The conversion of CO₂ into value-added cyclic carbonates over metal- and halogen-free heterogeneous catalyst has attracted much attention but remains a huge challenge. Herein, a covalent triazine framework (CTF) with hierarchical microstructure was synthesized from cyanuric chloride and 1,4-phenylenediamine by a simple solvothermal approach compared to traditional ionothermal trimerization methods. While functionalizing the CTF framework with imidazole (IM) groups, the resultant CTF-IM exhibits excellent catalytic activity for the synthesis of cyclic carbonate from CO₂ and epoxides under metal-, halogen- and solvent-free conditions. Under optimal reaction conditions, the representative epoxide, epichlorohydrin, afforded the corresponding cyclic carbonate in almost quantitative yield (94.6%), which is 5.4 times than that obtained over the parent CTF. The Lewis acidic C₂-H and Lewis basic nitrogen atom play vital roles in the activation of epoxide and CO₂, respectively, which help the cycloaddition reaction to proceed faster. In addition, CTF-IM has good chemical stability and recyclability, as well as could be applicable to a wide range of substituted epoxides.

在无金属和无卤多相催化剂上将CO ₂转化为增值的环状碳酸酯已引起广泛关注，但仍然是一个巨大的挑战。在此，与传统的离子热三聚法相比，采用简单的溶剂热法，由三聚氯氰和 1,4-苯二胺合成了具有分级微观结构的共价三嗪骨架 (CTF)。在用咪唑 (IM) 基团对 CTF 骨架进行功能化的同时，所得 CTF-IM 对 CO _{2合成环状碳酸酯表现出优异的催化活性}和无金属、无卤素和无溶剂条件下的环氧化物。在最佳反应条件下，代表性环氧化物环氧氯丙烷以几乎定量的收率（94.6%）得到相应的环状碳酸酯，是母体 CTF 的 5.4 倍。Lewis酸性C _{2 -H和Lewis碱性氮原子分别在环氧化物和CO 2}的活化中起重要作用，有助于环加成反应更快地进行。此外，CTF-IM具有良好的化学稳定性和可回收性，可适用于广泛的取代环氧化物。