Patent ID: 8779217

Claim:
Process for the preparation of fluoropropenes of formula (I) CF 3 CF═CHR, in which R represents a hydrogen atom or a fluorine atom, from at least one compound of formula (Ia) CF 3 CF═CFR, comprising the following steps: (i) hydrogenating, in an adiabatic reactor in the presence of a catalyst, at least one compound of formula CF 3 CF═CFR (Ia) with hydrogen in a superstoichiometric amount, to produce a stream comprising at least one hydrofluoropropane; (ii) partially condensing the stream to give a gas-phase fraction and a liquid-phase fraction, the gas-phase fraction comprising unreacted hydrogen and a first portion of hydrofluoropropane formed in step (i), and the liquid-phase fraction comprising a second portion of hydrofluoropropane formed in step (i), wherein the partial condensation is carried out at a temperature of between 0 and 50° C. and at a pressure of between 0.5 and 20 bar absolute such that the unreacted hydrogen is not condensed, and wherein said gas-phase fraction is recycled to step (i); (iii) dehydrofluorinating the second portion of hydrofluoropropane in an aqueous reaction medium comprising potassium hydroxide in a stirred reactor, to give a fluoropropene of formula (I) CF 3 CF═CHR and potassium fluoride (KF); and (iv) purifying the fluoropropene of formula (I) CF 3 CF═CHR.