Carbonyl fluoride is a chemical compound with the formula COF2. It is a carbon oxohalide. This gas, like its analog phosgene, is colourless and highly toxic. The molecule is planar with C2v symmetry, bond lengths of 1.174 Å (C=O) and 1.312 Å (C–F), and an F–C–F bond angle of 108.0°.[3]

Preparation and properties

Carbonyl fluoride is usually produced as a decomposition product of fluorinated hydrocarbons in the thermal decomposition thereof, for example from trifluoromethanol or tetrafluoromethane in the presence of water:

CF4 + H2O → COF2 + 2 HF

Carbonyl fluoride can also be prepared by reaction of phosgene with hydrogen fluoride and the fluorination of carbon monoxide, although the latter tends to result in over-fluorination to carbon tetrafluoride. The fluorination of carbon monoxide with silver difluoride is convenient:

CO + 2 AgF2 → COF2 + 2 AgF

Carbonyl fluoride is unstable in the presence of water, hydrolyzing to carbon dioxide and hydrogen fluoride:[4]

COF2 + H2O → CO2 + 2 HF

Safety

Carbonyl fluoride is very toxic with a recommended exposure limit of 2 ppm as an 8-hour time weighted average and a 5 ppm as a short-term (15-minute average) exposure, where 1 ppm = 2.70 mg of carbonyl fluoride per 1 m3 of air.[1]

References

  1. ^ a b "Carbonyl Fluoride". NIOSH Pocket Guide to Chemical Hazards. CDC Centers for Disease Control and Prevention. Retrieved 2013-09-10.
  2. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0108". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 304–305. ISBN 978-0-08-037941-8.
  4. ^ M. W. Farlow; E. H. Man; C. W. Tullock (1960). "Carbonyl Fluoride". Inorganic Syntheses. Inorganic Syntheses. Vol. 6. pp. 155–158. doi:10.1002/9780470132371.ch48. ISBN 9780470132371.
Allikas: https://en.wikipedia.org/wiki/Carbonyl_fluoride
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