Toluene (also known as methylbenzene) is a colorless, volatile, and flammable aromatic hydrocarbon with a sweet odor. It is widely used as a solvent in various industrial applications, including in paint thinners, adhesives, and coatings. Toluene has the chemical formula C₆H₅CH₃ and is composed of a benzene ring with a single methyl group (CH₃) attached.
Toluene is commonly found in petroleum and coal tar and is often used in the production of other chemicals. Although it has a wide range of uses, care must be taken when handling toluene, as it can be harmful if inhaled or ingested in large quantities.
Properties:
- Molecular Formula: C₆H₅CH₃
- IUPAC Name: Methylbenzene
- Boiling Point: 110.6°C (231.1°F)
- Melting Point: -95°C (-139°F)
- Density: 0.8669 g/cm³ at 20°C
- Flash Point: 4°C (39°F) – highly flammable
- Solubility: Slightly soluble in water (0.5 g/100 mL), but very soluble in organic solvents like ether, alcohol, and chloroform.
Key Uses of Toluene:
Solvent:
Toluene is widely used as a solvent in various products like paints, coatings, lacquers, adhesives, and varnishes due to its ability to dissolve resins, oils, and fats. It is also used as a cleaning agent and degreaser in industrial applications, particularly in the automotive and electronics sectors.
Chemical Intermediate:
- Benzene: Toluene is a key precursor in the production of benzene via toluene disproportionation or hydrogenation.
- Xylene: It is also used to produce xylene (through alkylation or methylation processes).
- Toluene diisocyanate (TDI): A major industrial chemical used in the production of polyurethanes, which are used in foams, paints, and coatings.
Fuel Additive:
Toluene is used as an octane booster in gasoline, improving the performance of fuel and increasing the octane rating for higher efficiency and smoother combustion.
Production of Chemicals:
Toluene is used to manufacture toluene sulfonic acid, an important chemical in detergent and surfactant production. It is also used in the production of alkylated aromatics, such as ethylbenzene, which is further used to make styrene.
Explosives:
Toluene is a key ingredient in the production of Trinitrotoluene (TNT), a widely known explosive.
Pharmaceuticals:
Toluene is used as a solvent in pharmaceutical formulations for drugs like antiseptics, analgesics, and topical ointments.