Toluene, also known as toluol, is an aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group. As such, its systematic IUPAC name is methylbenzene. It is also used in the production of TNT (trinitro toluene). Obtaining toluene from furnace gas, which is the main (primary) source of toluene production, has been replaced by catalytic decomposition of kerosene and vapor separation (distillation) to obtain liquid (raw) materials from pyrolysis gasoline.

Pyrolysis gasoline is obtained from the separation of liquid hydrocarbons (such as kerosene and petroleum) by means of vapor separation. This method is preferred increasingly. In order to obtain toluene, these separated liquid hydrocarbons, as they are not stable, must be hydrogenated before the aromatics can be extracted. An aromatic rich hydrocarbon mixture is applied to catalytic dehydrogenation between 17 and 21 bar pressure and at a temperature of 530 °C, to produce toluene via catalytic degradation.

After the removal of light (easily volatile) hydrocarbon gases via fraction, an even richer distillate in terms of aromaticity is obtained.

Areas of Usage

Toluene is a common solvent, e.g. for paints, paint thinners, many chemical reactants. Toluene is mainly used as a procursor to benzene and xylene. It is used in the production of plastic (rubber), ink, disinfectants. It can be used as Fullerene indicator. Toluene reacts with potassium permanganate to yield benzoic acid, and with chromyl chloride to yield benzaldehyde. It is an important source of carbon. Toluene can be used to break open red blood cells in order to extract hemoglobin in biochemistry experiments. Toluene can be used as an octane booster in gasoline fuels. It is the main ingredient of the explosive typically abbreviated TNT.


CAS number108-88-3
RTECS numberXS5250000
Chemical formulaC7H8
Molecular mass92,14 g mol−1
AppearanceColorless liquid
OdorSweet, pungent, similar to benzene
Density0.87 g/mL (20 °C)
Melting point−95 °C
Boiling point111 °C
Water solubility0.52 g/L (20 °C)
Vapor pressure21 mmHg (20°C)