pDinitrobenzene

1,4-Dinitrobenzene, commonly known as para-dinitrobenzene (p-dinitrobenzene), is an aromatic nitro compound with the formula C6H4(NO2)2. It is one of three dinitrobenzene isomers and is distinguished by two nitro groups positioned para to each other on a benzene ring. The molecule is symmetrical, with duplicative substituents across the ring.

Physically, it appears as a colorless to pale yellow crystalline solid. It is sparingly soluble in water and more soluble in many organic solvents such as ether and acetone. It is relatively stable under ordinary conditions but can be sensitive to heat or friction, as with many nitro compounds.

Industrial production and uses: p-Dinitrobenzene is typically produced by nitration of benzene-containing feedstocks with a mixture of nitric and sulfuric acids, followed by separation of the para isomer. It can also be formed via selective transformations of related intermediates. A primary use is as a precursor to p-phenylenediamine, which is obtained by reduction.

Applications follow from that precursor role: p-phenylenediamine is a key building block for azo dyes and various polymers, including certain polyurethanes. As such, p-dinitrobenzene occupies a place in the dye, pigment, and specialty chemical industries, where it provides a route to colorful compounds and functional materials through established coupling and polymerization reactions.

Safety: p-Dinitrobenzene is an irritant and toxic if inhaled or swallowed. It may cause skin sensitization and other adverse health effects; handling should use appropriate personal protective equipment and procedures. It should be stored away from reducing agents and heat, and spills must be managed as hazardous waste according to local regulations.