The Synthesis Of Functionalized Ionic Liquids And The Research Of Their Catalytic Performance In Fine Organic Synthesis

Ionic liquids(ILs) with their low toxicity,negligible vapor pressure, non-flammability,high thermal stability,wide liquid range,good solubility and ease of recycling have been considered as the perfect green solvent to instead of the volatile organic solvents.Recently,as a designed and modified functionalized molecular,the functionalized ionic liquids have been widely studied.Therefore,an oligomer of thioether-functionalized ionic liquid was synthesized and used to stabilize gold nanoparticles.The epoxidation of styrene was catalyzed by the functionalized oligomeric ionic liquid-stabilized gold nanoparticles.And nitrile-functionized ionic liquid was prepared to catalyze the Knoevenagel reaction.(1) 6,6'-dichloro-disulfide linked dihexane and methylimidazole were used to synthesize an oligomer of ionic liquid containing imidazolium chloride units and disulfide groups,which is miscible with the ionic liquid of[bmim]PF₆.The oligomer of ionic liquids and the intermediate products were characterized by NMR and IR.(2) The oligomer of ionic liquid was used to stabilize gold nanoparticles in the[bmim]PF₆.The UV-vis spectrum of the gold nanoparticles stabilized by the functionalized oligomeric IL in[bmim]PF₆ possessed a surface plasmon resonance around 526 nm.The formation of gold nanoparticles was confirmed by TEM observations and the mean size of the gold particles is ca.3.4 nm.As such,in the nonvolatile [bmim]PF₆ without using any VOC as solvent,the epoxidation of styrene could be catalyzed by the functionalized oligomeric ionic liquid-stabilized gold nanoparticles.The influence of the amount of catalyst,amount of oxidant,reaction time,reaction temperature were studied.Under optimum reaction conditions,a styrene conversion of 100%with the selectivity to styrene oxide of 90%was obtained.The catalyst can be easily separated from the reaction system and successively reused.(3) The new nitrile-functionalized ionic liquids were synthesized and catalyzed the Knoevenagel reaction without solvent.The influence of the kind of catalyst,the amount of catalyst,reaction time,reaction temperature were studied.Under 20℃,a benzaldehyde conversion of 100%with the selectivity of 100%was obtained within 5 min.The basic ionic liquid can be reused for 4 times without significant loss of activity.