Processes for the purification and use of 2-chloro-1,1,1,2,3,3,3-heptafluoropropane and zeotropes thereof with HF
申请人:E. I. du Pont de Nemours and Company
公开号:US06677493B1
公开(公告)日:2004-01-13
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 The organic-enriched phase can be withdrawn from the bottom of the separation zone and subjected to distillation in a distillation column to recover essentially pure CF3CClFCF3.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 The HF-enriched phase can be withdrawn from the top of the separation zone and subjected to distillation in a distillation column.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.
揭示了一种用于分离HF和CF3CClFCF3混合物的工艺。该工艺涉及将混合物放置在一个分离区域中,温度约为-30°C至约100°C,并在足以维持混合物处于液相的压力下,形成富含有机物的相,其中含有的HF摩尔分数低于50%,形成底层,以及富含HF的相,其中含有的HF摩尔分数高于90%,形成顶层。可以从分离区域底部提取富含有机物的相,并在精馏塔中进行蒸馏,以回收基本纯净的CF3CClFCF3。含有HF和CF3CClFCF3的馏分可以从精馏塔顶部移除,而基本纯净的CF3CClFCF3可以从精馏塔底部回收。富含HF的相可以从分离区域顶部提取,并在精馏塔中进行蒸馏。含有HF和CF3CClFCF3的馏分可以从精馏塔顶部移除,而基本纯净的HF可以从精馏塔底部回收。如果需要,这两种馏分可以回收到分离区域。还披露了氟化氢与有效量的CF3CClFCF3结合形成与氟化氢形成共沸物或类似共沸物的组合物。包括含有约38.4至47.9摩尔百分比CF3CClFCF3的组合物。还披露了生产1,1,1,2,3,3,3-七氟丙烷的工艺。一种工艺使用含有HF和CF3CClFCF3的混合物,其特点是制备如上所述的基本纯净的CF3CClFCF3,并将CF3CClFCF3与氢反应。另一种工艺使用如上所述的共沸物组合物,并在HF存在下将CF3CClFCF3与氢反应。还揭示了生产六氟丙烯的工艺。该工艺的特点是制备如上所述的基本纯净的CF3CClFCF3,并脱卤CF3CClFCF3。