Isolation and Characterization of Acetyl Hypofluorite

Article abstract of DOI:10.1021/ja00309a016

Acetyl hypofluorite, H3CC(O)OF, has been prepared by passage of diluted fluorine through solid KOAc*2HOAc and isolated by trapping at -78 deg C.It is a slightly yellow liquid (mp ca. -96 deg C) with a vapor pressure of about 4 torr at -40 deg C.Vapor-pressure measurements between -64 and -20 deg C led to an enthalpy of vaporization of 35.6 +/- 2.4 kJ/mol and an extrapolated normal boiling point of 53 +/- 6 deg C.At -78 deg C, in 1:1 (v/v) CCl4:CDCl3, its 19F NMR shift is 168.3 ppm vs.CFCl3.Its mass spectrum has been measured, as has its infrared spectrum in a solid argon matrix, and these support its identification.The vapor absorbs in the far ultraviolet, with an absorption maximum at 210 nm (ε ca. 103 L/mol*cm).The compound is of limited stability, particularly in the liquid phase, which sometimes explodes.The vapor is more stable, with a 2-h half-life at room temperature in Kel-F.The half-life is much shorter in Monel.Decomposition is inhibited by O2.Decomposition in a Kel-F container gives nearly quantitatively a 1:1 mixture of CH3F and CO2, but in a Monel apparatus or in the presence of O2, substantial amounts of H3COC(O)F are formed.