Study On The Organic Synthesis Of Carbon Dioxide Catalyzed By Nano-Porous Materials

The growing increase of greenhouse gas of CO₂ is driving the research on chemical fixation of CO₂.As the culprit of the greenhouse effect,CO₂ is also a rich resource of C1.Thus,how to capture and convert CO₂ efficiently and greenly has been the research hotspots recently.As a non-toxic and harmless C1 resource with the simple structure,CO₂ is often used in the organic synthesis to prepare a variety of fine chemicals,fuels and basic materials,which is also a common carboxylation and carbonylation reagent.However,the catalytic conversion of CO₂ is inseparable from high-performance catalysts,and the development of nanomaterials has made a great contribution not only to the materials science but also to the organic synthesis.In this thesis,a tertiary porous material of macroporous-mesoporous Cu-BDC with crystalline mesoporous walls through a method of co-assembly induced by solvent volatilization was prepared,which integrated highly ordered macroporous and mesoporous structures into one framework simultaneously.The macroporous-mesoporous Cu-BDC was used to chemical fixation of CO₂ under ambient conditions and the yield was up to 77%.Based on the research of macroporous-mesoporous Cu-BDC,a multi-level porous material Cu-BDC nanosheet@macroporous-mesoporous TiO₂ was prepared,which was used to catalyze the carboxylation coupling of CO₂ and benzyl halide under ultraviolet light.The Cu-BDC nanosheet@macroporous-mesoporous TiO₂ showed high photocatalytic activity for the substrates,including benzyl chloride and benzyl bromide,and the yield of carboxylation coupling was as high as 83%.Besides,Cu-BDC nanosheets@macroporous-mesoporous TiO₂ was produced by the template method and the solvent evaporation method,which had a tertiary pore structure with the macropores,mesopores and micropores.The microporous Cu-BDC nanosheets were limited to macropores of macroporous-mesoporous TiO₂,while the ordered mesoporous structure was in the macroporous wall.This multi-stage pore distribution significantly improved the active surface area and mass transfer efficiency of Cu-BDC nanosheet@macroporous-mesoporous TiO₂.