To obtain the subject compound in high yield and selectivity by hydrofluorinating perfluoropropene in a gas phase using a specific catalyst.

The compound expressed by CF3-CHF-CF3 (227ea) is obtained by hydrofluorinating perfluoropropene(PFP) in a gas phase. As a catalyst, a fluorinated alumina containing a trivalent chromium compound in the form o an oxide, an oxyfluoride or a fluoride containing at least 90 wt.%, preferably 95% of AlF3, preferably, of a gamma form is used. A mole ratio of HF/PFP is (4:1) to (20:1), preferably (6:1) to (14:1), more preferably (8:1) to (11:1). The temperature for the hydrofluorination is 320-420°C, preferably 340-420°C and the feed gas pressure is 1-30, preferably 2-10, more preferably 5-10 absolute atmosphere.