A perspective on the inevitable side reactions in ethylene-glycol based reactive-extractive distillation

This perspective article provides insights into the emerging field of ethylene glycol (EG) based reactive-extractive distillation (RED) for azeotropic mixture separation, challenging conventional practices in this area. RED has gained popularity for azeotropic separation, with at least 17 studies published since 2020. While it integrates chemical reactions and separation effectively, side reactions can significantly impact performance. Recent studies reveal instances where RED performs poorly with high energy consumption and economic disadvantages. On the other hand, there are instances where it performs worse than the original case without side reactions but still outperforms traditional distillation systems. Here, we share our perspective on the inevitable side reactions that may occur in RED, offering a balanced view that acknowledges both supporting evidence and contrasting opinions. We also propose a novel method using simple thermodynamic analysis to quickly assess whether RED excels, is comparable to, or performs worse than the conventional distillation.