Synergistic
IL
‐sulfolane extraction and energy‐efficient process design for toluene/methylcyclohexane separation
Yajuan Qu, Junwei Xie, Yang Li, Xiaoyu Mu, Zhiwei Liu, Xingyuan Liu, Haifeng Cong, Xingang Li Abstract
The separation of aromatics from non‐aromatics is a critical process in petrochemical production because TOL and MCH have similar boiling points and molecular sizes, achieving their efficient separation is extremely challenging. This study proposes a research strategy for separating TOL‐MCH using a mixture of imidazolium ionic liquids (ILs) and sulfolane (SUL). First, the COSMO‐SAC model was used to screen mixed solvents, and optimal operating conditions were determined through liquid–liquid equilibrium (LLE) experiments. The results showed that the [MMIM][DCA]‐SUL system exhibited the highest TOL selectivity. Quantum chemical calculations revealed that π–π interactions are the key mechanism for separation. Based on these findings, an Aspen Plus extraction process was developed. The results showed that, after thermal integration, the [MMIM][DCA]‐SUL process with heat exchange reduced the total annual cost by 19.53% compared to the conventional SUL process. This study provides a theoretical and process basis for the industrial separation of aromatics and non‐aromatics.