View source for Chlorotoluene

{{Distinguish|Benzyl chloride}}
'''Chlorotoluenes''' are [[aryl chloride]]s based on [[toluene]] in which at least one aromatic hydrogen atom is replaced with a [[chlorine]] atom. They have the general formula C<sub>7</sub>H<sub>8–''n''</sub>Cl<sub>''n''</sub>, where ''n'' = 1–5 is the number of chlorine atoms.

==Monochlorotoluene==

Monochlorotoluenes are chlorotoluenes containing one chlorine atom. There are three isomers, each with the formula C<sub>7</sub>H<sub>7</sub>Cl. 

=== Properties ===
The isomers differ in the location of the chlorine, but have the same chemical formula. All have very similar boiling points, although ''p''-chlorotoluene has a much higher melting point due to a more tightly packed crystal structure.

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{| align="center" border="1" cellspacing="0" cellpadding="3" style="margin: 0 0 0 0.5em; background: #FFFFFF; border-collapse: collapse; border-color: #C0C090;"

! {{Chemical datatable header}} align="center" colspan="4" | Monochlorotoluene isomers
|-
| Common name
| {{no redirect|2-Chlorotoluene|'''''o''-chlorotoluene'''}}
| {{no redirect|3-Chlorotoluene|'''''m''-chlorotoluene'''}}
| {{no redirect|4-Chlorotoluene|'''''p''-chlorotoluene'''}}
|-
| Structure
| align="center" | [[File:o-Chlortoluol.svg|90px]]
| align="center" | [[File:m-Chlortoluol.svg|90px]]
| align="center" | [[File:p-Chlortoluol.svg|55px]]
|-
| [[IUPAC nomenclature|Systematic name]]
| 1-chloro-2-methylbenzene
| 1-chloro-3-methylbenzene
| 1-chloro-4-methylbenzene
|-
| [[Chemical formula|Molecular formula]]
| align="center" colspan="3" | C<sub>7</sub>H<sub>7</sub>Cl (C<sub>6</sub>H<sub>4</sub>ClCH<sub>3</sub>)
|-
| [[Molar mass]]
| align="center" colspan="3" | 126.586 g/mol
|-
| Appearance
| align="center" colspan="3" | colorless liquid
|-
| [[CAS registry number|CAS number]]
| [95-49-8]
| [108-41-8]
| [106-43-4]
|-
! {{Chemical datatable header}} align="center" colspan="5" | Properties
|-
| [[Density]] and [[phase (matter)|phase]]
| 1.073 g/ml, liquid
| 1.072 g/ml, liquid
| 1.069 g/ml, liquid
|-
| [[Solubility]] in [[Water (molecule)|water]]
| align="center" colspan="3" | practically insoluble
|-
| Other solubilities
| align="center" colspan="4" | Soluble in non-polar [[solvent]]s such as [[aromatic hydrocarbon]]s
|-
| [[Melting point]]
| −35&nbsp;°C (−31&nbsp;°F; 238 K)
| −47&nbsp;°C (−52.6&nbsp;°F; 226 K)
| 7&nbsp;°C (44.6&nbsp;°F; 280 K)
|-
| [[Boiling point]]
| 159&nbsp;°C (318.2&nbsp;°F; 432 K)
| 162&nbsp;°C (323.6&nbsp;°F; 435 K)
| 162&nbsp;°C (323.6&nbsp;°F; 435 K)
|-
|Magnetic susceptibility
| −81.98·10<sup>−6</sup> cm<sup>3</sup>/mol
| −80.07·10<sup>−6</sup> cm<sup>3</sup>/mol
| −80.07·10<sup>−6</sup> cm<sup>3</sup>/mol
|}

[[Benzyl chloride]] is an isomer, which has a chlorine substituted for one of the hydrogens of [[toluene]]'s methyl group, and it is sometimes named α-chlorotoluene.

==Preparation==
A laboratory route to 2- and 4-chlorotoluene proceeds from 2- and 4-[[toluidine]]s (i.e. 2- and 4-aminotoluene).  These compounds are [[diazotization|diazotized]] followed by treatment with cuprous chloride.<ref>{{cite journal |doi=10.15227/orgsyn.003.0033|title=o-Chlorotoluene and p-Chlorotoluene|journal=Organic Syntheses|year=1923|volume=3|page=33|author=C. S. Marvel and S. M. McElvain}}</ref>  Industrially, the diazonium method is reserved for 3-chlorotoluene. The industrial route to 2- and 4-chlorotoluene entails direct reaction of toluene with chlorine.  The more valuable 4-chlorotoluene is separated from 2-chlorotoluene by distillation.  Distillation cannot be applied to separating 3-chlorotoluene from 4-chlorotoluene.<ref name=Ullmann>{{Ullmann |doi=10.1002/14356007.o06_o03|title=Chlorinated Benzenes and Other Nucleus-Chlorinated Aromatic Hydrocarbons|year=2011|last1= Beck|first1=Uwe|last2=Löser|first2=Eckhard|isbn=978-3527306732}}</ref>

==Uses==
2- and 4-chlorotoluene are precursors to the corresponding [[benzyl chloride]] (ClC<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>Cl), [[benzaldehyde]] (ClC<sub>6</sub>H<sub>4</sub>CHO), and [[benzoyl chloride]] (ClC<sub>6</sub>H<sub>4</sub>C(O)Cl).<ref name=Ullmann/> 2- and 4-chlorotoluenes are converted to [[2-Chlorobenzonitrile|2-chlorobenzonitrile]] and [[4-Chlorobenzonitrile|4-chlorobenzonitrile]], respectively.<ref>{{Ullmann|doi=10.1002/14356007.a17_363|title=Nitriles|year =2000|last1=Pollak|first1=Peter|last2=Romeder|first2=Gérard|last3=Hagedorn|first3=Ferdinand|last4=Gelbke|first4=Heinz-Peter|isbn=3527306730}}</ref>  Chlorotoluenes are precursors to [[dichlorotoluene]]s.

==See also==
*[[Bromotoluene]]
*[[Iodotoluene]]

==References==
{{Reflist}}
* [https://www.cdc.gov/niosh/npg/npgd0135.html CDC - NIOSH Pocket Guide to Chemical Hazards - o-Chlorotoluene]

[[Category:Chlorobenzene derivatives]]
[[Category:Toluenes]]
[[Category:Multiple compounds, tabular]]