Redefining Plastic Waste as a Sustainable Feedstock: Valorization and Chemical Sorting into Value-Added α-Hydroxy Acids

Abstract

Industrially valuable α-hydroxy acids (AHAs) are synthesized from plastic waste (polyesters/polycarbonates) and various alcohols via a one-pot strategy. This approach integrates base-mediated depolymerization with Ir(triNHC)-catalyzed dehydrogenative C–C coupling, offering a sustainable route to diverse Cn AHAs. Beyond its tolerance for post-consumer contaminants, this catalytic system exhibits the substrate-dependent coupling selectivity achieved through strategic alcohol pairing: poly(ethylene terephthalate) (PET) reacts preferentially with aliphatic alcohols, whereas poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC) favor coupling with benzyl alcohol derivatives. This divergent reactivity enables a “chemical sorting” strategy that transforms unsorted plastic mixtures into distinct, high-value chemical building blocks without prior physical separation. This methodology addresses a primary bottleneck in the circular plastic economy and provides a robust framework for complex waste valorization.