Dual-ionic imidazolium salts to promote synthesis of cyclic carbonates at atmospheric pressure
Tengfei Wang, Danning Zheng, Beibei An, Yi Liu, Tiegang Ren, Hans Ågren, Li Wang, Jinglai Zhang, Mårten S. G. Ahlquist
Abstract
Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure (0.1 MPa) without any solvent and co-catalyst leading to 96.1% product yield. It can be reused five times to keep the product yield over 90%. These intriguing results are attributed to a new reaction mechanism, which is supported by theoretical calculations along with the measurements of 13C NMR spectrum and Fourier transform infrared spectroscopy (FT-IR). The excellent catalytic activity can be traced to a CO2-philic group along with an electrophilic hydrogen atom. Our work shows that incorporation of CO2-philic group is an feasible pathway to develop the new efficient ionic liquids.