Patent ID: 7781626

Claim:
A process for separating 1,1,1,3,3-pentafluorobutane from an azeotropic mixture of 1,1,1,3,3-pentafluorobutane and hydrogen fluoride comprising the steps of: (A) providing a process stream derived from the production of 1,1,1,3,3-pentafluorobutane, wherein said process stream comprises a mixture comprising an azeotrope-like composition consisting essentially of about 90 weight percent to about 96 weight percent of 1,1,1,3,3-pentafluorobutane and from about 4 weight percent to about 10 weight percent of hydrogen fluoride; (B) distilling said mixture comprising said azeotrope-like composition at a first pressure to produce a first overhead stream enriched in either the 1,1,1,3,3-pentafluorobutane or the hydrogen fluoride and a first bottoms stream enriched in the other component; and (C) redistilling the first overhead stream at a second pressure to produce a second overhead stream enriched in the component enriched in the first bottoms stream and a second bottoms stream enriched in the component enriched in the first overhead stream.