Perfluoroisobutene

Perfluoroisobutene
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
CAS Number	382-21-8 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL4634291;
ChemSpider	55060 ;
ECHA InfoCard	100.108.743
EC Number	609-533-9;
PubChem CID	61109;
RTECS number	UD1800000;
UNII	1J9BGS6NTY ;
CompTox Dashboard (EPA)	DTXSID4073176 ;
	InChI InChI=1S/C4F8/c5-2(6)1(3(7,8)9)4(10,11)12 Key: DAFIBNSJXIGBQB-UHFFFAOYSA-N ; InChI=1/C4F8/c5-2(6)1(3(7,8)9)4(10,11)12 Key: DAFIBNSJXIGBQB-UHFFFAOYAF;
	SMILES FC(F)=C(C(F)(F)F)C(F)(F)F;
Properties
Chemical formula	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:
Pictograms
Signal word	Danger
Hazard statements	H330, H370
Precautionary statements	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). verify (what is ?) Infobox references

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

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.

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

^ ^a ^b ^c ^d 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.
^ ^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.
^ Michael Van Der Puy, Louis G. Anello (1985). "Hexafluoroacetone". Organic Syntheses. 63: 154. doi:10.15227/orgsyn.063.0154.

External links

International Chemical Safety Card 1216

[Ullmann-1] 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.

[Timp-3] 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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