High-Efficiency Synthesis of Cyclic Carbonates from Epoxides and CO2 over Hydroxyl Ionic Liquid Catalyst Grafted onto Cross-Linked Polymer

Hydroxyl ionic liquid grafted onto cross-linked divinylbenzene polymer (PDVB-HEIMBr) was fabricated and evaluated as a catalyst for the synthesis of cyclic carbonates from CO2 and epoxides without the use of any co-catalyst and organic solvent. The catalyst shows good performance across a wide range of epoxides, giving almost quantitative yield of carbonates (140 degrees C, 2.0 MPa of initial CO2, and <= 4 h). The effects of reaction temperature, time and initial CO2 pressure on product yield were investigated. It is suggested that the synergetic effect between the bromide ions and the hydroxyl groups facilitates the coupling reaction. Furthermore, the PDVB-HEIMBr catalyst shows excellent stability and reusability. From the viewpoint of industrial application, the catalyst is very attractive because of its simplicity, activity, stability, and reusability.