PROCESSES FOR THE PURIFICATION AND USE OF 2,2-DICHLORO-1,1,1,3,3,3-HEXAFLUOROPROPANE AND AZEOTROPES THEREOF WITH HF

摘要

A process is disclosed for the separation of a mixture of HF and CF3CC12CF3. The process involves placing the mixture in a separation zone at a temperature of from about 0 DEG C to about 100 DEG C and at a pressure sufficient to maintain the mixture in the liquid phase, whereby an organic-enriched phase comprising less than 69 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 The organic-enriched phase can be withdrawn from the bottom of the separation zone and subjected to distillation in a distillation column to recover essentially pure CF3CC12CF3. The distillate comprising HF and CF3CC12CF3 can be removed from the top of the distillation column, while essentially pure CF3CC12CF3 can be recovered from the bottom of the distillation column. Also, the HF-enriched phase can be withdrawn from the top of the separation zone and subjected to distillation in a distillation column.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 CF3CC12CF3 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 amout of CF3CC12CF3 to form an azeotrope or azeotrope-like composition with hydrogen fluoride. Included are compositions containing from about 13.8 to 31.3 mole percent CF3CC12CF3. Also disclosed is a process for producing 1,1,1,3,3,3-hexafluoropropane from a mixture comprising HF and CF3CC12CF3. This process is characterized by preparing essentially pure CF3CC12CF3 as indicated above, and reacting the CF3CC12CF3 with hydrogen. Another process for producing 1,1,1,3,3,3-hexafluoropropane disclosed herein is characterized by contacting an azeotrope of CF3CC12CF3 as indicated above with hydrogen and reacting the CF3CC12CF3 with hydrogen in the presence of HF.