Synthesis Of Chalcone Catalyzed By Metal-Organic Frameworks(IRMOF-3) Via Claisen-Schmidt Condensation Reaction

In order to resolve the low yield, equipment corrosion and problems of catalyst recovery of traditional catalysts in the synthesis of chalcone, metal-organic framework with the basic amino functional groups IRMOF-3 was prepared. The catalytic performance of IRMOF-3 in Claisen-Schmidt condensation was studied in detail and chalcone with biological and medicinal activity was synthesized in this research. The catalytic mechanism of IRMOF-3 on Claisen-Schmidt condensation was also discussed. The main contents were:Firstly, metal-organic framework material IRMOF-3 was synthesized through solvothermal method. Prepared IRMOF-3 was characterized by XRD, SEM, TG-DSC and N2 adsorption-desorption experiments. The results indicated that the prepared IRMOF-3 was cube porous materials with a large surface area and certain thermal stability. The FT-IR spectrum of IRMOF-3 indicated the presence of amino groups.Secondly, the amino-functionalized IRMOF-3 catalyst was applied to the synthesis of chalcone via the Claisen-Schmidt condensation reaction. The influences of reaction temperature, molar ratio, catalyst dosage, solvent and different catalysts on the yield of the chalcone were investigated. According to the results, IRMOF-3exhibited high catalytic activity for the Claisen-Schmidt condensation reaction and the highest yield of chalcone could reach 78% under the optimal reaction conditions. We found that the catalytic activity of IRMOF-3 in this reaction was far higher than that of its synthetic components(the metal ion and the organic ligand) and homogeneous aniline catalyst. Moreover, it was demonstrated that the IRMOF-3 catalyst was truly heterogeneous and could be reused for at least four times without losing its framework integrity and catalytic activity. Furthermore, IRMOF-3 also had certain catalytic activities for the Claisen-Schmidt condensation between a range of aromatic aldehydes with different substituents and ketones with various substituents.Finally, we explored the catalytic mechanism of IRMOF-3 on Claisen-Schmidt condensation reaction. The results indicated that IRMOF-3 reflected the site-isolated acid-base bifunctional character in the reaction system. The acid sites would come from a defective origin, while the basic sites would come from the amino groups in the organic ligand. The Zn site from the defective origins in close proximity to theamino group could accelerate the amino group and the aldehyde group to form imine intermediates by activating benzaldehyde molecules. The imine intermediate was then attacked by the acetophenone anion and chalcone product was formed.