Synergistic Catalytic Mechanism of Glutarimide Ionic Liquids in Atmospheric Pressure Cycloaddition of CO 2 With Epichlorohydrin
Xin Wang, Bingxin Wang, Ruiyu Zhang, Huali Jia, Chenyi Cai, Zichen Zhao, Xiaoming ZhuABSTRACT
The conversion of CO 2 into cyclic carbonates under mild conditions remained challenging due to the thermodynamic stability of CO 2 . Herein, a series of glutarimide‐based ionic liquids was developed for the cycloaddition of CO 2 to epoxides. Among them, [BZTMA][GLU] exhibited the highest activity, affording chloropropylene carbonate in 99.5% yield at 70°C within 7 h using only 2 mol% catalyst under 0.1 MPa CO 2 . Systematic variation of the cation ([BZTMA] + , [HDBU] + , [CH] + ), and anion ([GLU] – , [Im] – , [Pth] – ) revealed that catalytic performance was governed by a balance between CO 2 absorption capacity and cation‐anion interaction strength; excessively strong ion pairing counteracted the benefit of high CO 2 absorption. The catalyst was readily recovered and retained 95.9% yield after eight cycles. Substrate scope studies demonstrated that steric hindrance of both the epoxide and the anion critically influenced reactivity. This work established a clear structure‐activity relationship for the rational design of ionic liquid catalysts in CO 2 fixation.