Processes for separation of fluoroolefins from hydrogen fluoride by azeotropic distillation

摘要

The present disclosure relates to a process for separating a fluoroolefin from a mixture comprising hydrogen fluoride and fluoroolefin, comprising azeotropic distillation both with and without an entrainer. In particular are disclosed processes for separating any of HFC-1225ye, HFC-1234ze, HFC-1234yf or HFC-1243zf from HF.

主权项

1. A process for the purification of HF from a mixture comprising a fluoroolefin and HF, wherein HF is present in a concentration greater than the azeotrope concentration for HF and said fluoroolefin, said process comprising:
a. adding an entrainer to the mixture comprising fluoroolefin and HF thus forming a second mixture; b. distilling said second mixture in a first distillation step to form a first distillate composition comprising an HF, entrainer, and fluoroolefin, and a first bottoms composition comprising HF; c. condensing said first distillate composition to form two liquid phases, being i) an entrainer-rich phase and ii) an HF-rich phase; and d. optionally recycling the HF-rich phase back to the first distillation step; wherein said fluoroolefin comprises: (i) at least one compound selected from the group consisting of HFC-1225ye, HFC-1234ze, HFC-1234yf, and HFC-1243zf (ii) 1,3,4,4,4-pentafluoro-3-(trifluoromethyl)-1-butene (CHF═CHCF(CF3)2); and (iii) fluoroolefins of the formula E— or Z—R1CH═CHR2, wherein R1 and R2 are, independently, C1 to C6 perfluoroalkyl groups and wherein the entrainer is selected from the group consisting of hydrocarbons, chlorocarbons, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, perfluorocarbons, fluoroethers, HFPO, SF6, chlorine, hexafluoroacetone, and mixtures thereof.