- Hexamethylenediamine
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Hexamethylenediamine[1][2] Hexane-1,6-diamineOther names1,6-diaminohexane, 1,6-hexanediamineIdentifiers CAS number 124-09-4 PubChem 16402 ChemSpider 13835579 UN number 1783 (solution), 2280 (solid) Jmol-3D images Image 1 - NCCCCCCN
Properties Molecular formula C6H16N2 Molar mass 116.21 g/mol Appearance White crystals or powder Density 0.84 g/cm3 Melting point 42 °C, 315 K, 108 °F
Boiling point 205 °C, 478 K, 401 °F
Solubility in water 960 g/100 mL Acidity (pKa) 10.0, 11.1 Hazards R-phrases R20 R22 R34 R36 R37 R38 Main hazards Toxic, Corrosive NFPA 704 Flash point 93 °C (102 °C for 90% aq. soln) Explosive limits 0.7 - 6.3 % (verify) (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 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.[3]
Contents
Synthesis
Hexamethylenediamine was first reported by Theodor Curtius.[4] 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).[3]
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.[3] 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.[5][6]
Stability
Hexamethylenediamine is stable in air but combustible. Like all organic compounds, it is incompatible with strong oxidants.
References
Categories:- Monomers
- Polyamines
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