Production of 1,2-dihydro and 2,2-dihydro hexafluoropropanes and azeotropes thereof with HF

摘要

CF₃CHFCHF₂ production is disclosed which involves reacting CF₃CF═CHF with HF at an elevated temperature over a catalyst selected from the group consisting of aluminum fluoride, fluorided alumina, metals supported on aluminum fluoride, metals supported on fluorided alumina and catalysts comprising trivalent chromium. Also disclosed is enrichment of CF₃CF═CHF from a starting mixture containing CF₃CF═CHF and CF₃CH═CF₂ which involves reacting said starting mixture with HF at an elevated temperature over a catalyst consisting essentially of carbon, a catalyst consisting essentially of metal halides supported on carbon, a catalyst consisting essentially of Cr₂O₃, or mixtures thereof (provided that when Cr₂O₃ is present the temperature is about 250° C. or less) to produce a product mixture containing CF₃CH₂CF₃ and unreacted CF₃CF═CHF wherein the mole ratio of CF₃CF═CHF to CF₃CH═CF₂ is greater than the ratio thereof in the starting mixture. Compositions are disclosed which consist essentially of hydrogen fluoride in combination with an effective amount of a compound selected from the group consisting of CF₃CHFCHF₂ and CF₃CH₂CF₃ to form an azeotrope or azeotrope-like composition with hydrogen fluoride. Included are compositions containing from about 31 to 60 mole percent CF₃CHFCHF₂ and compositions containing from about 41 to 63 mole percent CF₃CH₂CF₃.