A series of low-cost and easily prepared benzyl substituted imidazolium ionic liquids are firstly synthesized and employed as catalyst for the cycloaddition of carbon dioxide with epoxides without any solvent and co-catalyst. The synthesized imidazolium ionic liquids are characterized by ¹H NMR, HRMS, and MS. The influence of different substituted groups in cation and reaction parameters on catalytic activity is investigated. The highest conversion yield of cyclic carbonate (94.89%) could be achieved with slight amount of catalyst (0.25 mol%) under 130 °C and 2.0 MPa during 4 h. Meanwhile, the mechanisms of cycloaddition of carbon dioxide with epoxides catalyzed by four benzyl substituted ionic liquids with different substituted groups are investigated by theoretical calculations. The role of hydrogen bond and other noncovalent interactions played in catalytic process is further uncovered to deeply understand the difference of various catalysts from atomistic level.

首先合成了一系列低成本且易于制备的苄基取代的咪唑鎓离子液体，并用作在没有任何溶剂和助催化剂的情况下用环氧化合物环化二氧化碳的催化剂。合成的咪唑鎓离子液体的特征在于¹1 H NMR，HRMS和MS。研究了阳离子和反应参数不同取代基对催化活性的影响。在130°C和2.0 MPa的条件下，在4小时内用少量催化剂（0.25 mol％）可以实现最高的环状碳酸酯转化率（94.89％）。同时，通过理论计算研究了四种具有不同取代基的苄基取代离子液体催化二氧化碳与环氧化物环加成反应的机理。进一步揭示了氢键和其他非共价相互作用在催化过程中的作用，以从原子水平深入理解各种催化剂的区别。