MOFs Material Constructed By Post-synthesis Modification Strategy And Studying On Carbon Dioxide Fixation

Metal organic framework?MOFs?materials have potential applications in gas separation,drug delivery,sensing,catalysis and other fields.Because the metal clusters in the MOFs have a large number of Lewis acid sites,some ligands have Lewis base sites.These Lewis acid sites and Lewis base sites can synergistically catalyze the cycloaddition reaction of CO₂ and epoxides to improve the reaction effectiveness.The main research contents of this article are as follows:The first chapter reviews the research progress of MOFs constructed by post-synthesis modification strategies.The second chapter introduces the preparation of MIL-101-Br functionalized with bromine ion after synthesis of MIL-101-NH₂.MIL-101-Br can provide not only the Lewis acid sites of Cr³⁺,but also the nucleophilic Br^-,which can catalyze the cycloaddition reaction of carbon dioxide and epoxide under mild conditions.The yield of propylene carbonate is 96.8%and the catalyst can still achieve more than 90.0%catalytic activity after five cycles.The possible catalytic mechanism of MIL-101-Br catalyzing the cycloaddition reaction of carbon dioxide and epoxide was discussed.The third chapter synthesizes the catalytic material of the mixed metal MOFs?Y-ZnTCPP?.The MOFs catalytic material can not only provide the Lewis acid sites of the rare earth metal Y³⁺,but also provide the Lewis acid sites of Zn²⁺.It is found that the mixed metal Y-ZnTCPP material catalyzes the cycloaddition reaction of carbon dioxide is much better than Y-TCPP and the yield of propylene carbonate is 97.3%under milder conditions.The catalyst can still achieve more than 90.0%catalytic activity after five cycles.The results show that Y-ZnTCPP obtained by modifying metals on Y-TCPP materials shows good catalytic activity and recyclability.The fourth chapter is the conclusion and prospect.In this paper,the post-synthesis modification strategy was used to prepare bromide functionalized MIL-101-Br and mixed metal Y-ZnTCPP catalytic materials.The two materials exhibit excellent catalytic activity in the cycloaddition of epoxide and carbon dioxide.The experimental results provide new ideas and methods for the design and synthesis of MOFs and their functional materials.And applying them to catalyze the cycloaddition of carbon dioxide.