What Is Nitrobenzene?
Nitrobenzene is an aromatic nitro compound with the chemical formula C6H4NO2, also called nitrobenzole. It has a melting point of 5.7°C, a boiling point of 210.8°C, a specific gravity of 1.20 (at 20°C), a pale yellow color, and an almond aromatic odor. It is soluble in organic solvents and insoluble in water. It is designated as a deleterious substance under the Poisonous and Deleterious Substances Control Law.
Formation of Nitrobenzene
Nitrobenzene can be synthesized by reacting benzene with a mixed acid adjusted by concentrated sulfuric acid and concentrated nitric acid, which is called nitration. In the reaction stage, nitronium ions (NO2+) are first produced by the mixed acid as active species, which react with benzene to synthesize nitrobenzene. This reaction is accompanied by a large exothermic reaction and is one of the most dangerous chemical reactions.
Reaction of Nitrobenzene
Nitrobenzene are further nitrated by concentrated sulfuric acid and fuming nitric acid to form meta-dinitrobenzene (1,3-dinitrobenzene). Nitrobenzene are also reduced in acidic conditions to aniline. As an example of application, there is a reaction that produces quinoline from nitrobenzene, glycerin, aniline, and sulfuric acid, which is called the Skraup quinoline synthesis.
Uses of Nitrobenzene
The main uses of this substance are as a synthetic intermediate (aniline, benzidine, quinoline, azo dye) in pharmaceuticals, agrochemicals, dyes, fragrances, and rubber. Reduction in acidic and neutral conditions yields aniline, while reduction in alkaline conditions yields azoxybenzene, azobenzene, and then hydrazobenzene. It is also a raw material for gas (adam site). It is sometimes used as a polar solvent and sometimes as a mild oxidizing agent.
Effects on Living Organisms
Although not highly toxic, both liquid and vapor are toxic and can be absorbed through the skin, causing nervous system and liver damage and anemia. 17 months of occupational exposure to the substance has resulted in headache, nausea, dizziness, weakness, numbness in the legs, hyperalgesia of the limbs, cyanosis, hypotension, splenomegaly, hepatomegaly, jaundice, and other symptoms. Effects on the nerves and liver such as swelling of the spleen, liver swelling and tenderness, jaundice, and methemoglobinemia have been reported as a result of exposure to this substance.