Synergistic Chlorine-Mediated Co-Upcycling of polyvinyl chloride and waste biomass for sustainable furfurals production

The co-upcycling of waste plastics and biomass presents a promising strategy for sustainable carbon utilization; however, the presence of polyvinyl chloride (PVC) often complicates this process due to chlorine-induced catalyst poisoning. Herein, an ionic liquid-assisted biphasic dichloromethane/water system is reported that transforms this challenge into an advantage by using in situ -generated HCl from PVC dechlorination to catalyze biomass conversion. Employing 1-butylpyridinium chloride ([Bpy]Cl) as a synergistic catalyst, exceptional yields of furfural (85.5 %) and 5-methylfurfural (62.8 %) were achieved from waste tobacco stalks under optimized conditions (140 °C, 8 h, 2.5 wt% PVC). This ionic liquid-PVC system demonstrated remarkable stability, maintaining > 85 % furfural yield over six consecutive cycles, and was successfully extended to corn stover mixtures with comparable efficiency. Mechanistic studies revealed that [Bpy]Cl serves dual functions: (1) accelerating PVC dehydrochlorination through nucleophilic chloride attack, and (2) facilitating the cleavage of β-1,4-glycosidic bonds in cellulose/hemicellulose, thereby enhancing acid-catalyzed sugar conversion to furfurals. This work establishes a novel paradigm for simultaneous waste valorization, achieving complete chlorine utilization from PVC while converting agricultural residues into valuable chemicals, with significant implications for circular economy implementation.