Methane oxidation to methyl trifluoroacetate by simple anionic palladium catalyst: Comprehensive understanding of K2S2O8-based methane oxidation in CF3CO2H

•PdCl42- can effectively convert methane to methyl trifluoroacetae in the K2S2O8-CF3CO2H oxidation system.•The anionic catalyst form appears to increase the Pd solubility in the polar protic HTFA solvent.•Pd(CF3CO2)42- is supposed to be the real catalytic species in this PdCl42- - catalyzed methane oxidation.•Solvent CF3CO2H oxidation limit the yield of methyl trifluoroacete.