Scientists say a new chemical recycling method could convert everyday plastic waste into key ingredients used in cancer medicines, potentially reducing reliance on fossil-based materials.
Researchers led by the University of St Andrews have discovered a way to turn household plastic waste into a valuable chemical building block used in the manufacture of anti-cancer drugs and other medicines.
The study, published on Monday in Angewandte Chemie International Edition, focuses on PET plastic, commonly found in bottles and textiles. Using a ruthenium-catalysed chemical process, the team was able to break PET down into ethyl-4-hydroxymethyl benzoate (EHMB), a compound used in pharmaceutical and agricultural products.
The researchers say EHMB is an important intermediate in the synthesis of several compounds, including Imatinib, a widely used cancer treatment, as well as tranexamic acid, which helps blood clot, and the insecticide fenpyroximate.
At present, such chemicals are typically produced from fossil-derived feedstocks, often involving hazardous reagents and generating large amounts of waste. The researchers carried out a streamlined life cycle assessment which suggested the new approach could offer environmental benefits compared with conventional production methods.
“By enabling the upcycling of plastic waste into premium products instead of reproducing the same class of plastics, such processes could meaningfully accelerate the transition to a circular economy.”
The study also found that EHMB could be used to create a new type of recyclable polyester, potentially opening up further applications for plastic waste.
Dr Amit Kumar, lead author of the paper from the School of Chemistry at St Andrews, said the findings showed how waste plastics could be repurposed into higher-value products.
“We are excited by this discovery, which reimagines PET waste as a promising new feedstock for generating high-value APIs and agrochemicals,” he said. “By enabling the upcycling of plastic waste into premium products instead of reproducing the same class of plastics, such processes could meaningfully accelerate the transition to a circular economy.”
The research was carried out in collaboration with scientists from TU Delft and chemical and pharmaceutical company Merck KGaA.
Professor Evgeny Pidko, from TU Delft, said understanding how catalysts degrade over time was key to making chemical upcycling commercially viable.
“In this study, we combined detailed kinetic and mechanistic analysis to understand catalyst behaviour under the reaction conditions and used this knowledge to optimise the system towards record turnover numbers,” he said.
Researchers from Merck KGaA said the findings highlighted the potential for more sustainable approaches to pharmaceutical manufacturing, which currently produces large amounts of waste per kilogram of product.