Upcycling of Polyamide Wastes to Tertiary Amines Using Mo Single Atoms and Rh Nanoparticles

Abstract

The pursuit of sustainable practices through the chemical recycling of polyamide wastes holds significant potential, particularly in enabling the recovery of a range of nitrogen-containing compounds. Herein, we report a novel strategy to upcycle polyamide wastes to tertiary amines with the assistance of H₂ in acetic acid under mild conditions (e.g., 180 °C), which is achieved over anatase TiO₂ supported Mo single atoms and Rh nanoparticles. In this protocol, the polyamide is first converted into diacetamide intermediates via acidolysis, which are subsequently hydrogenated into corresponding carboxylic acid monomers and tertiary amines in 100 % selectivity. It is verified that Mo single atoms and Rh nanoparticles work together to activate both amide bonds of the diacetamide intermediate, and synergistically catalyze its hydrodeoxygenation to form tertiary amine, but this catalyst is ineffective for hydrogenation of carboxylic acid. This work presents an effective way to reconstruct various polyamide wastes into tertiary amines and carboxylic acids, which may have promising application potential.