Harnessing CO2 into Carbonates Using Heterogeneous Waste Derivative Cellulose-Based Poly(ionic liquids) as Catalysts

Abstract

CO2 chemical transformation into chemicals is an interesting option to mitigate CO2 concentration in the atmosphere. CO2 is an important carbon source, non-toxic, non-flammable, abundant and renewable, making it an interesting raw material. In this work, cellulose-based poly(ionic liquids) (CPILs) was synthesized from cellulose extracted from rice husk, modified with citric acid and functionalized with different cations. CPILs were used as heterogeneous catalysts for CO2 chemical transformation into cyclic carbonates by cycloaddition of CO2 with epoxides [propylene (PO) and styrene oxides (SO)]. The effect of the cation present in CPILs in catalytic performance, use of ZnBr2 as a co-catalyst and catalytic reaction parameters (temperature, pressure and time) were investigated just as well. Results demonstrate that CPILs cation variation influence their catalytic activity. A higher CO2 yield and selectivity of 81.9%/95.3% for propylene carbonate (PC) and 78.7%/100% for styrene carbonate (SC) was obtained by CPIL-TBP/ZnBr2 at conditions of 40 bar, 110 °C and 6 h, being easily separated and recycled without significant loss of catalytic activity until the fourth cycle.