A Reductive Mechanochemical Approach Enabling Direct Upcycling of Fluoride from Polytetrafluoroethylene (PTFE) into Fine Chemicals
Matthew E. Lowe, Benjamin M. Gallant, Nathan Davison, Matthew N. Hopkinson, Dominik J. Kubicki, Erli Lu, Roly J. Armstrong
Abstract
Polytetrafluoroethylene (PTFE) is a highly versatile material that has found widespread application owing to its exceptionally high chemical resistance and thermal stability. However, these properties mean that PTFE disposal is an energy intensive process, producing fluorinated materials which pose serious concerns regarding toxicity and environmental persistence. Herein we report a straightforward mechanochemical approach for the reductive defluorination of PTFE generating an environmentally benign mixture of elemental carbon and sodium fluoride. The process employs cheap and readily available chunks of sodium metal, proceeding rapidly at room temperature, in the absence of any organic solvent to form sodium fluoride (NaF) in 98% yield. The fluoride generated in the process can be directly upcycled into fine chemicals through in situ mechanochemical fluorination reactions, delivering valuable sulfonyl fluoride and acyl fluoride products in excellent yields.