toluene (tōlˈyōēnˌ) [key] or methylbenzene mĕthˌəlbĕnˈzēn, C7H8, colorless liquid aromatic hydrocarbon that melts at - 95°C and boils at 110.8°C. It is insoluble in water but highly soluble in most organic solvents. Toluene is obtained from coal tar and petroleum by distillation. It is used as a solvent and as a starting material for the synthesis of many compounds, including dyes and explosives. When toluene is treated with a mixture of nitric and sulfuric acids (a process known as nitration), trinitrotoluene (TNT) is produced.