Toluene is the most abundant and lowest cost aromatic material. This is a reason to be the valuable raw material for the production of various chemical products. Toluene is a colorless organic liquid solvent widely used in the paint, lacquer and resin industries. Toluene can be absorbed through the skin or via inhalation with target sites.
Toluene is very sparingly miscible with water and it is not satisfactorily removed from an air stream by water scrubbing but it can be removed with a high boiling hydrocarbon absorbing oil. Toluene is derived from the fractional distillation of light coal tar oil or the catalytic cracking of petrochemicals. Toluene is also the name given to commercial mixtures.
What is Toluene?Back to Top
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. It is an organic solvent that is used in nail polishes, topcoats and base coats to help the polish stay on the nail.
Toluene is a methyl derivative of benzene. All carbon atoms of benzene are sp2 hybridized while the carbon atom of methyl group is sp3 hybridized bonded with three hydrogen atoms and one aromatic carbon atom. The carbon-carbon bond length is almost similar like in benzene; hence an intermediate value of single and double bond and carbon-hydrogen bond length is 1.1 A degree.
Nitration of TolueneBack to Top
Toluene is insoluble in water but is a useful organic solvent. It is used in paint, paint thinner, shellacs, varnishes, dyes and links. It is a common component of cosmetics, nail polish, stain removes, and glues. A small amount of toluene occurs in cigarette smoke. In recent years toluene has replaced benzene in a number of products because of benzene carcinogenic properties.
Toluene forms ortho-toluene & para-toluene and reaction is called as nitration of toluene. Reaction follows electrophilic substitution mechanism and mixture of concentrated sulfuric and nitric acids acts as nitrating agent. Here concentrated sulfuric acid acts as catalyst and generates nitronium ion which acts as electrophile.
Due to the presence of methyl group on aromatic ring in toluene, the nitration of toluene is around twenty five times faster than benzene. As the methyl group is an activating and ortho, para-directing group, therefore the nitration of toluene gives poly substituted nitro-products. However the use of low temperature can prevent the substitution of more than one nitro group on aromatic ring.
Toluene UsesBack to Top
- Toluene is used for the improvement of octan rating and in the production of benzene.
- It is used as a solvent in coatings, adhesives, inks, paints, synthetic fragrances, and cleaning agents.
- Toluene is used for the manufacturing of plastic soda bottles, cosmetic nail products, nylon, and polyurethanes and for pharmaceuticals and dyes.
- For the synthesis of organic chemicals like benzoic acid, benzaldehyde, benzyl chloride, saccharin, benzal chloride, benzyl alcohol etc.
- It is used in the manufacturing of trinitrotoluene (TNT).
- It mainly used for the manufacturing of certain dyes and drugs.
- Toluene is used as to make spray and wall paints, aviation gasoline, rubber, paint thinner, detergents, fingernail polish, lacquers, spot removers, adhesives and antifreeze.
- Toluene also acts as an industrial solvent and used in dry cleaning, as a petrol substitute.
- It is also used in leather tanning processes and in some printing processes.
- Toluene acts as a precursor for many petrochemicals such as urethane foam, phenol formaldehyde, downstream petrochemicals and pesticides.