Hexamethylenediamine

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Hexamethylenediamine[1][2]
Skeletal formula of hexamethylenediamine
Ball and stick model of hexamethylenediamine
Spacefill model of hexamethylenediamine
Identifiers
CAS number 124-09-4 YesY
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
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 The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
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 Corrosive C
R-phrases R21/22, R34, R37
S-phrases (S1/2), S22, S26, S36/37/39, S45
NFPA 704
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g., diesel fuel Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
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
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
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[edit]

Hexamethylenediamine was first reported by Theodor Curtius.[5] It is 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[edit]

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[edit]

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[edit]

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

References[edit]

  1. ^ Merck Index, 11th Edition, 4614.
  2. ^ MSDS
  3. ^ "1,6-diaminohexane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. Retrieved 29 May 2012. 
  4. ^ a b c Robert A. Smiley "Hexamethylenediamine" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a12 629
  5. ^ T. Curtius et al. J. Prakt. Chem., 1900, volume 62, p. 189.
  6. ^ BBC News
  7. ^ BBC News