| |||
| Names | |||
|---|---|---|---|
| Preferred IUPAC name Fluorobenzene | |||
| Other names Phenyl fluoride Monofluorobenzene | |||
| Identifiers | |||
| |||
3D model (JSmol) | |||
| 1236623 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
| ||
| ECHA InfoCard | 100.006.657 | ||
| EC Number |
| ||
| 49856 | |||
| KEGG |
| ||
| UNII | |||
| UN number | 2387 | ||
| |||
| |||
| Properties | |||
| C6H5F | |||
| Molar mass | 96.103 | ||
| Appearance | Colorless liquid | ||
| Density | 1.025 g/mL, liquid | ||
| Melting point | −44 °C (−47 °F; 229 K) | ||
| Boiling point | 84 to 85 °C (183 to 185 °F; 357 to 358 K) | ||
| low | |||
| −58.4·10−6 cm3/mol | |||
Refractive index (nD) | 1.46553 | ||
| Structure | |||
| Planar | |||
| Hazards | |||
| GHS labelling: | |||
   | |||
| Warning | |||
| H225,H318,H411 | |||
| P210,P233,P240,P241,P242,P243,P264,P273,P280,P303+P361+P353,P305+P351+P338,P310,P337+P313,P370+P378,P391,P403+P235,P501 | |||
| NFPA 704 (fire diamond) | |||
| Related compounds | |||
Related halobenzenes | |||
Related compounds | Benzene 1,2-Difluorobenzene | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Fluorobenzene is anaryl fluoride and the simplest of thefluorobenzenes, with the formula C6H5F, often abbreviatedPhF. A colorless liquid, it is a precursor to many fluorophenyl compounds.
PhF was first reported in 1886 by O. Wallach at theUniversity of Bonn, who prepared the compound in two steps.Phenyldiazonium chloride was first converted to atriazene using piperidine:
The triazine was then cleaved withhydrofluoric acid:
Historical note: in Wallach's era, the element fluorine was symbolized with "Fl". Thus, his procedure is subtitled "Fluorbenzol, C6H5Fl".[1]
On the laboratory scale, PhF is prepared by thethermal decomposition of thebenzenediazonium tetrafluoroborate:
According to the procedure, solid [PhN2]BF4 is heated with a flame to initiate anexothermic reaction, which also affordsboron trifluoride and nitrogen gas. Product PhF and BF3 are readily separated because of their differingboiling points.[2]
The technical synthesis is by the reaction ofcyclopentadiene withdifluorocarbene. The initially formedcyclopropane undergoes a ring expansion and subsequent elimination ofhydrogen fluoride.
PhF behaves rather differently from other halobenzene derivatives owing to the pi-donor properties of fluoride. For example, the para position is more activated than benzene toward electrophiles. For this reason, it can be converted to 1-bromo-4-fluorobenzene with relatively high efficiency.[3]
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PhF is a useful solvent for highly reactive species. Its melting point at −44 °C is lower than that of benzene. In contrast, the boiling points of PhF and benzene are very similar, differing by only 4 °C. It is considerably more polar than benzene, with a dielectric constant of 5.42 compared to 2.28 for benzene at 298 K.[4] Fluorobenzene is a relatively inert compound reflecting the strength of the C–F bond.
Although it is usually considered a non-coordinating solvent, a metal complex of PhF has been crystallized.[5]
