Abstract: The interaction sites and interaction force types between N-formylmorpholine (NFM) and aromatics/non-aromatics during the aromatic extraction process were investigated through spectroscopic analysis and molecular simulation calculations, aiming to elucidate the mechanism of NFM in aromatic extraction. The results indicate that the interaction between NFM and benzene is primarily governed by van der Waals forces, accompanied by steric hindrance effects. The interaction sites are identified as the C—O—C bond, the C—N bond, and the C=O bond, with their contributions to the overall interaction following the descending order: C=O bond > C—N bond > C—O—C bond. Electrostatic potential and interaction region indicator analyses of NFM analogues complexed with benzene reveal that the development of efficient and green aromatic extraction solvents should seek a balance between effective attractive networks and steric repulsion effects with the aromatic hydrocarbons, rather than pursuing the maximization of a single type of interaction.

Key words: N-formylmorpholine, aromatic hydrocarbon extraction, relative volatility, benzene, methylcyclohexane