Ether chain-modified Alkanolguanidine for CO2 capture and subsequent conversion

• Ether chain-modified alkanolguanidines (EMACs) were designed and synthesized. • The as-sunthesized EMACs can achieve equimolar CO 2 absorption under 1 bar CO 2 . • They can also serve as catalyst for the cycloaddition between CO 2 and epoxides. • The integrated CO 2 capture and conversion can be achieved by EMACs. Capturing CO 2 and converting it into valuable chemicals has attracted considerable attention in recent years. Herein, a kind of ether chain-modified alkanolguanidines (ECMAs) was designed and synthesized as a dual functional reagent for carbon dioxide capture and conversion. Due to the presence of basic sites and CO 2 -philic ether chains, these ECMAs demonstrated almost equimolar CO 2 capture at room temperature and atmospheric pressure through the synergy of physical and chemical absorption. Even for diluted CO 2 (15 % CO 2 ), 0.7 mol CO 2 per mole capture reagent can still be achieved, showing their potential application in post-combustion capture. The synthesized ECMAs can also serve as catalyst in the cycloaddition reaction of CO 2 with various epoxides, affording 75–99 % yield of corresponding cyclic carbonates under 3 MPa CO 2 with tetrabutylammonium iodide (TBAI) as co-catalyst. Moreover, these ECMAs can be applied to the integrated CO 2 capture and conversion, in which the ECMAs can react with CO 2 , forming the alkyl carbonate zwitterion as active CO 2 species in the capture step. And in the subsequent cycloaddition reaction with propylene oxide, 52 % yield of propylene carbonate was obtained.