Study On Preparation Of Cyclocarbonate From Carbon Dioxide And Epoxide Catalyzed By Iron-based Guide Catalyst

As one of the main components of greenhouse gases,carbon dioxide（CO₂）is not only the driving force of the intensification of greenhouse effect,but also an important source of C1 in the ecological cycle.Therefore,it is very important to use modern means to capture,store and utilize it（CCUS）.However,the chemical inertness of CO₂causes some problems to its utilization.At the same time,with the continuous development of green chemistry,higher requirements are put forward for the conversion of CO₂.At present,the reaction of CO₂and epoxide to produce cyclocarbonate can not only meet these requirements,but also create huge social and economic benefits.In this paper,by introducing the co-catalytic method of multiple active sites,zirconium iron composite metal oxides,nitrogen-containing heterocyclic porous organic polymers and doped bimetallic MOF catalysts were prepared respectively for the coupling reaction of CO2and epoxy compounds to produce different cyclic carbonates.The reaction was studied from the perspective of inorganic to organic systems.The main contents are as follows:First,Fe-zirconium composite metal oxides were prepared on the basis of hydrotalcite preparation methods,and the chemical composition and structure of the catalysts were determined by FT-IR,UV-Vis,XPS,etc.The yield of Zr6Fe2O15 was 77.9%and the substrate was suitable for general use.Through on-line infrared monitoring of the reaction process of CO2 cycloaddition,it was determined that catalyst Zr6Fe2O15 promoted the reaction through the co-activation of bimetal and the production of stable intermediates during the reaction.Secondly,the catalyst Fe-POC1 was prepared by synthesizing ligand POC1-6 and loading transition metal iron ions.With the help of TBAC,Fe-POC1 showed high catalytic activity and universality in the reaction.At 120℃and 1.0MPa CO2 for 6h,92%yield and94%selectivity were obtained.Combined with the research results,the high catalytic activity is mainly attributed to the more electrophilic metal center complexation with ligand and the free Cl-p-epoxide assisted ring-opening in the system.Finally,Fe/Zn-MOF-74 catalyst was prepared by grafting different proportions of iron and zinc bimetal onto MOF-74 structure.With the help of TBAC,Fe0.88Zn0.12-MOF-74showed good catalytic activity for the cycloaddition reaction of epoxides and CO2.At 100℃and 0.8MPa methanol solvent for 7h,the yield of 94%was obtained,with a selectivity of 93%.The experimental results showed that the high catalytic activity was mainly attributed to the synergistic action of bimetals.