Study On Synthesis Of Cyclic Carbonates Catalyzed By Functionalized Ionic Liquids

Chemical fixation of CO₂ into valuable chemicals has attracted much attention in both academia and industry from the standpoint of environmental protection and resource utilization.One of the most promising methodologies in this area is the synthesis of five-membered cyclic carbonates via the fixation of CO₂ with epoxides and the development of non-toxic and recyclable catalysts for a reaction under mild reaction conditions is still a very attractive topic.In this paper the polymerized ionic liquids and the methacrylic acid amide ionic liquids were investigated to catalyze the cycloaddition reactions.Nano-sized polydopamine grafted with alkyl halide was proved to be an efficient heterogeneous catalyst for synthesis of cyclic carbonates from epoxides and carbon dioxide.It was demonstrated that the abundant hydroxyl and bromide anion had an excellent synergetic effect on the ring opening of epoxide,resulting in the high performance of the PDAEBr-4.A high conversion（99 %）and an excellent selectivity（99 %）for cyclic carbonates could be achieved at the conditions of 3 MPa,120 oC and 3 h without any co-solvent.A Possible mechanism was also proposed.Four kinds of ionic liquids containing methyl methacrylate were synthesized and applied to the synthesis of cyclic carbonate without any co-solvent.The [DMAEMA-Et][Br] showed the best catalytic activity with a99 % conversion of propylene oxide and more than 99 % selectivity of propylene carbonate under mild conditions（120 oC,2 MPa）for 2h.