Iodobenzene

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.

Iodobenzene

Iodobenzene
Names
IUPAC name Iodobenzene
Other names Phenyl iodide
Identifiers
CAS Number	591-50-4
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL116296
ChemSpider	11087
DrugBank	DB02252
ECHA InfoCard	100.008.837
PubChem CID	11575
UNII	9HK5L7YBBR
CompTox Dashboard (EPA)	DTXSID8060452
InChI InChI=1S/C6H5I/c7-6-4-2-1-3-5-6/h1-5H Key: SNHMUERNLJLMHN-UHFFFAOYSA-N InChI=1/C6H5I/c7-6-4-2-1-3-5-6/h1-5H Key: SNHMUERNLJLMHN-UHFFFAOYAQ
SMILES c1ccc(cc1)I
Properties
Chemical formula	C6H5I
Molar mass	204.01 g/mol
Appearance	colorless liquid
Density	1.823 g/cm^3
Melting point	−29 °C (−20 °F; 244 K)
Boiling point	188 °C (370 °F; 461 K)
Solubility in water	Insoluble
log P	3
Magnetic susceptibility (χ)	-92.00·10^−6 cm^3/mol
Viscosity	1.5042 mPa·s (300.65 K)[1]
Hazards
Flash point	74.44 °C (165.99 °F; 347.59 K)
Thermochemistry
Heat capacity (C)	.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

Preparation

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.[2]

Alternatively, it can be produced by refluxing iodine and nitric acid with benzene.[3]

Reactions

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,[4] 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.

See also

• Fluorobenzene
• Chlorobenzene
• Bromobenzene

References

1. Viswanath, D.S.; Natarajan, G. (1989), Data Book on the Viscosity of Liquids, Hemisphere Publishing, ISBN 0-89116-778-1
2. H. J. Lucas, E. R. Kennedy (1939). "Iodobenzene". Organic Syntheses.; Collective Volume, 2, p. 351
3. F. B. Dains and R. Q. Brewster (1941). "Iodobenzene". Organic Syntheses.; Collective Volume, 1, p. 323
4. H. J. Lucas and E. R. Kennedy. "Iodobenzene dichloride". Organic Syntheses.; Collective Volume, 3, p. 482

Further reading

• 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.