1. Chemical Recycling of Polystyrene to Valuable Chemicals via Selective Acid-Catalyzed Aerobic Oxidation under Visible Light.
- Author
-
Huang Z, Shanmugam M, Liu Z, Brookfield A, Bennett EL, Guan R, Vega Herrera DE, Lopez-Sanchez JA, Slater AG, McInnes EJL, Qi X, and Xiao J
- Subjects
- Catalysis, Light, Oxidation-Reduction, Photosensitizing Agents chemistry, Polystyrenes, Singlet Oxygen chemistry
- Abstract
Chemical recycling is one of the most promising technologies that could contribute to circular economy targets by providing solutions to plastic waste; however, it is still at an early stage of development. In this work, we describe the first light-driven, acid-catalyzed protocol for chemical recycling of polystyrene waste to valuable chemicals under 1 bar of O
2 . Requiring no photosensitizers and only mild reaction conditions, the protocol is operationally simple and has also been demonstrated in a flow system. Electron paramagnetic resonance (EPR) investigations and density functional theory (DFT) calculations indicate that singlet oxygen is involved as the reactive oxygen species in this degradation process, which abstracts a hydrogen atom from a tertiary C-H bond, leading to hydroperoxidation and subsequent C-C bond cracking events via a radical process. Notably, our study indicates that an adduct of polystyrene and an acid catalyst might be formed in situ, which could act as a photosensitizer to initiate the formation of singlet oxygen. In addition, the oxidized polystyrene polymer may play a role in the production of singlet oxygen under light.- Published
- 2022
- Full Text
- View/download PDF