Iodobenzene

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Iodobenzene
Iodobenzene
Iodobenzene-3D-vdW.png
Names
IUPAC name
Iodobenzene
Other names
Phenyl iodide
Identifiers
3D model (Jmol)
ChemSpider
DrugBank
ECHA InfoCard 100.008.837
Properties
C6H5I
Molar mass 204.01 g/mol
Appearance colorless liquid
Density 1.823 g/cm3
Melting point −29 °C (−20 °F; 244 K)
Boiling point 188 °C (370 °F; 461 K)
Insoluble
log P 3
-92.00·10−6 cm3/mol
Hazards
Flash point 74.44 °C (165.99 °F; 347.59 K)
Thermochemistry
.779 J/gK
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Iodobenzene is an organoiodine compound consisting of a benzene ring substituted with one iodine atom. It is useful as a synthetic intermediate in organic chemistry. It is a volatile colorless liquid, although aged samples appear yellowish.

Preparation[edit]

Iodobenzene is commercially available, but it can be prepared in the laboratory from aniline via the Sandmeyer reaction. In the first step, the amine functional group is diazotized with hydrochloric acid and sodium nitrite. Potassium iodide is added to the resultant phenyldiazonium chloride, causing nitrogen gas to evolve. The product is separated by steam distillation.[1]

Sandmeyer-Reaction

Alternatively, it can be produced by refluxing iodine and nitric acid with benzene.[2]

Reactions[edit]

Since the C–I bond is weaker than C–Br or C–Cl, iodobenzene is more reactive than bromobenzene or chlorobenzene. Iodobenzene reacts readily with magnesium to form the Grignard reagent, phenylmagnesium iodide. Phenylmagnesium iodide, like the bromide analog, is a synthetic equivalent for the phenyl anion synthon. Iodobenzene reacts with chlorine to give the complex, iodobenzene dichloride,[3] which is used as a solid source of chlorine.

Iodobenzene can also serve as a substrate for the Sonogashira coupling, Heck reaction, and other metal-catalyzed couplings. These reactions proceed via the oxidative addition of iodobenzene.

References[edit]

  1. ^ H. J. Lucas, E. R. Kennedy (1939). "Iodobenzene". Org. Synth. ; Coll. Vol., 2, p. 351 
  2. ^ F. B. Dains and R. Q. Brewster (1941). "Iodobenzene". Org. Synth. ; Coll. Vol., 1, p. 323 
  3. ^ H. J. Lucas and E. R. Kennedy. "Iodobenzene dichloride". Org. Synth. ; Coll. Vol., 3, p. 482 

Further reading[edit]

  • Gattermann-Wieland, "Laboratory Methods of Organic Chemistry," p. 283. Translated from the twenty-fourth German edition by W. McCartney, The Macmillan Company, New York, 1937.