1,2-Difluorobenzene

1,2-Difluorobenzene^[1]
Names
	Preferred IUPAC name 1,2-Difluorobenzene
	Other names o-Difluorobenzene; ortho-Difluorobenzene
Identifiers
CAS Number	367-11-3 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:38583 ;
ChemSpider	9325 ;
ECHA InfoCard	100.006.074
PubChem CID	9706;
UNII	AW7QGMW29C ;
CompTox Dashboard (EPA)	DTXSID2075390 ;
	InChI InChI=1S/C6H4F2/c7-5-3-1-2-4-6(5)8/h1-4H Key: GOYDNIKZWGIXJT-UHFFFAOYSA-N ; InChI=1/C6H4F2/c7-5-3-1-2-4-6(5)8/h1-4H Key: GOYDNIKZWGIXJT-UHFFFAOYAN;
	SMILES Fc1ccccc1F;
Properties
Chemical formula	C6H4F2
Molar mass	114.093 g/mol
Appearance	colorless liquid
Density	1.1599 g/cm3
Melting point	−34 °C (−29 °F; 239 K)
Boiling point	92 °C (198 °F; 365 K)
Solubility in water	(insoluble) 1.14 g/L
Related compounds
Related compounds	1,2-Dichlorobenzene
	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

1,2-Difluorobenzene, also known as DFB, is an aromatic compound with formula C₆H₄F₂. This colorless flammable liquid is a solvent used in the electrochemical studies of transition metal complexes. Compared to most conventional halogenated aliphatic and aromatic solvents, it possesses an exceptionally high dielectric constant (ε₀ = 13.8 at 300 K). Thus, it can be a suitable solvent for cationic, and/or highly electrophilic organometallic complexes.^[2]

Synthesis

Difluorobenzenes can be prepared by the Balz-Schiemann reaction, which entails conversion of diazonium tetrafluoroborate salts to their fluorides. The synthesis of 1,2-difluorobenzene starts with 2-fluoroaniline:^[3]

C₆H₄F(NH₂) + HNO₂ + HBF₄ → [C₆H₄F(N₂)]BF₄ + 2 H₂O

[C₆H₄F(N₂)]BF₄ → C₆H₄F₂ + N₂ + BF₃

The syntheses of 1,3- and 1,4-difluorobenzene proceed respectively from 1,3- and 1,4-diaminobenzene, which are doubly diazotized.^[4]

Laboratory applications

Organometallic derivatives of 1,2-difluorobenzene have been well developed. It is found to be a weaker base than benzene.^[5]

1,2-Difluorobenzene has been used as solvent for the electrochemical analysis of transition metal complexes. It is relatively chemically inert, weakly coordinating and has a relatively high dielectric constant. It is a weakly coordinating for metal complexes, in contrast to acetonitrile, DMSO, and DMF.^[6]

It has anaesthetic properties.^[7]

1,2-Difluorobenzene can be acylated to 3',4'-difluoropropiophenone.^[8]

References

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