Chemical Recycling of Polystyrene to Valuable Chemicals via Selective Acid-Catalyzed Aerobic Oxidation under Visible Light



Huang, Zhiliang, Shanmugam, Muralidharan, Liu, Zhao, Brookfield, Adam, Bennett, Elliot L ORCID: 0000-0003-3798-4296, Guan, Renpeng, Herrera, David E Vega, Lopez-Sanchez, Jose A, Slater, Anna G ORCID: 0000-0002-1435-4331, McInnes, Eric JL
et al (show 2 more authors) (2022) Chemical Recycling of Polystyrene to Valuable Chemicals via Selective Acid-Catalyzed Aerobic Oxidation under Visible Light. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 144 (14). pp. 6532-6542.

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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<sub>2</sub>. 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.

Item Type: Article
Uncontrolled Keywords: Singlet Oxygen, Polystyrenes, Photosensitizing Agents, Oxidation-Reduction, Catalysis, Light
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 04 Apr 2022 15:28
Last Modified: 18 Jan 2023 21:05
DOI: 10.1021/jacs.2c01410
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3152066