Bi-functionalized ionic liquid porous copolymers for CO2 adsorption and conversion under ambient pressure

Developing solid materials with high CO 2 adsorption capacity and catalytic activity has been a hotspot due to the greenhouse effect. In this work, bi-functionalized ionic liquid 1-vinyl-3-methoxyethyl imidazolium glycinate ([VMOEim][Gly]) was copolymerized with crosslinker divinylbenzene (DVB) to obtain bi-functionalized ionic liquid porous copolymers P( n DVB-[VMOEim][Gly]) and HP( n DVB-[VMOEim][Gly]). These copolymers possess loose stack of small particles or laminates, and they contain mesopores and a small number of micropores. For HP(0.6DVB-[VMOEim][Gly]), surface area reaches up to 508 m 2 ·g −1 and the initial decomposition temperature is about 180 °C. Then these porous copolymers were applied for CO 2 adsorption at 25 °C and cycloaddition reaction of CO 2 with epichlorohydrin under ambient pressure and cocatalyst-free condition. The maximum CO 2 capture capacity is 64.5 mg/g with HP(0.6DVB-[VMOEim][Gly]) as adsorbent. The effects of catalyst type, catalyst dosage, reaction time and temperature on the yield of cyclic carbonate were also investigated. The optimum conditions are 4 wt% of HP(0.6DVB-[VMOEim][Gly]) (based on the epichlorohydrin) as catalyst at 130 °C for 10 h, and the yield of 4-(chloromethyl)-1,3-dioxolan-2-one can reach 94%. Furthermore, the catalytic activity of HP(0.6DVB-[VMOEim][Gly]) maintains and the yield is 91% after five-cycle experiment. The mechanism of cycloaddition reaction was also discussed.