Chemical utilization of CO₂ via carboxylation has attracted increasing attention in the field of synthesizing carboxylic acids. As the most promising substitute for terephthalic acid, 2,5-furandicarboxylic acid (2,5-FDCA) is a bio-based platform compound with wide application prospects. 2,5-FDCA could be sustainably and economically produced by direct carboxylation of 2-furoic acid (a biomass-derived raw material) and CO₂ over Cs₂CO₃ catalysis. In this paper, the effect of different reaction conditions on 2,5-FDCA yield was investigated, and only generation of 2,5-FDCA without 2,4-FDCA or 2,3-FDCA was determined by HPLC and GC/MS analyses of the resulting product mixtures. Furthermore, density functional theory (DFT) was used to gain deep insight into the mechanism of direct carboxylation reaction. The reaction involved the hydrogen abstraction of furan ring in cesium 2-furoate (FA-Cs) by CO₃²⁻ and subsequent CO₂ electrophilic addition to form CC bond, and the former step was rate-determining for the reaction. More interestingly, the selective formation of 2,5-FDCA relied on molecular features of FA-Cs during the hydrogen abstraction of furan ring.

在羧酸合成领域中，通过羧化作用对CO _2的化学利用已引起越来越多的关注。2,5-呋喃二甲酸（2,5-FDCA）是对苯二甲酸最有希望的替代品，是一种生物基平台化合物，具有广阔的应用前景。通过在Cs ₂ CO ₃上2-糠酸（一种生物质来源的原料）和CO ₂进行直接羧化，可以可持续且经济地生产2,5-FDCA。催化。本文研究了不同反应条件对2,5-FDCA收率的影响，并且仅通过HPLC和GC / MS分析确定了在没有2,4-FDCA或2,3-FDCA的情况下产生2,5-FDCA的情况。所得产物混合物。此外，使用密度泛函理论（DFT）来深入了解直接羧化反应的机理。该反应涉及通过CO ₃ ^2-除去^2-糠酸铯（FA-Cs）中呋喃环的氢原子，然后进行CO ₂亲电加成以形成C C键，反应的前一步是确定反应的速率。更有趣的是，2,5-FDCA的选择性形成依赖于呋喃环氢提取过程中FA-C的分子特征。