Rhodium-tungsten para-site MOF-based catalyst as well as preparation and application thereof

Abstract

The invention relates to the technical field of heterogeneous catalysis and fine chemical engineering, and discloses a rhodium-tungsten para-site MOF-based catalyst as well as preparation and application thereof. The invention relates to a rhodium-tungsten para-site MOF-based catalyst, which is composed of a catalytic active component, a metal additive and a carrier. The rhodium-tungsten para-site MOF-based catalyst provided by the invention takes a metal organic framework material as a carrier, an active component Rh and a metal additive W are stably anchored on the surface of the carrier, and an Rh-WOx para-site is successfully constructed; the rhodium-tungsten para-site MOF-based catalyst provided by the invention shows excellent catalytic activity and excellent cycle stability in olefin hydroformylation reaction, and overcomes the technical bottlenecks that noble metals in a homogeneous catalysis system are easy to lose and energy consumption is high in a product separation process; an efficient and stable catalyst design thought is provided for olefin hydroformylation reaction, and the catalyst has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical fields of heterogeneous catalysis and fine chemical engineering. Specifically, it relates to a rhodium-tungsten pair-site MOF-based catalyst and its preparation and application. Background Art

[0002] Since it was first reported by Otto Roelen in the 1930s, the hydroformylation reaction has become a crucial transformation process in organic synthesis and industrial chemistry. In this reaction, olefins react with syngas (CO / H 2 2) under the action of a transition metal catalyst to produce aldehyde compounds under appropriate temperature and pressure conditions. Due to its simple reaction pathway and high atom economy, the hydroformylation reaction has been widely used in the field of olefin functionalization. The aldehyde products generated by the hydroformylation reaction have important industrial application values. First of all, these aldehyde products can be further hydrogenated to produce long-chain alcohols, which are used in the production of daily chemicals and industrial raw materials such as detergents, emulsifiers, and plasticizers for plastics; secondly, branched-chain aldehydes and their derivatives also play important roles in the production of flavors and fragrances, pharmaceutical intermediates, and other high-value-added fine chemicals. In addition, due to its high selectivity and high reaction efficiency, the hydroformylation reaction has been widely applied in continuous flow processes, significantly reducing energy consumption and raw material waste, and providing reliable support for green and efficient chemical production.

[0003] Currently, olefin hydroformylation catalysts are still mainly homogeneous catalysts such as rhodium-phosphine complexes. Homogeneous catalysts have a clear active center structure and can exhibit significant catalytic activity and chemical / regioselectivity under mild reaction conditions. However, such catalysts still have some deficiencies, such as problems of metal and ligand loss, poor thermal stability, and difficulty in separating and recovering the catalyst, which to a certain extent limit their promotion in large-scale industrial applications. Compared with homogeneous catalysis, heterogeneous catalytic systems have gradually become the mainstream direction of industrial catalysis due to their advantages of easy separation and recovery. William et al. prepared a RhCo 3 / SBA-15 bimetallic catalyst using the wet impregnation method and used ethylene as the reaction olefin to obtain C 3The yield of the product reached 50%, which was 3.1 times that of Rh / SBA-15, indicating that the synergistic effect between Rh and Co significantly enhanced the catalytic performance (J. Catal. 2024, 438, 115733). Wei et al. also used the wet impregnation method to load Rh, Co, and P on ZnO to prepare the Rh-Co-P / ZnO catalyst. The introduction of Co and P effectively regulated the surface electronic environment of the active metal Rh, thus promoting the formation of the reaction product aldehyde (ACS Appl. Mater. 2021, 13(13), 15113-15121). Although these studies solved the problem of insufficient activity in the heterogeneous catalytic system by introducing new active metals, the accumulation of CO on the surface of the active components would still hinder the adsorption of hydrogen and olefins, thus limiting the further improvement of catalytic activity. Therefore, it is particularly important to design a reasonable catalytic structure and reduce the adsorption strength of the active metal Rh for CO.

[0004] Dual-site catalysis regulates the local electronic environment of the active metal without changing the nature of the active site by introducing metal promoters with variable valence states and strong electron transfer capabilities. This strategy effectively weakens the interaction between the active metal Rh and CO, promotes the conversion of surface CO by the metal promoter, thus significantly reducing the concentration of surface CO, optimizing the subsequent coordination process of olefins and CO, and significantly enhancing the catalytic performance. For example, Ro et al. prepared the Rh-ReO x / Al 2 O 3 dual-site catalyst by the conventional impregnation method. This catalyst showed excellent performance in the hydroformylation of ethylene, with the selectivity of propionaldehyde reaching 40% and the yield being 0.06 (mol 丙醛 ·mol Rh -1 ·min -1 ). Zheng et al. used Mn as the metal promoter to prepare the Rh-MnO x / CeO 2 dual-site catalyst. By reasonably constructing the Rh-MnO x dual-site, the electronic interaction between metals was successfully regulated, making the adsorption strength of the generated Rh δ+ (1 < δ < 2) for CO significantly weaker than that of Rh 3+ . At the same time, MnO x significantly enhanced the conversion ability of CO on the active metal Rh, thus effectively reducing the concentration of surface CO. In the hydroformylation of propylene, this catalyst showed excellent activity, with a TOF value as high as 7200 h -1(Appl. Catal. B-Environ. 2024, 350, 123923). Currently, there is little research on catalysts for the hydroformylation of styrene. Therefore, based on the construction strategy of the site-specific catalytic system, a catalyst Rh-WO x / ZIF-8 with high activity and stability was designed and prepared, providing a feasible solution for the efficient conversion of styrene. SUMMARY OF THE INVENTION

[0005] The purpose of the present invention is to provide a rhodium-tungsten site-specific MOF-based catalyst and its preparation and application. The rhodium-tungsten site-specific MOF-based catalyst has excellent catalytic effects on the hydroformylation of olefins.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A rhodium-tungsten site-specific MOF-based catalyst, which is composed of a catalytic active component, a metal promoter, and a support;

[0009] Among them, the catalytic active component is Rh;

[0010] Among them, the metal promoter is W;

[0011] Among them, the support is a MOF material ZIF-8 (Zn 4 O(BDC) 3 ) with Zn as the node metal.

[0012] Furthermore, the mass ratio of the catalytic active component to the metal promoter is 1∶(2 - 5).

[0013] Furthermore, the catalytic active component accounts for 0.2 - 1.0% of the mass of the support.

[0014] Furthermore, the catalytic active component, the metal promoter, and the support are connected by covalent bonds.

[0015] Two of the technical solutions of the present invention:

[0016] The preparation method of the above-mentioned rhodium-tungsten site-specific MOF-based catalyst includes the following steps:

[0017] 1) Place the rhodium salt in acetone to obtain solution A; place the tungsten salt in water to obtain solution B;

[0018] 2) Place the zinc salt and the organic ligand in methanol, stir, filter, wash, and dry to obtain ZIF-8 powder;

[0019] 3) Place the ZIF-8 powder obtained in step 2) in acetonitrile, add solution A and solution B obtained in step 1), stir, filter, and calcine to obtain the rhodium-tungsten pair-site MOF-based catalyst.

[0020] Further, in step 1), the rhodium salt is one or more of rhodium(II) acetylacetonate dicarbonyl, rhodium(III) chloride, rhodium(III) oxide anhydrous, rhodium(III) chloride hydrate, and rhodium(I) carbonylchloride bis(triphenylphosphine).

[0021] Further, in step 1), the concentration of the rhodium salt in solution A is 5-25 mg / mL.

[0022] Further, in step 1), the tungsten salt is one or more of ammonium metatungstate, ammonium paratungstate, tungsten hexacarbonyl, phosphotungstic acid, and sodium tungstate.

[0023] Further, in step 1), the concentration of the tungsten salt in solution B is 50-250 mg / mL.

[0024] Further, in step 2), the zinc salt is one or more of zinc nitrate hexahydrate, zinc acetate, zinc carbonate, zinc chloride, and zinc acetylacetonate.

[0025] Further, in step 2), the organic ligand is 2-methylimidazole.

[0026] Further, in step 2), the molar ratio of the zinc salt to the organic ligand is 1:(2-5).

[0027] Further, in step 2), the stirring is specifically: stirring at room temperature for 2-4 h.

[0028] Further, in step 3), the volume ratio of the ZIF-8 powder, solution A, and solution B is 1:0.5:1.

[0029] Further, in step 3), the stirring is specifically: stirring at room temperature for 12-24 h.

[0030] Further, in step 3), the calcination is specifically: controlling the heating rate to be 2-8 °C / min and calcining at 200-400 °C for 2-6 h.

[0031] The third technical solution of the present invention:

[0032] The application of the above-mentioned rhodium-tungsten pair-site MOF-based catalyst in the hydroformylation of olefins to aldehydes.

[0033] Further, the application specifically includes the following steps:

[0034] 1) Place the olefin, rhodium-tungsten pair-site MOF-based catalyst, and solvent in a high-pressure reactor;

[0035] 2) In the autoclave where olefins, rhodium-tungsten pair-site MOF-based catalyst and solvent are added in step 1), syngas is introduced, reacted, and cooled to obtain the product.

[0036] Further, in step 1), the olefin is styrene.

[0037] Further, in step 1), the solvent is one or more of toluene, tetrahydrofuran, N,N-dimethylformamide, N-methylpyrrolidone, acetonitrile, anisole, dioxane, dimethyl sulfoxide, and diethylene glycol dimethyl ether.

[0038] Further, in step 1), the dosage ratio of the olefin, rhodium-tungsten pair-site MOF-based catalyst and solvent is (5 - 15) mmol∶(50 - 100) mg∶(5 - 15) mL.

[0039] Further, in step 2), the syngas is composed of H 2 and CO mixed in a volume ratio of 1∶(1 - 3).

[0040] Further, in step 2), the syngas is introduced until the pressure in the autoclave is 4 - 6 MPa.

[0041] Further, in step 2), the reaction is specifically: reacting at 80 - 100 °C for 4 - 6 h.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] A rhodium-tungsten pair-site MOF-based catalyst provided by the present invention uses a metal-organic framework (MOF) material as a carrier, and stably anchors the active component Rh and the metal promoter W on the surface of the carrier, successfully constructing a Rh-WO x pair-site;

[0044] A rhodium-tungsten pair-site MOF-based catalyst provided by the present invention shows excellent catalytic activity and excellent cycle stability in the hydroformylation reaction of olefins, overcomes the technical bottlenecks of easy loss of precious metals in the homogeneous catalytic system and high energy consumption in the product separation process, provides an efficient and stable catalyst design idea for the hydroformylation reaction of olefins, and has good industrial application prospects. Description of the Drawings

[0045] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0046] Figure 1 Transmission electron microscope image and corresponding elemental analysis diagram of the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5. Detailed implementation manners

[0047] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation manners of the present invention. It should be understood that the terms used in the present invention are only for describing specific implementation manners and are not used to limit the present invention.

[0048] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0049] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0050] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are only exemplary.

[0051] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0052] In the following examples, a preparation method of a rhodium-tungsten pair-site MOF-based catalyst includes the following steps:

[0053] 1) Place the rhodium salt in acetone to obtain solution A with a rhodium salt concentration of 5 - 25 mg / mL; place the tungsten salt in water to obtain solution B with a tungsten salt concentration of 50 - 250 mg / mL;

[0054] Among them, the rhodium salt is one or more of rhodium(II) acetylacetonate dicarbonyl, rhodium(III) chloride, anhydrous rhodium(III) oxide, rhodium(III) chloride hydrate, and carbonylchlorobis(triphenylphosphine)rhodium(I);

[0055] Among them, the tungsten salt is one or more of ammonium metatungstate, ammonium paratungstate, tungsten hexacarbonyl, phosphotungstic acid, and sodium tungstate;

[0056] 2) According to the molar ratio of zinc salt to organic ligand being 1∶(2 - 5), the zinc salt and the organic ligand are placed in methanol, stirred at room temperature for 2 - 4 h, filtered, washed, and dried to obtain ZIF-8 powder;

[0057] Among them, the zinc salt is one or more of zinc nitrate hexahydrate, zinc acetate, zinc carbonate, zinc chloride, and zinc acetylacetonate;

[0058] Among them, the organic ligand is 2-methylimidazole;

[0059] 3) According to the volume ratio of ZIF-8 powder, solution A, and solution B being 1∶0.5∶1, the ZIF-8 powder obtained in step 2) is placed in acetonitrile, and solution A and solution B obtained in step 1) are added, stirred at room temperature for 12 - 24 h, filtered, the heating rate is controlled at 2 - 8 °C / min, and calcined at 200 - 400 °C for 2 - 6 h to obtain the rhodium-tungsten pair-site MOF-based catalyst.

[0060] Example 1

[0061] A rhodium-tungsten pair-site MOF-based catalyst

[0062] 1) 0.10 g of rhodium(II) acetylacetonate dicarbonyl is placed in 10 mL of acetone to obtain solution A with a rhodium salt concentration of 10 mg / mL;

[0063] 2) 1.10 g of zinc nitrate hexahydrate and 2.68 g of 2-methylimidazole are placed in 50 mL of methanol (the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1∶4), stirred at room temperature for 4 h, filtered, washed, and dried to obtain ZIF-8 powder;

[0064] 3) 0.50 g of the ZIF-8 powder obtained in step 2) is placed in 30 mL of acetonitrile, and 250 μL of solution A obtained in step 1) is added, stirred at room temperature for 24 h, filtered, the heating rate is controlled at 5 °C / min, and calcined at 250 °C for 4 h to obtain the rhodium-tungsten pair-site MOF-based catalyst, denoted as 0.2Rh / ZIF-8.

[0065] Example 2

[0066] A rhodium-tungsten pair-site MOF-based catalyst

[0067] 1) 0.10 g of rhodium(II) acetylacetonate dicarbonyl is placed in 10 mL of acetone to obtain solution A with a rhodium salt concentration of 10 mg / mL;

[0068] 2) Place 1.10 g of zinc nitrate hexahydrate and 2.68 g of 2-methylimidazole in 50 mL of methanol (the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:4), stir at room temperature for 4 h, filter, wash, and dry to obtain ZIF-8 powder;

[0069] 3) Place 0.50 g of the ZIF-8 powder obtained in step 2) in 30 mL of acetonitrile, add 750 μL of the solution A obtained in step 1), stir at room temperature for 24 h, filter, control the heating rate at 5 °C / min, and calcine at 250 °C for 4 h to obtain the rhodium-tungsten pair-site MOF-based catalyst, denoted as 0.6Rh / ZIF-8.

[0070] Example 3

[0071] A rhodium-tungsten pair-site MOF-based catalyst

[0072] 1) Place 0.10 g of rhodium(II) acetylacetonate dicarbonyl in 10 mL of acetone to obtain solution A with a rhodium salt concentration of 10 mg / mL;

[0073] 2) Place 1.10 g of zinc nitrate hexahydrate and 2.68 g of 2-methylimidazole in 50 mL of methanol (the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:4), stir at room temperature for 4 h, filter, wash, and dry to obtain ZIF-8 powder;

[0074] 3) Place 0.50 g of the ZIF-8 powder obtained in step 2) in 30 mL of acetonitrile, add 1250 μL of the solution A obtained in step 1), stir at room temperature for 24 h, filter, control the heating rate at 5 °C / min, and calcine at 250 °C for 4 h to obtain the rhodium-tungsten pair-site MOF-based catalyst, denoted as 1.0Rh / ZIF-8.

[0075] Example 4

[0076] A rhodium-tungsten pair-site MOF-based catalyst

[0077] 1) Place 0.10 g of rhodium(II) acetylacetonate dicarbonyl in 10 mL of acetone to obtain solution A with a rhodium salt concentration of 10 mg / mL; place 1.00 g of ammonium metatungstate in 10 mL of water to obtain solution B with a tungsten salt concentration of 100 mg / mL;

[0078] 2) Place 1.10 g of zinc nitrate hexahydrate and 2.68 g of 2-methylimidazole in 50 mL of methanol (the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:4), stir at room temperature for 4 h, filter, wash, and dry to obtain ZIF-8 powder;

[0079] 3) Place 0.50 g of the ZIF-8 powder obtained in step 2) in 30 mL of acetonitrile, add 750 μL of solution A obtained in step 1) and 800 μL of solution B obtained in step 1), stir at room temperature for 24 h, filter, control the heating rate at 5 °C / min, and calcine at 250 °C for 4 h to obtain the rhodium-tungsten pair-site MOF-based catalyst, denoted as 0.6Rh-1.2WO x / ZIF-8.

[0080] Example 5

[0081] A rhodium-tungsten pair-site MOF-based catalyst

[0082] 1) Place 0.10 g of rhodium(II) acetylacetonate dicarbonyl in 10 mL of acetone to obtain solution A with a rhodium salt concentration of 10 mg / mL; place 1.00 g of ammonium metatungstate in 10 mL of water to obtain solution B with a tungsten salt concentration of 100 mg / mL;

[0083] 2) Place 1.10 g of zinc nitrate hexahydrate and 2.68 g of 2-methylimidazole in 50 mL of methanol (the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:4), stir at room temperature for 4 h, filter, wash, and dry to obtain ZIF-8 powder;

[0084] 3) Place 0.50 g of the ZIF-8 powder obtained in step 2) in 30 mL of acetonitrile, add 750 μL of solution A obtained in step 1) and 1400 μL of solution B obtained in step 1), stir at room temperature for 24 h, filter, control the heating rate at 5 °C / min, and calcine at 250 °C for 4 h to obtain the rhodium-tungsten pair-site MOF-based catalyst, denoted as 0.6Rh-2.1WO x / ZIF-8.

[0085] Example 6

[0086] A rhodium-tungsten pair-site MOF-based catalyst

[0087] 1) Place 0.10 g of rhodium(II) acetylacetonate dicarbonyl in 10 mL of acetone to obtain solution A with a rhodium salt concentration of 10 mg / mL; place 1.00 g of ammonium metatungstate in 10 mL of water to obtain solution B with a tungsten salt concentration of 100 mg / mL;

[0088] 2) Place 1.10 g of zinc nitrate hexahydrate and 2.68 g of 2-methylimidazole in 50 mL of methanol (the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:4), stir at room temperature for 4 h, filter, wash, and dry to obtain ZIF-8 powder;

[0089] 3) Place 0.50 g of the ZIF-8 powder obtained in step 2) in 30 mL of acetonitrile, add 750 μL of solution A obtained in step 1) and 2000 μL of solution B obtained in step 1), stir at room temperature for 24 h, filter, control the heating rate at 5 °C / min, and calcine at 250 °C for 4 h to obtain the rhodium-tungsten pair-site MOF-based catalyst, denoted as 0.6Rh-3.0WO x / ZIF-8.

[0090] Application Example 1

[0091] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 1 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde

[0092] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst and 10 mL of toluene in a high-pressure reactor;

[0093] 2) Introduce syngas (composed of H 2 and CO mixed in a volume ratio of 1:2) into the high-pressure reactor containing the olefin, the rhodium-tungsten pair-site MOF-based catalyst and the solvent in step 1) until the pressure in the high-pressure reactor reaches 4 MPa, react at 80 °C for 4 h, and cool to obtain the product.

[0094] Application Example 2

[0095] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 2 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde

[0096] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst and 10 mL of toluene in a high-pressure reactor;

[0097] 2) Introduce syngas (composed of H 2 and CO mixed in a volume ratio of 1:2) into the high-pressure reactor containing the olefin, the rhodium-tungsten pair-site MOF-based catalyst and the solvent in step 1) until the pressure in the high-pressure reactor reaches 4 MPa, react at 80 °C for 4 h, and cool to obtain the product.

[0098] Application Example 3

[0099] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 3 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde

[0100] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst and 10 mL of toluene in a high-pressure reactor;

[0101] 2) In the autoclave where olefins, rhodium-tungsten pair-site MOF-based catalyst and solvent were added in step 1), syngas (formed by mixing H 2 and CO in a volume ratio of 1:2) was introduced until the pressure in the autoclave reached 4 MPa, and the reaction was carried out at 80 °C for 4 h, then cooled to obtain the product.

[0102] Application Example 4

[0103] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 4 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde was carried out

[0104] 1) Place 1.0 g of styrene, 100 mg of rhodium-tungsten pair-site MOF-based catalyst and 10 mL of toluene in an autoclave;

[0105] 2) In the autoclave where olefins, rhodium-tungsten pair-site MOF-based catalyst and solvent were added in step 1), syngas (formed by mixing H 2 and CO in a volume ratio of 1:2) was introduced until the pressure in the autoclave reached 4 MPa, and the reaction was carried out at 80 °C for 4 h, then cooled to obtain the product.

[0106] Application Example 5

[0107] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde was carried out

[0108] 1) Place 1.0 g of styrene, 100 mg of rhodium-tungsten pair-site MOF-based catalyst and 10 mL of toluene in an autoclave;

[0109] 2) In the autoclave where olefins, rhodium-tungsten pair-site MOF-based catalyst and solvent were added in step 1), syngas (formed by mixing H 2 and CO in a volume ratio of 1:2) was introduced until the pressure in the autoclave reached 4 MPa, and the reaction was carried out at 80 °C for 4 h, then cooled to obtain the product.

[0110] Application Example 6

[0111] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 6 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde was carried out

[0112] 1) Place 1.0 g of styrene, 100 mg of rhodium-tungsten pair-site MOF-based catalyst and 10 mL of toluene in an autoclave;

[0113] 2) In the autoclave where olefins, rhodium-tungsten pair-site MOF-based catalyst and solvent were added in step 1), syngas (formed by mixing H 2Mix H₂ and CO in a volume ratio of 1:2 until the pressure in the high-pressure reactor reaches 4 MPa, react at 80 °C for 4 h, and then cool to obtain the product.

[0114] Analyze the products obtained in Application Examples 1-6 using liquid chromatography and gas chromatography. The effects of different Rh and W loadings on the hydroformylation performance of the rhodium-tungsten pair-site MOF-based catalyst are shown in Table 1.

[0115] Table 1 Effects of different Rh and W loadings on the hydroformylation performance of the rhodium-tungsten pair-site MOF-based catalyst

[0116]

[0117] As can be seen from the data in Table 1, when the Rh loading is 0.6 wt% and the W loading is 2.1 wt%, the performance is the best, and the aldehyde yield can reach 70.76%.

[0118] Application Example 7

[0119] Use the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst for hydroformylation to produce aldehyde

[0120] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst, and 10 mL of toluene in a high-pressure reactor.

[0121] 2) Introduce syngas (formed by mixing H₂ and CO in a volume ratio of 1:2) into the high-pressure reactor in step 1) containing the olefin, the rhodium-tungsten pair-site MOF-based catalyst, and the solvent until the pressure in the high-pressure reactor reaches 4 MPa, react at 90 °C for 4 h, and then cool to obtain the product. 2 Mix H₂ and CO in a volume ratio of 1:2 until the pressure in the high-pressure reactor reaches 4 MPa, react at 90 °C for 4 h, and then cool to obtain the product.

[0122] Application Example 8

[0123] Use the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst for hydroformylation to produce aldehyde

[0124] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst, and 10 mL of toluene in a high-pressure reactor.

[0125] 2) Introduce syngas (formed by mixing H₂ and CO in a volume ratio of 1:2) into the high-pressure reactor in step 1) containing the olefin, the rhodium-tungsten pair-site MOF-based catalyst, and the solvent until the pressure in the high-pressure reactor reaches 4 MPa, react at 100 °C for 4 h, and then cool to obtain the product. 2 Mix H₂ and CO in a volume ratio of 1:2 until the pressure in the high-pressure reactor reaches 4 MPa, react at 100 °C for 4 h, and then cool to obtain the product.

[0126] Application Example 9

[0127] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde was carried out.

[0128] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst, and 10 mL of toluene in a high-pressure reactor.

[0129] 2) In the high-pressure reactor where the olefin, the rhodium-tungsten pair-site MOF-based catalyst, and the solvent were added in step 1), syngas (composed of H 2 and CO mixed in a volume ratio of 1:2) was introduced until the pressure in the high-pressure reactor reached 5 MPa, and the reaction was carried out at 90 °C for 4 h, then cooled to obtain the product.

[0130] Application Example 10

[0131] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde was carried out.

[0132] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst, and 10 mL of toluene in a high-pressure reactor.

[0133] 2) In the high-pressure reactor where the olefin, the rhodium-tungsten pair-site MOF-based catalyst, and the solvent were added in step 1), syngas (composed of H 2 and CO mixed in a volume ratio of 1:2) was introduced until the pressure in the high-pressure reactor reached 6 MPa, and the reaction was carried out at 90 °C for 4 h, then cooled to obtain the product.

[0134] Application Example 11

[0135] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde was carried out.

[0136] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst, and 10 mL of toluene in a high-pressure reactor.

[0137] 2) In the high-pressure reactor where the olefin, the rhodium-tungsten pair-site MOF-based catalyst, and the solvent were added in step 1), syngas (composed of H 2 and CO mixed in a volume ratio of 1:2) was introduced until the pressure in the high-pressure reactor reached 5 MPa, and the reaction was carried out at 90 °C for 5 h, then cooled to obtain the product.

[0138] Application Example 12

[0139] Using the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst, hydroformylation to produce aldehyde was carried out.

[0140] 1) Place 1.0 g of styrene, 100 mg of the rhodium-tungsten pair-site MOF-based catalyst, and 10 mL of toluene into a high-pressure reactor;

[0141] 2) Introduce syngas (formed by mixing H 2 and CO in a volume ratio of 1:2) into the high-pressure reactor containing the olefin, rhodium-tungsten pair-site MOF-based catalyst, and solvent in step 1) until the pressure in the high-pressure reactor reaches 5 MPa, react at 90 °C for 6 h, and then cool to obtain the product.

[0142] Analyze the products obtained in Application Examples 7 - 12 using liquid chromatography and gas chromatography. The influence of different process conditions on the hydroformylation performance of the catalyst 0.5Rh-2.1WO x / ZIF-8 is shown in Table 2;

[0143] Table 2 Influence of different process conditions on the hydroformylation performance of the catalyst 0.5Rh-2.1WO x / ZIF-8

[0144]

[0145] As can be seen from the data in Table 2, the catalyst 0.5Rh-2.1WO x / ZIF-8 approaches its optimal performance at 90 °C, 5 MPa, and 5 h. At this time, the aldehyde yield is 89.90%. Continuing to increase the reaction conditions has no obvious promoting effect on improving the catalyst performance.

[0146] Cyclic stability detection

[0147] Use the rhodium-tungsten pair-site MOF-based catalyst prepared in Example 5 as the rhodium-tungsten pair-site MOF-based catalyst for cyclic testing. The reaction conditions are 90 °C, 5 MPa, and 5 h;

[0148] The results of the cyclic stability detection are shown in Table 3;

[0149] Table 3 Results of the cyclic stability detection

[0150]

[0151] As can be seen from the data in Table 3, after 6 cycles, the aldehyde yield can retain 80% of the initial yield.

[0152] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: Modifications or equivalent substitutions can still be made to the specific implementation manners of the present invention, and any modification or equivalent substitution that does not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A rhodium-tungsten para-site MOF-based catalyst, characterized in that: The rhodium-tungsten para-site MOF-based catalyst is composed of a catalytically active component, a metal promoter and a carrier; Wherein, the catalytically active component is Rh; Wherein, the metal additive is W; Wherein, the carrier is a MOF material ZIF-8 (Zn4O(BDC)3) with Zn as the node metal.

2. A rhodium-tungsten para-site MOF-based catalyst according to claim 1, characterized in that: The mass ratio of the catalytically active component to the metal additive is 1:(2-5); the catalytically active component accounts for 0.2-1.0% of the mass of the carrier.

3. A rhodium-tungsten para-site MOF-based catalyst according to claim 1, characterized in that: The catalytically active component, the metal promoter and the carrier are connected by covalent bonds.

4. A method for preparing the rhodium-tungsten para-site MOF-based catalyst according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) Place rhodium salt in acetone to obtain solution A; place tungsten salt in water to obtain solution B; 2) placing zinc salt and organic ligand in methanol, stirring, filtering, washing and drying to obtain ZIF-8 powder; 3) The ZIF-8 powder obtained in step 2) is placed in acetonitrile, and the solution A and solution B obtained in step 1) are added, stirred, filtered, and calcined to obtain the rhodium-tungsten para-site MOF-based catalyst.

5. The preparation method according to claim 4, characterized in that: In step 1), the rhodium salt is one or more of dicarbonyl acetylacetonate rhodium, rhodium chloride, anhydrous rhodium oxide, hydrated rhodium trichloride and bis(triphenylphosphine)carbonyl rhodium chloride; the concentration of the rhodium salt in solution A is 5-25 mg / mL; the tungsten salt is one or more of ammonium metatungstate, ammonium paratungstate, hexacarbonyl tungsten, phosphotungstic acid and sodium tungstate; the concentration of the tungsten salt in solution B is 50-250 mg / mL.

6. The preparation method according to claim 4, characterized in that: In step 2), the zinc salt is one or more of zinc nitrate hexahydrate, zinc acetate, zinc carbonate, zinc chloride and zinc acetylacetonate; in step 2), the organic ligand is 2-methylimidazole; in step 2), the molar ratio of the zinc salt to the organic ligand is 1:(2-5); in step 2), the stirring is specifically: stirring at room temperature for 2-4 hours.

7. The preparation method according to claim 4, characterized in that: In step 3), the volume ratio of the ZIF-8 powder, solution A and solution B is 1:0.5:1; the stirring is specifically: stirring at room temperature for 12 to 24 hours; the calcination is specifically: controlling the heating rate to 2 to 8°C / min, and calcining at 200 to 400°C for 2 to 6 hours.

8. Use of the rhodium-tungsten para-site MOF-based catalyst as claimed in any one of claims 1 to 3 in the hydroformylation of olefins to produce aldehydes.

9. The use according to claim 8, characterized in that: The application specifically comprises the following steps: 1) placing olefin, rhodium-tungsten para-site MOF-based catalyst and solvent in a high-pressure reactor; 2) Synthesis gas is introduced into the high-pressure reactor to which olefin, rhodium-tungsten para-site MOF-based catalyst and solvent are added in step 1), and the reaction is carried out and the product is obtained by cooling.

10. The use according to claim 9, characterized in that: In step 1), the olefin is styrene; the solvent is one or more of toluene, tetrahydrofuran, N,N-dimethylformamide, N-methylpyrrolidone, acetonitrile, anisole, dioxane, dimethyl sulfoxide and diethylene glycol dimethyl ether; the amount ratio of the olefin, rhodium tungsten para-site MOF-based catalyst and solvent is (5-15) mmol: (50-100) mg: (5-15) mL; in step 2), the synthesis gas is formed by mixing H2 and CO in a volume ratio of 1: (1-3); the synthesis gas needs to be introduced until the pressure in the high-pressure reactor is 4-6 MPa; the reaction is specifically: reacting at 80-100°C for 4-6 hours.

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