O-Xylene is an aromatic hydrocarbon with the formula C6H4(CH3)2 with two methyl substituents bonded to adjacent carbon atoms of a benzene ring. It is a constitutional isomer of m-xylene and p-xylene, the mixture being called xylene or xylenes. o-Xylene is a colorless slightly oily flammable liquid.
A known method of producing orthoxylene by isolating it from a mixture of xylene and ethylbenzene isomers. Technical feed xylene, extracted from catalytic reforming distillate by extractive azeotropic distillation
Ortho-xylene is employed mostly to supply phthalic anhydride, a crucial intermediate that leads principally to varied coatings and plastics. The least valued of the isomers is meta-xylene, but it has uses in the manufacture of coatings and plastics.