Perfluoropolyethers: intramolecular disproportionation

TLDR: In this paper, the thermal degradation of commercial perfluoropolyethers (Fomblin Z and Y, Krytox, and Demnum) and PFPEO (perfluoropoly(ethylene oxide)) in the presence of Lewis acids (metal oxides and halides) was examined.

Abstract: Thermal degradation of commercial perfluoropolyethers (Fomblin Z and Y, Krytox, and Demnum) and PFPEO (perfluoropoly(ethylene oxide)) in the presence of Lewis acids (metal oxides and halides) was examined. It is shown that the degradation is dominated by the intramolecular disproportionation process of the following scheme RCF 2 OCF 2 (CH 2 ) 3 OR → RCOF + CF 3 (CH 2 ) 3 OR. The reaction occurs when the two oxygen atoms flanking a monomer unit of polyether chains interact with a Lewis acid site(s). The differentail charges induced at the carbons immediately outside and inside the unit cause a fluorine transdfer and effect the disproportionation process