Chemical Upcycling of PS via Visible Light Induced Photocatalysis
William Cheung, Justin Zheng, Yalan Xing*
Department of Chemistry, Hofstra University, Hempstead, NY
Mechanism of PSOOH Formation
The buildup of addition polymers is a major contributor to climate change due to their long natural lifespans Photochemistry, a subset of green chemistry, aims to design polymers for degradation in order to minimize waste and convert them into more valuable compounds after their end of function
https://www.nytimes.com/2019/10/11/science/plastics-ocean-degrade.html
Current Methods & Limitations of Polymer
● Expensive, energy intensive, and time-consuming
● Incomplete oxidation of the polymer chain
● Involves use of toxic or harmful reagents
● Products generated are not particularly valuable
Our Proposal
Few research articles have characterized the formation of a polystyrene hydrogen peroxide intermediate during the degradation of polystyrene. We propose that this intermediate can undergo further series of degradations to ultimately generate valuable products including acetic acid and phenol.
The reaction proceeds as a chain oxidation that is initiated by a photocatalyst.
Future Plans
● Experiment with different photocatalysts or wavelengths of light to maximize percent yield
● Confirm formation of polystyrene hydrogen peroxide using IR spectroscopy and NMR
Under acidic conditions, PSOOH can be further degraded to produce molecules of phenol and a biodegradablepoly-1,3-diketone that can be converted into acetic acid.
Conditions for PSOOH Formation
● Treat polystyrene hydrogen peroxide under acidic conditions to form a poly-1,3-diketone
● Deploy experimental design commercially if reaction is successful
References & Acknowledgements
Z.; Shanmugam, M.;
Z.; Brookfield,A.; Bennett,
Guan, R.; Vega Herrera, D. E.; Lopez-Sanchez, J.A.; Slater,A. G.; McInnes, E. J. L.; Qi, X.; Xiao, J. Chemical Recycling of Polystyrene to Valuable Chemicals via Selective Acid-CatalyzedAerobic Oxidation under Visible Light. Journal of the American Chemical Society 2022, 144 (14), 6532–6542. https://doi.org/10.1021/jacs.2c01410
❖ Inoa, J.; Patel, M.; Dominici G.; Reem Eldabagh Patel,A.; Lee, J. D.; Xing, Y. Benzylic Hydroperoxidation via VisibleLight-Induced Csp3–HActivation Journal of Organic Chemistry 2020 85 (9), 6181–6187. https://doi.org/10.1021/acs.joc.0c00385
❖ Li, T.; Vijeta A.; Casadevall C.; Gentleman,A. S.; Euser T.; Reisner, E. Bridging Plastic Recycling and Organic Catalysis: Photocatalytic Deconstruction of Polystyrene via a C–H Oxidation Pathway. ACS Catalysis 2022 12 (14), 8155–8163. https://doi.org/10.1021/acscatal.2c02292
❖ Nabi, I.; Bacha,A.-U.-R.;Ahmad, F.; Zhang, L.Application of Titanium Dioxide for the Photocatalytic Degradation of Macro- and Micro-Plastics:AReview. Journal of Environmental Chemical Engineering 2021 9 (5), 105964. https://doi.org/10.1016/j.jece.2021.105964
ASpecial Thanks To:
Dr. Yalan Xing
Fellow Xing Research Lab MembersAbigail Hart and Justin Alvarez
Department of Chemistry at Hofstra University
