Toluene

toluene (tōl`yēn') or methylbenzene (mĕth'əlbĕn`zēn), 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.

---

toluene

Colourless, flammable, toxic liquid hydrocarbon aromatic compound (C₆H₅CH₃), the methyl derivative of benzene. Found in coal-tar light oil and in petroleum, it is obtained chiefly from the processing of petroleum fractions. It is used as a solvent, diluent, and thinner; as an antiknock additive in airplane gasoline; and as a raw material for TNT, benzoic acid and its derivatives, saccharin, dyes, photographic chemicals, and pharmaceuticals.

---

toluene

a colourless volatile flammable liquid with an odour resembling that of benzene, obtained from petroleum and coal tar and used as a solvent and in the manufacture of many organic chemicals. Formula: C₆H₅CH₃

---

toluene [′täl·yə‚wēn]

(organic chemistry)

C₆H₅CH₃A colorless, aromatic liquid derived from coal tar or from the catalytic reforming of petroleum naphthas; insoluble in water, soluble in alcohol and ether, boils at 111°C; used as a chemical intermediate, for explosives, and in high-octane gasolines. Also known as methylbenzene; phenylmethane; toluol.

---

Toluene 

(or methylbenzene), a colorless, flammable liquid with an odor similar to that of benzene. Melting point, –95°C; boiling point, 110.6°C; density, 0.8669 g/cm³ at 20°C.

Toluene forms explosive mixtures with air in proportions of 1.27–7.0 percent by volume. Its ignition temperature is 552°C, and its flash point is 4.4°C. Toluene is miscible with most organic solvents; at 22°C, 0.492 g of toluene dissolves in 1 kg of water, and 0.526 g of water dissolves in 1 kg of toluene.

Toluene is a component of certain petroleums. In industry, it is isolated mainly from coal tars and the products of the thermal conversion of petroleum fractions. Toluene is an important chemical raw material. It is characterized by reactions of electro-philic substitution in the aromatic ring and transformations of the methyl group, with retention of the ring. Electrophilic substitution occurs more readily than in benzene and is directed mainly at the para (4-) and ortho (2,6-) positions. Thus, the nitration of toluene using a mixture of nitric and sulfuric acids yields, in sequence, the mononitro and dinitro derivatives and then 2,4,6-trinitrotoluene (TNT). Transformations of the methyl group occur through a radical mechanism. For example, chlorination under ultraviolet irradiation and with heating leads to benzyl chloride, C₆H₅CH₂C1, benzal chloride, C₆H₅CHC1₂, and trichloromethylbenzene, C₆H₅CC1₃. Nitration with a solution of HNO₃ in acetic acid yields α-nitrotoluene, C₆H₅CH₂NO₂, and oxidation yields benzyl alcohol, C₆H₅CH₂OH, benzaldehyde, C₆H₅CHO, and benzoic acid, C₆H₅COOH.

Toluene is used in the manufacture of dyes, explosives, pharmaceuticals, and various intermediates. It is also used as a solvent in the production of plastics, paints, varnishes, and printing inks, as well as in the rubber industry.

Toluene is less toxic than benzene. The maximum permissible concentration of toluene vapor in the air is 0.05 mg per liter.

B. L. DIATKIN