C18H12N2

C18H12N2 is the molecular formula for several organic compounds, most notably **benzidine**, a well-known aromatic amine. Benzidine is a symmetrical diamine with two amino groups (−NH2) attached to opposite carbons of a biphenyl structure, consisting of two benzene rings connected by a single bond. It was historically significant in the dye industry, particularly for producing azo dyes, which are widely used in textiles and pigments.

The structure of benzidine consists of two benzene rings linked at the 4 and 4' positions, with amino groups at the 3 and 3' positions, giving it the IUPAC name 4,4'-diaminobiphenyl. Due to its carcinogenic properties, benzidine and its derivatives have been restricted in many industrial applications, particularly in the production of dyes and pigments, following extensive research linking it to cancer in humans.

Another compound with the same molecular formula is **4,4'-diaminodiphenylmethane**, commonly known as **MDA** or **4,4'-methylenebis(2-chloroaniline)**, though its exact formula varies slightly depending on substituents. However, the most widely recognized compound with the formula C18H12N2 is benzidine itself.

Benzidine was first synthesized in 1863 by German chemist Carl Graebe and has since been studied extensively for its chemical reactivity and toxicological effects. Its synthesis typically involves the reduction of nitro groups in nitrobenzene derivatives or through the coupling of aniline derivatives. Due to its hazardous nature, benzidine is now largely replaced by safer alternatives in industrial processes.