1,6-Diaminohexane · 1,6-hexanediamine · HMDA · Molten and aqueous solution
Hexamethylenediamine is a six-carbon chain with a primary amine at each end, and it is one of the two molecules that make nylon 6,6 — pair it with adipic acid and you get the nylon salt that every 6,6 polymerisation starts from. Convert the amines to isocyanate groups instead and you get HDI, the aliphatic diisocyanate behind weatherable polyurethane coatings. It is a solid at room temperature, melting at about 41 °C, which is the single fact that shapes how it is shipped and stored: most of it moves molten or as a concentrated aqueous solution. Chelora Amines supplies HMDA in molten, solid and solution form, with a batch-wise COA and SDS on every dispatch.
72.07 + 16.13 + 28.01 = 116.21 g/mol
Hexamethylenediamine — 1,6-diaminohexane, 1,6-hexanediamine, HMDA — is a colourless to pale crystalline solid melting at about 41 °C, with a strong ammoniacal odour. It is completely miscible with water, strongly alkaline, corrosive to skin, and hygroscopic. Above its melting point it is a mobile, water-thin liquid.
Almost all of it goes into nylon 6,6. Reacted with adipic acid it forms hexamethylenediammonium adipate — nylon salt — which is polymerised to the polyamide used in tyre cord, airbag fabric, carpet fibre, engineering plastics and film. The second significant outlet converts the two amino groups to isocyanate groups, giving hexamethylene diisocyanate and its trimers: the aliphatic isocyanates behind automotive clearcoats and other coatings that must not yellow in sunlight.
The melting point is the practical issue. HMDA solidifies in any store that is not kept warm, and a solidified drum or tanker is a real problem rather than an inconvenience. That is why most industrial volume moves either molten in heated equipment or as a concentrated aqueous solution, and why the choice between the two should be made before the first order rather than after the first delivery.
| Chemical name | Hexamethylenediamine |
| Common synonyms | HMDA, HMD, 1,6-diaminohexane, 1,6-hexanediamine, hexane-1,6-diamine |
| CAS number | 124-09-4 |
| EC / EINECS number | 204-679-6 |
| HS / HSN code | 2921 22 (hexamethylenediamine and its salts; HSN 2921 22 on Indian invoices) |
| Molecular formula | C₆H₁₆N₂ (H₂N(CH₂)₆NH₂) |
| Molecular weight | 116.21 g/mol |
| Appearance | Colourless to pale crystalline solid; clear mobile liquid when molten |
| Odour | Strong ammoniacal odour |
| Melting point | About 39–42 °C |
| Boiling point | About 204 °C at atmospheric pressure |
| Density | About 0.84 g/cm³ at 60 °C (molten) |
| Solubility in water | Completely miscible; also soluble in alcohols and benzene |
| Amine value | About 955–975 mg KOH/g |
| Amine hydrogen equivalent weight | About 29.1 (four active hydrogens per molecule) |
| Flash point | About 80 °C (closed cup) |
| UN number | UN 2280, Hexamethylenediamine, solid, Class 8, Packing Group III (solutions ship as UN 1783) |
Figures are typical values for the anhydrous technical grade. Aqueous solution grades differ on freezing point, density, flash point and amine value. All values for the material you order are stated on its Certificate of Analysis and Safety Data Sheet.
Two ordinary primary aliphatic amines separated by a flexible six-carbon spacer. The chemistry is simple; what makes it commercially enormous is the spacing.
Reaction with adipic acid gives hexamethylenediammonium adipate in solution — the 1:1 salt that is crystallised or concentrated and then polymerised. Stoichiometry here sets the molecular weight downstream.
HMDA + adipic acid → nylon saltHeating the salt drives off water and condenses the amine and acid to amide links, building poly(hexamethylene adipamide) — nylon 6,6.
nylon salt → nylon 6,6 + H₂OConverting both amino groups to isocyanate groups gives hexamethylene diisocyanate, and from it the biurets and isocyanurate trimers used in light-stable coatings.
HMDA → HDI (–NH₂ → –NCO)Each N–H adds across an epoxide ring. Four active hydrogens at an AHEW of about 29.1 give a ratio near fifteen parts per hundred and a tougher, more flexible network than the short-chain amines.
AHEW ≈ 29.1 · 4 active HReacts rapidly with isocyanates to give substituted ureas, which is both the basis of its use as a chain extender and the reason it works as a crosslinker in polyurethane dispersions.
R–NCO + H₂N–R′ → ureaAlkylation of both nitrogens gives bis-quaternary ammonium compounds used as biocides, flocculants and cationic polymer intermediates.
HMDA + 2 RX → bis-quaternaryCondensation with fatty acids gives amidoamines and, after ring closure, imidazolines — the route into corrosion inhibitors and cationic surfactants.
HMDA + RCOOH → amidoamineA strong aliphatic base, forming salts readily with mineral and organic acids. The adipate salt is the one that matters commercially, but the chemistry is general.
HMDA + 2 HCl → dihydrochlorideMolten, solid or solution — decide before you order. HMDA freezes at about 41 °C, so this is not a preference but a design decision about your receiving equipment. Molten supply needs heated, traced, nitrogen-blanketed receipt; solid needs a melting facility and an exposure plan for charging it; solution removes both problems but brings water into your process. Tell us which you can actually handle and we will quote the form, not just the molecule.
Discuss your receipt arrangementIndustrially, HMDA is made by hydrogenating adiponitrile. Where the adiponitrile itself comes from is what distinguishes one producer's route from another's.
Made either by the hydrocyanation of butadiene or by the electrochemical dimerisation of acrylonitrile, depending on the plant.
Both nitrile groups are hydrogenated over a cobalt, iron or Raney-type catalyst in the presence of ammonia, which suppresses secondary amine formation.
Excess ammonia and hydrogen are stripped and recycled, and the catalyst separated from the crude amine stream.
Vacuum distillation removes hexamethyleneimine, aminocapronitrile and heavier by-products, taking the assay above 99.5%.
Product is held molten under nitrogen and loaded hot, flaked and drummed, or blended to a concentrated aqueous solution for easier transport.
Nylon producers almost always take molten HMDA or the aqueous solution, because both feed straight into a continuous salt-making step where water is removed anyway. For them the solution is often the easier option: no heated storage, no solidification risk, and the water goes out with the condensate. Everyone else has to think harder. A coatings or epoxy formulator usually cannot accept the water, which means solid material and a melting step, or molten delivery into a heated vessel. Solid HMDA is the most awkward of the three from an exposure point of view, because charging warm flake or lump by hand puts an operator close to a corrosive, strongly odorous material. Where the volume justifies it, molten receipt into a traced tank is both the safest and the least troublesome arrangement.
HMDA is hygroscopic and takes up carbon dioxide from the air readily, forming carbamate that can deposit solids in tanks, lines and vents and quietly consume product. Storage should be sealed and nitrogen-blanketed throughout, with a carbon dioxide absorber on anything vented and held for long periods. Colour drifts towards yellow on air exposure and with prolonged hot holding; it has little effect on reactivity but carries into nylon and into pale coatings, so colour-critical users should specify a limit and avoid long molten residence times. Carbon steel is generally suitable for the anhydrous material; stainless is preferred for solutions and where colour matters. Avoid copper, copper alloys, aluminium and zinc throughout.
Assay, water and colour set the grade. For polymer users the impurity profile matters more than the headline purity, because a monofunctional impurity caps a growing chain.
Molten or solid material for nylon salt, HDI manufacture and any process where added water is unacceptable.
Stays liquid at ambient temperature and pumps straight out. Suited to salt-making and aqueous formulation work.
Highest purity for analytical, research and reference use, supplied in small sealed packs with full batch documentation.
| Parameter | Test method | Typical specification |
|---|---|---|
| Appearance | Visual | Colourless solid; clear colourless melt |
| Assay | GC | ≥ 99.5% w/w |
| Water | Karl Fischer | ≤ 0.3% w/w |
| Melting point | Capillary | 39 – 42 °C |
| Colour, molten (APHA) | APHA / Hazen | ≤ 20 |
| Amine value | Potentiometric titration | 955 – 975 mg KOH/g |
| Hexamethyleneimine | GC | ≤ 0.1% w/w |
| Total monofunctional amines | GC | ≤ 0.2% w/w |
| Ash | Gravimetric | ≤ 0.02% w/w |
Indicative specification for planning. The controlling document is the Certificate of Analysis issued for your batch. Polymer-grade requirements are quoted against your own specification sheet.
One outlet dominates to an unusual degree. The others are smaller but technically demanding.
The dominant outlet by a wide margin. Combined with adipic acid to give nylon salt, then polymerised for tyre cord, airbag fabric, carpet fibre, engineering plastics and film.
Converted to hexamethylene diisocyanate and its biuret and trimer derivatives — the aliphatic isocyanates behind automotive clearcoats and non-yellowing finishes.
A diamine chain extender and crosslinker for polyurethane and polyurea systems and for waterborne polyurethane dispersions.
Condensed with dimer and dibasic acids to give flexible polyamide resins for hot-melt adhesives, inks and flexible packaging.
Quaternised and polymerised to cationic flocculants, coagulants and biocidal polymers for municipal and industrial water treatment.
Amidoamine and imidazoline derivatives for oilfield, pipeline and metalworking inhibitor packages, and for pickling and acidising.
A tougher, more flexible aliphatic hardener than the short-chain amines, used neat or adducted at around fifteen parts per hundred of resin.
A building block for chelating agents, rubber chemicals, textile auxiliaries, pharmaceutical intermediates and crosslinkers for specialty polymers.
From airbag fabric to car clearcoat — the value chain downstream of hexamethylenediamine.
| Derivative | Made by | End use |
|---|---|---|
| Nylon salt (hexamethylenediammonium adipate) | 1:1 reaction with adipic acid in aqueous solution | Feedstock for every nylon 6,6 polymerisation |
| Nylon 6,6 | Polycondensation of the salt with loss of water | Tyre cord, airbag fabric, carpet fibre, engineering plastics, film |
| Hexamethylene diisocyanate (HDI) | Conversion of both amino groups to isocyanate groups | Aliphatic isocyanate for weatherable coatings and elastomers |
| HDI biurets and isocyanurate trimers | Oligomerisation of HDI | Automotive clearcoats and high-durability industrial finishes |
| Polyamide hot-melt resins | Condensation with dimer and dibasic acids | Hot-melt adhesives, inks, flexible packaging laminates |
| Bis-quaternary ammonium compounds | Alkylation of both nitrogens | Biocides, flocculants and cationic polymer intermediates |
| HMDA-cured epoxy networks | Stoichiometric cure of epoxy resin at AHEW ≈ 29.1 | Tough, flexible coatings, adhesives and castings |
Every container carries the Chelora Amines label with product name, grade, net weight, batch number, manufacturing date, UN number and the corrosive pictogram. Packs are sealed and nitrogen-blanketed.
Lined steel drums of flake or cast product under nitrogen. Simple to ship and store, but they have to be melted before use.
UN-approved composite or stainless IBCs of concentrated aqueous solution — liquid at ambient temperature and ready to pump.
Heated road and ISO tankers for molten delivery into traced storage; 250 g to 2 kg sealed containers for laboratory use.
A solidified consignment is the thing to design against. Molten material cooling in an untraced line, or a drum stored outside in winter, turns a routine delivery into a thawing exercise with a corrosive, odorous material. If you cannot keep it warm, take the aqueous solution. Export consignments are packed in UN-specification packaging with full dangerous goods documentation and shipped FOB, CIF or CFR through Nhava Sheva and Mundra.
Plan my supplyHMDA causes severe skin burns and eye damage, is harmful if swallowed and may cause respiratory irritation. Because it is usually handled above its melting point, thermal burns and corrosive burns are a combined risk, and the vapour above a hot tank is both irritant and strongly malodorous. The notes below are a summary for planning only; always work to the Safety Data Sheet and your own site risk assessment.
| Parameter | Specification | Result |
|---|---|---|
| Appearance | Colourless solid / clear melt | Complies |
| Assay (GC) | ≥ 99.5% | Complies |
| Water (KF) | ≤ 0.3% | Complies |
| Melting point | 39 – 42 °C | Complies |
| Colour, molten (APHA) | ≤ 20 | Complies |
| Amine value | 955 – 975 mg KOH/g | Complies |
HMDA is checked before dispatch. Each consignment leaves with the paperwork your QC, EHS, stores and accounts teams need on day one — including the monofunctional amine figures that polymer users care about most.
Five steps for a first order of HMDA. Step two decides the form, which decides almost everything else.
Quantity, intended application, your water and colour limits, what receiving equipment you have, and your delivery location.
Molten, solid or aqueous solution — we match the form to your receiving arrangement and to whether your process tolerates water.
We quote, then the batch is tested — assay, water, melting point, colour and amine value — and the COA and SDS are prepared.
Sealed, labelled drums, IBCs or a heated tanker move under dangerous goods documentation for a Class 8 corrosive.
Material reaches your gate and repeat dispatches are scheduled to your usage, with delivery timing planned around your storage temperature.
Buyers who order HMDA usually source these from the same list. See the full product range for the complete picture.
Short answers to what purchase, lab, EHS and plant teams ask us most. Anything else, ask us directly.
Send the grade, form, quantity, pack size, intended end use and your delivery address or destination port. We come back with a price, the documents that go with the batch and a dispatch or shipping plan, usually within 24 hours.