Efficient mineralization of ethylene-tetrafluoroethylene copolymer in superheated water with permanganate

ABSTRACT Copolymer of ethylene and tetrafluoroethylene (ETFE) was treated in superheated water with KMnO4. ETFE efficiently decomposed to F– and CO2. Specifically, when ETFE (30 mg) was treated for 6 h with aqueous KMnO4 (52.7 mM; the molar amount was 1.7-fold excess of that of the fluorine atoms in ETFE) at 320°C, the yields of F– and CO2 were 92 ± 1% and 73 ± 8%, respectively, and the total organic carbon content in the reaction solution was reduced to 4% of the carbon atom number in the initial ETFE. When the reactivity of ETFE was compared with that of poly(vinylidene fluoride) (PVDF), that is, an isomer of ETFE, ETFE required higher temperature to achieve mineralization. The present approach can reduce the reaction temperature allowing efficient mineralization of ETFE by 60°C, compared to the previous method using supercritical water with dioxygen.