methylbenzenes

Methylbenzenes, also known as toluenes, are a group of aromatic hydrocarbon compounds characterized by a benzene ring with one or more methyl groups attached. The simplest methylbenzene is toluene, which has one methyl group. When two methyl groups are attached to the benzene ring, the compounds are called dimethylbenzenes or xylenes. There are three isomers of xylene: ortho-xylene (o-xylene), meta-xylene (m-xylene), and para-xylene (p-xylene), differing in the relative positions of the methyl groups on the ring. Further substitution with methyl groups leads to trimethylbenzenes (e.g., mesitylene) and so on, up to hexamethylbenzene.

These compounds are typically colorless liquids with characteristic odors. They are generally insoluble in water but soluble in organic solvents. Methylbenzenes are flammable and their vapors can form explosive mixtures with air. Their chemical reactivity is primarily related to the aromatic ring and the methyl group. The methyl groups can be oxidized to carboxylic acids, and the aromatic ring can undergo electrophilic substitution reactions.

Methylbenzenes are widely used as solvents in paints, lacquers, and adhesives. Toluene, in particular, is a significant industrial solvent and a precursor in the production of many chemicals, including benzene, phenol, and explosives like TNT. Xylenes are also important solvents and are used in the production of plastics, synthetic fibers, and as components in gasoline.