Hexafluorobutadiene

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Hexafluorobutadiene
Hexafluorobutadiene.png
Names
Preferred IUPAC name
Hexafluorobuta-1,3-diene
Other names
1,1,2,3,4,4-Hexafluoro-1,3-butadiene, FC 2316
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.010.620 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 211-681-0
PubChem CID
UNII
  • InChI=1S/C4F6/c5-1(3(7)8)2(6)4(9)10
    Key: LGPPATCNSOSOQH-UHFFFAOYSA-N
  • C(=C(F)F)(C(=C(F)F)F)F
Properties
C4F6
Molar mass 162.034 g·mol−1
Appearancecolorless gas
Density 1.44 g/cm3 (@15 °C)
Melting point −132 °C (−206 °F; 141 K)
Boiling point 6 °C (43 °F; 279 K)
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-skull.svg
Danger
H220, H331
P210, P261, P271, P304+P340, P311, P321, P377, P381, P403, P403+P233, P405, P410+P403, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Hexafluorobutadiene is an organofluorine compound with the formula (CF2=CF)2. A colorless gas, it has attracted attention as an etchant in microelectronics. It is the perfluoroanalogue of butadiene.

Contents

Preparation

It can be prepared by coupling of fluorinated C2 precursors. Addition of iodine monochloride to chlorotrifluoroethylene gives iododichlorotrifluoroethane that can be coupled in the presence of mercury to give 1,2,3,4-tetrchlorohexafluorobutane:

2 CF2Cl−CFCl(I) + Hg → CF2Cl−CFCl−CFCl−CF2Cl + HgI2

Zn-induced dechlorination of this tetrachloride gives the desired perfluorinated diene: [1]

CF2Cl−CFCl−CFCl−CF2Cl + 2 Zn → CF2=CF−CF=CF2 + 2 ZnCl2

Reactions

The diene can be rehalogenated, e.g. with bromine upon UV irradiation: [1]

CF2=CF−CF=CF2 + 2 Br2 → CF2Br−CFBr−CFBr−CF2Br

Hexafluorobutadiene dimerizes via a [2+2] process at 150 °C to give perfluorinated divinylcyclobutanes. [2]

In the presence of the strong Lewis acid aluminium chlorofluoride, hexafluorobutadiene isomerizes to hexafluoro-2-butyne: [3]

CF2=CFCF=CF2 → CF3C≡CCF3

See also

References

  1. 1 2 Haszeldine, R. N. (1952). "849. Fluoro-olefins. Part I. The Synthesis of Hexafluorobuta-1:3-diene". Journal of the Chemical Society (Resumed): 4423. doi:10.1039/jr9520004423.
  2. ↑ Lemal, David M.; Chen, Xudong (2005). "Fluorinated Cyclobutanes and Their Derivatives". In Zvi Rappoport; Joel F. Liebman (eds.). The Chemistry of Cyclobutanes. PATAI'S Chemistry of Functional Groups. pp. 955–1029. doi:10.1002/0470864028.ch21. ISBN   0470864001.
  3. ↑ Petrov, V.A.; Krespan, C.G.; Smart, B.E. (1996). "Electrophilic reactions of fluorocarbons under the action of aluminum chlorofluoride, a potent Lewis acid". Journal of Fluorine Chemistry. 77 (2): 139–142. Bibcode:1996JFluC..77..139P. doi:10.1016/0022-1139(96)03391-x.
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