What Is Nitrobenzene?
Nitrobenzene, an aromatic nitro compound with the chemical formula C6H5NO2, is also known as nitrobenzole. It is a pale yellow liquid with an almond-like aroma, a melting point of 5.7°C, a boiling point of 210.8°C, and a specific gravity of 1.20. Soluble in organic solvents but insoluble in water, nitrobenzene is classified as a deleterious substance under various laws and regulations.
Formation of Nitrobenzene
Nitrobenzene is synthesized through nitration, reacting benzene with a mixed acid of concentrated sulfuric and nitric acids. This exothermic reaction produces nitronium ions (NO2+), which react with benzene to form nitrobenzene, and are considered highly hazardous.
Reaction of Nitrobenzene
Nitrobenzene undergoes further nitration to form meta-dinitrobenzene and can be reduced to aniline. It participates in the Skraup quinoline synthesis, reacting with glycerin, aniline, and sulfuric acid to form quinoline.
Uses of Nitrobenzene
Nitrobenzene is used as a synthetic intermediate in pharmaceuticals, agrochemicals, dyes, fragrances, and rubber production. It is a precursor to aniline, azoxybenzene, azobenzene, and hydrazobenzene, and is used as a polar solvent and mild oxidizing agent.
Effects on Living Organisms
While not highly toxic, nitrobenzene is harmful and can cause nervous system, liver damage, and anemia upon exposure. Symptoms from prolonged occupational exposure include headache, nausea, dizziness, limb numbness, cyanosis, hypotension, splenomegaly, hepatomegaly, jaundice, and methemoglobinemia.