Xylene, whose chemical formula is C8H10, is the product of the substitution of two hydrogens on the benzene ring by methyl. There are three isomers, namely, o-xylene (CAS number 95-47-6), m-xylene (CAS number 108-38-3) and p-xylene (CAS number 106-42-3). In industry, xylene refers to a mixture of these isomers.

Colorless and transparent liquid. It has a special smell of aromatic hydrocarbons. It is a mixture of 45% ~ 70% m-xylene, 15% ~ 25% p-xylene and 10% ~ 15% o-xylene isomers. It is easy to flow and can be miscible with anhydrous ethanol, ether and many other organic solvents.

Xylene has pungent smell, flammable, and ethanol, chloroform or ether can be mixed arbitrarily, insoluble in water. The boiling point is 137 ~ 140℃. The U.S. Conference of Governmental Industrial Hygienists (ACGIH) classifies xylene as a low-toxic chemical that lacks evidence of carcinogenicity in humans and animals. Plastics, fuel, rubber, additives of various coatings and various adhesives, waterproof materials, but also from fuel and tobacco combustion gas.

Xylene is widely used in coating, resin, dye, ink and other industries to do solvent; Used in medicine, explosives, pesticides and other industries to do synthetic monomer or solvent; It can also be used as high octane gasoline component, which is an important raw material of organic chemical industry. It can also be used to remove asphalt from the car body. Hospital pathology department is mainly used for tissue and section transparency and dewaxing.