Plastic waste is being converted into construction sites for cancer drugs.

Plastic waste is being converted into construction sites for cancer drugs.

Revolutionary discovery by the University of St. Andrews

A groundbreaking discovery from the University of St Andrews has found a way to turn ordinary household plastic waste into the basis of anti-cancer drugs.

Plastic waste and recycling methods

Household PET (polyethylene terephthalate) waste, such as plastic bottles and textiles, can be recycled in two main ways: mechanically or chemically.

• Mechanisches Recycling: Hierbei wird der Plastikabfall zerkleinert und wiederverwendet, ohne die chemische Struktur zu verändern.
• PET chemisch recyceln: Dabei werden die langen Polymerketten von PET in einzelne Einheiten, die man Monomere nennt, oder in andere wertvolle Chemikalien zerlegt.

New insights into the conversion of PET waste

Published today inApplied Chemistry International Edition, researchers discovered that a ruthenium-catalyzed semi-hydrogenation process can convert PET waste into a valuable chemical, ethyl 4-hydroxymethylbenzoate (EHMB).

Meaning of EHMB

Notably, EHMB serves as an important intermediate for the synthesis of several important compounds, including:

• Das Krebsmedikament Imatinib
• Tranexamsäure, die bei der Blutgerinnung hilft
• Das Insektizid Fenpyroximate

Currently, such drugs are manufactured from fossil raw materials, often using hazardous reagents that produce significant waste. This groundbreaking research offers significant environmental benefits compared to traditional industrial methods for producing EHMB.

Sustainability and circular economy

Additionally, the researchers discovered that EHMB can be converted into a new, recyclable polyester.

"We are excited by this discovery, which reimagines PET waste as a promising new raw material for the production of high-value active pharmaceutical ingredients and agrochemicals. Although chemical recycling is a key strategy for building a circular economy, many current technologies lack economic viability. By converting plastic waste into high-value products rather than the same type of plastics, such processes could significantly accelerate the transition to a circular economy."

Dr. Amit Kumar, lead author of the study, School of Chemistry, St. Andrews

Efficiency of catalysts

The head of the collaborating partner organization, TU Delft in the Netherlands, Professor Evgeny Pidko, said: "To make catalytic conversion practical, the catalyst must work efficiently at low quantities and remain active for a long time. All catalysts deactivate at some point, so it is crucial to understand when and how this happens in order to bring the conversion numbers to real-world applications. In this study, we combined detailed kinetic and mechanistic analyzes to understand the behavior of the catalyst under the reaction conditions and used this knowledge to optimize the system to record conversion numbers of up to 37,000.”

Dr. Benjamin Kuehne and Dr. Alexander Dauth from the cooperation partner organization, the chemical and pharmaceutical company Merck KGaA, said: “Pharmaceutical manufacturing generates significant amounts of waste per kilogram of product, which underlines the urgent need for innovative sustainable chemical processes and raw materials with a smaller ecological footprint.”

Sources: