An in-depth in situ IR study of the thermal decomposition of copper trifluoroacetate hydrate

The pyrolysis of Cu(CF3COO)2·nH2O at temperatures up to 1000 °C, under flowing pure Ar, O2 and O2 saturated with water vapour, was extensively analysed. Decomposition reaction paths in all three media are proposed and various solid intermediates and gaseous products are identified. Cu2(CF3COO)3(OH) and Cu(CF3COO)2·CuO formed sequentially, liberating TFAH at both stages. Cu(CF3COO)2·CuO decomposition occurred in a single endothermic step with an onset temperature of 263 °C in flowing dry Ar, but proceeded by a violent, exothermic and multistage route with onset temperatures of 216 and 209 °C in flowing dry O2 and wet O2 respectively, in all cases forming CuO. The formation of HF was also observed directly and the existence of a:CF2 radical inferred. The onset temperatures of the main decomposition are significantly lower than previously reported. This observation, and the violent exothermic nature of the decomposition in O2 atmospheres, are suggested to have implications for sol–gel processing.