Ionic liquids grafted on carbon nanotubes as highly efficient heterogeneous catalysts for the synthesis of cyclic carbonates

A variety of multi-walled carbon nanotubes grafted with immidazolium-based ionic liquids (CNT-ILs) were synthesized and utilized as highly efficient heterogeneous catalysts for the production of cyclic carbonates via cylcoaddition reactions of epoxides and CO2. In comparison with conventional heterogeneous catalysts that employ porous silica and polymer supports, CNT-ILs exhibited significantly enhanced catalytic reactivity towards the cycloaddition reactions. The effects of the IL molecular structure (alkyl chain length and counter anions) and the reaction parameters (temperature, CO2 pressure, and time) on the catalytic performance of the corresponding heterogeneous catalysts were also systematically investigated.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (174 K)Download as PowerPoint slideHighlights► Imidazolium-based ionic liquids were grafted onto carbon nanotube nanohybrids. ► They showed enhanced catalytic performance in the cycloaddition reaction of CO2 and epoxides. ► Tunable catalytic activity can be achieved depending on the molecular structure of the immobilized ionic liquids. ► Reaction conditions have significant effects on the catalytic performance of the heterogeneous catalysts.