Polymer grafted with asymmetrical dication ionic liquid as efficient and reusable catalysts for the synthesis of cyclic carbonates from CO2 and expoxides

• Published in: Catalysis today Vol. 233; pp. 92 - 99
• Main Authors: Wei-Li, Dai, Bi, Jin, Sheng-Lian, Luo, Xu-Biao, Luo, Xin-Man, Tu, Chak-Tong, Au
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2014
• Subjects: Asymmetrical dication ionic liquid; Carbon dioxide; Cyclic carbonate; Epoxide; Heterogeneous catalysis; Heterogeneous catalysis; Cyclic carbonate; Asymmetrical dication ionic liquid; Carbon dioxide; Epoxide
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2014.02.042

•Polymer grafted with asymmetrical dication ionic liquid (PDIL) was synthesized.•The PDIL shows high catalytic activity and selectivity for cycloaddition reactions.•The PDIL shows good stability and reusability.•A plausible mechanism for cycloaddition reaction over PDIL is proposed. Polymer grafted with asymmetrical dication ionic liquid (IL) based on imidazolium and phosphonium ([P-Im-C4H8Ph3P]Br2) was fabricated, and for the first time evaluated as catalyst for the synthesis of cyclic carbonates from epoxides and CO2 without using any co-catalyst and solvent. The catalyst showed much superior activity than monocation imidazolium and phosphonium ILs. At a low catalyst loading (0.38mol%), high yield (96.8%) and selectivity (99.5%) of propylene carbonate can be obtained over [P-Im-C4H8Ph3P]Br2 at 130°C and 2.5MPa in 4h. The cooperation of nucleophilic attack of bromine anions as well as the activation of the two cations may contribute to the good activity of the catalyst. Furthermore, the catalyst shows excellent stability and reusability. It can be reused for up to five runs without any significant loss of catalytic activity after simple filtration.