in the form of air enriched air or high purity oxygen according to the invention this stage is carried out in particular under a pressure of greater than 1 5 bar absolute advantageously the pressure is between 2 and 15 bar in particular between 2 2 and 5 bar the hf compounds to be fluorinated molar ratio is between 50 1 and 1 1 preferably 30 1 and 5 1 advantageously between 25 1 and 5 1 the reaction temperature can be highly variable for example it can be between 200 and 500 u00b0 c preferably between 250 and 400 u00b0 c advantageously between 275 and 380 u00b0 c the oxygen compounds to be fluorinated molar ratio is between 0 01 and 1 preferably between 0 05 and 0 2 the contact time ct between the gas mixture comprising the reactants and the catalyst defined in the present invention according to the formula below in which w represents the amount of catalyst in the fluidized bed in grams f represents the velocity of the gas flow under standard temperature and pressure conditions t represents the reaction temperature in u00b0 c and p represents the pressure in pascals is preferably between 1 and 50 s and advantageously between 2 and 40 s the linear velocity of the gas flow comprising the reactants which is introduced into the fluidized bed reactor defined in the present invention by the formula below in which f t and p are defined as above and s is the area of the internal cross section of the reactor cm 2 u2014 also known as empty column linear velocity u2014 is preferably between 0 5 and 200 cm s and advantageously between 1 and 100.