Perfluoroisobutene (PFIB) is the perfluorocarbon counterpart of the hydrocarbon isobutene and has the formula (CF3)2C=CF2. A fluoroalkene, it is a colorless gas that is notable as a highly toxic perfluoroalkene. Few simple alkenes are as toxic.

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 ☒N
    Key: DAFIBNSJXIGBQB-UHFFFAOYSA-N ☒N
  • InChI=1/C4F8/c5-2(6)1(3(7,8)9)4(10,11)12
    Key: DAFIBNSJXIGBQB-UHFFFAOYAF
  • C(=C(F)F)(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).
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Safety

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Perfluoroisobutene is highly toxic with an LCt = 880 mg⋅min⋅m−3 (mice).[1] It is a Schedule 2 substance of the Chemical Weapons Convention.

Perfluoroisobutene is highly reactive toward nucleophiles. It hydrolyzes readily to give the relatively innocuous (CF3)2CHCO2H, which readily decarboxylates to give hexafluoropropane. It forms addition compounds with thiols, and it is this reactivity that may be related to its toxicity.[1]

PFIB is a product of pyrolysis of polytetrafluoroethylene (PTFE), one of the substances invoked to explain polymer fume fever.

See also

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References

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  1. ^ a b 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.
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