{{Short description|Group of chemical compounds}} {{Distinguish|Benzyl iodide}} '''Iodotoluenes''' are aryl iodides based on toluene in which at least one aromatic hydrogen atom is replaced with an iodine atom. They have the general formula C<sub>7</sub>H<sub>8–''n''</sub>I<sub>''n''</sub>, where ''n'' = 1–5 is the number of iodine atoms.
==Monoiodotoluene== thumb|150px|''p''-Iodotoluene sample Monoiodotoluenes are iodotoluenes containing one iodine atom. There are three isomers, each with the formula C<sub>7</sub>H<sub>7</sub>I.
=== Properties === The isomers differ in the location of the iodine, but have the same chemical formula.
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! {{Chemical datatable header}} align="center" colspan="4" | Monoiodotoluene isomers<ref>{{Cite PubChem|cid=5128|title=2-Iodotoluene|access-date=January 19, 2023}}</ref><ref>{{Cite PubChem|cid=12268|title=3-Iodotoluene|access-date=January 19, 2023}}</ref><ref>{{Cite PubChem|cid=12207|title=4-Iodotoluene|access-date=January 19, 2023}}</ref> |- | Common name | {{no redirect|2-Iodotoluene|'''''o''-iodotoluene'''}} | {{no redirect|3-Iodotoluene|'''''m''-iodotoluene'''}} | {{no redirect|4-Iodotoluene|'''''p''-iodotoluene'''}} |- | Structure | align="center" | 90px | align="center" | 90px | align="center" | 55px |- | Systematic name | 1-iodo-2-methylbenzene | 1-iodo-3-methylbenzene | 1-iodo-4-methylbenzene |- | Other names | 2-iodotoluene | 3-iodotoluene | 4-iodotoluene |- | Molecular formula | align="center" colspan="3" | C<sub>7</sub>H<sub>7</sub>I (C<sub>6</sub>H<sub>4</sub>ICH<sub>3</sub>) |- | Molar mass | align="center" colspan="3" | 218.03 g/mol |- | Appearance | Clear dark brown liquid | | white to yellow solid |- | CAS number | [615-37-2] | [625-95-6] | [624-31-7] |- ! {{Chemical datatable header}} align="center" colspan="5" | Properties |- | Melting point | | | 35 °C (95 °F; 308 K)<ref name="Datta"></ref> |- | Boiling point | 211-212 °C (412-414 °F; 484-485 K)<ref name="Datta"></ref> | | 211.5 °C (412.7 °F; 484.7 K)<ref>{{cite web |url=https://www.sigmaaldrich.com/US/en/product/aldrich/206555 |title=4-Iodotoluene |author=<!--Not stated--> |website=Sigma Aldrich |access-date=January 31, 2023}}</ref> |}
Benzyl iodide is an isomer, which has an iodine substituted for one of the hydrogens of toluene's methyl group, and it is sometimes named α-bromoiodine.
==Preparation== A laboratory route to ''o''- and ''p''-iodotoluene proceeds from toluene, which is treated with a mixture of iodine and nitric acid in an electrophilic aromatic substitution. The resulting mixture of ''o'' and ''p''-iodotoluene is then separated by fractional freezing; cooling the mixture in an ice bath results in solidification of ''p''-iodotoluene, which can then be isolated by filtration, while the ''o''-iodotoluene remains behind as a liquid.<ref name="Datta">{{cite journal |last1=Datta |first1=Rasik Lal |last2=Chatterjee |first2=Nihar Ranjan |title=Halogenation. Xv. Direct Iodination of Hydrocarbons by Means of Iodine and Nitric Acid |date=1917 |journal=Journal of the American Chemical Society |volume=39 |issue=3 |pages=435–441 |doi=10.1021/ja02248a012}}</ref>
==Uses== Iodotoluenes are precursors to many organic building blocks. For example, the methyl group of ''o''-iodotoluene and ''p''-iodotoluene may be oxidized using potassium permanganate to form 2-iodobenzoic acid and 4-iodobenzoic acid, respectively.<ref>{{cite journal |last1=Varma |first1=P. S. |last2=Panickerp |first2=P. B. |date=1928 |title=Influence of substitution on the oxidation of side chains in the benzene nucleus |journal=Proc. 15th Indian Sci. Cong.}}</ref>
==See also== *Chlorotoluene *Bromotoluene
== References == {{reflist}}
Category:Iodobenzene derivatives Category:Toluenes Category:Multiple compounds, tabular