In Situ Catalytic Conversion of Low-Concentration CO₂ to Formanilide Through Base-Functionalized Porous Organic Polymers

Formanilide, an important organic intermediate widely used in pharmaceuticals and pesticides is traditionally synthesized via complex, hazardous methods incompatible with green chemistry principles. Addressing this challenge, we developed a multifunctional synergistic solid base catalyst, POP3-DBU, which achieves 90% yield in converting low-concentration (<30 vol %) carbon dioxide (CO2) directly from lime kiln flue gas to formanilide under mild conditions (30 °C, 1 atm). Mechanistic studies reveal a triple-functional synergy of POP3-DBU: (1) selectively adsorb and enrich CO2, (2) multisite CO2 activation, and (3) DBU loading reduces the reaction energy barrier by activating the amine substrate, this was confirmed by DFT calculations. This work provides fundamental insights into organic base-functionalization strategies and CO2 activation mechanisms for sustainable catalysis.