Researchers at the University of St. Andrews have developed a method to convert common household plastic waste into chemical components used in anti-cancer drugs. The study, published in Angewandte Chemie International Edition on December 18, outlines how PET (polyethylene terephthalate) from items like bottles and textiles can be chemically recycled.
The process uses a ruthenium-catalysed semi-hydrogenation technique to break down PET into ethyl-4-hydroxymethyl benzoate (EHMB). This compound is a key intermediate for producing several important substances, including the anti-cancer drug Imatinib, Tranexamic acid—a medication that promotes blood clotting—and the insecticide Fenpyroximate.
Current methods for making these medications rely on fossil-based materials and often involve hazardous chemicals that create significant waste. The new approach offers environmental benefits over traditional production methods. Researchers performed a comparative analysis using a streamlined life cycle assessment to identify which stages of the process have the most environmental impact and where improvements are most effective.
The research team also found that EHMB can be converted into a new recyclable polyester, potentially expanding its applications beyond pharmaceuticals.
Professor Evgeny Pidko of TU Delft in the Netherlands, who led one of the partner organizations involved in the study, stated: "For catalytic upcycling to become practical, the catalyst must operate efficiently at low loadings and maintain activity over long periods. All catalysts eventually deactivate, so understanding when and how this happens is critical to pushing turnover numbers to levels relevant for real applications. In this study, we combined detailed kinetic and mechanistic analysis to understand catalyst behaviour under the reaction conditions and used this knowledge to optimize the system towards record turnover numbers of up to 37,000. This emphasizes the importance of fundamental mechanistic insights to optimize catalyst durability and overall process efficiency."
Dr. Benjamin Kuehne and Dr Alexander Dauth from Merck KGaA added: "Pharmaceutical manufacturing generates substantial amounts of waste per kilogram of product, highlighting the urgent need for innovative sustainable chemical processes and raw materials with reduced environmental footprints."
