M-Xylene
m-Xylene is an aromatic hydrocarbon. It is one of the three isomers of dimethylbenzene known collectively as xylenes. The m- stands for meta-, indicating that the two methyl groups in m-xylene occupy positions 1 and 3 on a benzene ring. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and p-xylene. All have the same chemical formula C6H42. All xylene isomers are colorless and highly flammable.contains about 1 weight percent xylenes.
The major use of meta-xylene is in the production of isophthalic acid, which is used as a copolymerizing monomer to alter the properties of polyethylene terephthalate. The conversion m-xylene to isophthalic acid entails catalytic oxidation. meta-Xylene is also used as a raw material in the manufacture of 2,4- and 2,6-xylidine as well as a range of smaller-volume chemicals. Ammoxidation gives isophthalonitrile.Xylenes are not acutely toxic, for example the LD50 is 4300 mg/kg. Effects vary with animal and xylene isomer. Concerns with xylenes focus on narcotic effects.
