Chemistry:Perfluoroisobutene
Perfluoroisobutene (PFIB) is the perfluorocarbon with the formula (CF
3)
2C=CF
2. Classified as a perfluoroalkene, it is the fluorinated counterpart of the hydrocarbon isobutene. This colorless gas is notable for its high toxicity.[1]
Production and reactions
PFIB is one product of pyrolysis of polytetrafluoroethylene (PTFE).[2] Tetrafluoroethylene thermally dimerizes to octafluorocyclobutane, which above 600 °C degrades to hexafluoropropylene and PFIB.[1]
Perfluoroisobutene is highly reactive toward nucleophiles, e.g. methanol.[1] It also forms addition compounds with thiols, and it is this reactivity that may be related to its toxicity.[3] It hydrolyzes readily to give the relatively innocuous (CF3)2CHCO2H, which readily decarboxylates to give hexafluoropropane.[citation needed]
Oxidation of HFIB with potassium permanganate gives hexafluoroacetone.[4]
Safety
Perfluoroisobutene is highly toxic with an LCt = 880 mg⋅min⋅m−3 (mice).[3] It is a Schedule 2 substance of the Chemical Weapons Convention. Its toxicity is comparable to that of phosgene.[1]
References
- ↑ 1.0 1.1 1.2 1.3 Siegemund, Günter; Schwertfeger, Werner; Feiring, Andrew; Smart, Bruce; Behr, Fred; Vogel, Herward; McKusick, Blaine (2000). "Fluorine Compounds, Organic". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a11_349. ISBN 978-3-527-30385-4.
- ↑ Stewart, Charles E. (2006). Weapons of mass casualties and terrorism response handbook. American Academy of Orthopaedic Surgeons. Sudbury, Mass: Jones and Bartlett. ISBN 978-0-7637-2425-2.
- ↑ 3.0 3.1 Timperley, Christopher M. (2000). "Highly-toxic fluorine compounds". Fluorine Chemistry at the Millennium. pp. 499–538. doi:10.1016/B978-008043405-6/50040-2. ISBN 9780080434056.
- ↑ Michael Van Der Puy, Louis G. Anello (1985). "Hexafluoroacetone". Organic Syntheses 63: 154. doi:10.15227/orgsyn.063.0154.
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