TOULENE                                                                                      

Chemical Formula : C6H5CH3                CAS Registry Number 108-88-3

Toluene, also known as methylbenzene, or Toluol, is a clear water-insoluble liquid with the typical smell of paint thinners. Chemically it is mono-substituted benzene derivative (benzene derivative in which one hydrogen atom from the benzene molecule has been replaced by a univalent group; in this case CH3).It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent. Like other solvents, toluene is also used as an inhalant drug for its intoxicating properties; however, this causes severe neurological harm.

In the industry, hexanes are used in the formulation of glues for shoes, leather products, and roofing. They are also used to extract cooking oils from seeds, for cleansing and degreasing all sorts of items, and in textile manufacturing.A typical laboratory use of hexanes to extract oil and grease contaminants from water and soil for analysis.  Since hexane cannot be deprotonated, it is used in the laboratory for reactions that involve very strong bases, such as the preparation of Grignard reagents.

Toluene reacts as a normal aromatic hydrocarbon towards electrophilic aromatic substitution. The methyl group makes it around 25 times more reactive than benzene in such reactions. It undergoes smooth sulfonation to give p-toluenesulfonic acid, and chlorination by Cl2 in the presence of FeCl3 to give ortho and para isomers of chlorotoluene. It undergoes nitration to give ortho and para nitrotoluene isomers, but if heated it can give dinitrotoluene and ultimately the explosive trinitrotoluene (TNT).		Application   Currently, three grades of toluene purity are available in the market: TDI, nitration, and commercial. TDI grade toluene is used to make isocyanates, which are combined with polyols in the manufacture of polyurethanes. In turn, polyurethanes are used in a wide variety of consumer goods, such as foams for furniture and bedding, coatings for floors and furniture, artificial sports tracks, ski suits and waterproof leisure wear. Nitration grade toluene is widely used in the solvent market and also in the production of phenol, particularly in Europe. Both nitration and commercial grades are used as feed in the hydrodealkylation process, which strips off the methyl group from toluene to make benzene. These grades are also used in the disproportionation process, which removes the methyl group from one toluene molecule and attaches it to another, resulting in one benzene and one xylene molecule. Toluene is produced in very large quantities, most of which is never removed from the gasoline manufacturing streams. Most commercial grade toluene is returned to the gasoline pool as a blend component resulting in higher-octane grades.

PDF VERSION