Dichlorotoluenes are

organochlorine compounds Organochlorine chemistry is concerned with the properties of organochlorine compounds, or organochlorides, organic compounds that contain one or more carbon–chlorine bonds. The chloroalkane class (alkanes with one or more hydrogens substituted b ...

, in particular

aryl chloride In organic chemistry, an aryl halide (also known as a haloarene) is an aromatic compound in which one or more hydrogen atoms directly bonded to an aromatic ring are replaced by a halide ion (such as fluorine F''−'', chlorine Cl−1,−3,−5, bro ...

s, with the formula . Six

constitutional isomer In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a compound is a compound that contains the same number and type of atoms, but with a different connectivity (i.e. arrangement of bonds) between them. The ...

s exist, differing in the relative position of the two chlorine

substituent In organic chemistry, a substituent is one or a group of atoms that replaces (one or more) atoms, thereby becoming a moiety in the resultant (new) molecule. The suffix ''-yl'' is used when naming organic compounds that contain a single bond r ...

s around the ring. They are all colorless and lipophilic. The 3,5 isomer is a solid at room temperature, whereas the others are liquids.

Preparation and uses

Several dichlorotoluenes are prepared by treatment of toluene or mono

chlorotoluene Chlorotoluenes are aryl chlorides based on toluene in which at least one aromatic hydrogen atom is replaced with a chlorine atom. They have the general formula C7H8–''n''Cl''n'', where ''n'' = 1–5 is the number of chlorine atoms. Monochlorotol ...

s with chlorine in the presence of various

Lewis acid A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any ...

s. Purification is challenging because the individual isomers have similar properties. The 2,6 and 3,5 isomers do not form acceptably from toluene or chlorotoluenes, so these isomers are prepared by indirect methods. For example, 2,6-dichlorotoluene can be prepared by chlorination of

4-toluenesulfonyl chloride 4-Toluenesulfonyl chloride (''p''-toluenesulfonyl chloride, toluene-''p''-sulfonyl chloride) is an organic compound with the formula CH3C6H4SO2Cl. This white, malodorous solid is a reagent widely used in organic synthesis. Abbreviated TsCl or To ...

followed by

desulfonation In organic chemistry, the desulfonation reaction is the hydrolysis of sulfonic acids: :RC6H4SO3H + H2O → RC6H5 + H2SO4 The reaction applied to aryl and naphthylsulfonic acids. It is the reverse of sulfonation.Otto Lindner, Lars Rodefeld "Benze ...

. Some dichlorotoluenes are precursors to commercial pesticides. 2,4-Dichlorotoluene is the precursor to pyrifenox,

butafenacil Butafenacil is the International Organization for Standardization, ISO trivial name, common name for an organic compound of the pyrimidinedione chemical class used as an herbicide. It acts by enzyme inhibitor, inhibiting the enzyme protoporphyrino ...

, and the

pyrazole Pyrazole is an organic compound with the chemical formula, formula . It is a heterocycle characterized as an azole with a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in Arene substitution pattern, ortho-substi ...

derivatives pyrazoxyfen and pyrazolynate. The 2,6 isomer is a precursor to

dichlobenil 2,6-Dichlorobenzonitrile (DCBN or dichlobenil) is an organic compound with the chemical formula C6H3Cl2CN. It is a white solid soluble in organic solvents. It is widely used as a herbicide and organic chemistry building block.Franz Müller and A ...

(2,6-dichloro

benzonitrile Benzonitrile is the chemical compound with the formula , abbreviated PhCN. This aromatic organic compound is a colorless liquid with a cherry or almond like odour. It is mainly used industrially to produce the melamine resin precursor benzoguanam ...

). 3,5-Dichlorotoluene is used to prepare propyzamide.

Related compounds

Benzal chloride Benzal chloride is an organic compound with the formula C6H5CHCl2. This colourless liquid is a lachrymator and is used as a building block in organic synthesis. Preparation and usage Benzal chloride is produced by the free radical chlorination ...

(α,α-dichlorotoluene) *

Trichlorotoluene Trichlorotoluenes are organochlorine compounds, in particular aryl chlorides, with the formula . Six constitutional isomers exist, differing in the relative position of the three chlorine substituents around the ring. All isomers colorless and li ...

References

{{Reflist Toluenes Chlorobenzene derivatives Multiple compounds, tabular