Preparation And Application Of Ionic Liquid Oxime And Imine Ligand Palladium

Three kinds of aryl oxime ligand, including acetophenone oxime,2-hydroxyacetophenone oxime and4-hydroxy acetophenone oxime were synthesized, and thencoordinated with the palladium chloride to obtaine three kind of the palladiumcoordinated ionic liquid-phase catalysts with oxime ligand. In order to investigate theoptimal reaction conditions, the Suzuki coupling reaction of4-bromoacetophenoneand benzene boric acid was carried out over4-hydroxy acetophenone oximepalladium catalyst as probe reaction.The optimal reaction conditions were obtainedas follows: methanol as solvent, potassium carbonate (2mmol) as base, methanol:water=1:1,0.25×10-3mmol of catalyst,30℃of reaction temperature，45min ofthe reaction time. Under the optimal conditions, the good yields of Suzuki reactionbetween benzene boric acid and substituted bromobenzene with different substituentgroup were obtaned over three kinds of catalysts, but three kinds of homogeneouscatalysts were difficutly recycled.In order to solve the above problems, two kinds of imidazole tetrafluoroborateionic liquids functionalized oxime ligands were synthesized, and then coordinatedwith the palladium chloride to prepare palladium catalyst with oxime ligand. Thegood activity for Suzuki reaction between benzene boric acid and substitutedbromobenzene with different substituent group was showed over two kinds ofcatalysts. The yield of the reaction products can still be around90%after thesecatalysts were reused for five times.Another two kinds of ionic liquids catalysts were synthesized, and thencoordinated with the palladium chloride to obtaine the palladium coordinated ionicliquid-phase catalysts with imine ligand. The optimal reactionconditions weredetermined as follows: methanol as solvent, potassium carbonate (2mmol) as base, methanol: water=1:1,0.5×10-3mmol of catalyst,50℃of reaction temperature，60min of the reaction time. The above catalysts got higher activity and selectivityfor Suzuli reaction between benzene boric acid and substituted bromobenzene withdifferent substituent group. After the above catalysts reused for four times, theyield of target product was still above85%.