Nitrobenzene

PROPERTIES

Nitrobenzene is a colourless to pale yellow, oily, highly toxic liquid with a bitter almond-like odor. It freezes to give greenish-yellow crystals. Nitrobenzene is moderately soluble in water and soluble in acetone, benzene, diethyl ether, and ethanol. Stable under normal laboratory conditions. Flammable following moderate heating. Incompatible with strong oxidizing agents, strong reducing agents, strong bases.

APPLICATIONS

SOLVENT

Nitrobenzene is used as a solvent in the manufacture of cellulose ethers and in refining lubricating oils. In the laboratory, it is occasionally used especially for electrophilic reagents. This chemical is applied in Friedel-Crafts reactions to hold the catalyst in solution. It dissolves anhydrous aluminium chloride as a result of the formation of a complex.

MANUFACTURE OF ANILINE (approx. 95% of nitrobenzene use)

Nitrobenzene is a precursor to aniline. It is heated with iron and dilute hydrochloric acid, and the resulting anilinium chloride is treated with sodium carbonate to release aniline.

Aniline is commercially the most important amine which is a chemical intermediate used during the manufacture of polyurethane foams, plastics and rubbers, dyes, agrochemicals and petrol additives.

DYES

Nitrobenzene is an intermediate in the production of dyes such as nigrosines and magenta.

PHARMA

Nitrobenzene is used in the production of the analgesic paracetamol (also known as acetaminophen).

COSMETICS

Redistilled, as oil of mirbane, nitrobenzene has been used as an inexpensive perfume for soaps and cosmetics as a flavouring known as ‘artificial oil of bitter almonds’ due to its strong odour. Now it is considered too toxic for such applications.

Other uses:

Precursor to explosive.

Usage in shoe and floor polishes, leather dressings, paint solvents, and other materials to mask unpleasant odors.

Manufacture of benzidine, quinoline, azobenzene, pyroxylin compounds, isocyanates, dinitrobenzenes and dichloroanilines.

It is used in Kerr cells, as it exhibits unusually large Kerr constant.

Notes:

Nitrobenzene has been classified by the International Agency for Research on Cancer as possibly causing cancer in humans.