Production and uses-
1,2-Dichlorobenzene is obtained as a side-product of the production of chlorobenzene:
5Cl + Cl
2 → C
2 + HCl
The reaction also affords the 1,4- and small amounts of the 1,3-isomer. The 1,4- isomer is preferred over the 1,2- isomer due to steric hindrance. The 1,3- isomer is uncommon because it is a meta- compound, while chlorine, like all halogens, is a ortho/para- directors in terms of electrophilic aromatic substitution.
It is mainly used as a precursor to 1