Conversion of all polyester units to amines: Ruthenium-catalyzed, acid-assisted hydrogenative amination

Herein, we report an efficient strategy for upcycling waste polyesters into a range of primary, secondary, and tertiary diamines and amines via ruthenium-catalyzed, acid-assisted hydrogenative amination. To our knowledge, this previously unknown methodology can convert all structural units of end-of-life polyesters into corresponding (di)amines. The protocol demonstrates excellent applicability by successfully transforming even the most challenging real-world polyester wastes containing diverse impurities, achieving high yields of up to 98%. Mechanistic investigations elucidate two distinct reaction pathways: The acyl moiety undergoes transformation via a hydrogenation-condensation-hydrogenation sequence, while an acid-assisted hydrogen-borrowing pathway converts the alcohol moiety. This study provides fundamental insights into concurrent hydrogenation and dehydrogenation processes within a unified catalytic system.