A diamine is an organic compound with two amino groups. Diamines are used as monomers to prepare polyamides, polyimides, and polyureas. In terms of quantities produced, 1,6-diaminohexane, a precursor to Nylon 6-6, is most important, followed by ethylenediamine. Vicinal diamines (1,2-diamines) are a structural motif in many biological compounds and are used as ligands in coordination chemistry.
Linear aliphatic diamines
- 2 carbons: ethylenediamine (1,2-diaminoethane). Related derivatives include the N-alkylated compounds, 1,1-dimethylethylenediamine, 1,1-dimethylethylenediamine, ethambutol and TMEDA.
- 3 carbons: 1,3-diaminopropane (propane-1,3-diamine)
- 4 carbons: putrescine (butane-1,4-diamine)
- 5 carbons: cadaverine (pentane-1,5-diamine)
- 6 carbons: hexamethylenediamine (hexane-1,6-diamine)
Branched aliphatic diamines
Derivatives of ethylenediamine are prominent:
- 1,2-diaminopropane, which is chiral.
- diphenylethylenediamine, which is C2-symmetric.
- trans-1,2-diaminocyclohexane, which is C2-symmetric.
Cyclic aliphatic diamines
Xylylenediamines are classified as alkylamines since the amine is not directly attached to an aromatic ring.
- o-xylylenediamine or OXD
- m-xylylenediamine or MXD
- p-xylylenediamine or PXD
- o-phenylenediamine or OPD
- m-phenylenediamine or MPD
- p-phenylenediamine or PPD. 2,5-Diaminotoluene is related to PPD but contains a methyl group on the ring.
Various N-methylated derivatives of the phenylenediamines are known:
- Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke "Amines, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH Verlag, Weinheim. doi:10.1002/14356007.a02_001
- Lucet, D., Le Gall, T. and Mioskowski, C. (1998), The Chemistry of Vicinal Diamines. Angew. Chem. Int. Ed., 37: 2580–2627. doi: 10.1002/(SICI)1521-3773(19981016)37:19<2580::AID-ANIE2580>3.0.CO;2-L
- Robert A. Smiley "Phenylene- and Toluenediamines" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a19_405