Task-specific deep eutectic solvent for efficient dissolution and further accelerating alkaline hydrolysis of polyesters into their monomers

Abstract

Polyester plastics have brought great convenience to modern society. However, the continuous accumulation of their production increasingly threatens human health. Polyethylene terephthalate (PET) is one of the largest type of polyester plastics and its recycling is a major challenge. In this work, deep eutectic solvent (DES) composed of thenyl alcohol and choline chloride (ChCl) was designed for efficient dissolution of PET at 165 °C for 20 min, and further accelerating complete alkaline hydrolysis of PET into its monomer terephthalic acid (TPA) and ethylene glycol (EG) with a high TPA monomer yield (98.2%) in 25 min at 100 °C. Moreover, the designed DES is also efficient for dissolution and alkaline hydrolysis of other polyester plastics, including poly(trimethylene terephthalate) (PTT) and poly(ethylene furanoate) (PEF) into their monomers. This work provides a feasible and sustainable solution for the recycling of polyester wastes.

Keywords: Deep eutectic solvent; alkaline hydrolysis; dissolution; polyethylene terephthalate; recycling.