Hexafluoro-2-butyne
Chemical compound
From Wikipedia, the free encyclopedia
Hexafluoro-2-butyne (HFB) is a fluorocarbon with the chemical structure CF3Câ¡CCF3. HFB is a particularly electrophilic acetylene derivative, and hence a potent dienophile for DielsâAlder reactions.[2][3]
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| Names | |
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| Preferred IUPAC name
1,1,1,4,4,4-Hexafluorobut-2-yne | |
| Other names
HFB | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.010.667 |
| EC Number |
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PubChem CID |
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| RTECS number |
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CompTox Dashboard (EPA) |
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| Properties | |
| C4F6 | |
| Molar mass | 162.034 g·molâ1 |
| Appearance | Colorless gas |
| Density | 1.602 g/cm3 |
| Melting point | â117 °C (â179 °F; 156 K) |
| Boiling point | â25 °C (â13 °F; 248 K) |
| Insoluble | |
| Structure | |
| 0 D | |
| Hazards[1] | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
Toxic gas |
| GHS labelling: | |
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| Danger | |
| H331 | |
| 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).
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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.
In the presence of the strong Lewis acid aluminium chlorofluoride, hexafluorobutadiene isomerizes to HFB:[4]
- CF2=CFCF=CF2 â CF3Câ¡CCF3
HFB 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.[5]
As an electrophilic alkyne, HFB forms a variety of alkyne complexes by reaction with low-valent metal complexes.[6]