One-pot method converts unwanted polycarbonates to value-added poly(aryl ether sulfone)s

In the classification scheme for recycling polymers, polycarbonates typically fall into the forsaken “other” category. That means millions of tons of polycarbonates produced each year for compact disks, headlight lenses, and other applications can’t be easily recycled by conventional methods. Gavin O. Jones, Jeannette M. Garcia, and coworkers at IBM Research-Almaden have come up with a process that could help avoid relegating polycarbonates to landfills. Their method allows the easy conversion of polycarbonates into poly(aryl ether sulfone)s in the presence of a carbonate salt and a bis(aryl fluoride) (Proc. Natl. Acad. Sci. USA 2016, DOI: 10.1073/pnas.1600924113). The carbonate salt initiates depolymerization of the polycarbonate, and the sulfone-containing aryl fluoride condenses the resulting reactive phenoxide intermediates into poly(aryl ether sulfone)s, with the loss of carbon dioxide as a by-product. The researchers performed computational studies to determine that the carbonate salt’s role is twofold: It decomposes the polycarbonate by nucleophilic attack and promotes the reaction of subsequently formed phenolate dimers with the aryl fluoride.