A Solvent‐Free Approach for the Mechanochemical Upcycling of Bio‐ and Fossil‐Based Polyesters Into Value‐Added Chemicals and Bio‐Based Plasticizers

Plastic waste poses a major environmental challenge, yet it also represents a valuable feedstock to produce high‐value chemicals. In this work, we report an ecofriendly and efficient mechanochemical strategy for upcycling of bio‐ and fossil‐based polyesters under mild conditions into synthetically useful building blocks. Bio‐based polyethylene furanoate (PEF), polybutylene furanoate (PBF), and polylactic acid (PLA), as well as fossil‐derived polyethylene terephthalate (PET), were successfully transformed into their corresponding transesterification and amidation products in excellent yields using sodium methoxide as a catalyst. These reactions generate the corresponding diol, methanol, and sodium chloride as byproducts, which can be recovered and reused. Furthermore, using the same protocol, PEF was converted into bio‐based plasticizers, including diethylhexyl furanate (DEHF) and diisoamyl furanoate (DIAF) in excellent yields. Importantly, the method is not limited to pure polymers but is also effective for commercially available PET‐ and PLA‐based packaging materials. The products were isolated by simple aqueous workup and characterized using NMR, IR, HRMS, and XRD techniques. Overall, this mechanochemical route offers a sustainable, cost‐effective, and versatile approach for polyester waste valorization, contributing significantly to a circular plastic economy.