Study On Preparation And Application Of Hetero-polynuclear Rare Earth Complexes And Attapulgite Nano-catalysts

CO₂ is not only a major greenhouse gas,but also a valuable renewable C₁ resource.Developing high-efficiency,green and cheap catalysts to convert CO₂ into high-value-added green chemical products can not only effectively alleviate the“greenhouse effect”and turn waste into treasure,and can also get industrial products with application value.The preparation of multi-functional catalysts with high activity,low cost and recyclability,exploring the relationship between structural structure and catalyst activity,screening high performance catalysts,can provide important theory for the fixation and conversion of CO₂ to high value-added organic chemical products.Therefore,this work has important theoretical and practical application research value.In this paper,we use multi-nuclear rare earth complexes and natural nano-mineral-attapulgite as the main research objects,and explore the catalytic activity and application performance of different types of catalysts.This article is divided into six chapters:?1?The synthesis methods and applications of cyclic carbonates are mainly introduced.The recent progress in the synthesis of cyclic carbonates is reviewed.The comprehensive utilization and modification of natural nano-mineral-attapulgite rods are further summarized.Finally,the design and synthesis of the catalyst are briefly introduced.?2?Based on the functionally oriented design concept,a series of novel hydrazide ligands were designed and synthesized,and a rare earth complexes of multinuclear elements was constructed,which was used to catalyze the reaction of coupling CO₂ and epoxy compounds to synthesize cyclic carbonates.The effects of different rare earth metals?La,Nd and Sm?on the structure and activity of the catalyst were investigated,and the possible catalytic reaction mechanism was described.?3?Using the mechanism of synergistic catalysis between hetero-metals,we designed two 3d/4d-4f heterometallic coordination polymers with multi-nuclear M-Dy?M=Zn,Cd?motifs,which were used to catalyze CO₂ and ring.In the reaction of oxygen compound coupling to prepare cyclic carbonate,the effects of different metals on the structure and activity of the catalyst were systematically investigated,and the catalytic mechanism of the catalyst was discussed in depth.?4?After understanding the mechanism of the addition reaction of CO₂ and epoxy compounds,the natural one-dimensional nano-porous material-attapulgite was successfully used as a natural nano-catalyst for the first time to catalyze the coupling of CO₂ and epoxy compounds to prepare cyclic carbonate.The mechanism of adsorption of CO₂ by attapulgite was studied systematically.The role of multi-metal synergistic catalysis in the structure was expounded.The catalytic performance of the catalyst prepared by different treatment methods was further discussed.Finally,the nano-catalysts for different epoxy substrates were studied.Applicability,selectivity and catalytic activity,and discussed the possible catalytic mechanism of the catalyst system.?5?Using attapulgite as a multifunctional carrier,a nanocomposite catalyst based on attapulgite and ZIF-8 was designed and constructed,which was used to catalyse the reaction of CO₂ and epoxy compound coupling to synthesize cyclocarbonate.The system research the effect of ZIF-8 loading on the catalytic performance of the composite catalyst was discussed,and the possible catalytic reaction mechanism was discussed.?6?Based on the special pore structure of attapulgite and excellent carrier properties,Ag/ATP nanocomposite catalyst was designed and prepared to catalyze the reaction of CO₂ and propargyl alcohol to prepare cyclic carbonate.The amount of AgNO₃ was controlled to control the loading of Ag⁰.A series of nanocomposites with different loadings of silver were prepared.The stability of the catalysts and the catalytic activities in the catalytic reactions were systematically studied.The catalytic mechanism of the catalysts was discussed in depth.