Processes for the purification and use of 2-chloro-1,1,1,2,3,3,3-heptafluoropropane and azeotropes thereof with hf

摘要

A process is disclosed for the separation of a mixture of HF and CF3CClFCF3. The process involves placing the mixture in a separation zone at a temperature of from about -30° C. to about 100° C. and at a pressure sufficient to maintain the mixture in the liquid phase, whereby an organic-enriched phase comprising less than 50 mole percent HF is formed as the bottom layer and an HF-enriched phase comprising more than 90 mole percent HF is formed as the top layer. The organic-enriched phase can be withdrawn from the bottom of the separation zone and subjected to distillation in a distillation column to recover essentially pure CF3CClFCF3. The distillate comprising HF and CF3CClFCF3 can be removed from the top of the distillation column while essentially pure CF3CClFCF3 can be recovered from the bottom of the distillation column. The HF-enriched phase can be withdrawn from the top of the separation zone and subjected to distillation in a distillation column. The distillate comprising HF and CF3CClFCF3 can be removed from the top of the distillation column while essentially pure HF can be recovered from the bottom of the distillation column. If desired, the two distillates can be recycled to the separation zone.Also disclosed are compositions of hydrogen fluoride in combination with an effective amount of CF3CClFCF3 to form an azeotrope or azeotrope-like composition with hydrogen fluoride. Included are compositions containing from about 38.4 to 47.9 mole percent CF3CClFCF3.Also disclosed are processes for producing 1,1,1,2,3,3,3-heptafluoro-propane. One process uses a mixture comprising HF and CF3CClFCF3 and is characterized by preparing essentially pure CF3CClFCF3 as indicated above, and reacting the CF3CClFCF3 with hydrogen. Another process uses an azeotropic composition as described above, and reacts the CF3CClFCF3 with hydrogen in the presence of HF.Also disclosed is a process for producing hexafluoropropene. This process is characterized by preparing essentially pure CF3CClFCF3 as indicated above, and dehalogenating the CF3CClFCF3.