Hexamethylenediamine

Hexamethylenediamine[1][2]
IUPAC name Hexane-1,6-diamine[3]
Other names 1,6-Diaminohexane 1,6-Hexanediamine
Identifiers
CAS number	124-09-4 Y
PubChem	16402
ChemSpider	13835579 N
EC number	204-679-6
UN number	2280
DrugBank	DB03260
MeSH	1,6-diaminohexane
ChEBI	CHEBI:39618 N
ChEMBL	CHEMBL303004 N
RTECS number	MO1180000
Beilstein Reference	1098307
Gmelin Reference	2578
Jmol-3D images	Image 1
SMILES NCCCCCCN
InChI InChI=1S/C6H16N2/c7-5-3-1-2-4-6-8/h1-8H2 N Key: NAQMVNRVTILPCV-UHFFFAOYSA-N N
Properties
Molecular formula	C6H16N2
Molar mass	116.20 g mol−1
Appearance	Colourless crystals
Density	0.84 g/mL
Melting point	39 to 42 °C; 102 to 108 °F; 312 to 315 K
Boiling point	204.6 °C; 400.2 °F; 477.7 K
Solubility in water	490 g L−1
log P	0.386
Thermochemistry
Std enthalpy of formation ΔfHo298	−205 kJ mol−1
Hazards
GHS pictograms
GHS signal word	DANGER
GHS hazard statements	H302, H312, H314, H335
GHS precautionary statements	P261, P280, P305+351+338, P310
EU Index	612-104-00-9
EU classification	C
R-phrases	R21/22, R34, R37
S-phrases	(S1/2), S22, S26, S36/37/39, S45
NFPA 704	2 3 0
Flash point	80 °C; 176 °F; 353 K
Explosive limits	0.7–6.3%
LD50	750 mg kg−1 (oral, rat) 1.11 g kg−1 (dermal, rabbit)
Related compounds
Related alkanamines	Pentylamine Cadaverine Methylhexanamine Tuaminoheptane
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Hexamethylenediamine is the organic compound with the formula H₂N(CH₂)₆NH₂. The molecule is a diamine, consisting of a hexamethylene hydrocarbon chain terminated with amine functional groups. The colorless solid (yellowish for some commercial samples) has a strong amine odor, similar to piperidine. About 1 billion kilograms are produced annually.^[4]

Synthesis

Hexamethylenediamine was first reported by Theodor Curtius.^[5] It is presently produced by the hydrogenation of adiponitrile:

NC(CH₂)₄CN + 4 H₂ → H₂N(CH₂)₆NH₂

The hydrogenation is conducted molten adiponitrile diluted with ammonia, typical catalysts being based on cobalt and iron. The yield is good, but commercially significant side products are generated by virtue of reactivity of partially hydrogenated intermediates. These other products include 1,2-diaminocyclohexane, hexamethyleneimine, and the triamine bis(hexamethylenetriamine).

An alternative process operates in diluted ADN conditions using HMD itself as a solvent and Ni Raney as catalyst. This process operates without ammonia and at lower pressure and temperature^[4]

Applications

Hexamethylenediamine is used almost exclusively for the production of polymers, an application that takes advantage of its bifunctional structure. The great majority of the diamine is consumed by the production of nylon 6-6 via condensation with adipic acid. Otherwise hexamethylene diisocyanate (HDI) is generated from this diamine as a monomer feedstock in the production of polyurethane. The diamine also serves as a cross-linking agent in epoxy resins.

Safety

Hexamethylenediamine is moderately toxic, with LD₅₀ of 792-1127 mg/kg.^[4] Nonetheless, like other basic amines, it can cause serious burns and severe irritation. Such injuries were observed in the accident at the BASF site in Seal Sands, near Billingham (UK) on 4 January, 2007. 37 injured and 16 seriously injured.^[6][7]

Stability

Hexamethylenediamine is stable in air but combustible. Like all organic compounds, it is incompatible with strong oxidants.

References