Hexafluoro-2-butyne

Hexafluoro-2-butyne
Names
	Preferred IUPAC name 1,1,1,4,4,4-Hexafluorobut-2-yne
	Other names HFB
Identifiers
CAS Number	692-50-2 ;
3D model (JSmol)	Interactive image;
ChemSpider	62855 ;
ECHA InfoCard	100.010.667
EC Number	211-732-7;
PubChem CID	69654;
RTECS number	ES0702500;
CompTox Dashboard (EPA)	DTXSID3061003 ;
	InChI InChI=1S/C4F6/c5-3(6,7)1-2-4(8,9)10 Key: WBCLXFIDEDJGCC-UHFFFAOYSA-N ; InChI=1/C4F6/c5-3(6,7)1-2-4(8,9)10 Key: WBCLXFIDEDJGCC-UHFFFAOYAY;
	SMILES FC(F)(F)C#CC(F)(F)F;
Properties
Chemical formula	C4F6
Molar mass	162.034 g·mol−1
Appearance	Colorless gas
Density	1.602 g/cm3
Melting point	−117 °C (−179 °F; 156 K)
Boiling point	−25 °C (−13 °F; 248 K)
Solubility in water	Insoluble
Structure
Dipole moment	0 D
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Toxic gas
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H331
Precautionary statements	P261, P311, P410+P403
Related compounds
Related compounds	Dimethyl acetylenedicarboxylate; Hexachlorobutadiene; Acetylene
	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

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Hexafluoro-2-butyne (HFB) is a fluorocarbon with the chemical structure CF₃C≡CCF₃. HFB is a particularly electrophilic acetylene derivative, and hence a potent dienophile for Diels–Alder reactions.^[2]^[3]

Synthesis and reactions

HFB is prepared by the action of sulfur tetrafluoride on acetylenedicarboxylic acid or by the reaction of potassium fluoride (KF) with hexachlorobutadiene.

It reacts with sulfur to give 3,4-bis(trifluoromethyl)-1,2-dithiete.

Cycloaddition of HFB and dithionitronium (NS₂⁺) gives the 1,2,5-dithiazolium cation. This derivative can be reduced to the 7 electron neutral radical. This particular 1,3,5-dithiazole is also rare example of a radical that can be obtained as solid, liquid, and gaseous states. As a gas, it is blue.^[4]

References

^ "Hexafluoro-2-butyne 99%". Sigma-Aldrich.
^ Essers, Michael; Haufe, Günter (2006). "Hexafluoro-2-butyne". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn00669. ISBN 0471936235.
^ E S Turbanova, A A Petrov (1991). "Perfluoroalkyl(aryl)acetylenes". Russian Chemical Reviews. 60 (5): 501–523. Bibcode:1991RuCRv..60..501T. doi:10.1070/RC1991v060n05ABEH001092.
^ Brownridge, Scott; Du, Hongbin; Fairhurst, Shirley A.; Haddon, Robert C.; Oberhammer, Heinz; Parsons, Simon; Passmore, Jack; Schriver, Melbourne J.; Sutcliffe, Leslie H.; Westwood, Nicholas P. C. (2000). "The Isolation, Characterisation, Gas Phase Electron Diffraction and Crystal Structure of the Thermally Stable Radical CF₃CSNSCCF₃". Journal of the Chemical Society, Dalton Transactions (19): 3365–3382. doi:10.1039/B001489N.

[1] "Hexafluoro-2-butyne 99%". Sigma-Aldrich.

[2] Essers, Michael; Haufe, Günter (2006). "Hexafluoro-2-butyne". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn00669. ISBN 0471936235.

[3] E S Turbanova, A A Petrov (1991). "Perfluoroalkyl(aryl)acetylenes". Russian Chemical Reviews. 60 (5): 501–523. Bibcode:1991RuCRv..60..501T. doi:10.1070/RC1991v060n05ABEH001092.

[4] Brownridge, Scott; Du, Hongbin; Fairhurst, Shirley A.; Haddon, Robert C.; Oberhammer, Heinz; Parsons, Simon; Passmore, Jack; Schriver, Melbourne J.; Sutcliffe, Leslie H.; Westwood, Nicholas P. C. (2000). "The Isolation, Characterisation, Gas Phase Electron Diffraction and Crystal Structure of the Thermally Stable Radical CF₃CSNSCCF₃". Journal of the Chemical Society, Dalton Transactions (19): 3365–3382. doi:10.1039/B001489N.

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