Upcycling of Poly(ϵ-caprolactone) to Valuable Chemicals by TBD-Catalyzed Efficient Methanolysis Strategy.

As a petroleum-derived polyester material, poly(ϵ-caprolactone) (PCL) plays an essential role in biomedical field due to its excellent biocompatibility and non-toxicity. With the increasing use of PCL in recent years, its waste disposal has become a significant challenge. To address this challenge, we demonstrate a high-efficiency organocatalysis strategy for the chemical upcycling of PCL to valuable chemical. Among organocatalysts explored in this article, 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) shows superior performance for transforming end-of-life poly(ϵ-caprolactone) into highly value-added methyl 6-hydroxyhexanoate with quantitative conversion in a short time. The endwise unzipping depolymerization mechanism is corroborated by monitoring molecular weight during depolymerization process and 1 H NMR control experiments. Furthermore, this approach is also practicable for large-scale depolymerization for commercial PCL plastics, providing idea for promoting the sustainable development of PCL plastics.