1,2-Difluorobenzene

Last updated
1,2-Difluorobenzene [1]
O-Difluorobenzene.svg
1,2-Difluorobenzene-3D-balls.png
Names
Preferred IUPAC name
1,2-Difluorobenzene
Other names
o-Difluorobenzene
ortho-Difluorobenzene
DFB
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.006.074 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C6H4F2/c7-5-3-1-2-4-6(5)8/h1-4H Yes check.svgY
    Key: GOYDNIKZWGIXJT-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C6H4F2/c7-5-3-1-2-4-6(5)8/h1-4H
    Key: GOYDNIKZWGIXJT-UHFFFAOYAN
  • Fc1ccccc1F
Properties
C6H4F2
Molar mass 114.093 g/mol
Appearancecolorless liquid
Density 1.1599 g/cm3
Melting point −34 °C (−29 °F; 239 K)
Boiling point 92 °C (198 °F; 365 K)
(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).
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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]

Contents

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. In contrast to acetonitrile, DMSO, and DMF it is a weakly coordinating solvent for metal complexes, . [6]

It has anaesthetic properties. [7]

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

Related Research Articles

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Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often have distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Several fluorocarbons and their derivatives are commercial polymers, refrigerants, drugs, and anesthetics.

<span class="mw-page-title-main">Tetrahydrofuran</span> Cyclic chemical compound, (CH₂)₄O

Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water-miscible organic liquid with low viscosity. It is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. It is an isomer of another solvent, butanone.

<span class="mw-page-title-main">Dicarbonyl</span> Molecule containing two adjacent C=O groups

In organic chemistry, a dicarbonyl is a molecule containing two carbonyl groups. Although this term could refer to any organic compound containing two carbonyl groups, it is used more specifically to describe molecules in which both carbonyls are in close enough proximity that their reactivity is changed, such as 1,2-, 1,3-, and 1,4-dicarbonyls. Their properties often differ from those of monocarbonyls, and so they are usually considered functional groups of their own. These compounds can have symmetrical or unsymmetrical substituents on each carbonyl, and may also be functionally symmetrical or unsymmetrical.

<span class="mw-page-title-main">Organolithium reagent</span> Chemical compounds containing C–Li bonds

In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom to the substrates in synthetic steps, through nucleophilic addition or simple deprotonation. Organolithium reagents are used in industry as an initiator for anionic polymerization, which leads to the production of various elastomers. They have also been applied in asymmetric synthesis in the pharmaceutical industry. Due to the large difference in electronegativity between the carbon atom and the lithium atom, the C−Li bond is highly ionic. Owing to the polar nature of the C−Li bond, organolithium reagents are good nucleophiles and strong bases. For laboratory organic synthesis, many organolithium reagents are commercially available in solution form. These reagents are highly reactive, and are sometimes pyrophoric.

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<span class="mw-page-title-main">Triphenylphosphine</span> Chemical compound

Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to PPh3 or Ph3P. It is versatile compound that is widely used as a reagent in organic synthesis and as a ligand for transition metal complexes, including ones that serve as catalysts in organometallic chemistry. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether.

<span class="mw-page-title-main">Radical anion</span> Free radical species

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<span class="mw-page-title-main">Diazonium compound</span> Group of organonitrogen compounds

Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group [R−N+≡N]X where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. The parent compound where R is hydrogen, is diazenylium.

The nitrosonium ion is NO+, in which the nitrogen atom is bonded to an oxygen atom with a bond order of 3, and the overall diatomic species bears a positive charge. It can be viewed as nitric oxide with one electron removed. This ion is usually obtained as the following salts: NOClO4, NOSO4H (nitrosylsulfuric acid, more descriptively written ONSO3OH) and NOBF4. The ClO−4 and BF−4 salts are slightly soluble in acetonitrile CH3CN. NOBF4 can be purified by sublimation at 200–250 °C and 0.01 mmHg (1.3 Pa).

<span class="mw-page-title-main">1,2-Dichlorobenzene</span> Chemical compound

1,2-Dichlorobenzene, or orthodichlorobenzene (ODCB), is an aryl chloride and isomer of dichlorobenzene with the formula C6H4Cl2. This colourless liquid is poorly soluble in water but miscible with most organic solvents. It is a derivative of benzene, consisting of two adjacent chlorine atoms.

Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, refrigerants, and reagents in catalysis. In addition to these applications, some organofluorine compounds are pollutants because of their contributions to ozone depletion, global warming, bioaccumulation, and toxicity. The area of organofluorine chemistry often requires special techniques associated with the handling of fluorinating agents.

<span class="mw-page-title-main">Organoactinide chemistry</span> Study of chemical compounds containing actinide-carbon bonds

Organoactinide chemistry is the science exploring the properties, structure, and reactivity of organoactinide compounds, which are organometallic compounds containing a carbon to actinide chemical bond.

<span class="mw-page-title-main">Fluorobenzene</span> Chemical compound

Fluorobenzene is an aryl fluoride and the simplest of the fluorobenzenes, with the formula C6H5F, often abbreviated PhF. A colorless liquid, it is a precursor to many fluorophenyl compounds.

(Benzene)chromium tricarbonyl is an organometallic compound with the formula Cr(C6H6)(CO)3. This yellow crystalline solid compound is soluble in common nonpolar organic solvents. The molecule adopts a geometry known as “piano stool” because of the planar arrangement of the aryl group and the presence of three CO ligands as "legs" on the chromium-bond axis.

<span class="mw-page-title-main">Rhodocene</span> Organometallic chemical compound

Rhodocene is a chemical compound with the formula [Rh(C5H5)2]. Each molecule contains an atom of rhodium bound between two planar aromatic systems of five carbon atoms known as cyclopentadienyl rings in a sandwich arrangement. It is an organometallic compound as it has (haptic) covalent rhodium–carbon bonds. The [Rh(C5H5)2] radical is found above 150 °C (302 °F) or when trapped by cooling to liquid nitrogen temperatures (−196 °C [−321 °F]). At room temperature, pairs of these radicals join via their cyclopentadienyl rings to form a dimer, a yellow solid.

<span class="mw-page-title-main">Tetrakis(3,5-bis(trifluoromethyl)phenyl)borate</span> Chemical compound

Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate is an anion with chemical formula [{3,5-(CF3)2C6H3}4B], which is commonly abbreviated as [BArF4], indicating the presence of fluorinated aryl (ArF) groups. It is sometimes referred to as Kobayashi's anion in honour of Hiroshi Kobayashi who led the team that first synthesised it. More commonly it is affectionately nicknamed "BARF." The BARF ion is also abbreviated BArF24, to distinguish it from the closely related BArF
20
, [(C6F5)4B]. However, for a small group of chemists, the anion is abbreviated as TFPB otherwise, short for Tetrakis[3,5-bis(triFluoromethyl)Phenyl]Borate.

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A metal-centered cycloaddition is a subtype of the more general class of cycloaddition reactions. In such reactions "two or more unsaturated molecules unite directly to form a ring", incorporating a metal bonded to one or more of the molecules. Cycloadditions involving metal centers are a staple of organic and organometallic chemistry, and are involved in many industrially-valuable synthetic processes.

<span class="mw-page-title-main">1,4-Bis(diphenylphosphino)butane</span> Chemical compound

1,4-Bis(diphenylphosphino)butane (dppb) is an organophosphorus compound with the formula (Ph2PCH2CH2)2. It is less commonly used in coordination chemistry than other diphosphine ligands such as dppe. It is a white solid that is soluble in organic solvents.

References

  1. David R. Lide, ed., CRC Handbook of Chemistry and Physics, 89th Edition (Internet Version 2009), CRC Press/Taylor and Francis, Boca Raton, FL.
  2. Pike, Sebastian D.; Crimmin, Mark R.; Chaplin, Adrian B. (2017). "Organometallic chemistry using partially fluorinated benzenes" (PDF). Chemical Communications. 53 (26): 3615–3633. doi:10.1039/C6CC09575E. PMID   28304406.
  3. Yu, Zhiqun; Lv, Yanwen; Yu, Chuanming (2012). "A Continuous Kilogram-Scale Process for the Manufacture of o-Difluorobenzene". Organic Process Research & Development. 16 (10): 1669–1672. doi:10.1021/op300127x.
  4. Siegemund, Günter; Schwertfeger, Werner; Feiring, Andrew; Smart, Bruce; Behr, Fred; Vogel, Herward; McKusick, Blaine (2000). "Fluorine Compounds, Organic". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a11_349. ISBN   3527306730.
  5. Pike, Sebastian D.; Crimmin, Mark R.; Chaplin, Adrian B. (2017). "Organometallic chemistry using partially fluorinated benzenes" (PDF). Chemical Communications. 53 (26): 3615–3633. doi:10.1039/c6cc09575e. PMID   28304406.
  6. O'toole, Terrence R.; Younathan, Janet N.; Sullivan, B. Patrick; Meyer, Thomas J. (1989). "1,2-Difluorobenzene: a relatively inert and noncoordinating solvent for electrochemical studies on transition-metal complexes". Inorganic Chemistry. 28 (20): 3923. doi:10.1021/ic00319a032.
  7. "1,2-Difluorobenzene". PubChem. Retrieved 11 February 2021.
  8. GB 1140754,Danilewicz, John Christopher&Szelke, Michael,"3,4-difluorophenyl compounds",published 1969-01-22, assigned to Pfizer Ltd.