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CN-118142585-B - Pd@MOF-APBA catalyst and preparation method thereof

CN118142585BCN 118142585 BCN118142585 BCN 118142585BCN-118142585-B

Abstract

The invention discloses a Pd@MOF-APBA catalyst and a preparation method thereof, wherein Pd (OAc) 2 is used as a precursor, and a 3-amino-4- (pyridine-2-yl) benzoic acid (3-amino-4- (pyridine-2-yl) benzoic acid, hereinafter referred to as APBA) is used for carrying out ligand exchange on MOF-808 to obtain a MOF material MOF-APBA with Pd coordination sites, and Pd (OAc) 2 is combined. The invention has high catalytic activity, is easy to separate and recycle, and can still keep high catalytic activity when being recycled for multiple times.

Inventors

  • LU YI
  • XU XIAOLI
  • WANG NIANNIAN

Assignees

  • 南京大学

Dates

Publication Date
20260508
Application Date
20240131

Claims (4)

  1. 1. A Pd@MOF-APBA catalyst is characterized in that APBA is 3-amino-4- (pyridin-2-yl) benzoic acid, pd (OAc) 2 is used as a precursor of the catalyst, and partial acetic acid coordinated with zirconium clusters in the MOF-808 is replaced by APBA through ligand exchange on the MOF-808 by using the APBA to obtain a MOF material MOF-APBA with Pd coordination sites, and then Pd (OAc) 2 is combined.
  2. 2. A preparation method of Pd@MOF-APBA catalyst comprises the following steps: (1) Preparation of MOF-808 Weighing trimesic acid and zirconium oxychloride octahydrate with the mass ratio of 1:4-5, and dissolving the trimesic acid and the zirconium oxychloride in a mixed solvent with the volume ratio of water to acetic acid of 1:1 to prepare a solution with the mass concentration of 70.2-80 g.L -1 ; Stirring and reacting for 24 hours at 100 ℃, cooling to room temperature to obtain powder precipitate, washing the precipitate with water, centrifuging at 10000rpm, and drying the solid at 120 ℃ for 10-12 hours to obtain MOF-808; (2) Solvent-assisted ligand exchange method for preparing MOF-APBA Weighing MOF-808 and APBA with the mass ratio of 1:0.14-0.686 in methanol to prepare an APBA solution with the mass concentration of 22.8-33.72 g.L -1 , stirring at room temperature for 24 hours, centrifuging at 10000rpm, completely washing free APBA by methanol, and drying at 100-120 ℃ for 24 hours to obtain MOF-APBA; (3) Preparation of Pd@MOF-APBA The MOF-APBA and Pd (OAc) 2 with the mass ratio of 1:0.09-0.18 are weighed and put into methylene dichloride to form a solution with the mass concentration of 21.8-23.6 g.L -1 , the solution is stirred at room temperature for 24 hours, centrifugal separation is carried out at 10000rpm, the free Pd (OAc) 2 is completely washed out by methylene dichloride, and the solution is dried under reduced pressure at 40-60 ℃ to obtain Pd@MOF-APBA.
  3. 3. The process for preparing Pd@MOF-APBA catalyst according to claim 2, wherein the methanol in the step (2) is replaced by water, and the dichloromethane in the step (3) is replaced by acetonitrile.
  4. 4. The process for preparing Pd@MOF-APBA catalyst according to claim 2, wherein the methanol in the step (2) is replaced by ethanol, and the dichloromethane in the step (3) is replaced by methanol.

Description

Pd@MOF-APBA catalyst and preparation method thereof Technical Field The invention belongs to the technical field of chemistry, and particularly relates to a Pd@MOF-APBA catalyst and a preparation method of the Pd@MOF-APBA catalyst. Background The Heck reaction is a palladium-catalyzed cross-coupling reaction of an olefin with an aryl or vinyl halide for the synthesis of substituted olefins, one of the most widely used carbon-carbon coupling reactions in organic chemistry, known as "screws" of an olefin with an organic halide. Is widely applied to the synthesis of dyes, medicines, natural products and other chemicals. However, in the homogeneous catalysis process, the residual palladium catalyst can pollute the product, on the other hand, the catalyst has high cost, and the recovery process is complicated and difficult to recover, so that the environment is polluted, and the factors limit the application of Heck reaction. To overcome these limitations, the development of supported palladium catalysts is one of the effective approaches. However, the current supported palladium catalyst has serious palladium leaching or aggregation phenomenon, so that the catalyst has low cycle times and low metal utilization rate. Disclosure of Invention The invention aims to provide the Pd@MOF-APBA catalyst which has high catalytic activity, is easy to separate and recycle, and can still maintain high catalytic activity when being recycled for multiple times. It is another object of the present invention to provide a process for preparing the Pd@MOF-APBA catalyst. The invention aims at realizing the following technical scheme: The Pd@MOF-APBA catalyst is prepared by taking Pd (OAc) 2 as a precursor, carrying out ligand exchange on MOF-808 by using 3-amino-4- (pyridin-2-yl) benzoic acid (3-amino-4- (pyridine-2-yl) benzoic acid, hereinafter called APBA) to obtain a MOF material MOF-APBA with Pd coordination sites, and combining Pd (OAc) 2. The invention relates to a preparation method of a Pd@MOF-APBA catalyst, which comprises the following steps: (1) Preparation of MOF-808 And weighing the trimesic acid and the zirconium oxychloride octahydrate with the mass ratio of 1:4-5, and dissolving the trimesic acid and the zirconium oxychloride into a mixed solvent with the volume ratio of water to acetic acid of 1:1 to prepare a solution with the mass concentration of 70.2-80 g.L -1. Stirring and reacting for 24 hours at 100 ℃, cooling to room temperature to obtain powder precipitate, washing and precipitating with water, centrifuging at 10000rpm, and drying the solid at 120 ℃ for 10-12 hours to obtain MOF-808; (2) Solvent-assisted ligand exchange method for preparing MOF-APBA Weighing MOF-808 and APBA with the mass ratio of 1:0.14-0.686 in methanol to prepare an APBA solution with the mass concentration of 22.8-33.72 g.L -1, stirring at room temperature for 24 hours, centrifugally separating at 10000rpm, completely washing free APBA by methanol, and drying at 100-120 ℃ for 24 hours to obtain MOF-APBA; (3) Preparation of Pd@MOF-APBA The MOF-APBA and Pd (OAc) 2 with the mass ratio of 1:0.09-0.18 are weighed into methylene dichloride to form a solution with the mass concentration of 21.8-23.6 g.L -1, the solution is stirred for 24 hours at room temperature, centrifugal separation is carried out at 10000rpm, the free Pd (OAc) 2 is completely washed out by methylene dichloride, and the solution is dried under reduced pressure at 40-60 ℃ to obtain Pd@MOF-APBA. The preparation method of the Pd@MOF-APBA catalyst comprises the step (2) of preparing water, methanol or ethanol as a solvent. The preparation method of the Pd@MOF-APBA catalyst comprises the step (3) of preparing a solvent from dichloromethane, acetonitrile or methanol. Compared with the prior art, the method has obvious beneficial effects, and the technical scheme shows that the method synthesizes MOF-808 by a solvothermal method, then prepares MOF-APBA by a solvent-assisted ligand exchange method, finally loads Pd (OAc) 2 into the material by coordination to obtain Pd@MOF-APBA, and the catalyst preparation process is simple to operate, short in time consumption and easy to repeat. The catalyst is easy to separate from a reaction system, can be repeatedly used for many times and always keeps higher conversion rate. The catalyst has stable structure and high activity of catalyzing Heck reaction between iodobenzene and ethyl acrylate, and the conversion number of the catalytic reaction can exceed 80000 when the ratio of the catalyst to the substrate is 1.5:100. Drawings FIG. 1 is a structural simulation of MOF-808; FIG. 2 is a simulated view of the intermediate mesoporous structure of FIG. 1; FIG. 3 is a structural simulation of the MOF-APBA; FIG. 4 is a structural simulation of Pd@MOF-APBA. Detailed Description Example 1: A preparation method of a Pd@MOF-APBA catalyst comprises the following steps: (1) Preparation of MOF-808 Weighing 117.0 mg trimesic acid and 585.0 mg zirconium o