CN111013661A

CN111013661A - MOF @ POP core-shell material and application thereof in preparation of cyclic carbonate

Info

Publication number: CN111013661A
Application number: CN201911402028.7A
Authority: CN
Inventors: 韩正波; 张月; 刘琳
Original assignee: Liaoning University
Current assignee: Liaoning University
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-04-17
Anticipated expiration: 2039-12-31
Also published as: CN111013661B

Abstract

The invention relates to a MOF @ POP core-shell material, a synthesis method thereof and application thereof in preparation of cyclic carbonate. The technical scheme is as follows: is NH₂-UiO-66(Hf) is used as a core, a porous organic polymer CoTPy-CAP generated by TBMBr reaction of 5,10,15, 20-tetra (4-pyridyl) porphyrin cobalt Co-TPy and 2,4, 6-tri (bromomethyl) trimethylbenzene is used as a shell, and the constructed MOF POP core-shell material NH₂‑UiO‑66(Hf)@CoTPy‑CAP。NH₂-UiO-66(Hf) @ CoTPy-CAP as catalyst can catalyze CO under the conditions of no cocatalyst, no solvent and mild condition₂And cycloaddition of epoxide to synthesize the corresponding cyclic carbonate. The method has the characteristics of mild reaction conditions, high catalytic activity, single product, good cyclicity and the like.

Description

MOF @ POP core-shell material and application thereof in preparation of cyclic carbonate

Technical Field

The invention relates to a catalyst prepared from CO₂Method for preparing cyclic carbonate by cycloaddition with epoxide, in particular to MOF @ POP core-shell material (NH)₂-UiO-66(Hf) @ CoTPy-CAP) catalytic preparation of cyclic carbonates.

Background

Carbon dioxide (CO)₂) The main greenhouse gas is also a C1 resource which is cheap, nontoxic and abundant in reserves. Thus, use of CO₂The raw material is used for preparing chemical products, and the chemical products are effective fixed CO₂The method of (1). By CO₂Cycloaddition reaction with epoxides to synthesize cyclic carbonsAcid esters are one of the attractive and sustainable strategies, not only because of their 100% atomic economy, but also because cyclic carbonates have great industrial potential. The carbonate compound is a valuable chemical substance and widely applied to electrolyte components of lithium batteries, intermediates of plastics, medicines, polar aprotic solvents and many fine chemicals. Albeit with CO₂And epoxy compounds have been widely studied for the synthesis of cyclic carbonates, but severe conditions of high temperature and high pressure still exist. Therefore, an efficient CO-promoting agent was sought₂Heterogeneous catalysts that react with epoxides under mild conditions are desirable. To date, a variety of catalytic systems have been developed including metal-based catalysts and organic catalysts. However, in most cases, these catalytic systems require a cocatalyst, which complicates the separation and purification process due to its homogeneous nature. To avoid this, it is possible to design a combination of nucleophilic functional groups and catalysts to synergistically catalyze CO without the addition of a cocatalyst and under mild conditions₂And epoxide cycloaddition reaction to prepare cyclic carbonate.

Metal-Organic Frameworks (MOFs) are a promising class of porous crystalline materials consisting of Metal ions and Organic linkers, and have excellent properties such as large surface area, adjustable pore structure, and multiple functions. In recent years, in order to improve the performance of a single MOFs material, the MOFs material and other functional materials are hybridized to prepare a MOFs-based hybrid material, the functional materials comprise metal oxides/nanoparticles, enzymes, metalloporphyrins, MOFs, COFs, POPs and the like, and the synthesized MOFs-based hybrid material not only has the structural characteristics of single components, but also shows new characteristics. Among them, porous organic framework materials (POPs) have received increasing attention in gas/liquid separation, gas storage, catalysis, sensors, charge carriers, etc. due to their large surface area and well-defined pore structure, stable framework and extended pi-conjugation effect. The hybrid material as a single catalytic system can combine the advantages of the hybrid material and effectively eliminate the disadvantages of the hybrid material. Therefore, the preparation of MOFs @ POPs hybrid materials with multifunctional catalytic sites provides a wide prospect for the application of the MOFs and the POPs.

Disclosure of Invention

One purpose of the invention is to provide a MOF @ POP core-shell material (NH)₂-UiO-66(Hf)@CoTPy-CAP)。

The invention also aims to provide a preparation method of the MOF @ POP core-shell material.

The invention also aims to provide the MOF @ POP core-shell material for catalyzing CO₂And epoxide cycloaddition reaction to prepare cyclic carbonate.

The technical scheme adopted by the invention is as follows: an MOF @ POP core-shell material is a metal organic framework material NH₂-UiO-66(Hf) is used as a core, a porous organic polymer CoTPy-CAP generated by TBMBr reaction of 5,10,15, 20-tetra (4-pyridyl) porphyrin cobalt Co-TPy and 2,4, 6-tri (bromomethyl) trimethylbenzene is used as a shell, and the constructed MOF POP core-shell material NH₂-UiO-66(Hf)@CoTPy-CAP。

A preparation method of an MOF @ POP core-shell material comprises the following steps:

1) reacting HfCl₄2-amino terephthalic acid NH₂-H₂Evenly mixing BDC, formic acid and DMF, transferring the mixture into a polytetrafluoroethylene high-pressure reaction kettle, sealing the kettle, putting the kettle into an oven, heating the kettle to 398K, reacting the mixture for 40 hours, slowly cooling the mixture to room temperature, filtering the mixture, washing the mixture by DMF and methanol in sequence, and drying the mixture to obtain a metal organic framework material NH₂-UiO-66(Hf)；

2) Adding 5,10,15, 20-tetra (4-pyridyl) porphyrin cobalt (Co-TPy), 2,4, 6-tri (bromomethyl) trimethylbenzene (TBMBr) and Tetrahydrofuran (THF) into a container, ultrasonically dissolving at normal temperature, and adding NH₂-UiO-66(Hf), and after continuing the sonication for 60min, the mixture was placed in N₂Heating to 60-70 ℃, refluxing for 90 hours, washing with Tetrahydrofuran (THF) and chloroform, filtering and drying to obtain the MOF @ POP core-shell material NH₂-UiO-66(Hf)@CoTPy-CAP。

Application of MOF @ POP core-shell material in catalyzing CO₂And epoxide cycloaddition reaction to prepare cyclic carbonate. The method comprises the following steps: in a reaction kettleAdding epoxide, and under the condition of no solvent, using the MOF @ POP core-shell material NH₂-UiO-66(Hf) @ CoTPy-CAP as catalyst, introducing carbon dioxide to the reaction pressure of 0.5MPa and the reaction temperature of 80 ℃ for reaction for 10h to catalyze CO₂And epoxide cycloaddition reaction to prepare cyclic carbonate.

The epoxide is:

preferably, 50mg of catalyst is added per 10mol of epoxy compound.

The invention catalyzes CO₂The general reaction formula for the cycloaddition reaction with epoxides to produce the corresponding cyclic carbonates is as follows:

wherein R is Me, Et, C₄H₉OCH₂，C₃H₅OCH₂，Ph。

The invention has the beneficial effects that: MOF @ POP core-shell material (NH) prepared by using method₂UiO-66(Hf) @ CoTPy-CAP) contains two Lewis acid sites, unsaturated Hf (IV) and Co (II) centers, and a large amount of free bromide can be used as a nucleophile. Thus, NH can be reacted₂-UiO-66(Hf) @ CoTPy-CAP as bifunctional catalyst for catalyzing CO₂Reaction with epoxide to form cyclic carbonate, NH₂-UiO-66(Hf) @ CoTPy-CAP exhibited very good catalytic performance. MOF @ POP core-shell material (NH) prepared by the invention₂the-UiO-66 (Hf) @ CoTPy-CAP) synthesis method is simple and has wide application prospect.

Drawings

FIG. 1 shows the MOF @ POP core-shell material (NH) of the present invention₂Schematic synthesis of-UiO-66 (Hf) @ CoTPy-CAP).

FIG. 2 shows the MOF @ POP core-shell material (N) of the present inventionH₂PXRD spectrum of-UiO-66 (Hf) @ CoTPy-CAP).

FIG. 3 shows the MOF @ POP core-shell material (NH) of the present invention₂FT-IR spectrum of-UiO-66 (Hf) @ CoTPy-CAP).

FIG. 4 is a MOF @ POP core-shell material (NH) of the present invention₂SEM and TEM spectra of-UiO-66 (Hf) @ CoTPy-CAP);

wherein, a is NH₂-SEM spectrum of UiO-66 (Hf); SEM spectrogram of CoTPy-CAP; c, MOF @ POP core-shell material NH₂-UiO-66(Hf) @ CoTPy-CAP SEM chromatogram; d is MOF @ POP core-shell material NH₂TEM spectrum of-UiO-66 (Hf) @ CoTPy-CAP.

FIG. 5 shows the MOF @ POP core-shell material NH of the present invention₂N of-UiO-66 (Hf) @ CoTPy-CAP₂sortionisototherms spectra.

FIG. 6 MOF @ POP core-shell material NH of the present invention₂CO of-UiO-66 (Hf) @ CoTPy-CAP₂sortionisototherms spectra.

FIG. 7 shows the MOF @ POP core-shell material NH of the present invention₂Catalytic activity of-UiO-66 (Hf) @ CoTPy-CAP for 10 cycles of catalytic reactions.

FIG. 8 is the MOF @ POP core-shell material NH of the present invention₂PXRD pattern for 10 cycles catalytic reaction under UiO-66(Hf) @ CoTPy-CAP.

Detailed Description

Example 1 MOF @ POP core-shell Material (NH)₂-UiO-66(Hf)@CoTPy-CAP)

The preparation method comprises the following steps:

1)NH₂preparation of-UiO-66 (Hf)

Reacting HfCl₄(0.48g,2.0mmol), 2-Aminoterephthalic acid (NH)₂-H₂BDC) (0.27g,1.5mmol), 6mL formic acid and 54mL DMF are mixed evenly, transferred to a polytetrafluoroethylene high-pressure reaction kettle, sealed and put into an oven, heated to 398K, reacted for 40h, cooled to room temperature slowly, filtered, washed by DMF and methanol for 3-5 times respectively in sequence, and dried to obtain NH₂-UiO-66(Hf)。

2) Preparation of CoTPy-CAP

Mixing 5,10,15, 20-tetra (4-pyridyl) porphyrin cobalt (Co-TPy) (257.5mg,0.38mmol), 2,4, 6-tri (bromomethyl) trimethylbenzene (TBMBr) ((TBMBr))199.5mg,0.5mmol) and 25mL Tetrahydrofuran (THF) were mixed well under sonication in N₂Heating and refluxing for 90h when the temperature is raised to 66 ℃, centrifuging, washing for 3-5 times by using chloroform, and drying to obtain the CoTPy-CAP.

3)NH₂Preparation of-UiO-66 (Hf) @ CoTPy-CAP

5,10,15, 20-tetrakis (4-pyridyl) porphyrin cobalt (Co-TPy) (127.05mg,0.19mmol), 2,4, 6-tris (bromomethyl) trimethylbenzene (TBMBr) (99.74mg,0.25mmol) and 25mL Tetrahydrofuran (THF) were charged into a vessel, and after sonication at room temperature, NH was added₂-UiO-66(Hf) (150mg), and after continuing sonication for 60min, the mixture was placed under N₂Heating to 66 deg.C under reflux for 90 hr, washing with Tetrahydrofuran (THF) and chloroform for 3-5 times, filtering, and drying to obtain NH₂-UiO-66(Hf)@CoTPy-CAP。

(II) detection

1. As can be seen from FIG. 2, NH was confirmed by X-ray powder diffraction (PXRD)₂-UiO-66(Hf) @ CoTPy-CAP core-shell material was successfully synthesized, NH₂Diffraction peak and NH of-UiO-66 (Hf) @ CoTPy-CAP core-shell material₂Diffraction peaks of-UiO-66 (Hf) and CoTPy-CAP were coincident. NH due to weaker peak intensity of CoTPy-CAP₂-UiO-66(Hf) @ CoTPy-CAP core-shell material appears to be similar to NH₂-UiO-66(Hf) peak type structure.

2. As can be seen from FIG. 3, the FT-IR spectrum shows that 1,2 and 3 in FIG. 3 are each represented by NH₂-UiO-66(Hf) @ CoTPy-CAP, CoTPy-CAP and NH₂-UiO-66(Hf)。NH₂Typical characteristic peak and NH of-UiO-66 (Hf) @ CoTPy-CAP core-shell material₂The characteristic peaks of-UiO-66 (Hf) or CoTPy-CAP are similar. E.g. at 1659cm^-1And 1495cm^-1The characteristic peak is derived from NH₂Symmetric and asymmetric tensile vibrations of the UiO-66(Hf) carboxyl group, 1635m^-1Characteristic peak is derived from-C ═ N of CoTPy-CAP⁺Stretching vibrations, the results of which indicate NH₂the-UiO-66 (Hf) @ CoTPy-CAP core-shell material was successfully synthesized.

3. FIG. 4 shows that NH was studied by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM)₂-UiO-66(Hf) @ CoTPy-CAP core-shell material morphology. NH of a in FIG. 4₂SEM spectrum of-UiO-66 (Hf) shows NH₂-UiO-66(Hf) is an octahedron with smooth surface; the SEM spectrum of the CoTPy-CAP in b of FIG. 4 shows that the CoTPy-CAP is in a flake form. NH of c in FIG. 4₂SEM spectrogram of-UiO-66 (Hf) @ CoTPy-CAP and NH of d in FIG. 4₂TEM spectrum of-UiO-66 (Hf) @ CoTPy-CAP shows when NH₂Original NH when the-UiO-66 (Hf) surface grows flake-like CoTPy-CAP₂the-UiO-66 (Hf) surface becomes rough. TEM image analysis shows NH₂the-UiO-66 (Hf) surface was coated with a CoTPy-CAP layer to a thickness of about 15 nm.

4. As can be seen from FIG. 5, the BET method is used to pass N₂Method of adsorption-desorption NH is measured₂Pore characteristics of-UiO-66 (Hf) @ CoTPy-CAP core-shell material, and results show that NH₂-UiO-66(Hf) @ CoTPy-CAP core-shell material shows microporous property and specific surface area 397m²g^-1。

5. As can be seen from FIG. 6, NH₂CO of-UiO-66 (Hf) @ CoTPy-CAP core-shell material at temperatures of 298,273 and 195K₂The adsorption amounts of (A) and (B) were 23.0,36.3, and 120.9mLg^-1。

Example 2

First, MOF @ POP core-shell material (NH) prepared in example 1₂-UiO-66(Hf) @ CoTPy-CAP) as catalyst vs. CO₂And epoxide cycloaddition reaction.

The method comprises the following steps:

1) activating treatment of the catalyst: a certain amount of the MOF @ POP core-shell material (NH) prepared in example 1 is taken₂-UiO-66(Hf) @ CoTPy-CAP) was vacuum activated under heating at 393K for 12 hours.

2) The method comprises the following steps: taking 50mg of activated MOF @ POP core-shell material (NH)₂-UiO-66(Hf) @ CoTPy-CAP), 10mmol of the epoxide as in Table 1 in a autoclave, sealed and charged with CO₂The pressure in the vessel was set to 0.5MPa and the temperature was set to 80 ℃ and the results of the experiment were measured by gas chromatography. The results are shown in Table 1.

TABLE 1

MOF @ POP core shells as shown in Table 1Material (NH)₂Catalytic reaction of cycloaddition reaction of-UiO-66 (Hf) @ CoTPy-CAP) to various epoxides, NH can be seen from Table 1₂the-UiO-66 (Hf) @ CoTPy-CAP has good catalytic effect on different epoxides, and proves that NH₂the-UiO-66 (Hf) @ CoTPy-CAP has good substrate versatility. However, as the substrate size increased, there was a slight decrease in conversion, probably because the substrate size increased slowing the rate of substrate diffusion, thereby affecting the substrate contact with the catalyst.

Recyclability of catalyst in (di) cycloaddition reaction

And (3) recovering the catalyst: after the reaction is finished, filtering, separating the catalyst from the reaction mixture, washing with methanol, soaking in methanol for six hours, filtering and drying.

Specific operation of the cycling experiment: catalysis of CO with recycled catalyst (50mg)₂(0.5MPa) and propylene oxide (10mmol) at 80 ℃ for 10 hours.

The results of the experiment are shown in fig. 7 and 8, and the activity of the catalyst was only slightly decreased by the cycle experiment to run 10. Illustrating the MOF @ POP core-shell material (NH)₂-UiO-66(Hf) @ CoTPy-CAP) as CO₂The catalyst for cycloaddition reaction with epoxide can be recycled.

Claims

1. A MOF @ POP core-shell material is characterized in that a metal organic framework material NH is used₂-UiO-66(Hf) is used as a core, a porous organic polymer CoTPy-CAP generated by the reaction of 5,10,15, 20-tetra (4-pyridyl) porphyrin cobalt (Co-TPy) and 2,4, 6-tri (bromomethyl) trimethylbenzene (TBMBr) is used as a shell, and the constructed MOF @ POP core-shell material NH is formed₂-UiO-66(Hf)@CoTPy-CAP。

2. A preparation method of an MOF @ POP core-shell material is characterized by comprising the following steps:

1) reacting HfCl₄2-amino terephthalic acid (NH)₂-H₂BDC), formic acid and DMF are evenly mixed, transferred into a polytetrafluoroethylene high-pressure reaction kettle, sealed and put into an oven, heated to 398K and reactedSlowly cooling to room temperature for 40-45h, filtering, washing with DMF and methanol in sequence, and drying to obtain metal organic framework material NH₂-UiO-66(Hf)；

3. The MOF @ POP core-shell material of claim 1 in catalyzing CO₂And epoxide cycloaddition reaction to prepare cyclic carbonate.

4. Use according to claim 3, characterized in that the method is as follows: adding epoxide into a reaction kettle, and adding the MOF @ POP core-shell material NH of claim 1 under the solvent-free condition₂-UiO-66(Hf) @ CoTPy-CAP is used as a catalyst, carbon dioxide is introduced until the reaction pressure is 0.5MPa and the reaction temperature is 80 ℃, the reaction is carried out for 10h, and the cycloaddition reaction of epoxide and carbon dioxide is catalyzed to prepare the cyclic carbonate.

5. Use according to claim 3 or 4, wherein the epoxide is:

6. use according to claim 5, wherein 50mg of catalyst is added per 10mol of epoxy compound.