Synthetic methodologies for the chemical recycling of fluorocarbons

Fluorochemicals are ubiquitous in modern life. Despite their importance, current approaches to manufacture fluorochemicals are linear and fluorine-containing products tend to be single-use, causing environmental and ecosystem damage on disposal. In this Review, we describe synthetic methods that harvest fluoride (F^-) from fluorocarbons and deliver it to other molecules through either transfer fluorination or fluoride shuttling. We also summarize related approaches, transfer hydrofluorination and HF shuttling in which hydrogen fluoride (HF) is generated in situ from one fluorocarbon and used to prepare another, along with recent breakthroughs in fluoroalkene cross-metathesis. Our focus is on reactions that can be applied to industrially relevant fluorochemicals, namely refrigerants and fluoropolymers. We provide insight into the mechanisms that break and remake carbon-fluorine bonds as part of linear reaction sequences or catalytic manifolds. Limitations of the current methodologies are highlighted, and opportunities for future developments are discussed.