Described is a method for producing fluoropropenes of formula CF3CX═CX2 wherein each X is F or H, at least one X is H, and at least one X is F, comprising pyrolyzing a hydrofluorochloropropane of formula CF3CXYCX2Y, wherein each X is F or H, at least one X is H, and at least one X is F, and one Y is Cl and the other Y is H, in the gas-phase in a reaction vessel, maintained at a temperature high enough to effect the pyrolysis of said hydrofluorochloropropane to said fluoropropene, wherein the selectivity for the production of the fluoropropene is at least 80%, in he absence of a catalyst.