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Jai Ganesh

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Toluene

Toluene

Gist

Toluene is a clear, colorless liquid with a sweet odor. It is obtained from crude petroleum and is highly flammable. Toluene is used in a variety of industries and is a common solvent for products such as paints, thinners, and glues. It is found in small amounts in gasoline.

Toluene is a good solvent (a substance that can dissolve other substances). It is used in making paints, paint thinners, fingernail polish, lacquers, adhesives, and rubber and in some printing and leather tanning processes. Toluene is also used in the manufacture of other chemicals, nylon, and plastics.

Pure toluene (melting point, -95° C [-139° F]; boiling point, 110.6° C [231.1° F]) is a colourless, flammable, toxic liquid, insoluble in water but soluble in all common organic solvents. Its chemical formula is that of methylbenzene, C6H5CH3.1

Summary:

What is toluene?

Toluene is a clear, colorless liquid with a distinctive smell. It occurs naturally in crude oil and in the tolú tree. Toluene is produced in the process of making gasoline and other fuels from crude oil and in making coke from coal.

Toluene is a good solvent (a substance that can dissolve other substances). It is used in making paints, paint thinners, fingernail polish, lacquers, adhesives, and rubber and in some printing and leather tanning processes. Toluene is also used in the manufacture of other chemicals, nylon, and plastics. It is also added to gasoline along with benzene and xylene to improve octane ratings.

What happens to toluene in the environment?

Toluene can enter the air from car exhaust or when materials that contain it (such as paints or fingernail polish) are used. It can get into surface waters (like lakes and streams), groundwater, or soil if solvents or petroleum products are accidently spilled, or from leaking underground storage tanks at gasoline stations and other facilities. When toluene-containing products are placed in landfills or waste disposal sites, toluene can enter the soil or water near the waste site.

Toluene does not usually stay in the environment long. In surface water or soil, it will readily evaporate into the air or be degraded by bacteria. In the air, toluene rapidly breaks down by reacting with other chemicals or oxygen in the air. Below the surface, microorganisms will break down toluene.

How can I be exposed to toluene?

You may be exposed to toluene by breathing contaminated air or touching products that contain this chemical. Car exhaust contains toluene; therefore, if you spend time in or near vehicles or traffic, you may be exposed to this chemical. People who work with gasoline, paint, or dyes may be exposed to higher levels of toluene than most people.

Toluene is not frequently detected in drinking water or food. People that abuse (inhale) certain products such as glue or paint thinner can be exposed to toluene.

Details

Appearance  :  Colorless liquid
Odor  :  sweet, pungent, benzene-like
Density  :  0.8623 g/mL (25 °C)
Melting point  :  -95.0 °C (-139.0 °F; 178.2 K)
Boiling point  :  110.60 °C (231.08 °F; 383.75 K).

Toluene, also known as toluol, is a substituted aromatic hydrocarbon with the chemical formula C6H5CH3, often abbreviated as PhCH3, where Ph stands for the phenyl group. It is a colorless, water-insoluble liquid with the odor associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group by a single bond. As such, its systematic IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent.

As the solvent in some types of paint thinner, permanent markers, contact cement and certain types of glue, toluene is sometimes used as a recreational inhalant and has the potential of causing severe neurological harm.

History

The compound was first isolated in 1837 through a distillation of pine oil by Pierre Joseph Pelletier and Filip Neriusz Walter, who named it rétinnaphte. In 1841, Henri Étienne Sainte-Claire Deville isolated a hydrocarbon from balsam of Tolu (an aromatic extract from the tropical Colombian tree Myroxylon balsamum), which Deville recognized as similar to Walter's rétinnaphte and to benzene; hence he called the new hydrocarbon benzoène. In 1843, Jöns Jacob Berzelius recommended the name toluin. In 1850, French chemist Auguste Cahours isolated from a distillate of wood a hydrocarbon which he recognized as similar to Deville's benzoène and which Cahours named toluène.

Production

Toluene occurs naturally at low levels in crude oil and is a byproduct in the production of gasoline by a catalytic reformer or ethylene cracker. It is also a byproduct of the production of coke from coal. Final separation and purification is done by any of the distillation or solvent extraction processes used for BTX aromatics (benzene, toluene, and xylene isomers).

Uses

Toluene is one of the most abundantly produced chemicals. Its main uses are (1) as a precursor to benzene and xylenes, (2) as a solvent for thinners, paints, lacquers, adhesives, and (3) as an additive for gasoline.

Additional Information

Toluene is an aromatic hydrocarbon used extensively as starting material for the manufacture of industrial chemicals. It comprises 15–20 percent of coal-tar light oil and is a minor constituent of petroleum. Both sources provide toluene for commercial use, but larger amounts are made by catalytic reforming of petroleum naphtha. The compound is used in the synthesis of trinitrotoluene (TNT), benzoic acid, saccharin, dyes, photographic chemicals, and pharmaceuticals. It is also used as a solvent and antiknock additive for aviation gasoline. Pure toluene (melting point, -95° C [-139° F]; boiling point, 110.6° C [231.1° F]) is a colourless, flammable, toxic liquid, insoluble in water but soluble in all common organic solvents. Its chemical formula is that of methylbenzene, C6H5CH3.

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