Preparation And Activity Study Of Egg-nuclear Supported Bimetallic Catalysts

The use of a multifunctional catalyst to achieve a series reaction in a one-pot reaction can simplify the steps and increase the production efficiency,and therefore has become a research hotspot in the field of catalysis.However,simply catalyzing two or more catalysts mixed together,the catalysts usually interact with each other,and even lead to a decrease in the activity of the catalyst.Therefore,it is of great significance to study and explore new methods for separating the active sites of catalysts.This dissertation has completed two parts of work,using yolk-shell-structured nanomaterials as carriers to expand two different types of bimetallic heterogeneous catalysts.It is expected to utilize the structural characteristics of yolk-shell-structured materials to load the two catalysts separately.The core and the shell enable the separation of the different active centers of the catalyst,reducing the interaction between the two catalysts and improving the performance of the catalyst.1)In this paper,palladium-carbon nanoparticles were used as cores,and an organosilicon shell containing a chiral diamine-indole catalyst was assembled on the surface,and a yolk-shell-structured heterogeneous catalyst of palladium carbon-chiral diamine-anthracene bimetallic was successfully prepared.Through the characterization of the structure and morphology of the catalyst,finally determined that the prepared catalyst meets the expected design goals.Subsequently,the catalyst was applied to the reduction of phenylethynyl acetophenones compounds in a one-pot.The results showed that the prepared catalysts have good catalytic activity and selectivity.In addition,the catalyst has a wide range of substrates and has a certain degree of the practical application prospects.2)In this paper,a temperature-sensitive polymer was used to surface-modified the yolk-shell-structured silicon material carrier,and then functionalized with a metal catalyst.A temperature-sensitive yolk-shell-structured palladium chiral-rhodium heterogeneous catalyst was successfully prepared.The structure and morphology of the catalyst were characterized,and it was confirmed that the prepared catalyst meets the design expectations of this paper.The catalyst has been successfully applied in the synthesis of asymmetric biaryl alcohols in a one-pot reaction,and has good catalytic activity and selectivity.In addition,the control of the reaction temperature can control the shrinkage and extension of the surface temperature-sensitive polymer,thereby realizing the control of the catalytic process.Finally,the catalyst can be recovered by centrifugation and reused eight times,still has high catalytic activity and good enantioselectivity.