A diamine is an

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituen ...

with exactly two

amino group In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent such ...

s. Diamines are used as

monomers In chemistry, a monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. Classification M ...

to prepare

polyamide A polyamide is a polymer with repeating units linked by amide bonds. Polyamides occur both naturally and artificially. Examples of naturally occurring polyamides are proteins, such as wool and silk. Artificially made polyamides can be made through ...

s, polyimides, and

polyurea Polyurea is a type of elastomer that is derived from the reaction product of an isocyanate component and a synthetic resin blend component through step-growth polymerization. The isocyanate can be aromatic or aliphatic in nature. It can be mon ...

s. The term ''diamine'' refers mostly to primary diamines, as those are the most reactive. In terms of quantities produced, 1,6-diaminohexane (a precursor to

Nylon 6-6 Nylon 66 (loosely written nylon 6-6, nylon 6/6, nylon 6,6, or nylon 6:6) is a type of polyamide or nylon. It, and nylon 6, are the two most common for textile and plastic industries. Nylon 66 is made of two monomers each containing 6 carbon atoms, ...

) is most important, followed by

ethylenediamine Ethylenediamine (abbreviated as en when a ligand) is the organic compound with the formula C2H4(NH2)2. This colorless liquid with an ammonia-like odor is a basic amine. It is a widely used building block in chemical synthesis, with approximately ...

. Vicinal diamines (1,2-diamines) are a structural motif in many biological compounds and are used as

ligands In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electro ...

coordination chemistry A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many ...

Aliphatic diamines

Linear

* 1 carbon: methylenediamine (diaminomethane) of theoretical interest only * 2 carbons:

(1,2-diaminoethane). Related derivatives include the N-alkylated compounds, 1,1-dimethylethylenediamine, 1,2-dimethylethylenediamine,

ethambutol Ethambutol (EMB, E) is a medication primarily used to treat tuberculosis. It is usually given in combination with other tuberculosis medications, such as isoniazid, rifampicin and pyrazinamide. It may also be used to treat ''Mycobacterium avi ...

tetrakis(dimethylamino)ethylene Tetrakis(dimethylamino)ethylene (TDAE) is an organic compound with the formula (NMe2)2sub>2 (where Me = CH3). A colorless liquid, this compound is classified as an enamine. Primary and secondary enamines tend to isomerize, but tertiary enamines a ...

, TMEDA. File:Ethylene_diamine.png, Ethylenediamine * 3 carbons: 1,3-diaminopropane (propane-1,3-diamine) * 4 carbons:

putrescine Putrescine is an organic compound with the formula (CH2)4(NH2)2. It is a colorless solid that melts near room temperature. It is classified as a diamine. Together with cadaverine, it is largely responsible for the foul odor of putrefying flesh, ...

(butane-1,4-diamine) * 5 carbons:

cadaverine Cadaverine is an organic compound with the formula (CH2)5(NH2)2. Classified as diamine, it is a colorless liquid with an unpleasant odor. It is present in small quantities in living organisms but is often associated with the putrefaction of an ...

(pentane-1,5-diamine) File:Pentane-1,5-diamine 200.svg,

Cadaverine Cadaverine is an organic compound with the formula (CH2)5(NH2)2. Classified as diamine, it is a colorless liquid with an unpleasant odor. It is present in small quantities in living organisms but is often associated with the putrefaction of an ...

* 6 carbons: hexamethylenediamine (hexane-1,6-diamine),

trimethylhexamethylenediamine Trimethylhexamethylenediamine is the name used to refer to a mixture of two isomers of trimethyl- 1,6-hexanediamine. The mixture is used as a monomer in nylon TMDT. It is available commercially under the trade name Vestamin TMD from the company E ...

Branched

Derivatives of ethylenediamine are prominent: * 1,2-diaminopropane, which is chiral. *

diphenylethylenediamine 1,2-Diphenyl-1,2-ethylenediamine, DPEN, is an organic compound with the formula H2NCHPhCHPhNH2, where Ph is phenyl (C6H5). DPEN exists as three stereoisomers: meso and two enantiomers S,S- and R,R-. The chiral diastereomers are used in asymmetric ...

, two diastereomers, one of which is C₂-symmetric. * 1,2-diaminocyclohexane, two diastereomers, one of which is C₂-symmetric.

Cyclic

* 1,4-Diazacycloheptane File:DACH.png, 1,4-Diazacycloheptane

Xylylenediamines

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

Aromatic diamines

Three

phenylenediamine Phenylenediamine may refer to: * ''o''-phenylenediamine or OPD, a chemical compound C6H4(NH2)2 * ''m''-phenylenediamine or MPD, a chemical compound C6H4(NH2)2 * ''p''-phenylenediamine or PPD, a chemical compound C6H4(NH2)2 * ''N,N''-dimethyl-''p'' ...

s are known:Robert A. Smiley "Phenylene- and Toluenediamines" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. * ''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. File:P-phenylenediamine.svg, p-phenylenediamine Various N-methylated derivatives of the phenylenediamines are known: *

dimethyl-4-phenylenediamine Dimethyl-4-phenylenediamine is an amine. It has been used as an accelerator for the vulcanization of rubber. It can be used in oxidase tests. Synthesis Dimethyl-4-phenylenediamine is made by the nitrosylation of dimethylaniline followed by reduct ...

, a reagent. *

N,N'-di-2-butyl-1,4-phenylenediamine ''N'',''N''′-Di-2-butyl-1,4-phenylenediamine is an aromatic amine used industrially as an antioxidant to prevent degradation of turbine oils, transformer oils, hydraulic fluids, lubricants, waxes, and greases. It is particularly effective for ...

, an antioxidant. Examples with two aromatic rings include derivatives of

biphenyl Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one ...

and

naphthalene Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromati ...

: * 4,4'-diaminobiphenyl * 1,8-diaminonaphthalene

References

External links

* {{MeshName, Diamines
Synthesis of diamines
Monomers