1,3-Propanediamine CAS 109-76-2

What is 1,3-Propanediamine?

1,3-Propanediamine is a straight-chain diamine with three carbons between the nitrogens, H₂N(CH₂)₃NH₂. That one extra carbon relative to ethylenediamine changes more than it appears to — it is the difference between a five-membered chelate ring and a six-membered one, and between a tight, brittle epoxy network and a slightly tougher one.

It is a clear, colourless liquid boiling at about 140 °C with a strong ammoniacal odour, freezing well below zero and a flash point near 48 °C. It is fully miscible with water, strongly hygroscopic, and takes up carbon dioxide from air like the other short diamines.

Four active amine hydrogens on two unhindered primary amines make it a reactive, high-functionality building block. The three-carbon bridge is flexible enough to close into six-membered rings readily, which is useful in heterocyclic synthesis and occasionally a nuisance elsewhere.

Commercially, 1,3-propanediamine is a specialty intermediate rather than a bulk commodity. Its markets are epoxy curing agents where a slightly tougher network than EDA gives is wanted, corrosion inhibitors and asphalt additives, chelating agents, agrochemical and pharmaceutical intermediates, and surfactant chemistry.

Why 1,3-propanediamine specifically

• A six-membered chelate ring. Three carbons between nitrogens gives a six-membered ring with a metal ion rather than ethylenediamine's five — weaker binding, but different selectivity that is occasionally exactly what is wanted.
• Tougher epoxy networks than EDA. The longer bridge gives slightly more distance between crosslinks, trading a little hardness for impact resistance.
• Clean ring-closing chemistry. The three-carbon spacing closes readily into six-membered heterocycles, which is useful in pharmaceutical and agrochemical synthesis.
• Four active hydrogens, unhindered. High functionality per unit weight with two fully accessible primary amines.

How PDA is Manufactured

1,3-Propanediamine is made either by hydrogenating a nitrile precursor or by aminating a three-carbon alcohol. The nitrile route dominates.

• Nitrile route. Acrylonitrile is reacted with ammonia to give 3-aminopropionitrile, which is then hydrogenated over a nickel or cobalt catalyst with ammonia present to suppress secondary amine formation. This is the principal commercial route.
• Alcohol amination route. An alternative aminates 1,3-propanediol or its derivatives with ammonia and hydrogen over a supported metal catalyst.
• By-product control. Intramolecular and intermolecular side reactions give cyclic and higher polyamine by-products. Ammonia pressure during hydrogenation is the main control, and residual levels are the figures that distinguish grades.
• Separation and finishing. The product is purified by distillation and filled with nitrogen blanketing where colour and water matter.

Typical Commercial Specification

Figures below are representative of standard commercial grade. Epoxy-hardener and fine chemical grades with tighter limits are available — send us the specification you work to and we will quote against it.

Physical & Chemical Properties

Reactivity in practice

Two unhindered primary amines three carbons apart. The spacing shapes what it does:

• Epoxide ring opening. Four active hydrogens crosslink epoxy resin, with slightly longer segments between junctions than EDA gives — a little less hardness, a little more toughness.
• Ring closure to six-membered heterocycles. The three-carbon spacing closes readily into pyrimidines, tetrahydropyrimidines and related rings, used in pharmaceutical and agrochemical synthesis.
• Amide and imidazoline-type formation. Condensation with fatty acids gives amides and cyclic derivatives used in corrosion inhibitors and asphalt additives.
• Chelant synthesis. Carboxymethylation gives propylenediaminetetraacetic acid, a chelant with different metal selectivity from EDTA because of the larger ring it forms.

1,3-Propanediamine vs the Other Diamines

Aliphatic diamines are chosen almost entirely on the length of the bridge between the two nitrogens. That distance decides whether the molecule can chelate a metal, how flexible a polymer chain built from it will be, and how readily it closes into a ring instead of reacting the way you intended.

Stated plainly: two carbons is the chelating distance and nothing else comes close; three carbons gives a six-membered chelate ring that binds less strongly but makes a tougher epoxy network; six carbons is too far apart to chelate at all but exactly right for a polyamide chain with the flexibility and melting point that nylon 6,6 needs. The bridge is the design variable, and substituting across it is always a reformulation.

Industries We Supply PDA To

The same molecule leaves our warehouse for very different factories. What changes between them is not the CAS number but the grade and the documentation each sector expects.

Where PDA is Used

1,3-Propanediamine is a specialty intermediate across a spread of smaller markets. These are the end uses our customers buy it for.

As an epoxy curing agent

1,3-Propanediamine sits a step along from ethylenediamine: four active hydrogens, a fast ambient cure, but with one extra carbon between the nitrogens giving slightly longer segments between crosslinks. The practical result is a network a little less hard and a little less brittle than an EDA cure, with a marginally longer pot life. It is a specialty choice rather than a default — formulators reach for it when EDA is too brittle and DETA's pot life or viscosity is wrong.

In corrosion inhibitors and asphalt additives

Condensation with fatty acids gives amides and cyclic derivatives that anchor to metal and mineral surfaces. In oilfield service these film on steel; in asphalt they bind bitumen to wet aggregate and resist the moisture stripping that destroys road surfaces. Blenders generally care about batch-to-batch consistency of the amine distribution more than about absolute purity, since a circuit or a formulation is tuned to a particular behaviour.

In heterocyclic synthesis

The three-carbon spacing is geometrically ideal for closing six-membered nitrogen rings, which makes 1,3-propanediamine a convenient entry to tetrahydropyrimidines and related systems used in pharmaceutical and agrochemical chemistry. Where ethylenediamine naturally closes to five-membered imidazolines, PDA closes to six — a different ring with a different biological profile.

In chelant chemistry

Carboxymethylating PDA gives propylenediaminetetraacetic acid, which binds a metal ion through a six-membered ring rather than EDTA's five. The binding is weaker overall but the selectivity between metals differs, which occasionally makes it the better choice — though in volume terms EDTA dominates the market by an enormous margin.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis. The methods behind the numbers are standard across the industry, and we are happy to share them or to work to your own in-house test protocol.

• Assay and amine distribution — gas chromatography quantifying higher polyamines and cyclic by-products alongside the main component.
• Amine value and AHEW — titration. Epoxy formulators derive the mix ratio from this, and the by-products move it.
• Water content — Karl Fischer titration. Strongly hygroscopic, with carbon dioxide uptake compounding the drift in an open drum.
• Colour — APHA / Hazen against a standard. Colour carries into coatings and finished derivatives.
• Distillation range — a fast, revealing check for by-product and moisture carry-over.
• Metals and residue — iron and evaporation residue, relevant in coating and fine chemical service.

Common Process Problems & Likely Causes

When 1,3-propanediamine misbehaves in a plant, the cause is usually one of a short list of things. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Standard packing. 180 kg net in lined steel or HDPE drums, with 1000 L IBCs for larger users.
• Bulk packing. Road tankers and ISO tank containers arranged where volumes justify them.
• Carbon dioxide exclusion. Like the other short diamines, PDA absorbs carbon dioxide from air to form carbamate, which consumes amine functionality. Keep containers sealed and blanket bulk storage.
• Storage. Cool, dry, well-ventilated and bunded, with containers tightly closed and protected from air and moisture.
• Inert blanketing. Nitrogen-blanketed at fill where colour matters. The ethyleneamines darken on air contact more readily than most amines, and they also absorb carbon dioxide to form carbamate.
• Materials of construction. Stainless steel or suitable lined vessels. Avoid copper, brass, bronze, aluminium and mercury.
• Shelf life. Typically 12 months in unopened original packing under those conditions. Beyond that, re-test rather than assume.
• Transport classification. Typically UN 2734, Amines, liquid, corrosive, flammable, n.o.s., Class 8 with subsidiary risk 3, Packing Group II. Because this is a generic entry, confirm against the current SDS and the shipper's declaration for your destination and mode.

Hazards & Safe Handling

1,3-Propanediamine is corrosive, combustible and a skin sensitiser. It must be handled by trained personnel under a proper risk assessment. The classifications below are indicative — the current SDS supplied with your consignment is the governing document.

• Sensitisation. The ethyleneamines are recognised skin sensitisers, and several are respiratory sensitisers as well. Once a worker is sensitised, exposures previously tolerated can provoke a reaction, so preventing first contact matters far more than managing repeat contact. This is the dominant occupational concern across this whole family.
• Exposure control. Handle in a closed system or under local exhaust ventilation. Where the material is warmed or sprayed, vapour and mist exposure rise sharply and need their own controls.
• PPE. Chemical-resistant gloves rated for amines, chemical goggles and face shield, and chemical-resistant clothing. Glove breakthrough time is worth checking rather than assuming.
• Mixed-system handling. In a two-part epoxy system the uncured mixture carries the hazards of both hardener and resin. Applicators handling mixed material need controls for both, which is often where site assessments fall short.
• Incompatibilities. Strong oxidising agents, strong acids, acid chlorides, nitrites and isocyanates — the amine-isocyanate reaction is violently exothermic. Also copper, brass, bronze and aluminium.
• Spill response. Contain, absorb with inert non-combustible material and collect in a labelled closed container. Ventilate. Do not wash to drain.
• Environment. Harmful to aquatic life. Do not allow to enter drains, surface water or groundwater. Dispose through a licensed chemical waste contractor.
• First aid. Remove contaminated clothing immediately, wash skin with plenty of water and soap, flush eyes for at least 15 minutes, and seek medical attention with the SDS to hand. Report any skin or breathing reaction, which may indicate developing sensitisation.

Regulatory & Compliance Notes

1,3-Propanediamine is an established industrial chemical and is listed on the major national chemical inventories. Because obligations differ by territory, volume and use, the notes below are orientation rather than legal advice — confirm your own position with your regulatory adviser before importing.

• Inventory status. Listed on the principal chemical inventories in the major importing regions. Ask us for the inventory confirmation relevant to your destination country.
• Import registration. Several territories require the importer to hold a registration or notification before a consignment lands. Start that process early — it is the most common cause of delay at destination.
• Hazard communication. Supplied with an SDS compliant with the format applicable to your region, and labelled in line with the GHS classification for the product.
• Sensitiser classification. As a skin sensitiser it triggers specific labelling and, in several jurisdictions, exposure control obligations for workers handling epoxy and amine systems.
• Isomer identity. 1,3-Propanediamine and 1,2-propanediamine are different substances with different CAS numbers and different chemistry — the 1,2 isomer chelates like ethylenediamine while the 1,3 does not. Confirm which one an enquiry means.
• Dangerous goods. Typically UN 2734, Class 8 with subsidiary risk 3, Packing Group II. Confirm against the current SDS; declarations prepared for IMDG (sea) or IATA (air) as appropriate.

We Supply PDA Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship 1,3-Propanediamine from India to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, dangerous-goods paperwork and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other Indian ports arranged where it suits the routing.
• Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and dangerous-goods declaration issued as a complete set.
• Flexible volumes. A single drum for laboratory qualification, through LCL consolidations, up to repeat full loads on a supply contract.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying PDA from Chelora

We are an independent sourcing and supply partner. For 1,3-propanediamine that means confirming two things at enquiry: that you mean the 1,3 isomer rather than the 1,2, and what amine value your formulation is built on — because the by-product tail moves it.

• Documentation on every lot. Batch-specific COA including amine value and distribution, current SDS and TDS.
• Samples before commitment. Trial quantities for formulation qualification ahead of a commercial order.
• Quantities. From a single 180 kg drum through to IBC and tank quantities on contract supply.
• Export experience. Class 8 dangerous-goods documentation, packing and labelling handled for sea and road freight.
• Technical support. Direct access to people who know the chemistry, for questions on AHEW, ring-closing behaviour or isomer identity.
• Related intermediates. EDA, DETA, HMDA, IPDA and the wider diamine and epoxy hardener range from one supplier.

How ordering works

• Send the enquiry. Product, grade or specification, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing and a sample COA, normally within one working day.
• Sample and qualify. For first orders or critical applications, we send a trial quantity so your lab can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Production and QC. Material allocated and released against a batch-specific COA, with a pre-shipment sample where the application calls for it.
• Ship and document. Packed, labelled and loaded with the full export and dangerous-goods document set, and tracked through to arrival.

Related Diamines & Epoxy Hardeners

Buyers of 1,3-propanediamine usually source several of these alongside it. Consolidating them on one order cuts freight cost and gives you a single point of contact for documentation.