Fabrication Of Metal Organic Frameworks Based On Copper Metal And Study Of Their Application In Catalysis

Metal organic frameworks(MOFs)are highly porous hybrid organic-inorganic materials that consist of metal ions and organic bridging ligands.They possess large specific surface areas and porosity as well as tunable structure and properties.Due to these outstanding properties,MOFs could be highly desirable and promising materials for applications in gas storage,separating and catalysis et al.However,the design and preparation of highly-efficient MOF-based catalysts remains a challenging research target.Their catalytic performances in green synthesis reactions were investigated in details and the structure-performance relationships were explored.In the paper,on the one hand,MOFs were functionalized by post-synthesis modification(PSM)method,and then loaded with coordination compound catalysts via chelating metal salts;on the other hand,magnetic core-shell nanocomposite catalysts have been synthesized through loading metal oxide,coating the matal-organic frameworks on the magnetic nanoparticles.Catalytic active components are introduced into the core-shell structure,realizing the controllable design and functional assembly of novel hierarchical core-shell magnetic nanocomposite catalyst.In the meanwhile,we added the MOFs to macromolecular polymer to obtain the MOFs-based mixed matrix membranes.We futher set out to explore their application in the areas of catalysis.The studies provide the theoretical foundation for the practical application of MOFs.Research in this paper includes three kinds of copper-based catalysts-with different’s structure and compositions and their applications in different catalytic reactions,the main conclusions are sumerized as follows:(1)The three-dimensional Zr-based metal-organic framework UiO-66-NH2 was functionalized with salicylaldehyde using a post-synthetic modification strategy.Then three kinds of copper(Ⅱ)salts were successfully immobilized onto the surface of the modified UiO-66-NH2.The obtained UiO-66-Sal-CuⅡ catalyst exhibited excellent catalytic activity in the selective aerobic oxidation of various alcohols by molecular oxygen as oxidant.(2)The core-shell Fe3O4(PAA)@P4VP magnetic microspheres were first synthesized by a polymerization approach,in which the 4-vinylpyridine(4-VP)monomer interacted with a-COOH group of poly(acrylic acid)modified Fe3O4 by means of hydrogen-bond interaction.Then Zn2+ was adsorbed on the surface of the P4VP shell,followed by the ZIF-8 porous shell formation with 2-methylimidazolate.Finally,nearly 5.45 wt%copper content was incorporated with the ZIF-8 framework to form a magnetic core-shell copper-doped Fe3O4@P4VP@ZIF-8.The obtained copper-doped Fe3O4@P4VP@ZIF-8 catalyst was applied in the selective oxidation of alcohols and epoxidation of olefins using molecular oxygen as the oxidant.The Fe3Oa microspheres offered fast and effective recycling properties for the catalyst.Copper salt synthesized MOFs have many more catalytic effective active sites than necessary.On the one hand,the well-dispersed copper active sites were linked by covalent bonds in the copper-doped ZIF-8 structure,which prevented the leaching of the copper ions.On the other hand,copper active sites are on the surface of the core-shell structure,which allows the substrate molecules to enter and exit the porous MOF structure freely.In this way,our Cu-FPZ catalyst demonstrates much improved TON and TOF.(3)MOFs are not as malleable as organic polymers,which limits their manipulation and processability.Films or membranes of MOFs are of potential interest for a wide variety of applications and technologies,which expanded the potential application of MOFs.In our paper.metal-organic framework(MOF)-based mixed matrix membranes(MMMs)were fabricated by a combination of Cu3(BTC)2 MOF and polymer cellulose acetate.The cellulose acetate in the MMMs served as the continuous phase and the Cu3(BTC)2 MOF as the dispersed phase.The as-synthesized MMMs were utilized as a heterogeneous catalyst for aldehyde acetalization.The characterization techniques indicated that the Cu3(BTC)2 crystals were uniformly dispersed in the MMMs.The BET surface area of the Cu3(BTC)2-based MMM was measured to be 459 m2/g at 60 wt%Cu3(BTC)2 loading.Furthermore,the porous mixed matrix membranes were served as an excellent catalyst under our continuous flow catalytic reaction condition.The Cu3(BTC)2 crystals was the catalytic component in the Cu3(BTC)2/CA MMMs.The conversion of benzaldehyde was 85%and the selectivity of benzaldehyde diethyl acetal was 99%under atmospheric pressure.It achieved the continuous production of benzaldehyde diethyl acetal in 24 hours.