3-(2-Hydroxyl-Ethyl)-1-Propylimidazolium Bromide Immobilized on SBA-15 as Efficient Catalyst for the Synthesis of Cyclic Carbonates via the Coupling of Carbon Dioxide with Epoxides

Abstract

3-(2-hydroxyl-ethyl)-1-propylimidazolium bromide (HEPIMBr) was immobilized onto SBA-15, Al-SBA-15 mesoporous molecular sieves and SiO 2 by chemical grafting method. The materials were characterized and used as catalysts for solvent-free synthesis of cyclic carbonates from CO 2 and epoxides under relatively mild conditions. Among them, the HEPIMBr immobilized on SBA-15 performs the best, showing carbonate selectivity and yield of ca. 100% (120°C, 2.0 MPa, 2 h). The catalyst is thermally stable and shows good reusability. Based on the experimental results, a plausible reaction mechanism has been proposed for the catalytic reaction.

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

“…Zhu et al [32] reported that the molecular sieve-supported choline chloride/urea exhibited good catalytic activity, but urea was indispensable. We also fabricated hydroxyl ionic liquid catalyst immobilized SBA-15 molecular sieve, and found it showed good catalytic activity towards the coupling reaction [35]. But its reusability is not satisfactory, similar to the ionic liquid catalysts immobilized on MgO, SiO 2 , or MCM-41 [27,[29][30][31].…”

Supported imidazole as heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO2

“…Although, this catalyst is active at relatively lower temperature, i.e., 353 K, the selectivity for the cyclic carbonate was reported to be less because of the formation of diol by-products. A number of groups have reported imidazoliumbased ionic liquids supported on mesoporous silica [21], commercial silica surfaces [22], SBA-15 [23] and polymers [24,25] as effective catalysts for this transformation. Most importantly, these catalysts are not active without the halide anions present in the ionic liquids.…”

Transition Metal-Free Incorporation of CO2

“…ILs immobilized on mesoporous sieves (SBA-15 [78,79] and MCM-41 [80][81][82]) and polymeric materials [83,84] could act as efficient catalysts for the transformation of CO 2 into cyclic carbonates with high yield and excellent selectivity under relatively mild conditions. High activity is displayed when ILs immobilized on carboxymethyl cellulose (CMC) and chitosan (CS) are applied as heterogeneous catalysts for cycloaddition of epoxides with CO 2 , since CMC or CS is rich in hydroxyl and carboxyl groups [85][86][87].…”