Ionic liquid-assisted N-formylation of morpholine with carbon dioxide and hydrogen catalyzed by N,P-ruthenium knitted aromatic polymers

Abstract

The N-formylation reaction of amines with CO₂ is a promising method to utilize CO₂ for the production of high value-added chemicals. Herein, we developed an efficient process for integrating CO₂ capture and morpholine formylation catalyzed by a N,P-ruthenium knitted aromatic polymers (KAPs-N/Ru/P) catalyst, producing the corresponding N-formylmorpholine in good yield and high selectivity under relatively mild reaction conditions. TON up to 4711 can be achieved for the formylation of morpholine with CO₂ and H₂, which represents the highest one for the reported heterogeneous Ru-based catalysts to date. The morpholine and CO₂ could be activated in the presence of ionic liquids and N-donor ligand (BPY). Simultaneously, phosphine ligand (PPh₃) also contributed to the activation of H₂ and CO₂ based on DFT calculation.