Preparation Of Functionalized Ionic Liquids And Its Application In Heck Reaction

Heck reaction is one of the most effective methods for C-C bond formation,which has been widely used in the synthesis of pharmaceuticals,pesticides and natural products.In the traditional Heck reaction,organophosphonic as ligands,but its structure is complex,and can cause the pollution of the environment and be easily oxidized,thus resulting in the deactivation of the palladium catalyst a;by-product salt generated by inorganic alkaline or organic amine after the capture of the acid can be mixed with organic matter to form a paste,making the separation more difficult,Also can cause the pollution of the environment.However,the functionalized ionic liquids could not only be used as a reaction medium,but also function as a ligand and acid-binding agent,which can enhance the activity and stability of palladium catalyst,can be recovered and reused,and can effectively solve the above problems.In this paper,applying the functionalized ionic liquids to the Heck reaction not only has an important academic significance,but also has a broad application prospect.The specific work carried out in this thesis is summarized as follows:?1?Taking the ordinary imidazoles ionic liquids as a design object and introducing functional groups on its ions can successfully synthesize two types of functionalized ionic liquids:basic-functionalized ionic liquids and phosphine-functionalizeds ionic liquids.?2?Using the Heck reaction of 2-bromo-6-methoxy naphthalene with allyl alcohol as a template,we have investigated the effect of basic-functionalized ionic liquids and phosphine-functionalized ionic liquids on the reaction,and found that basic-functionalized ionic liquids can effectively replace Et₃N as acid-binding agent,overcoming the drawbacks of slurry mixture deposition and un-recyclability in the reaction.Phosphine-functionalized ionic liquids can effectively replace PPh₃ as ligand,improving oxidation tolerance in the reaction,and no precipitation of palladium black.?3?Making the use of the Heck reaction of 2-bromo-6-methoxy naphthalene with allyl alcohol as a template,we have contrasted the recycle utilization of the multi-functionalized ionic liquids system,basic-functionalized ionic liquids system and phosphine-functionalized ionic liquids systems in the Heck reaction,and found that after eight recycle utilization of the complex system consisting of Pd?OAc?₂ and[OPPh₂-C₂mim]PF₆-[Bmim]OAc-[Bmim]PF₆,it still has a good selectivity to the product,and no active loss of catalyst,completely avoiding the use of organic phosphine ligands,inorganic alkali or organic amine and organic solvent,but after five recycle utilization of another two systems,the palladium black has been precipitated gradually and the catalyst deactivated.