The low temperature fluorination of hexafluoroacetone monohydrate (CF3)(2)C(OH)(2) in the presence of KF or CsF forms 2,2-bis(fluoroxy)perfluoropropane in high yield. A strong interaction between (CF3)(2)C(OH)(2) and the MF is a key factor in the selectivity and yield of the target compound. The decomposition of (CF3)(2)C(OF)(2) to CF4 and CO2 proceeds via the intermediate CF3C(O)OF.