Green and Sustainable Extractive Distillation: Advances in Effective Separation Strategies for Multi-Polar Mixtures via Mechanism-Based and Factor-Driven Design

Extractive distillation (ED) uses an organic solvent entrainer and is an essential technique for separating azeotropic and near-boiling mixtures in the fuel, petrochemical, and basic organic synthesis industries. The process faces significant challenges due to the diversity of mixture types and its inherently high energy demand. While ED has been widely reviewed, a systematic classification and analysis organized by mixture types remains lacking. To address this gap, this review examines the physicochemical mechanisms and key operating parameters of ED, and subsequently assesses the separation status and challenges of polar, nonpolar, and polar-nonpolar mixture systems. Both common principles and system-specific challenges are highlighted. Furthermore, from the perspectives of energy integration, entrainer greening, and process coupling, potential pathways are explored for advancing ED toward low-carbon and intelligent development, thereby supporting its industrial application as a sustainable separation technology.