What does diamine mean?
A diamine is an organic chemical compound characterised by the presence of two amino groups (—NH2) within its molecular structure. The term belongs to the vocabulary of chemistry rather than everyday speech, and it covers a wide range of substances: simple aliphatic examples such as ethylenediamine and putrescine sit alongside aromatic varieties like phenylenediamine. Diamines matter chiefly because their paired reactive groups allow them to link with other molecules into long chains, making them essential raw materials in polymer science — most famously in the manufacture of nylon, where hexamethylenediamine combines with adipic acid to form polyamide fibres. Some diamines also have biological significance: they arise naturally from the decay of proteins and play roles in cellular chemistry. The word is formed from the prefix 'di-', meaning 'two', combined with 'amine', the class of nitrogen-bearing compounds to which it belongs. For readers outside the laboratory, encountering 'diamine' usually signals a text about plastics, textiles, or biochemistry, where precision about molecular structure matters more than rhetorical flourish.
nounA chemical compound containing two amino groups (-NH2), especially one in which both groups attach to carbon atoms of an organic molecule. Diamines are important building blocks in the synthesis of polymers such as nylon.
- A chemical compound containing two amino groups attached to carbon atoms, typically within an organic molecule.
"Hexamethylenediamine is a key diamine used in the production of nylon 6,6."
"The diamine reacts with adipic acid to form polyamide chains in nylon production."
"Putrescine is a naturally occurring diamine produced by the breakdown of proteins in decaying matter."
Standard regular plural, used when referring to multiple compounds of this class.
"Aliphatic diamines tend to be more soluble in water than their aromatic counterparts."
The nylon in your toothbrush bristles exists because chemists learned to pair a diamine with a dicarboxylic acid — two amino groups shaking hands across a polymer chain.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of diamine
The word 'diamine' derives from combining the Greek-derived prefix 'di-', meaning 'two', with 'amine', itself rooted in 'ammonia' — a term ultimately traced to 'sal ammoniac', so named after the Egyptian god Amun near whose temple the substance was first collected. The compound entered English in the nineteenth century as chemists systematically classified organic compounds by their functional groups. It shares this ammoniac root with related terms such as 'amino', 'ammonium', and 'amino acid'.
How diamine is actually used
A technical term used almost exclusively in organic and industrial chemistry; it does not occur in general conversation. In formal writing, it is often preceded by a specific modifier naming the parent structure (e.g., 'hexamethylenediamine', 'phenylenediamine').
Easily confused with diamine
A diatom is a type of single-celled alga with a silica cell wall, whereas a diamine is an organic compound bearing two amino groups.