Synthesis And Application Study Of Schiff Based Polymetallic Coordination Catalysts

Catalyst can be divided into homogeneous catalyst and heterogeneous?also called polyphase?catalyst according to the phase homogeneity of the catalytic reaction system.Among them,metal complex catalysts classified as homogeneous catalysts,especially metal schiff based complex catalysts,have good catalytic performance.However,homogeneous catalysts have some disadvantages such as difficult separation in later period,while heterogeneous catalysts could make up for these disadvantages.In this paper,based on the improvement of metal schiff based complex catalysts,we synthesized two different schiff based multi-metal center coordination catalysts.They both have good catalytic activity and selectivity for CO₂ epoxidation.The specific contents of the experiment are as follows:?1?By hydrothermal synthesis method,the schiff based bimetallic tubular polymer catalyst is designed and synthesized.Experiments prove that the schiff based tubular polymer with the incorporation of cobalt ions is more stable in performance and exhibits excellent catalytic activity in the catalytic epoxidation of CO₂ and epoxides with presence of cocatalysts,the catalytic yield is as high as 96%and the selectivity reaches almost 100%.Moreover,as heterogeneous catalyst,it has good performance after repeated six times of catalyst experiments.?2?Further exploration on other applications of schiff based bimetallic tubular polymer show that the tubular polymer has paramagnetism and unique electronic structure.The introduction of cobalt ions reduces the band gap and shifts the Fermi level to the left by 0.5 eV.?3?Schiff base chiral macrocyclic tricobalt catalyst is synthesized by hydrothermal synthesis method and its single crystal structure is obtained.Its crystalline form is determined by the single crystal structure and its chiral catalytic performance is further investigated.Experiments prove that the schiff based macrocyclic tricobalt catalyst has excellent catalytic performance on the epoxidation reaction of CO₂ without adding a cocatalyst,and cyclic carbonate can be selectively formed by controlling the reaction conditions.