Process for obtaining high purity perfluoro-n-heptane

Claim 1

The process for obtaining a high purity perfluoro-n-heptane from an electrochemical fluorination product stream derived from the electrochemical fluorination of n-heptane, wherein said product stream comprises perfluoro-n-heptane, n-heptane, partially fluorinated heptanes, and water soluble acidic components comprising hydrofluoric acid, which process comprises: a. water-washing said electrochemical fluorination product stream, thereby removing substantially water soluble acidic components and producing a water-washed stream, b. fractionating said water-washed stream, thereby producing a first overhead fraction rich in perfluoro-n-heptane and n-heptane, a second higher boiling fraction, and a bottoms fraction, c. washing said first overhead perfluoro-n-heptane rich fraction with toluene, thereby substantially extracting said n-heptane as an n-heptane-toluene admixture and leaving a raffinate admixture comprising perfluoro-n-heptane and toluene, d. distilling said raffinate, thereby producing a toluene fraction and a toluene/perfluoro-n-heptane azeotrope, e. effecting phase separation between said toluene and said perfluoro-n-heptane from said perfluoro-n-heptane/toluene azeotrope, thereby resulting in a substantially toluene rich phase and a substantially rich perfluoro-n-heptane rich phase, f. drawing off said toluene rich phase from said perfluoro-n-heptane rich phase, and g. recovering said perfluoro-n-heptane as a substantially pure material.