Lignin is a biodegradable, abundant and renewable natural polymer on earth. In this study, deep eutectic solvents (DESs)-modified lignin heterogeneous catalysts were prepared for the first time via a facile acid-base interaction between choline chloride (ChCl) and p-aminobenzoic acid (PABA) or its derivatives, which were used to efficiently catalyze the cycloaddition of CO₂ and terminal epoxides under green and mild conditions. Among them, lignin-ChCl-PABA was found to exhibit the highest catalytic activity for the cycloaddition of epoxides in the presence of 1.0 MPa of CO₂ while retaining high selectivity, which far outperformed those achieved on the homogeneous EDSs catalytic system. A series of cyclic carbonates could be obtained in high yields (90–99%), and lignin-ChCl-PABA was stable and reusable for the cycloaddition reaction (84% yield after 5 recycles). The attaching DES of ChCl/PABA onto the functional lignin increased the catalytic activity and also made the catalyst easier to recycle from the reaction mixture. The OH and NH₂ groups on the surface of lignin-ChCl-PABA played a very important role in the acceleration of the cycloaddition reaction under solvent free conditions.

木质素是地球上可生物降解的，丰富的和可再生的天然聚合物。在这项研究中，首次通过氯化胆碱（ChCl）与对氨基苯甲酸（PABA）或其衍生物之间容易的酸碱相互作用制备了深共熔溶剂（DESs）改性的木质素非均相催化剂，在绿色和温和的条件下可有效催化CO ₂和末端环氧化物的环加成反应。其中，发现木质素-ChCl-PABA在1.0 MPa的CO ₂存在下对环氧化物的环加成反应表现出最高的催化活性。同时保留了高选择性，远胜于均相EDS催化系统。可以高产率（90-99％）获得一系列环状碳酸酯，木质素-ChCl-PABA稳定且可用于环加成反应（5次循环后产率为84％）。ChCl / PABA附着在功能性木质素上的DES增加了催化活性，也使催化剂更易于从反应混合物中回收。木质素-ChCl-PABA表面的OH和NH ₂基团在无溶剂条件下促进环加成反应中起着非常重要的作用。