Preparation method and application of olefin hydroformylation catalyst

Abstract

The invention discloses a preparation method and application of an olefin hydroformylation catalyst. The preparation method comprises the following steps: firstly, taking zirconium oxychloride and 4, 4 ', 4' '-phosphoryl tribenzoic acid as raw materials, and preparing a metal organic framework Zr-PTBA through a solvothermal method; then, preparing a Zr-PTBA-Rh powder material with Rh < 3 + > coordination adsorption through a dipping and adsorption method; and then, roasting and reducing in a reducing atmosphere to prepare the phosphorus-doped Zr-MOFs carrier loaded Rh catalyst Rh / Zr-PTBA. In the hydroformylation reaction of olefin, the Rh / Zr-PTBA catalyst, terminal olefin and a solvent toluene are added into a high-pressure reaction kettle, 1.0-3.0 MPa CO / H2 mixed gas (VCO: VH2 = 1: 1) is introduced, the reaction is performed for 4-16 hours at 80-140 DEG C, the olefin conversion rate is as high as 99%, the aldehyde selectivity is as high as 94%, the catalyst can be used for five times, the activity is still kept, and Rh is not lost. According to the method disclosed by the invention, the preparation method of the Rh / Zr-PTBA catalyst is simple, the active site superfine Rh nanoparticles are highly dispersed and embedded into the pore channels of the Zr-PTBA carrier, relatively high catalytic activity and stability can be kept in olefin hydroformylation reaction, and the Rh / Zr-PTBA catalyst is easy to industrially produce and convert.

Description

Technical Field

[0001] This invention provides a catalyst for the hydroformylation of olefins to synthesize aldehydes and its preparation method, belonging to the field of fine chemical technology. Background Technology

[0002] Olefin hydroformylation is a key process for the efficient conversion of olefins into high-value-added aldehydes. This process can produce over ten million tons of aldehyde compounds annually. Aldehydes are important raw materials for the synthesis of fine chemicals such as alcohols, acids, and esters. Discovered by Otto Roelen in 1938, this reaction is one of the most widely used homogeneous catalytic processes and is considered an ideal route for the green synthesis of aldehydes due to its 100% atom economy (Angew. Chem. Int. Ed., 2018, 57, 14817-14821).

[0003] The core challenge in olefin hydroformylation lies in controlling the regioselectivity of CO insertion. Early industrial applications used cobalt-based catalysts (such as Co₂(CO)₈), but their activity and stability were insufficient. Subsequently, rhodium-based complexes became mainstream due to their superior catalytic performance. From HRh(CO)(PPh₃)₃, an improvement on Wilkinson catalysts, to a series of novel Rh complexes designed based on the electronic and steric effects of phosphine ligands, the regioselectivity of catalytic systems has been effectively controlled (Organic Chemistry, 2019, 39, 207-214). However, homogeneous systems suffer from inherent limitations such as unstable rhodium active sites, high cost, and difficult separation. Therefore, heterogeneous catalytic systems have attracted widespread attention. For example, the CeO2-supported single-atom Rh catalyst (Angew. Chem. Int. Ed., 2020, 59, 7430-7434) and the TiO2-supported Rh catalyst (CCS Chem., 2021, 3, 1814-1822) developed by Academician Zhang Tao's team both achieved efficient hydroformylation under phosphine-free conditions, but their linear aldehyde selectivity (<50%) needs improvement. In contrast, Ding Yunjie's team constructed a phosphine-ligand-intercalated copolymer-supported Rh catalyst using a "homogeneous catalyst heterogeneity" strategy, achieving both high activity and high regioselectivity (J. Catal., 2017, 353, 123-132). In summary, developing phosphorus-doped support-supported Rh catalysts based on heterogeneity strategies to achieve highly regioselective hydroformylation of olefins (including butadiene) remains a key research direction in this field.

[0004] Heterogeneous Rh-based catalysts are considered an ideal alternative to homogeneous systems, but their development faces two major challenges: First, without the introduction of phosphine ligands, the metal active sites lack the necessary electronic and spatial microenvironment regulation, resulting in generally poor regioselectivity. More seriously, under high-pressure syngas (CO / H2) reaction conditions, the metal active components on the support surface are prone to carbonylation, forming volatile metal carbonyl compounds and leading to activity loss. Research data shows that this phenomenon is widespread: for example, for Co / AC catalysts, the loss rate of active cobalt is as high as approximately 20% and 50% at syngas pressures of 3.0 MPa and 5.0 MPa, respectively, consistent with the conclusion that more than 50 cobalt-containing heterogeneous catalysts exhibit severe cobalt loss during the reaction (Chem. Eur. J., 2019, 25, 5534-5538).

[0005] The loss of metal carbonylation has severely restricted the development of heterogeneous catalytic systems in two ways: First, it prevents the catalyst from maintaining its heterogeneous form, thus losing its core advantage of easy separation and recycling; second, the metal carbonyl compounds that have been lost into the reaction solution are themselves catalytically active, forming a mixed catalytic system in which homogeneous and heterogeneous phases coexist. This not only increases the difficulty of product purification but also seriously interferes with the accurate study of intrinsic catalytic structure-activity relationships. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for preparing a phosphorus-doped Zr-MOFs-supported Rh catalyst; and using the prepared catalyst, a method for catalytic hydroformylation of olefins to synthesize aldehyde compounds is provided (taking styrene catalytic hydroformylation as an example, see the following formula).

[0007]

[0008] The following technical solution is adopted to solve the technical problem of the present invention:

[0009] A method for preparing an olefin hydroformylation catalyst and its application, the specific method for preparing a phosphorus-doped Zr-MOFs-supported Rh catalyst is as follows: First, using zirconium oxychloride and 4,4”,4”'-phosphoryltribenzoic acid as raw materials, a metal-organic framework (Zr-PTBA) is prepared by a solvothermal method; then, a certain amount of Zr-PTBA is added to an ethanol solution containing RhCl3, stirred at room temperature to allow for full adsorption, and the solvent is removed by rotary evaporation to obtain Zr-PTBA-Rh powder; then, the obtained Zr-PTBA-Rh powder is placed in a tube furnace and heated to 100-200℃ and calcined in a hydrogen atmosphere for 2 hours to obtain the Rh / Zr-PTBA catalyst.

[0010] The precursor material used in the prepared Rh / Zr-PTBA catalyst is Zr-PTBA, which is synthesized by a solvothermal method. This precursor material has abundant micro-mesoporous structures and triphenylphosphine oxide (O=PPh3) coordination sites, enabling it to efficiently adsorb and coordinate Rh. 3+ This leads to the preparation of Zr-PTBA-Rh precursor materials.

[0011] In the preparation method of the Rh / Zr-PTBA catalyst, PTBA-Rh is used as the precursor material, and 4,4”,4”'-phosphoryltribenzoic acid is used as the phosphorus source. A Zr-PTBA support with a large specific surface area, excellent stability, and hierarchical porous structure can be derived by solvothermal synthesis. The specific surface area of ​​the Zr-PTBA support is 505 m². 2 ·g -1 The average pore size is 1.2 nm.

[0012] In the method for preparing the Rh / Zr-PTBA catalyst, the calcination temperature in the reducing atmosphere is 100-200℃, and the reducing atmosphere is V. H2 V Ar =1:9, reducing gas flow rate is 20mL / min, and heating rate is 2-10℃ / min.

[0013] In the Rh / Zr-PTBA catalyst preparation method, Rh nanoparticles are highly dispersed and embedded in the pores of the Zr-PTBA support, effectively preventing the loss of Rh active sites.

[0014] The mass ratio of metal to support in the prepared Rh / Zr-PTBA catalyst is Rh:Zr-PTBA = 0.01-0.04:1.

[0015] The application of the Rh / Zr-PTBA catalyst in the hydroformylation reaction of olefins, taking styrene as an example, is as follows: A certain amount of Rh / Zr-PTBA catalyst, styrene, and solvent are added to a high-pressure reactor, and a high-pressure CO and H2 mixture with a molar ratio of 1:1 is introduced into the high-pressure reactor. The reactor temperature is set, and the reaction progress is analyzed by gas chromatography. The conversion rate of styrene is as high as 99.9%, and the yield of aldehydes is as high as 94.3%.

[0016] The gas pressure for the olefin hydroformylation reaction is 1.0-3.0 MPa, the reaction temperature is 80-140℃, and the reaction time is 4-16 hours.

[0017] The Rh / Zr-PTBA catalyst can be reused up to 5 times for the olefin hydroformylation reaction, while still maintaining stable catalytic activity.

[0018] Advantages of this invention: 1. The phosphorus-doped Zr-MOFs-supported Rh catalyst Rh / Zr-PTBA designed and prepared in this invention is mainly prepared by a simple impregnation adsorption method and a calcination reduction method. The catalyst preparation method is simple, the conditions are mild, and the catalyst is easy to scale up for production. 2. The ultrafine Rh nanoparticles in the Rh / Zr-PTBA catalyst are uniformly dispersed and encapsulated in the pores of the Zr-PTBA support. The catalyst has excellent stability, retaining high activity even after five reuses, and there is no Rh loss. 3. The Rh / Zr-PTBA catalyst provided in this invention exhibits high olefin conversion and aldehyde yield in the hydroformylation reaction of olefins. The reaction operation is simple and easy to control, making it easy for industrial application and scale-up production. Attached Figure Description

[0019] Figure 1 The XRD patterns are of the Zr-PTBA support and Rh / Zr-PTBA catalyst prepared in Example 1 of this invention.

[0020] Figure 2 Thermogravimetric analysis diagram of the Rh / Zr-PTBA catalyst prepared in Example 1 of this invention.

[0021] Figure 3 The N2 adsorption-desorption curve (a) and pore size distribution diagram (b) of the Zr-PTBA support prepared in Example 1 of this invention.

[0022] Figure 4 Transmission electron microscopy (TEM) images of the Zr-PTBA support (a) and Rh / Zr-PTBA catalyst (b) prepared in Example 1 of this invention.

[0023] Figure 5 This is a diagram illustrating the effect of catalyst reuse in the hydroformylation reaction of styrene catalyzed by the Rh / Zr-PTBA catalyst in Example 1 of this invention. Detailed Implementation

[0024] Example 1

[0025] A method for preparing an olefin hydroformylation catalyst and its application are disclosed. The specific operation method is as follows: 0.12 g of zirconium oxychloride octahydrate, 0.21 g of 4,4”,4”'-phosphoryltribenzoic acid, 20 mL of N,N-dimethylformamide, and 12 mL of acetic acid are added to a round-bottom flask and dissolved uniformly. The mixture is then stirred continuously at room temperature for 0.5 h. The mixed solution is transferred to a 50 mL stainless steel autoclave with a polytetrafluoroethylene liner and heated at 120 °C for 48 h. After cooling to room temperature, the mixture is centrifuged, washed three times each with N,N-dimethylformamide and ethanol, and then dried at 60 °C for 24 h in a vacuum drying oven to obtain phosphorus-doped Zr-MOFs support Zr-PTBA. Dissolve 10-100 mg RhCl3·3H2O in 40 mL of ethanol solution and stir at 60 °C for 2 h to ensure complete dissolution. Then add 1 g of catalyst support Zr-PTBA and stir for 2 h to ensure complete adsorption. Remove the ethanol solvent by rotary evaporation. Place the resulting solid powder in a tube furnace and heat it to 200 °C at a rate of 5 °C / min. Calcinate the powder under an H2 / Ar atmosphere for 2 h to obtain the Rh / Zr-PTBA catalyst, in which the Rh content is 1.0%-4.0%.

[0026] Example 2

[0027] A method for preparing an olefin hydroformylation catalyst and its application are disclosed. The specific method is as follows: 5 mg of Rh(1%) / Zr-PTBA catalyst from Example 1, 57 μL of styrene, and 5 mL of 1,4-dioxane are added to a 25 mL high-pressure reactor, and a CO / H2 mixture at 2 MPa (V) is introduced. CO V H2 The reaction mixture was prepared at a ratio of 1:1 and reacted at 120℃ for 8 hours. Gas chromatography analysis showed that the conversion rate of styrene was 99.9%, with a selectivity of 94.3% for aldehydes.

[0028] Examples 3-7

[0029] A method for preparing an olefin hydroformylation catalyst and its application are disclosed. The specific method is as follows: Following the method in Example 2, 5 mg of the Rh(1%) / Zr-PTBA catalyst from Example 1, 57 μL of the olefin compound, and 5 mL of 1,4-dioxane were added to a 25 mL high-pressure reactor, and a CO / H2 mixture at 2 MPa (V) was introduced. CO V H2 =1:1), reacted at 120℃ for 8h, and the olefin conversion rate and the selectivity of the product aldehyde were detected by gas chromatography. The results are shown in Table 1 below.

[0030] Table 1. Results of hydroformylation of different olefins catalyzed by Rh / Zr-PTBA.

[0031]

[0032] Example 8

[0033] A method for preparing an olefin hydroformylation catalyst and its application are disclosed. The specific method is as follows: The Rh(1%) / Zr-PTBA catalyst from Example 2 is filtered and washed, then added to a 25 mL high-pressure reactor along with 57 μL of styrene and 5 mL of 1,4-dioxane. A CO / H2 mixture at 2 MPa (V) is then introduced. CO V H2 =1:1), reacted at 120℃ for 8h, and analyzed by gas chromatography. The conversion rate of styrene was higher than 99% when the Rh(1%) / Zr-PTBA catalyst was reused 5 times, and the selectivity of aldehydes was higher than 90%. The Rh content was detected by ICP and no Rh loss was observed.

Claims

1. A method for preparing an olefin hydroformylation catalyst and its application, characterized in that: First, Zr-PTBA, a metal-organic framework, was prepared by a solvothermal method using zirconium oxychloride and 4,4”,4”'-phosphoryltribenzoic acid as raw materials. Then, Rh was prepared by impregnation and adsorption methods. 3+ The Zr-PTBA-Rh powder material was coordinated and adsorbed; then, it was calcined and reduced in a reducing atmosphere to obtain the Rh catalyst Rh / Zr-PTBA supported on a phosphorus-doped Zr-MOFs support.

2. The preparation method of the olefin hydroformylation catalyst according to claim 1 and its application, characterized in that: The precursor material used in the prepared Rh / Zr-PTBA catalyst is Zr-PTBA, which is synthesized by a solvothermal method using zirconium oxychloride and 4,4”,4”'-phosphoryltribenzoic acid. This precursor material possesses abundant micro-mesoporous structures and triphenylphosphine oxide (O=PPh3) coordination sites, enabling efficient adsorption and coordination of Rh. 3+ Thus, Rh was obtained 3+ Coordination-type Zr-PTBA-Rh precursor materials.

3. The preparation method of the olefin hydroformylation catalyst according to claim 1 and its application, characterized in that: Using Zr-PTBA as a precursor and 4,4”,4”'-phosphoryltribenzoic acid as the phosphorus source, a Zr-PTBA support with a large specific surface area, excellent stability, and hierarchical porous structure can be synthesized via a solvothermal method. The specific surface area of ​​the Zr-PTBA support is 505 m². 2 ·g -1 The average pore size is 1.2 nm.

4. The preparation method of the olefin hydroformylation catalyst according to claim 1 and its application, characterized in that: In the method for preparing the Rh / Zr-PTBA catalyst, the calcination temperature in the reducing atmosphere is 100-200℃, and the reducing atmosphere is V. H2 V Ar =1:9, reducing gas flow rate is 20mL / min, heating rate is 2-10℃ / min.

5. The preparation method of the olefin hydroformylation catalyst according to claim 1 and its application, characterized in that: In the Rh / Zr-PTBA catalyst preparation method, Rh nanoparticles are highly dispersed and embedded in the pores of the Zr-PTBA support, effectively preventing the loss of Rh active sites. The mass ratio of metal to support in the Rh / Zr-PTBA catalyst is Rh:Zr-PTBA = 0.01-0.04:

1.

6. The preparation method of the olefin hydroformylation catalyst according to claim 1 and its application, characterized in that: The Rh / Zr-PTBA catalyst was applied to the hydroformylation reaction of terminal olefins. The Rh / Zr-PTBA catalyst, styrene, and toluene solvent were added to a high-pressure reactor, which was then purged with a CO / H2 mixture at 1.0-3.0 MPa (V). CO V H2 =1:1), react at 80-140℃ for 4-16 hours, the styrene conversion rate is as high as 99.9%, and the selectivity of aldehydes is as high as 94.3%.

7. The preparation method of the olefin hydroformylation catalyst according to claims 1 and 6 and its application, characterized in that: The Rh / Zr-PTBA catalyst was applied to the hydroformylation reaction of styrene to evaluate the reusability and stability of the catalyst. The catalyst can be reused 5 times while maintaining high catalytic activity and Rh is not lost. The styrene conversion rate is higher than 99% and the selectivity of aldehydes is higher than 90%.

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