O-Xylene


o-Xylene is an aromatic hydrocarbon with the formula C6H42. 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.

Production and use

contains about one weight percent xylenes. Most o-xylene is produced by cracking petroleum, which affords a distribution of aromatic compounds, including xylene isomers. m-Xylene is isomerized to o-xylene. Net production was approximately 500,000 tons in the year 2000.
o-Xylene is largely used in the production of phthalic anhydride, which is a precursor to many materials, drugs, and other chemicals.

Toxicity and exposure

Xylenes are not acutely toxic, for example the is 4300 mg/kg. Effects vary with animal and xylene isomer. Concerns with xylenes focus on narcotic effects.