Xylene
The term xylenes refers to a group of 3 benzene derivatives which encompasses ortho-, meta-, and para- isomers of dimethyl benzene. The o-, m- and p- isomers specify to which carbon atoms (of the main benzene ring) are the 2 methyl groups attached. Counting the carbon atoms from any arbitrary point, and C1 being to the right of C2, and C2 being to the right to C3, and so on, the o- isomer has the IUPAC name of 1,2-dimethylbenzene. The m- isomer has the IUPAC name of 1,3-dimethylbenzene. And p- isomer has the IUPAC name of 1,4-dimethylbenzene.
It is a colorless, sweet-smelling liquid that catches on fire easily. It occurs naturally in petroleum and coal tar and is formed during forest fires. You can smell xylene in air at 0.08 to 3.7 parts of xylene per million parts of air (ppm) and begin to taste it in water at 0.53 to 1.8 ppm.
Chemical industries produce xylene from petroleum. It's one of the top 30 chemicals produced in the United States in terms of volume. Xylene is used as a solvent and in the printing, rubber, and leather industries. p-Xylene is used as a feedstock in the production of terephthalic acid, which in turn is a monomer used in the production of polymers. It is also used as a cleaning agent, a thinner for paint, and in paints and varnishes. It is found in small amounts in airplane fuel and gasoline.
Structure
Background: Hydrocarbons can be divided into two main groups, aliphatics and aromatics. Aliphatics are furthur subdivided into alkanes, alkenes, alkynes and brain. High levels from exposure for short periods (14 days or less) or long periods (more than 1 year) can cause headaches, lack of muscle coordination, dizziness, confusion, and changes in ones sense of balance. Exposure of people to high levels of xylene for short periods can also cause irritation of the skin, eyes, nose, and throat; difficulty in breathing; problems with the lungs; delayed reaction time; memory difficulties; stomach discomfort; and possibly changes in the liver and kidneys. It can cause unconsciousness and even death at very high levels.
Studies of unborn animals indicate that high concentrations of xylene may cause increased numbers of deaths, and delayed growth and development. In many instances, these same concentrations also cause damage to the mothers. We do not know if xylene harms the unborn child if the mother is exposed to low levels of xylene during pregnancy.
