Meta Phenylenediamine
Meta Phenylenediamine — m-PDA or 1,3-diaminobenzene — is a diamine best known as the monomer behind meta-aramid fibre (the fibre family that includes Nomex-type heat- and flame-resistant textiles), and as a widely used epoxy resin curing agent. It also serves in hair-dye and dye intermediate chemistry.
Chelora Chemicals supplies m-PDA to fibre and resin manufacturers, dye houses and specialty chemical producers worldwide, in bags, drums and container quantities, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 108-45-2
- IUPAC name
- Benzene-1,3-diamine
- Molecular formula
- C6H8N2
- Molecular weight
- 108.14 g/mol
- EC / EINECS
- 203-584-7
- UN Number
- 1673
- SMILES
- Nc1cccc(N)c1
- HS Code
- 2921 51*
* Confirm the exact HS heading with your customs broker — classification of phenylenediamine isomers varies between destination tariffs.
What Meta Phenylenediamine is used for
Meta Phenylenediamine is benzene carrying two amino groups in the 1,3 (meta) pattern. That geometry — two nucleophilic amine ends set at 120° around the ring — makes it a natural monomer for step-growth polymerisation with aromatic diacid chlorides, and the reaction that matters most commercially is condensation with isophthaloyl chloride to give poly(m-phenylene isophthalamide), the meta-aramid polymer spun into heat-, flame- and cut-resistant fibres used in protective clothing, filtration media and electrical insulation.
The same two-amine, moderate-reactivity structure also makes m-PDA a workhorse epoxy resin curing agent, and a coupling component in hair-dye and textile-dye chemistry, where it is prized for producing blue shades.
Why the isomer matters
The three phenylenediamine isomers have distinct chemistry, hazard profiles and end-markets, and a substitution downstream is not recoverable:
- 1,3-Diaminobenzene / meta phenylenediamine (CAS 108-45-2) — this product. The meta-aramid and epoxy-curing isomer, with a suspected-mutagenicity classification.
- 1,2-Diaminobenzene / ortho phenylenediamine (CAS 95-54-5) — the ortho isomer, the benzimidazole-chemistry workhorse, used across fungicide and pharma synthesis. See our ortho phenylenediamine page.
- 1,4-Diaminobenzene / para phenylenediamine (CAS 106-50-3) — the para isomer, the oxidative hair-dye and aramid-fibre (para-aramid, e.g. Kevlar-type) monomer. See our para phenylenediamine page.
If your purchase order simply says "phenylenediamine," quote us the CAS number and we will confirm the correct material before the order is placed. We supply all three isomers across our full product catalogue.
Appearance and handling character
m-PDA ships as a colourless to white crystalline solid or flake melting around 65 °C. It is soluble in water and readily soluble in alcohols and most polar organic solvents. Like the other phenylenediamine isomers it oxidises and darkens (turns red, then brown) on exposure to air, sometimes quite quickly — samples are often stored under nitrogen or in sealed opaque packaging for this reason. Read the safety section before planning any handling: this material is a suspected mutagen and a skin sensitiser, and that should shape your controls from the outset.
| Parameter | Typical value |
|---|---|
| Appearance | Colourless to white crystalline flakes |
| Assay (GC/titration) | 99.0% min |
| Moisture (KF) | 0.3% max |
| Melting range | 63 – 66 °C |
| Colour (molten, APHA) | Reported per batch |
| Iron content | Reported per batch (fibre-grade material) |
Important: the figures above are indicative of commercial grade material and are offered for planning only. The batch certificate of analysis is the governing document. Aramid-fibre production is especially sensitive to trace metals and colour; if that is your route, send us the specification and we will quote against it rather than against a generic grade.
| Property | Value |
|---|---|
| Physical state | Crystalline solid at ambient |
| Melting point | ≈ 64 – 66 °C |
| Boiling point | ≈ 282 – 284 °C |
| Flash point | ≈ 187 °C |
| Water solubility | Freely soluble |
| Organic solubility | Soluble in alcohols & most polar organic solvents |
| pKa (conjugate acid) | ≈ 5.1 |
| Odour | Faint, amine-like |
Physical constants compiled from public reference data for CAS 108-45-2 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
m-PDA's largest outlet is high-performance fibre and resin chemistry, with established secondary demand from dye and specialty chemical producers.
Meta-aramid fibre
The defining outlet. m-PDA condenses with isophthaloyl chloride to give poly(m-phenylene isophthalamide), the polymer spun into heat- and flame-resistant meta-aramid fibres used in firefighter and industrial protective clothing.
- Polymerisation-grade purity and colour are critical
- Trace-metal control matters for fibre performance
- See our full aromatic diamine range
Epoxy resin curing agents
m-PDA's two moderately reactive amine groups make it a classic hardener for epoxy resin systems used in coatings, composites and electrical insulation, where it cures at ambient to moderate temperatures.
- Two-amine crosslinking chemistry
- Coatings, composite and adhesive applications
- See our specialty intermediate range
Hair dye & textile dye chemistry
m-PDA is a well-established coupling agent in oxidative hair-dye formulations, producing blue shades, and appears in dyes used for leather and textiles.
- Coupling agent in oxidative colour systems
- Leather and textile dye chemistry
- See also para phenylenediamine
Corrosion inhibitors & adhesive accelerators
m-PDA and its derivatives are used as corrosion inhibitors in select formulations, and as an accelerator in adhesive resin systems, drawing on the same reactive diamine chemistry.
- Specialty formulation chemistry
- Adhesive resin accelerator use
- Available in trial and laboratory quantities
Fine & specialty synthesis
A well-characterised diamine building block for custom polyamides, benzimidazoles and heterocyclic chemistry where the 1,3-diaminobenzene pattern is specifically required.
- Custom polyamide and polyimide chemistry
- Ligand and coordination chemistry
- Available in trial and laboratory quantities
Contract & scheduled supply
Fibre and resin plants run to campaign, not to a calendar month. Most m-PDA buyers want tonnage released against a production plan rather than in one shipment. We hold inventory and release it to your schedule.
- Annual contracts with scheduled call-off
- Price held across the contract period
- Second source held in reserve
How we supply Meta Phenylenediamine
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. We own no phenylenediamine plant — and for a polymer-grade, specification-sensitive intermediate like this one, that independence works in your favour. We are never obliged to push you whatever a captive unit happens to be running that month.
Instead we place your order with whichever qualified producer best matches your assay, your colour and trace-metal limits, your price point and your delivery window.
We keep a second qualified source on this line. When a plant goes down for maintenance, your campaign switches source rather than stalling.
- Specification read against the CAS first. We confirm you need 108-45-2 and not the ortho or para isomer before we quote a price.
- Batch COA shared before dispatch. You approve the assay, colour, moisture and trace-metal profile against your own spec while the material is still in our warehouse.
- Hazard status stated up front. This material carries a suspected-mutagenicity classification and a skin sensitisation entry, and we say so at enquiry stage — not in the small print of a document pack that arrives with the goods.
- Pre-shipment samples for qualification. New account or new source, your R&D team runs a lab batch — polymerisation or curing trial — before the full quantity ever moves.
- Packing chosen to limit oxidation. Given how readily this material darkens in air, we arrange sealed, nitrogen-blanketed packing on request to protect colour through transit.
- Export machinery handled in-house. Hazard classification, UN-approved packing, labelling, freight booking and customs paperwork are ours to manage.
- Consolidation onto one bill of lading. Ship m-PDA alongside other intermediates from our range — one invoice, one shipment, one counterparty.
Packed the way your plant receives it
Pack format drives your landed cost, your handling effort, and — since this material oxidises readily — your finished colour. Tell us how it will be charged at your end and we will quote the format that suits your operation.
Multi-wall paper & PE bags
Laminated multi-wall bags with an inner liner, palletised and shrink-wrapped. The default for LCL movements and for plants charging batch-wise by hand.
Fibre & HDPE drums
UN-certified drums with liner — nitrogen-blanketed on request — for longer sea transits and humid destinations, protecting colour and moisture-sensitive polymer-grade material.
Jumbo / FIBC bags
Bulk bags with liner for high-volume fibre and resin producers with mechanical charging. Fewer handling movements and materially lower packing cost per kilo.
Samples & trial packs
Laboratory samples and pilot quantities dispatched by courier so your R&D team can run a polymerisation or curing trial before committing to campaign volume.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to. Ocean, air and road freight arranged end-to-end with documentation filed before booking.
Campaign despatch
Fibre and resin production runs to campaign. We hold contracted tonnage and release it against your production calendar instead of landing it all at once.
Handle this as a suspected mutagen & sensitiser
This is the point on the page that matters most. Meta phenylenediamine is toxic by all three exposure routes, a skin sensitiser, and suspected of causing genetic defects (H341). The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document and should govern your risk assessment, PPE selection, exposure monitoring and emergency planning.
Classified hazards
H341Suspected of causing genetic defects.H301Toxic if swallowed.H311Toxic in contact with skin.H331Toxic if inhaled.H317May cause an allergic skin reaction.H319Causes serious eye irritation.H410Very toxic to aquatic life with long lasting effects.
Hazard statements reflect the harmonised GHS classification commonly published for CAS 108-45-2 (GHS06 Toxic, GHS07 Exclamation mark, GHS08 Health hazard). Supplier classifications may differ in detail; always read the SDS issued with your specific batch, and treat the mutagenicity and sensitisation entries as the ones that shape your controls.
Spill & emergency orientation
Plan your response before the pallet arrives, not after a bag splits. The points below are orientation for your emergency planners — sections 4, 5 and 6 of the SDS are the authoritative instructions and should be posted at the point of use.
- Sweep, do not hose. The material is very toxic to aquatic life with long-lasting effects. Collect spilled solid mechanically into a labelled container; never wash it to a drain.
- Suppress dust. Dry sweeping of a fine solid generates an inhalable aerosol — use vacuum collection or dampen carefully in line with the SDS.
- Assume skin absorption and sensitisation risk. Contaminated clothing is a continuing exposure route — remove it immediately and wash the skin thoroughly.
- Have the SDS with the casualty. Phenylenediamines can cause methaemoglobinaemia and severe allergic reactions; the treating clinician needs the product identity and CAS number in hand.
- Record the exposure. For a suspected mutagen, most occupational regimes expect an exposure record to be created and retained. That is a decision for your EHS function, and it is easier made before an incident than after one.
Storage
- Cool, dry, well-ventilated store, away from direct sunlight and heat sources. The melting point is only about 65 °C, so an uncooled store in a hot climate can soften the contents.
- Keep containers tightly closed, and blanket with nitrogen where practical. This material oxidises and darkens on air exposure faster than many other anilines — an open drum will show visible colour change within days in humid conditions.
- Segregate from oxidising agents, strong acids and acid chlorides. As a diamine it reacts exothermically with acylating and oxidising reagents.
- Access-controlled storage. For a suspected mutagen, restricting who can reach the store is part of the control, not an administrative nicety.
- Shelf life is typically 6–12 months in sealed original packing under these conditions — shorter than many anilines given its oxidation sensitivity. Re-assay before use after storage.
Handling & PPE
- Design exposure out, do not manage it down. Closed transfer and mechanical charging first, ventilation second, PPE last.
- Skin protection is the priority. This material is absorbed through intact skin and is a confirmed sensitiser (H317) — chemical-resistant gloves and coveralls, not just splash protection.
- Respiratory protection where dust may be generated — particularly when breaking a caked drum or emptying a bulk bag — per your own exposure assessment.
- Health surveillance and exposure records. Where a mutagenicity classification triggers obligations at your site, your occupational health provider and EHS function own the detail. We flag the classification; the programme is yours to run.
- Never discharge to drain or watercourse. H410 applies — collect spills as solid waste and dispose of them as regulated chemical waste.
Transport
m-PDA moves as regulated cargo under UN 1673 (Phenylenediamines). We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. The applicable class and packing group are stated on your shipping documents and SDS — ask us for the current DG paperwork when you plan the shipment.
What travels with every consignment
A chemical shipment is only as good as the file that travels with it. Verifying what the source plant sends is precisely the work you are buying from a supplier.
Certificate of Analysis
Batch-specific assay by GC or titration, moisture by Karl Fischer, colour (APHA), melting range and trace-metal profile — checked against your purchase specification before we release the goods.
GHS Safety Data Sheet
Full 16-section SDS in GHS format covering hazards, exposure controls, handling, storage, spill response, toxicology and disposal — issued in the language your destination requires.
Dangerous Goods Declaration
UN 1673, hazard class, packing group and IMDG or IATA declaration prepared and filed before the container is booked, with correctly marked and labelled packaging.
Certificate of Origin
Chamber-attested where required, plus preferential-origin forms where a trade agreement gives your import duty relief at the destination.
Third-party inspection
SGS, Intertek or Bureau Veritas sampling and inspection arranged on request before loading, giving you independent verification of what actually ships.
Retained & pre-shipment samples
Pre-shipment samples carry the same COA as the commercial lot, so what your laboratory qualifies is exactly what arrives. Retention samples held against the batch.
Why the meta geometry makes the difference
Two amine groups, set 120° apart around the ring, is the whole story. That geometry shapes both the fibre-forming polymer chemistry and the curing chemistry that follows. The routes below are the general industrial pattern, not a process disclosure.
Start with the diamine
m-PDA provides two primary aromatic amine groups in the 1,3 pattern — reactive at both ends, with a geometry that favours flexible, high-strength polymer chains rather than the rigid, linear chains the para isomer gives.
Door one — polycondense
Low-temperature solution polycondensation with isophthaloyl chloride builds poly(m-phenylene isophthalamide), which is dry- or wet-spun into meta-aramid fibre.
Door two — cure an epoxy
Both amine groups react with epoxide rings in a crosslinking reaction, building the three-dimensional network that gives cured epoxy resin its mechanical and thermal properties.
Door three — couple for colour
In oxidative hair-dye and textile-dye systems, m-PDA acts as a coupler, reacting with an oxidised primary intermediate to build the final blue-shade chromophore.
Why feed quality carries through the whole route
All three doors depend on both amine groups being free and unreacted. Anything in the feed that competes for that chemistry, or carries colour of its own, follows the material down the line:
- Isomeric phenylenediamines polymerise or cure in parallel and give structurally different chain geometries — a real defect risk in fibre-grade polymer work.
- Residual moisture can hydrolyse the acid chloride comonomer in fibre polymerisation, reducing molecular weight and fibre strength.
- Oxidation products — the coloured species responsible for the red-brown drift — introduce colour defects into fibre and cured resin alike.
- Trace metals can catalyse unwanted oxidation during storage and processing, and are tightly controlled in fibre-grade specifications.
That chain of consequences is the reason we quote against your written specification rather than a generic "99% technical" grade, and the reason the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Intermediate | Principal outlet |
|---|---|
| Meta Phenylenediamine CAS 108-45-2 — this product | Meta-aramid fibre Epoxy curing agents Hair & textile dyes |
| Ortho Phenylenediamine CAS 95-54-5 | Benzimidazole chemistry Fungicide & pharma intermediates |
| Para Phenylenediamine CAS 106-50-3 | Oxidative hair dyes Para-aramid fibre Rubber antiozonants |
If your route calls for one of the others, we supply those as well — see our full product catalogue. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this intermediate
m-PDA is not a commodity with a screen price. Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Fibre and resin demand cycles
Protective-clothing and technical-textile demand for meta-aramid fibre, and industrial and electrical demand for epoxy systems, both pull on the same diamine at different points in their cycles.
- Quote early for campaign tonnage
- Spot buying at peak costs materially more
- Contracted call-off smooths the exposure
Upstream feedstock
The route back to m-PDA runs through m-dinitrobenzene and catalytic hydrogenation. Movements in benzene, nitric acid and hydrogen feed through to the diamine within a quarter or so.
- Benzene and nitric acid set the floor
- Catalyst and energy costs weigh on the reduction step
- We flag feedstock-driven moves in the quote
Regulatory pressure
The mutagenicity and sensitisation classifications raise the compliance cost of producing, storing and moving this material. That cost sits inside the price.
- Handling obligations vary by jurisdiction
- Some markets restrict certain consumer end uses
- We check destination rules before quoting
Pack format
Cost per kilo falls from 25 kg bags to drums to jumbo bags — and given the material's oxidation sensitivity, sealed or nitrogen-blanketed drums also protect finished product colour.
- Small bags carry the highest packing cost
- FIBC is cheapest per kilo at volume
- Nitrogen blanketing protects colour in transit
Freight & DG surcharges
This is regulated cargo, so ocean freight carries a hazardous surcharge and space is tighter than for general cargo. Destination and Incoterm move landed cost as much as the ex-works price does.
- Compare on landed cost, not ex-works
- DG space books out ahead of peak season
- We quote FOB, CIF, CFR or DDP as you prefer
Source availability
A plant turnaround or a shift in fibre or resin demand can take capacity offline at short notice on this line. Single-sourced buyers feel this hardest.
- We hold a second qualified source on this line
- Qualify the alternate before you need it
- Ask us about dual-source contracts
| If your end use is… | Specify |
|---|---|
| Meta-aramid fibre | Polymerisation grade, tight colour and trace-metal limits |
| Epoxy resin curing | High assay, controlled moisture and colour |
| Hair & textile dye chemistry | Colour ceiling, controlled impurity profile |
| Fine chemical synthesis | Tight purity; metals and residues reported |
| Laboratory / R&D | Small pack, high purity, full analytical pack |
Not sure which column you are in? Describe the reaction or process you are running and our technical desk will recommend the grade — including telling you when a cheaper specification would do the job just as well.
Support that goes beyond shipping the bag
What our technical desk will do
- Match a grade to your process. Tell us whether you are polymerising, curing or dyeing, and we will recommend the specification — and say so plainly when a tighter, costlier grade would add nothing.
- Be straight about the hazard profile. We state the mutagenicity and sensitisation classifications at enquiry stage so your EHS team can price the controls into the decision, rather than meeting it for the first time on the label.
- Advise on handling and storage for your site conditions — protecting colour against oxidation looks different in a humid coastal plant than in a dry inland one.
- Review your specification before it goes into a contract, so you are not locked into a limit that no plant can consistently hit.
Regulatory & compliance notes
- Mutagen and sensitiser obligations are jurisdiction-specific. Several regimes impose exposure monitoring and record retention for chemicals with this hazard profile. Confirm what applies at your site before the first delivery.
- Import controls vary by destination. Some jurisdictions apply registration, licensing or end-use declaration requirements to this material, and some restrict its use in consumer products such as hair dyes. We check the destination rules before quoting, not after you have raised the PO.
- Chemical inventory listings differ between regions. Confirm your obligations under the applicable inventory regime for your import volume — we will supply the identity data you need for that filing.
- Downstream article restrictions can apply to certain dye and cosmetic applications. Your regulatory team should confirm the finished-article position for the end use you have in mind.
None of the above is legal advice — your own regulatory affairs team owns the final compliance position for your import and your workplace. What we commit to is giving you accurate product identity data, an honest statement of the hazard classification and complete documentation to work from.
From enquiry to delivered pallet
Send the specification
Product name or CAS 108-45-2, the assay and colour limits you work to, quantity, pack preference and destination port.
Receive a firm quote
Pricing, lead time, packing and Incoterm confirmed in writing within 24 hours — our sourcing desk is staffed around the clock.
Qualify and approve
Sample dispatched if you are qualifying a new source. Batch COA shared for your approval before the material is released.
Ship and track
DG classification filed, freight booked, export documents issued, and the consignment tracked through transit and clearance to your plant.
Often bought alongside this grade
Consolidate several intermediates onto one shipment and one invoice. These are the diamines and aromatics our fibre, resin and dye customers most often order in the same programme. Each of the following is part of our wider aromatic amine range — browse the full product catalogue for current availability and specification sheets.
What buyers ask us about Meta Phenylenediamine
Is this material classified as a carcinogen or mutagen?
Can I use the ortho or para isomer instead?
What purity do you normally supply?
What is the minimum order quantity?
How long does delivery take?
Why does the solid darken so quickly?
How should we store it, and what is the shelf life?
Is this a dangerous good? What paperwork comes with it?
- Batch certificate of analysis
- GHS-format safety data sheet
- Dangerous-goods declaration with UN number, class and packing group
- Commercial invoice, packing list and bill of lading or airway bill
- Certificate of origin and any destination-specific forms
Do you supply to my country?
Do you manufacture this yourself?
Can you hold stock against a production plan?
Request pricing on Meta Phenylenediamine
Send your required assay, quantity, pack format and destination port. Our sourcing desk is available 24 hours a day, 7 days a week, and comes back with pricing, lead time and packing options — whether that is a single trial bag or a contracted container programme for the year.