Low-Temperature Catalytic Approaches for Upcycling Plastics into Oxygenated Aromatic Compounds

Abstract

Plastic upcycling is an emerging strategy to address the global plastic waste crisis, where these abundant polymers are converted into products of higher economic value. This not only complements and adds to existing recycling efforts, but also offers opportunities to retain the inherent chemical value of the plastics within circular loops, albeit in different forms for alternative uses. With aromatics constituting a major component of current petrochemical production, the production of aromatics from post-synthetic conversion of plastics can potentially alleviate the demand on fossil fuels. Although BTX (benzene, toluene, and xylenes) production has been a major focus of these efforts, oxygenated aromatic compounds (OACs), such as benzoic acids, are also highly-valued across various industrial sectors, and necessitate fundamentally different processes from BTX synthesis from plastics. In this concepts article, some of the most promising emerging methods for direct synthesis of OACs from commodity petroleum-based plastics are spotlighted, including from nonoxygenated hydrocarbon polymers such as polystyrene. With a special emphasis on emerging low temperature technologies (<150 °C), which encompass but are not limited to photo- and biocatalysis, this concepts article aims to position plastics as a viable source of OACs accessible under sustainable conditions for future industrial translations.