Preparation And Performance Of Catalysts For Reaction Of Carbon Dioxide With Epoxides

The synthesis of cyclic carbonates can fix CO2as a C1resource, which has received increasing attention in recent years. As novel green media, ionic liquids (ILs) have shown broad prospects in the catalysis of this cycloaddition reaction due to their thermal stability and widely tunable properties. In order to overcome disadvantages, such as unsatisfactory activities, difficulties in separation, tough reaction conditions and requirement of co-solvents or co-catalysts, we conducted a functional ionic liquid and chemical load type poly ionic liquid catalytic synthesis of cyclic carbonate. The major work and innovative results for this dissertation are as follows.1.2-hydroxymethyl-l-methyl-imidazole kind of quaternary ammonium salt ionic liquids was developed and showed high activity and selectivity for the coupling reaction of CO2and epoxides under the mild conditions. It was found that a98%conversion of propylene oxide with100%propylene carbonate selectivity could be achieved by using2-Hydroxymethyl-l-methyl-3-n-buthylimidazole bromide as catalyst at catalyst amount1.0mol%,120℃,2.0MPa and1h without any co-solvents or co-catalysts. The catalyst also found to be extended to different kinds of terminal epoxides.2. A series of poly-(hydroxyl-functionalized)-ionic liquids were prepared and employed as catalysts for synthesis of cyclic carbonates from CO2and epoxides without the use of any co-catalyst and organic solvent. It was investigated that hydroxyl and bromide anion had excellent synergetic effect on promoting the reaction, and the poly-ionic liquids (PILs) copolymerized of bromide with the cross-linker divinylbenzene (DVB) was observed to be the most efficient. The different effects such as temperature, pressure, reaction time on the reaction were also investigated. Moreover, the catalysts can be easily recovered by filtration and reused over five times with slight loss of its catalytic activity.