Abstract
To reduce the pressure on the environment created by the increasing amount of plastic waste, the need to develop suitable plastic recycling methods has become more evident. However, the chemical recycling toolbox for polyethylene (PE), the most abundant type of plastic waste, remains underdeveloped. In this work, analytical methods were developed to explore the possibility to oxidatively convert PE into di-carboxylic acids as reaction products. A multi-analytical approach including gas chromatography-mass spectrometry, gas chromatography-flame ionization detection, several (2D) nuclear magnetic resonance methods as well as in-situ transmission infrared spectroscopy was used. This led to a thorough qualitative and quantitative analysis on the product mixture, which extends and clarifies the existing literature. Without a catalyst (thermally) already up to 7 mol % di-carboxylic acids can be formed. Furthermore, it was found that the majority of the oxidized functionalities are carboxylic acids, (methyl) ketones, γ-lactones, γ-ketones and esters. An intra-molecular hydrogen shift seemed key in the cleavage step and the formation of late-stage side products. In addition, crosslinking reactions due to esterification reactions seem to limit the di-carboxylic acid yield. Therefore, these two handles can be taken into account to study and design similar (catalytic) systems for the oxidative conversion of plastic waste.
Original language | English |
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Article number | e202301198 |
Journal | ChemSusChem |
Volume | 17 |
Issue number | 7 |
Early online date | 27 Nov 2023 |
DOIs | |
Publication status | Published - 8 Apr 2024 |
Bibliographical note
Publisher Copyright:© 2023 The Authors. ChemSusChem published by Wiley-VCH GmbH.
Funding
. The authors acknowledge Jochem Wijten and Ramon van Oord, both from the Inorganic Chemistry and Catalysis research group of Utrecht University (UU), for their technical support for the building of the experimental setup. We thank Hugo van Ingen (UU) and Andrei Gurinov (UU) from the NMR Spectroscopy research group for recording the NMR spectra. This work was supported by a joint funding through TNO/Brightsite and MCEC, a Netherlands Organization for Scientific Research (NWO) funded Gravitation program as well as by Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC), which is co‐founded and co‐financed by NWO and the Netherlands Ministry of Economic Affairs and Climate Policy
Funders | Funder number |
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Advanced Research Center Chemical Building Blocks Consortium | |
MCEC | |
Netherlands Ministry of Economic Affairs and Climate Policy | |
Australian Research Council | |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek |
Keywords
- aerobic oxidation
- chemical recycling
- di-carboxylic acids
- polyethylene
- spectroscopy