From Plastic Waste to Pharmaceutical Precursors: PET Upcycling Through Ruthenium Catalyzed Semi‐Hydrogenation
Abstract
Abstract We report here the upcycling of PET (polyethylene terephthalate) waste via semihydrogenation to make ethyl 4‐(hydroxymethyl)benzoate. The reaction is catalyzed by a ruthenium pincer catalyst at 80 °C in bioderived solvents – a combination of 2‐methyl THF and ethanol. A detailed mechanistic investigation through organometallic and kinetic studies, as well as chemical exchange saturation transfer (CEST) NMR spectroscopy, provides insights into the nature of active species and factors that promote and inhibit the catalytic hydrogenation of PET. Using this mechanistic knowledge, a record high turnover number of >30 000 was achieved for the hydrogenative depolymerization of end‐of‐life PET waste (e.g., bottles and textiles). The semihydrogenation product, ethyl 4‐(hydroxymethyl)benzoate, was utilized to make precursors of various known pharmaceutical drugs, an agrochemical, as well as a new and recyclable polyester. A cradle‐to‐gate life cycle assessment demonstrated that using PET waste as a feedstock for EHMB production significantly reduces the environmental footprint compared to the conventional route from p ‐toluic acid.
Article Details
Authors (13)
Pavel S. Kulyabin
EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews KY16 9ST UK
James Luk
EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews KY16 9ST UK
Evgeny A. Uslamin
Inorganic Systems Engineering group, Department of Chemical Engineering, Faculty of Applied Sciences Delft University of Technology Van der Maasweg 9 Delft, HZ 2629 The Netherlands
Alexander A. Kolganov
Inorganic Systems Engineering Group, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
Garima Saini
EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews KY16 9ST UK
Raymundo Marcial‐Hernandez
EaStCHEM, School of Chemistry University of St Andrews St Andrews UK
Ketan Pancholi
Benjamin Kühne
Corporate Sustainability Merck Group Frankfurter Straße 250 Darmstadt 64293 Germany
Alexander Dauth
Corporate Sustainability Merck Group Frankfurter Straße 250 Darmstadt 64293 Germany
Aidan P. McKay
EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K.
David B. Cordes
EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K.
Evgeny A. Pidko
Inorganic Systems Engineering Group, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
Amit Kumar