A pd@moF-apba catalyst and a preparation method thereof
By preparing the Pd@MOF-APBA catalyst, the problem of easy deactivation of supported palladium catalysts was solved, achieving high catalytic activity and easy recovery, making it suitable for repeated use in the Heck reaction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING UNIV
- Filing Date
- 2024-01-31
- Publication Date
- 2026-05-08
AI Technical Summary
Existing supported palladium catalysts suffer from palladium leaching or aggregation, resulting in fewer catalyst cycles, low metal utilization, difficulty in recovery, and environmental pollution.
Using Pd(OAc)2 as a precursor, MOF-808 was ligand exchanged with 3-amino-4-(pyridin-2-yl)benzoic acid to prepare Pd@MOF-APBA catalyst. MOF-808 was synthesized by solvothermal method, and MOF-APBA was prepared by solvent-assisted ligand exchange method. Pd(OAc)2 was then loaded into the material.
The catalyst is easy to separate and reuse multiple times, maintains high catalytic activity, and can achieve a conversion number of over 80,000 when catalyzing the Heck reaction. It has a stable structure and is suitable for a variety of substrates.
Smart Images
Figure CN118142585B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of chemical technology, and in particular relates to a Pd@MOF-APBA catalyst, as well as a method for preparing the Pd@MOF-APBA catalyst. Background Technology
[0002] The Heck reaction, a palladium-catalyzed cross-coupling reaction involving the synthesis of substituted alkenes from aryl or vinyl halides, is one of the most widely used carbon-carbon coupling reactions in organic chemistry, often referred to as the "cog" between alkenes and organohalides. It is widely applied in the synthesis of dyes, pharmaceuticals, and natural products. However, in homogeneous catalysis, residual palladium catalyst can contaminate the product; furthermore, the catalyst is expensive and its recovery process is complex and environmentally polluting. These factors limit the application of the Heck reaction. Developing supported palladium catalysts is one effective way to overcome these limitations.
[0003] However, current supported palladium catalysts suffer from severe palladium leaching or aggregation, resulting in fewer catalyst cycles and lower metal utilization. Summary of the Invention
[0004] The purpose of this invention is to provide a Pd@MOF-APBA catalyst that has high catalytic activity, is easy to separate and recover, and can maintain high catalytic activity even after multiple recycling and reuse, in order to address the above-mentioned problems.
[0005] Another object of the present invention is to provide a method for preparing the Pd@MOF-APBA catalyst.
[0006] The objective of this invention is achieved through the following technical solution:
[0007] The present invention provides a Pd@MOF-APBA catalyst, which is obtained by using Pd(OAc)2 as a precursor and exchanging MOF-808 with 3-amino-4-(pyridine-2-yl)benzoic acid (hereinafter referred to as APBA) to obtain MOF material MOF-APBA with Pd coordination sites, and then combining it with Pd(OAc)2.
[0008] The present invention provides a method for preparing a Pd@MOF-APBA catalyst, comprising the following steps:
[0009] (1) Preparation of MOF-808
[0010] Weigh out pyromellitic acid and zirconium oxychloride octahydrate in a mass ratio of 1:4-5, dissolve them in a mixed solvent of water and acetic acid in a volume ratio of 1:1, and prepare a solution with a mass concentration of 70.2-80 g•L.-1 The solution was stirred at 100°C for 24 hours, cooled to room temperature, and a powder precipitate was obtained. The precipitate was washed with water, centrifuged at 10,000 rpm, and the solid was dried at 120°C for 10-12 hours to obtain MOF-808.
[0011] (2) Preparation of MOF-APBA by solvent-assisted ligand exchange method
[0012] Weigh MOF-808 and APBA in a mass ratio of 1:0.14-0.686 into methanol to prepare a solution with a mass concentration of 22.8-33.72 g•L. -1 The solution of APBA was stirred at room temperature for 24 hours, centrifuged at 10,000 rpm, the free APBA was completely washed away with methanol, and dried at 100-120℃ for 24 hours to obtain MOF-APBA.
[0013] (3) Preparation of Pd@MOF-APBA
[0014] MOF-APBA and Pd(OAc)₂ in a mass ratio of 1:0.09-0.18 were weighed into dichloromethane to form a solution with a mass concentration of 21.8-23.6 g•L⁻¹. -1 The solution was stirred at room temperature for 24 hours, centrifuged at 10,000 rpm, and the free Pd(OAc)2 was completely washed away with dichloromethane. The solution was then dried under reduced pressure at 40-60 °C to obtain Pd@MOF-APBA.
[0015] The above-mentioned method for preparing a Pd@MOF-APBA catalyst, wherein the solvent in step (2) is water, methanol or ethanol.
[0016] The above-mentioned method for preparing a Pd@MOF-APBA catalyst, wherein the solvent in step (3) is dichloromethane, acetonitrile or methanol.
[0017] Compared with existing technologies, this invention has significant advantages. As can be seen from the above technical solution: this invention synthesizes MOF-808 via a solvothermal method, then prepares MOF-APBA via a solvent-assisted ligand exchange method, and finally loads Pd(OAc)2 into the material through coordination to obtain Pd@MOF-APBA. The catalyst preparation process is simple, time-saving, and easily reproducible. Post-reaction processing is simple; the catalyst is easily separated from the reaction system and can be reused multiple times while maintaining a high conversion rate. The catalyst of this invention has a stable structure and high activity in catalyzing the Heck reaction between iodobenzene and ethyl acrylate. When the catalyst-to-substrate ratio is 1.5:100, the catalytic conversion number can exceed 80,000. Attached Figure Description
[0018] Figure 1 Here is a structural simulation diagram of MOF-808;
[0019] Figure 2 for Figure 1 Simulation diagram of the intermediate mesoporous structure;
[0020] Figure 3 Here is a structural simulation diagram of MOF-APBA;
[0021] Figure 4 The structure simulation diagram of Pd@MOF-APBA is shown. Detailed Implementation
[0022] Example 1:
[0023] A method for preparing a Pd@MOF-APBA catalyst includes the following steps:
[0024] (1) Preparation of MOF-808
[0025] Weigh 117.0 mg of trimesic acid and 585.0 mg of zirconium oxychloride octahydrate and dissolve them in 10.0 mL of a mixed solvent of water and acetic acid in a 1:1 volume ratio. Stir the mixture at 100 °C for 24 hours, then cool to room temperature to obtain a powder precipitate. Wash the precipitate three to five times with water, centrifuge at 10,000 rpm, and dry the solid at 100 °C for 12 hours to obtain MOF-808. (See [link to relevant documentation]). Figure 1 This is a structural simulation diagram. The red spheres represent oxygen atoms, the gray spheres represent carbon atoms, and the blue blocks represent zirconium-oxygen clusters formed by the coordination of zirconium with oxygen atoms. These zirconium-oxygen clusters form a framework structure through coordination with trimesic acid. Acetic acid also coordinates with the zirconium in the zirconium-oxygen clusters to achieve coordination saturation, but does not participate in the framework formation. The large yellow spheres represent small pores in the material, and there are also mesopores in between. See [link to diagram]. Figure 2 This is a simulation diagram of the mesopore; some atoms have been omitted for clarity.
[0026] (2) Preparation of MOF-APBA by solvent-assisted ligand exchange method
[0027] Weigh 50.0 mg MOF-808 and 34.3 mg APBA into 2.5 mL of methanol, stir at room temperature for 24 hours, centrifuge at 10,000 rpm to completely wash away the free APBA with methanol, centrifuge at 10,000 rpm for 1 minute, and dry at 100 °C for 24 hours to obtain MOF-APBA. Figure 3 This is a structural simulation diagram, showing APBA replacing part of the acetic acid coordinated with the zirconium cluster in MOF-808;
[0028] (3) Preparation of Pd@MOF-APBA
[0029] Weigh 50.0 mg MOF-APBA and 4.5 mg Pd(OAc)₂ into 2.5 mL of dichloromethane, stir at room temperature for 24 hours, centrifuge at 10000 rpm for 3 minutes, wash away the free Pd(OAc)₂ completely with dichloromethane, and dry at 40 °C to obtain Pd@MOF-APBA, which is then sealed and stored. See also Figure 4 This is a structural simulation diagram of Pd@MOF-APBA. In MOF-APBA, APBA is fixed in the material through coordination of amino nitrogen and pyridine nitrogen with palladium acetate.
[0030] Example 2:
[0031] A method for preparing a Pd@MOF-APBA catalyst includes the following steps:
[0032] (1) Preparation of MOF-808
[0033] Weigh 190.5 mg of trimesic acid and 877.5 mg of zirconium oxychloride octahydrate and dissolve them in 13.4 mL of a mixed solvent of water and acetic acid in a volume ratio of 1:1. Stir the mixture at 100 °C for 24 hours, cool it to room temperature, and obtain a powder precipitate. Wash the precipitate with water three to five times, centrifuge at 10,000 rpm, and dry the solid at 100 °C for 12 hours to obtain MOF-808.
[0034] (2) Preparation of MOF-APBA by solvent-assisted ligand exchange method
[0035] Weigh 50.0 mg MOF-808 and 7.0 mg APBA into 2.5 mL of water, stir at room temperature for 24 hours, centrifuge at 10,000 rpm to separate them, wash away the free APBA completely with water, centrifuge at 10,000 rpm for 1 minute, and dry at 120℃ for 24 hours to obtain MOF-APBA.
[0036] (3) Preparation of Pd@MOF-APBA
[0037] Take 50.0 mg MOF-APBA and 9.0 mg Pd(OAc)2 in 2.5 mL of acetonitrile, stir at room temperature for 24 hours, centrifuge at 10000 rpm for 1 minute, wash with acetonitrile to completely remove free Pd(OAc)2, dry under reduced pressure at 60 °C to obtain Pd@MOF-APBA, and store in a sealed container.
[0038] Example 3:
[0039] A method for preparing a Pd@MOF-APBA catalyst includes the following steps:
[0040] (1) Preparation of MOF-808
[0041] Weigh 292.5 mg of trimesic acid and 1170.0 mg of zirconium oxychloride octahydrate and dissolve them in 19.5 mL of a mixed solvent of water and acetic acid in a volume ratio of 1:1. Stir the mixture at 100 °C for 24 hours, cool it to room temperature, and obtain a powder precipitate. Wash the precipitate with water three to five times, centrifuge at 10,000 rpm, and dry the solid at 100 °C for 12 hours to obtain MOF-808.
[0042] (2) Preparation of MOF-APBA by solvent-assisted ligand exchange method
[0043] Weigh 50.0 mg MOF-808 and 21.4 mg APBA into 2.5 mL of ethanol, stir at room temperature for 24 hours, centrifuge at 10,000 rpm to separate them, wash away the free APBA completely with ethanol, centrifuge at 10,000 rpm for 3 minutes, and dry at 100℃ for 20 hours to obtain MOF-APBA.
[0044] (3) Preparation of Pd@MOF-APBA
[0045] Take 50.0 mg MOF-APBA and 6.8 mg Pd(OAc)2 in 2.5 mL of methanol, stir at room temperature for 24 hours, centrifuge at 10000 rpm for 3 minutes, wash away the free Pd(OAc)2 completely with methanol, dry under reduced pressure at 60 °C to obtain Pd@MOF-APBA, and store in a sealed container.
[0046] Experimental Example 1: Pd@MOF-APBA catalyst catalyzes the Heck reaction of iodobenzene and ethyl acrylate.
[0047] The catalytic performance of the synthesized novel catalyst was tested. The effects of temperature, time, solvent, catalyst dosage, and coupling reagent dosage on the Heck reaction of iodobenzene and ethyl acrylate catalyzed by the novel palladium catalyst were investigated. The results showed that the catalyst exhibits high catalytic activity, can be repeatedly recycled, achieves a reaction conversion number of up to 81914, and has a wide substrate applicability range.
[0048] Experimental Example 2: Preparation of Pd@MOF-APBA catalyst and its catalytic Heck reaction of 4-cyanoiodobenzene and styrene.
[0049] The catalytic performance of the synthesized novel catalyst was tested. The effects of temperature, time, solvent, catalyst dosage, and coupling reagent dosage on the Heck reaction of 4-chloroiodobenzene and styrene were investigated. The results showed that the catalyst also exhibits high catalytic activity, can be repeatedly recycled, and has a wide range of applicable substrates.
[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments without departing from the technical essence of the present invention shall still fall within the scope of the present invention.
Claims
1. A Pd@MOF-APBA catalyst, characterized in that: APBA is 3-amino-4-(pyridin-2-yl)benzoic acid. The catalyst is based on Pd(OAc)2 as a precursor. By exchanging the ligands of MOF-808 with APBA, APBA replaces part of the acetic acid coordinated with the zirconium cluster in MOF-808, resulting in MOF material MOF-APBA with Pd coordination sites, which is then combined with Pd(OAc)2.
2. A method for preparing a Pd@MOF-APBA catalyst, comprising the following steps: (1) Preparation of MOF-808 Weigh out pyromellitic acid and zirconium oxychloride octahydrate in a mass ratio of 1:4-5, dissolve them in a mixed solvent of water and acetic acid in a volume ratio of 1:1, and prepare a solution with a mass concentration of 70.2-80 g•L. -1 The solution; The mixture was stirred at 100℃ for 24 hours, cooled to room temperature, and a powder precipitate was obtained. The precipitate was washed with water, centrifuged at 10,000 rpm, and the solid was dried at 120℃ for 10-12 hours to obtain MOF-808. (2) Preparation of MOF-APBA by solvent-assisted ligand exchange method Weigh MOF-808 and APBA in a mass ratio of 1:0.14-0.686 into methanol to prepare a solution with a mass concentration of 22.8-33.72 g•L. -1 The solution of APBA was stirred at room temperature for 24 hours, centrifuged at 10,000 rpm, the free APBA was completely washed away with methanol, and dried at 100-120℃ for 24 hours to obtain MOF-APBA. (3) Preparation of Pd@MOF-APBA MOF-APBA and Pd(OAc)₂ in a mass ratio of 1:0.09-0.18 were weighed into dichloromethane to form a solution with a mass concentration of 21.8-23.6 g•L⁻¹. -1 The solution was stirred at room temperature for 24 hours, centrifuged at 10,000 rpm, and the free Pd(OAc)2 was completely washed away with dichloromethane. The solution was then dried under reduced pressure at 40-60 °C to obtain Pd@MOF-APBA.
3. The method for preparing a Pd@MOF-APBA catalyst as described in claim 2, wherein: In step (2), methanol is replaced with water, and in step (3), dichloromethane is replaced with acetonitrile.
4. The method for preparing a Pd@MOF-APBA catalyst as described in claim 2, wherein: In step (2), methanol is replaced with ethanol, and in step (3), dichloromethane is replaced with methanol.