Chlorotoluene is a group of three
isomeric chemical compounds. They (''ortho''-chlorotoluene, ''meta''-chlorotoluene, and ''para''-chlorotoluene) consist of a disubstituted
benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...
ring with one chlorine atom and one
methyl group
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ma ...
.
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.
Benzyl chloride is an isomer, which has a chlorine substituted for one of the hydrogens of
toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) a ...
'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
There are three isomers of toluidine, which are organic compounds. These isomers are ''o''-toluidine, ''m''-toluidine, and ''p''-toluidine, with the prefixed letter abbreviating, respectively, ''ortho''; ''meta''; and ''para''. All three are ary ...
s (i.e. 2- and 4-aminotoluene). These compounds are
diazotiized followed by treatment with cuprous chloride. 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.
Uses
2- and 4-Chlorotoluene are precursors to the corresponding
benzyl chloride (ClC
6H
4CH
2Cl),
benzaldehyde (ClC
6H
4CHO), and
benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula . It is a colourless, fuming liquid with an irritating odour, and consists of a benzene ring () with an acyl chloride () substituent. It is ...
(ClC
6H
4C(O)Cl). 2- and 4-Chlorotoluenes are converted to
2-chlorobenzonitrile
2-Chlorobenzonitrile is an organic compound with the formula ClC6H4CN. It is a white solid. The compound, one of three isomers of chlorobenzonitrile, is produced industrially by ammoxidation
In organic chemistry, ammoxidation is a process for ...
and
4-chlorobenzonitrile
4-Chlorobenzonitrile is an organic compound with the formula ClC6H4CN. It is a white solid. The compound, one of three isomers of chlorobenzonitrile, is produced industrially by ammoxidation of 4-chlorotoluene. The compound is of commercial int ...
, respectively.
References
{{Reflist
CDC - NIOSH Pocket Guide to Chemical Hazards - o-Chlorotoluene
Chlorobenzenes
Alkyl-substituted benzenes
Multiple compounds, tabular