Several environmentally benign eutectic-based ionic liquids (ILs) were developed as novel homogeneous catalysts for efficient conversion of carbon dioxide to cyclic carbonates. Propylene oxide (PO) was selected as a benchmark substrate to optimize the catalytic activity, and on account of the catalytic cooperativity between the cation and anion in the [urea-Zn]I₂ catalyst, excellent yield (95%) and selectivity (98%) to propylene carbonate (PC) was obtained under the optimized reaction conditions of 120 °C and 1.5 MPa for 3.0 h in the absence of cocatalyst and solvent. Also [urea-Zn]I₂ was proved to be an efficient and versatile catalyst, and could realize catalytic conversion of CO₂ with various epoxides. Moreover, the synergistic reaction mechanism involving cation structure and halogen anion for CO₂ conversion was proposed, and the eutectic-based ILs were easily recyclable with high activity. The eutectic-based ILs that possessing low cost, moisture-stability, facile synthesis and efficiently bifunctional properties reported herein displayed the exceptionally outstanding features for efficient conversion of CO₂ to cyclic carbonates.

中文翻译：

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轻松合成基于[urea-Zn] I _2的共晶离子液体，可有效地将二氧化碳转化为环状碳酸酯

几种环境友好的基于共晶的离子液体（IL）被开发为新型的均相催化剂，用于有效地将二氧化碳转化为环状碳酸酯。选择环氧丙烷（PO）作为基准底物以优化催化活性，并考虑到[脲-Zn] I ₂催化剂中阳离子与阴离子之间的催化协同作用，极佳的收率（95％）和选择性（98）在没有助催化剂和溶剂的情况下，在120℃和1.5 MPa的最佳反应条件下反应3.0小时，获得了碳酸亚丙酯（PC）的收率。还证明了[脲-Zn] I ₂是一种高效且用途广泛的催化剂，可以实现CO _2的催化转化。与各种环氧化物。此外，提出了阳离子结构和卤素阴离子协同转化CO ₂的协同反应机理，基于共晶的离子液体易于回收利用，具有较高的活性。本文报道的具有低成本，湿气稳定性，易于合成和有效的双功能性质的基于共晶的IL表现出将CO ₂有效转化为环状碳酸酯的异常突出的特征。