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Perfluoroisobutene

From Wikipedia, the free encyclopedia
(Redirected from PFIB)
Perfluoroisobutene
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name
1,1,3,3,3-Pentafluoro-2-(trifluoromethyl)prop-1-ene
Other names
Perfluoroisobutene, Perfluoroisobutylene, Octafluoroisobutylene, Octafluoro-sec-butene, PFIB
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.108.743 Edit this at Wikidata
EC Number
  • 609-533-9
RTECS number
  • UD1800000
UNII
  • InChI=1S/C4F8/c5-2(6)1(3(7,8)9)4(10,11)12 X markN
    Key: DAFIBNSJXIGBQB-UHFFFAOYSA-N X markN
  • InChI=1/C4F8/c5-2(6)1(3(7,8)9)4(10,11)12
    Key: DAFIBNSJXIGBQB-UHFFFAOYAF
  • FC(F)=C(C(F)(F)F)C(F)(F)F
Properties
C4F8
Molar mass 200.030 g/mol
Appearance colorless gas
Density 8.2 g/l
Melting point −130 °C (−202 °F; 143 K)
Boiling point 7.0 °C (44.6 °F; 280.1 K)
Hazards
GHS labelling:
GHS06: ToxicGHS08: Health hazard
Danger
H330, H370
P260, P264, P270, P271, P284, P304+P340, P307+P311, P310, P320, P321, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X markN verify (what is checkYX markN ?)

Perfluoroisobutene (PFIB) is the perfluorocarbon with the formula (CF3)2C=CF2. 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

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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

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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

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  1. 1 2 3 4 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.
  2. 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. 1 2 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.
  4. Michael Van Der Puy, Louis G. Anello (1985). "Hexafluoroacetone". Organic Syntheses. 63: 154. doi:10.15227/orgsyn.063.0154.
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