Upcycling C–O Bond Polymers into Value-Added Chemicals with Air as the Sole Oxidant

Abstract

The C(sp³)−O bond is a crucial structure frequently encountered in both natural products and synthetic molecules. Its cleavage plays a pivotal role in the degradation and conversion of plastics and biomass into valuable chemicals; this strategy can significantly alleviate the strain on our ecosystem while generating economic value. Herein, a novel protocol is reported for the degradation and transformation of polymers, namely, polyethylene glycol (PEG), into quinolines through the cleavage of C(sp³)−O bonds. Furthermore, air serves as the sole oxidant in the conversion process, thereby reducing conversion costs. This strategy offers a pathway to convert so-called "waste" materials into valuable chemicals and paves the way for innovative methods in the production of fine chemicals. Moreover, the scalability of this method has been demonstrated with the successful upcycling of expired commercial products into high-value-added products. To elucidate the mechanism behind this transformation, detailed mechanistic studies were performed, and a proposed mechanism was summarized and further supported by density functional theory calculations.

Keywords

Upcycling / Quinolines / C–O bonds / Polymer degradation / Polyethylene glycol / Cascade cyclization / N-Heterocycles / Density functional theory

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