Electrofluorination of Hexafluorobutanol in Anhydrous Hydrofluoric Acid: Quasi on Line Mass Spectrometry and X-Ray Photoelectron Spectroscopy Studies

Certain aspects of the electrochemical fluorination (ECF) of hexafluorobutanol (HFB) in anhydrous HF (AHF) on Ni electrodes have been examined by mass spectrometry (MS) and X-ray photoelectron spectroscopy (XPS). Measurements were performed using a portable ultrahigh vacuum compatible chamber that allows for the transfer and characterization of specimens without exposure to the ambient atmosphere. Quasi on line MS analysis of the gases released during ECF of HFB/AHF solutions revealed features attributable to perfluorobutyryl fluoride [PBF = CF₃CF₂CF₂C(O)F] with no evidence of the presence of other reaction products. Ex situ XPS analysis of Ni electrodes following ECF yielded spectra consistent with the formation ot a rather thick, irregular layer of NiF₂ of average thickness of about 150-200 monolayers. with small contributions due to O (6%) and C (7%) localized primarily in the surface region.