Sustainable separation of 1-methoxy-2-propanol and water azeotrope: Mechanistic insights and hybrid process innovation

Efficient separation of high water-content azeotropes such as 1-methoxy-2-propanol (PGME) and water is crucial but challenging. Herein, a green and low-energy hybrid extraction-distillation process was developed using dibutyl oxalate (DBO) as the extractant. Experimental evaluations revealed the superior performance of DBO with high selectivity and minimal solvent loss at various PGME concentrations. Mechanistic studies via molecular simulations and FT-IR analyses demonstrated that hydrogen bonding between the carbonyl group of DBO and the hydroxyl group of PGME drives the selective extraction. Process simulation indicated a 37.0% reduction in solvent circulation, 52.6% in energy consumption, and 57.9% in carbon footprint compared to conventional benzene-based azeotropic distillation. Life cycle assessment further confirmed the environmental benefits of DBO, highlighting its low toxicity, biodegradability, and renewable synthesis potential. This work presents a sustainable and cost-effective strategy not only for PGME-water separation but also for other high water-content azeotropes separation.