078] (3) The dicarbonyl acetylacetone rhodium was dissolved and added to NQ62 / γ-Al2O3 by the equal volume impregnation method while stirring. Then it was placed in 80 o Drying in a C oven yields 0.1Rh-NQ62 / γ-Al2O3 catalysts with different support types. As shown in the figure, compared to other Al2O3 supports, the Al2O3 support exposing the 110-type crystal facets exhibits a TOF of 710 h⁻¹ for propylene after loading ligands and Rh species onto its surface. -1 .
[0079] Example 7:
[0080] (1) Dissolve 2.5 mg of different types of Rh precursors (Rh(NO3)3, RhCl3·3H2O, Rh(acac)(CO)2) in 1.2 mL of solvent.
[0081] (2) Dissolve 71.2 mg of diethylenetriaminepropyltrimethoxysilane (NQ62) in 0.9 mL of anhydrous ethanol. Weigh 1.0 g of γ-Al2O3 and add the diethylenetriaminepropyltrimethoxysilane solution to the γ-Al2O3 powder using the equal volume impregnation method, stirring while adding. Then place it in 80 mL of anhydrous ethanol. o Drying in an oven at C yields NQ62 / γ-Al2O3.
[0082] (3) The dicarbonyl acetylacetone rhodium was dissolved and added to NQ62 / γ-Al2O3 by the equal volume impregnation method while stirring. Then it was placed in 80 o The catalysts were dried in an oven at C to obtain Rh-NQ62 / γ-Al2O3 catalysts prepared from different types of Rh precursors.
[0083] Catalytic performance test
[0084] (1) The catalysts described in Examples 1-7 are pressed into 20-40 mesh particles and placed in a fixed-bed reactor;
[0085] (2) In a continuous flow fixed bed reactor, a mixture of propylene, CO and H2 is continuously introduced into the reactor, and then the reactor is heated to 110℃~170℃ to obtain the product butyraldehyde and its partial hydrogenation product butanol.
[0086] (3) The reaction products were determined by gas chromatograph (Hope GC-9860) equipped with an Innowax capillary column (30 m × 0.32 mm × 0.25 μm) and an FID detector.
[0087] Figure 7-11 This invention provides an evaluation of the catalytic activity and selectivity of the catalysts in Examples 3-7 of the present invention in the propylene hydroformylation reaction.
[0088] Using the catalyst of Example 3, without changing other preparation conditions, only changing the Rh species loading, for the propylene hydroformylation reaction, the preferred propylene conversion rate is 69.3% and the propylene TOF is 705 h⁻¹ when the Rh loading is 0.1 wt%. -1 ,like Figure 7 As shown.
[0089] Using the catalyst from Example 4, and without changing other preparation conditions, only the molar amount of the polynitrogen ligand was varied to form different L / Rh molar ratios. For the propylene hydroformylation reaction, when the L / Rh ratios were 8.07, 18.17, 27.7, and 34.15, the TOF of propylene were 116, 179, 710, and 175 h⁻¹, respectively. -1 Preferably, when the L / Rh molar ratio is 27.7, the propylene conversion rate is 70.5% and the propylene TOF is 716 h. -1 ,like Figure 8 As shown.
[0090] Using the catalyst of Example 5, without changing other preparation conditions but only changing the ligand type, the TOF of propylene in the hydroformylation reaction was 101.79, 253.51, 297.94, and 695 h⁻¹ under ligand-free conditions and with ligands KH550, KH792, and N62, respectively. -1 When NQ62 is selected as the preferred ligand, the propylene conversion rate is 68.7% and the propylene TOF is 695 h⁻¹. -1 ,like Figure 9 As shown.
[0091] Using the catalyst of Example 6, without changing other preparation conditions but only the support type, the TOF of propylene in the hydroformylation reaction was 206, 370, and 710 h⁻¹ for commercial Al₂O₃, 111 crystal facet, and 110 crystal facet, respectively. -1Preferably, when the support is γ-Al₂O₃ (110 crystal facet), the propylene conversion rate is 69.5% and the propylene TOF is 710 h⁻¹. -1 ,like Figure 10 As shown.
[0092] Using the catalyst of Example 7, without changing other preparation conditions, the TOF of propylene in the hydroformylation reaction was 58.9, 86.3, and 712 h⁻¹ when the precursor types were Rh(NO₃)₃, RhCl₃·3H₂O, and Rh(acac)(CO)₂, respectively. -1 When rhodium dicarbonyl acetylacetone is preferably selected as the rhodium precursor, the propylene conversion rate is 70.1% and the propylene TOF is 712 h. -1 ,like Figure 11 As shown.
[0093] The catalyst characterization results after the reaction in Examples 1 and 2 are as follows: Figure 12-14 As shown. Figure 12 These are aberration-corrected electron microscopy results after the catalyst reaction in Example 1. From... Figure 12 It can be seen that the catalyst after the reaction in Example 1 exhibits obvious Rh species aggregation. Figure 13 These are the aberration-corrected electron microscopy results after the catalyst reaction in Example 2. From... Figure 13 It can be seen that the Rh species in Example 2 are still in a uniformly dispersed state after the catalyst reaction, which indicates that the polynitrogen ligand can disperse and stabilize the Rh species. Figure 14 Synchrotron radiation test results also illustrate this point. Without the addition of polynitrogen ligands, significant Rh-Rh scattering occurred on the catalyst surface of Example 1, indicating the formation of rhodium clusters. After the addition of polynitrogen ligands, the Rh species in the catalyst of Example 2 were uniformly dispersed on the support surface, with no significant Rh-Rh scattering and only single Rh-N coordination. This indicates that the Rh species on the support surface only coordinate with polynitrogen ligands.
[0094] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A rhodium-based composite catalyst containing polynitrogen ligands, characterized in that, The general formula of the rhodium-based composite catalyst containing polynitrogen ligands is: xRh-N / γ-Al2O3; The molar ratio of Rh to N ligand is 0~35; Where x represents the load quality fraction of Rh, which is 0.05 to 1; The loading mass fraction of Rh is calculated based on the mass of Rh atoms.
2. The rhodium-based composite catalyst containing polynitrogen ligands according to claim 1, characterized in that, The rhodium-based composite catalyst containing polynitrogen ligands is 0.05Rh-N / γ-Al2O3, 0.08Rh-N / γ-Al2O3, 0.1Rh-N / γ-Al2O3, 0.21Rh-N / γ-Al2O3, 0.32Rh-N / γ-Al2O3, or 0.72Rh-N / γ-Al2O3.
3. The rhodium-based composite catalyst containing polynitrogen ligands according to claim 1, characterized in that, The Rh mentioned is derived from Rh salts, which are selected from rhodium dicarbonyl acetylacetone Rh(acac)(CO)2, rhodium trichloride, and rhodium nitrate.
4. The rhodium-based composite catalyst containing polynitrogen ligands according to claim 1, characterized in that, The N-ligand is a polynitrogen ligand as shown in formula (I). , （I）, Where R1 represents -CH3, -CH2CH3, and -CH2CH2CH3; and R2 represents -NH2, -CH2CH2NH2, and -CH2CH2NHCH2CH2NH2.
5. The rhodium-based composite catalyst containing polynitrogen ligands according to claim 1, characterized in that, The polynitrogen ligand has the following structure: 。 6. A method for preparing a rhodium-based composite catalyst containing polynitrogen ligands, characterized in that, Includes the following steps: (1) Mix the polynitrogen ligand as shown in formula (I) with anhydrous ethanol; (2) Dissolve the Rh salt in acetone; (3) Load the solution shown in step (1) onto the surface of the γ-Al2O3 support; (4) The solution obtained in step (2) is added to the powder obtained in step (3) by the equal volume impregnation method, and the powder is dried by standing to obtain the xRh-N / γ-Al2O3 catalyst.
7. The preparation method according to claim 6, characterized in that, The polynitrogen ligand in step (1) is selected from diethylenetriaminepropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β-aminoethyl-γ-aminopropyltrimethoxysilane; the Rh salt in step (2) is selected from rhodium dicarbonylacetylacetone Rh(acac)(CO)2, rhodium trichloride trihydrate, and rhodium nitrate; the polynitrogen ligand as shown in formula (I) is 1 to 15 times the molar amount of the Rh salt.
8. The application of a rhodium-based composite catalyst containing polynitrogen ligands as described in any one of claims 1-6, and the rhodium-based composite catalyst containing polynitrogen ligands obtained by the preparation method according to claim 7 or 8, in the hydroformylation reaction of olefins.
9. The application according to claim 8, characterized in that: The application of the rhodium-based composite catalyst containing polynitrogen ligands in the hydroformylation reaction of propylene.
10. The application according to claim 9, characterized in that, Includes the following steps; (1) The rhodium-based composite catalyst containing polynitrogen ligands is pressed into 20-40 mesh particles and placed in a fixed-bed reactor. (2) In a continuous flow fixed bed reactor, a mixture of propylene, CO and H2 is continuously introduced into the reactor, and then the reactor is heated to 110℃~170℃ to obtain the products butyraldehyde and butanol.