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°.
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 HFCarbonyl 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 AgFCarbonyl fluoride is unstable in the presence of water, hydrolyzing to carbon dioxide and hydrogen fluoride:2
COF2 + H2O → CO2 + 2 HFSafety
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.3
References
Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 304–305. ISBN 978-0-08-037941-8. 978-0-08-037941-8 ↩
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. {{cite book}}: ISBN / Date incompatibility (help) 9780470132371 ↩
"Carbonyl Fluoride". NIOSH Pocket Guide to Chemical Hazards. CDC Centers for Disease Control and Prevention. Retrieved 2013-09-10. https://www.cdc.gov/niosh/npg/npgd0108.html ↩