CN102921465A

CN102921465A - Bimetallic Pd/Y-MOF heterogeneous catalyst and preparation method and application thereof

Info

Publication number: CN102921465A
Application number: CN2012104223828A
Authority: CN
Inventors: 黄金萍; 凌红亚; 李和兴
Original assignee: Shanghai Normal University
Current assignee: Shanghai Normal University; University of Shanghai for Science and Technology
Priority date: 2012-10-30
Filing date: 2012-10-30
Publication date: 2013-02-13
Anticipated expiration: 2032-10-30
Also published as: CN102921465B

Abstract

The invention discloses a bimetallic Pd/Y-MOF heterogeneous catalyst. The bimetallic Pd/Y-MOF heterogeneous catalyst is characterized in that an active site Pd2+ of the catalyst is connected to an N atom and two Cl atoms of 2,2'-bipyridyl-5,5'-dicarboxylic acid to form similarly-laminar (BPDC)PdCl2 secondary structure units; and the secondary structure units are connected together through Y3+ bonded on a carboxylic acid functional group to form a 3D (three-dimensional) extending structure. With the structure, the bimetallic Pd/Y-MOF heterogeneous catalyst disclosed by the invention has an excellent catalytic property when being used for catalyzing Suzuki-Miyaura reaction and Sonogashira reaction in a water solution.

Description

A kind of bimetallic Pd/Y-MOF heterogeneous catalysis and its preparation method and application

Technical field

The present invention relates to the synthetic field of catalyst, be specifically related to a kind of bimetallic Pd/Y-MOF heterogeneous catalysis and its preparation method and application.

Background technology

In organic synthesis, carbon-to-carbon (C-C) coupled reaction can make up the synthetic biphenyl unit of a lot of routes, and modal example utilizes Pd catalysis Suzuki – Miyaura and Sonogashira coupled reaction exactly.Now, although homogeneous phase Pd catalyst is widely adopted in organic synthesis, correlative study also is constantly deeply, but remain a challenge in the such reaction of industrial employing, this is because homogeneous phase Pd catalyst is expensive, is difficult for recycling separation difficulty from solution.Therefore, design heterogeneous Pd catalyst system great meaning is arranged.Up to now, a lot of solid materials are carbon for example, polymer, and be situated between empty silicon and zeolite are all once as the carrier of Pd.But, no matter be the nano particle of Pd, or Pd salt or compound, they seldom are fixed in these carrier surfaces or the empty road.

Metal organic frame (MOF) compound is as a kind of novel, special functional material, and it has obtained a lot of people's concern.This material be by metal ion or metal cluster as node, and multi-functional organic ligand forms as connected body.Because MOF has the topological geometry that can control, and adjustable space function is so that it can be applied to a lot of fields.It is except being applied to absorption, and gas storage is beyond the luminous field, about its application aspect catalysis also usually is in the news.Although the stability of MOF is not as similar inorganic material, it is specially suitable material when immobilized when having the molecular catalyst in single catalytic site and open duct, this have the heterogeneous catalysis in single-activity site can provide well selective, and be easy to separate from reactant and product.At present, relevant bimetallic catalyst has become the focus of scientific research, but the synthetic catalyst of relevant bimetallic and metal organic frame (MOF) coupling but also seldom.Bimetallic MOF material is that as the benefit of catalyst wherein a metal ion species makes up stable MOF framework as the node of MOF network, and another kind of metal ion is as the center of catalytic active site.

Summary of the invention

The object of the invention is to for the deficiencies in the prior art of mentioning in the above-mentioned background, proposing a kind of simple synthetic method is the synthetic a kind of bimetallic Pd/Y-MOF heterogeneous catalysis of microwave method, to utilize this heterogeneous catalysis take water as medium catalysis Suzuki – Miyaura and Sonogashira coupled reaction.

Purpose of the present invention is achieved through the following technical solutions:

A kind of bimetallic Pd/Y-MOF heterogeneous catalysis is characterized in that avtive spot Pd ²⁺By 2,2 '-bipyridyl-5, the N atom on 5 '-dicarboxylic acids with are connected a Cl atom and connect, form (BPDC) PdCl of similar stratiform ₂Secondary structure unit, these secondary structure units are by being bonded in the Y on the carboxylic acid functional ³⁺Couple together, form the 3D extended structure.

The preparation method of above-mentioned bimetallic Pd/Y-MOF heterogeneous catalysis is:

(1) with K ₂PdC _l4, Y (NO ₃) ₃6H ₂O and 2,2 '-bipyridyl-5,5 '-dicarboxylic acids are the ratio mixing of 0.5-1.5:2.0-6.0.1.5-4.5:0.5-1.5 according to mol ratio and are dissolved in the deionized water, stir 10-15min;

(2) step (1) gained solution is warmed up to 120 ℃-130 ℃, and keeps 8h-10h, be precipitated thing, with the deionized water washing, drying obtains the light yellow solid powder, is the Pd/Y-MOF heterogeneous catalysis after the centrifugation.

The Pd/Y-MOF catalyst of above-mentioned gained can be obtained extraordinary catalytic effect for aqueous solution catalysis Suzuki – Miyaura reaction and Sonogashira reaction, even after reusing repeatedly, still keeping very high efficient.

Because rare earth metal y ³⁺The network frame that ion consists of has enough stability, and the Pd/Y-MOF heterogeneous catalysis that obtains has very high heat endurance and chemical stability; Because the avtive spot Pd of catalyst of the present invention ²⁺With firmly coordination of metal organic frame, the shortcoming of the easy disengaging of avtive spot and polymerization when having overcome reaction is so catalyst of the present invention can repeatedly use; Because the organometallic skeletal compound has high hydrophobicity, so that in catalysis during with the organic reaction of aqueous medium, organic substrates is easier in the duct diffusion, thereby improves catalytic efficiency; In addition, rare earth metal y ³⁺And precious metals pd ²⁺Act synergistically, kept the high activity of catalyst.More than these factors guaranteed that catalyst of the present invention has good catalytic performance.

Description of drawings

Fig. 1 is the XRD Rietveld structure refinement collection of illustrative plates of the Pd/Y-MOF in the embodiment of the invention.

Fig. 2 is the crystal structure figure that the Pd/Y-MOF in the embodiment of the invention observes along [100] direction.

Fig. 3 be in the embodiment of the invention Pd/Y-MOF catalysis Suzuki – Miyaura coupled reaction apply mechanically experiment.

Fig. 4 be in the embodiment of the invention Pd/Y-MOF catalysis Suzuki-Miyaura coupled reaction apply mechanically experiment, each corresponding XRD changes, the structure before a representative reaction, b-f represents respectively the structure after repetition 1-5 time.

Fig. 5 is the TG-DTA curve of the Pd/Y-MOF catalyst in the embodiment of the invention.

The specific embodiment

Used K in the following example ₂PdCl ₄, Y (NO ₃) ₃6H ₂O, 2,2 '-bipyridyl-5,5 '-dicarboxylic acids, aromatic halohydrocarbon, phenyl boric acid, phenylacetylene, decane and K ₂CO ₃Deng being AR all, the water of use all is deionized water.

Embodiment 1:

Get 97.9mg K ₂PdCl ₄, 0.498mg Y (NO ₃) ₃6H ₂O and 73.0mg 2,2 '-bipyridyl-5,5 '-dicarboxylic acids are put in the polyfluortetraethylene pipe, then add the 20mL deionized water, stir 10min in air.Then, mentioned solution is put into micro-wave oven be warmed up to rapidly 120 ℃, and keep 8h, through centrifugal, the deionized water washing, drying can obtain buff powder, is the Pd/Y-MOF heterogeneous catalysis.

Fig. 1 is the XRD Rietveld structure refinement collection of illustrative plates of Pd/Y-MOF, and the model that refine is adopted is the compound model that the Pt of same structure is arranged with it, and experiment records collection of illustrative plates and represents with point, calculates collection of illustrative plates and represents that with the solid black line difference of the two represents with following line.Obtain the structure of Pd/Y-MOF by XRD Rietveld refine: avtive spot Pd ²⁺By 2,2 '-bipyridyl-5, the N atom on 5 '-dicarboxylic acids with are connected a Cl atom and connect, formed (BPDC) PdCl of a kind of similar stratiform ₂Construction unit, these secondary structure units are by being bonded in the Y on the carboxylic acid functional ³⁺Couple together, formed the extended structure of a kind of 3D.

Fig. 2 is the crystal structure figure that the Pd/Y-MOF in the embodiment of the invention observes along [100] direction, can find out the avtive spot Pd of catalyst ²⁺With firmly coordination of metal organic frame.

As shown in Figure 5, Pd/Y-MOF heterogeneous catalysis of the present invention has very high heat endurance, and its structure just changes in the time of 450 ℃.

Embodiment 2:

The step of catalysis Suzuki – Miyaura reaction in the aqueous solution: before experiment, the Pd/Y-MOF catalyst is 100 ℃ of degassed 2h under vacuum.Get respectively iodobenzene 0.50mmol, phenyl boric acid 0.75mmol, K ₂CO ₃1.5mmol Pd/Y-MOF catalyst 30mg, deionized water 4.0mL join in the 10mL round-bottomed flask, are heated to 80 ℃, extract with ethyl acetate behind the reaction 8h, analyze with GC again, decane is as internal standard compound.Remaining heterogeneous catalysis washs 3 times with deionized water, and 80 ℃ of lower vacuum drying are reused next time.

As shown in Figure 3, use catalyst of the present invention catalysis Suzuki – Miyaura when reaction in the aqueous solution, the productive rate of catalysis iodobenzene is 95%, reuses after 5 times, still can reach about 70%.

Embodiment 3:

The step of catalysis Sonogashira reaction in the aqueous solution: before experiment, the Pd/Y-MOF catalyst is 100 ℃ of degassed 2h under vacuum.Get respectively iodobenzene 0.50mmol, phenylacetylene 0.60mmol, DBU0.10mmol, Pd/Y-MOF catalyst 30mg, deionized water 4.0mL join in the 10mL round-bottomed flask, are heated to 90 ℃, extract with ethyl acetate behind the reaction certain hour, analyze with GC, decane is as internal standard compound.Remaining heterogeneous catalysis washs 3 times with deionized water, and 80 ℃ of lower vacuum drying are reused next time.

As shown in Figure 4, use catalyst of the present invention when catalysis Sonogashira in the aqueous solution reacts, the productive rate of iodobenzene and phenylacetylene reaction reaches 92%, and can use repeatedly.

Embodiment 4:

The Pd/Y-MOF catalyst is to the reactant iodobenzene, the adsorption test of phenylacetylene and 4-tert-butyl group iodobenzene follows these steps to carry out: get respectively iodobenzene, phenylacetylene and each 0.050mmol of 4-tert-butyl group iodobenzene join in the 2.0mL ethyl acetate, add catalyst 0.018mmol again, at room temperature stir.In the different time intervals, mentioned solution is also passed through the content of GC detecting reactant by centrifugation.

Experimental results show that this catalyst reveals certain catalytic selectivity energy for the reactant molecule size table, namely its substrate of being conducive to little molecular dimension enters and stops large molecule.

The above is preferred embodiment of the present invention, but the present invention should not be confined to the disclosed content of this embodiment.So everyly do not break away from the equivalence of finishing under the spirit disclosed in this invention or revise, all fall into the scope of protection of the invention.

Claims

1. a bimetallic Pd/Y-MOF heterogeneous catalysis is characterized in that avtive spot Pd ²⁺By 2,2 '-bipyridyl-5, the N atom on 5 '-dicarboxylic acids with are connected a Cl atom and connect, form (BPDC) PdCl of similar stratiform ₂Secondary structure unit, these secondary structure units are by being bonded in the Y on the carboxylic acid functional ³⁺Couple together, form the 3D extended structure.

2. the preparation method of the described bimetallic Pd/Y-MOF of claim 1 heterogeneous catalysis is characterized in that, may further comprise the steps:

(1) with K ₂PdCl ₄, Y (NO ₃) ₃6H ₂O and 2,2 '-bipyridyl-5,5 '-dicarboxylic acids are the ratio mixing of 0.5-1.5:2.0-6.0.1.5-4.5:0.5-1.5 according to mol ratio and are dissolved in the deionized water, stir 10-15min;

(2) step (1) gained solution is warmed up to 120 ℃-130 ℃, and keeps 8h-10h, be precipitated thing, with the deionized water washing, drying obtains pressed powder, is the Pd/Y-MOF heterogeneous catalysis after the centrifugation.

3. the preparation method of the described bimetallic Pd/Y-MOF of claim 2 heterogeneous catalysis is characterized in that, the heating means in the step (2) adopt heating using microwave, and programming rate is 10-20 ℃/min.

4. the described bimetallic Pd/Y-MOF of claim 1 heterogeneous catalysis is used for aqueous solution catalysis Suzuki-Miyaura reaction and Sonogashira reaction.