Magnetic Supported Aza-crown Ether Complex Cation Ionic Liquids:Preparation And Applications In Organic Reaction

The facile designability and functionalization of ILs can lead to many innovations.Supported ionic liquids?SILs?are among the most important branches in the IL community drawning great attention in both fundamental research and practical applications.They not only retain the advantages of ILs and supports but also derive a series of new performances and novel properties due to the synergistic effect of ILs and supports,while also overcoming many of negative aspects of conventional.Our team has been committed to the preparation and application of crown ether ionic liquids.In 2011 our team prepared a series of novel crown ethers ionic liquids,which of melting points are below 200 °C and cations consist of crown ether chelation ion.In 2014,we synthesized and preparaed aza-crown ether complex ionic liquids as well as new Br???nsted acidic aza-crown ether complex cation ionics.The ionic liquids above are difficult to recycle in spite of their advantages.Their immobilization would overcome this problem.In my work,crown ether ionic liquids were immobilized on the surface of Fe₃O₄@SiO2 by formming covalent bond between the nitrogen atom of the aza-crown ether and the carrier carbon atom.The catalytic activity and recycling properties of prepared ILs catalysts were investigated in detail.This work is divided into three parts:?1?We have immobilized the aza crown ether ionic liquid on Fe₃O₄@SiO2 successfully,and a total of five kinds of catalysts were synthesized.Furthermore,they were characterized by elemental analysis,TEM,TG-DTAand FT-IR.?2?Catalyst 5a was applied in the synthesis of the bis-indolymethanes.It catalyzed the condensation reaction of indole with aldehyde in higher catalytic activity.At room temperature,methanol as solvent,this reactin could give a yield of substantially about 90%.We also conducted a study about its recovery and reusage,found that catalytic activity was not significantly reduced after five recycles.?3?The Hantzsch reaction of benzaldehyde,ammonium acetate and ethylacetoacetate was researched when catalyzed by catalyst 5b containing[BF4]-.When the ratio of benzaldehyde:sodium acetate:ethyl acetoacetate was 1:3:1,the reaction could achieve good yield at alcohol reflux.Through separating and recovering catalyst by an external magnet,our results demonstrated that the catalyst could remain high catalytic efficiency after five times recycling.