A process for the manufacture of CF.sub.3CH.dbd.CHF and/or CF.sub.3CH.dbd.CF.sub.2 is disclosed. The process involves (a) reacting HF and at least one halopropene of the formula CX.sub.3CCI.dbd.CCIX (where each X is independently F or CI) to produce a product including both CF.sub.3CCI.dbd.CF.sub.2 and CF.sub.3CHCICF.sub.3; (b) reacting CF.sub.3CCI.dbd.CF.sub.2 and/or CF.sub.3CHCICF.sub.3 produced in (a) with hydrogen to produce a product including CF.sub.3CH.sub.2CHF.sub.2 and/or CF.sub.3CH.sub.2CF.sub.3; (c) dehydrofluorinating CF.sub.3CH.sub.2CHF.sub.2 and/or CF.sub.3CH.sub.2CF.sub.3 produced in (b) to produce a product comprising CF.sub.3CH.dbd.CHF and/or CF.sub.3CH.dbd.CF.sub.2; and (d) recovering CF.sub.3CH.dbd.CHF and/or CF.sub.3CH.dbd.CF.sub.2 from the product produced in (c). In (a), the CF.sub.3CCI.dbd.CF.sub.2 and CF.sub.3CHCICF.sub.3 are produced in the presence of a fluorination catalyst comprising at least one chromium-containing component selected from (i) a crystalline alpha-chromium oxide where at least 0.05 atom % of the chromium atoms in the alpha-chromium oxide lattice are replaced by divalent copper, and (ii) a chromium-containing composition of (i) which has been treated with a fluorinating agent.