Meta Phenylene Diamine
A high-purity aromatic diamine supplied for aramid fibre and resin manufacture, epoxy curing systems, azo dye intermediates, and polymer chemistry.
What is Meta Phenylene Diamine?
Meta Phenylene Diamine — MPDA, or 1,3-phenylenediamine — is a white to light brown crystalline solid carrying two amino groups in the meta relationship. It darkens quickly on exposure to air.
The meta arrangement is what makes it a polymer monomer rather than a heterocycle precursor. Two amines set apart across the ring cannot close onto each other, so instead they react at both ends with a difunctional partner, building the extended chain that gives meta-aramid fibres and cured epoxy networks their strength and heat resistance.
At Chelora Chemicals, MPDA is crystallised and packaged with assay, melting range, and isomer content held to specification, and handled to limit the rapid air oxidation to which aromatic diamines are prone.
- Appearance
- White to light brown crystalline flakes
- Odour
- Faint amine odour
- Solubility
- Soluble in water, alcohol, and ether
- Function
- Monomer / chemical intermediate
- Grade
- Technical / polymer
Formula diagram
Two amino groups in the meta relationship
- Molecular formulaC6H8N2
- Molecular weight108.14 g/mol
- IUPAC name1,3-Phenylenediamine
- Functional groupsTwo primary aromatic amines
- CAS number108-45-2
Technical product information
Standard specification for Chelora Chemicals' technical grade Meta Phenylene Diamine. Custom-grade and bulk specifications are available on request.
| Chemical name | Meta Phenylene Diamine |
|---|---|
| Synonyms | MPDA, 1,3-Phenylenediamine, m-Phenylenediamine, 1,3-Diaminobenzene |
| CAS number | 108-45-2 |
| Molecular formula | C6H8N2 |
| Molecular weight | 108.14 g/mol |
| Assay (purity) | ≥ 99.0% |
| Appearance | White to light brown crystalline flakes |
| Melting point | 63–66°C |
| Boiling point | 282–284°C |
| Flash point | > 150°C (closed cup) |
| Isomer content | ≤ 0.5% |
| Moisture | ≤ 0.5% |
| Packaging | 25 kg drums, 500 kg jumbo bags, molten tanker |
| Shelf life | 12 months in sealed original packaging |
Applications of Meta Phenylene Diamine
Aramid fibre & resin
Polymerised with isophthaloyl chloride to build meta-aramid polymers used in heat and flame resistant fibres.
Epoxy curing agents
Cures epoxy resins into rigid, heat-resistant networks for coatings, composites, and electrical laminates.
Azo dyes & pigments
Used as a coupling and diazo component in azo dye and pigment manufacture.
Polyurethane & polyimide
Applied as a chain extender and monomer in high-performance polymer systems.
Corrosion inhibitors
Feeds the synthesis of amine-based inhibitors and metal treatment chemicals.
Ion exchange & specialty resins
Used in resin and specialty polymer manufacture requiring a difunctional aromatic amine.
Why choose Chelora Chemicals
Every batch of Meta Phenylene Diamine is manufactured, tested, and documented to a standard that formulators and process chemists can build on with confidence — from first sample to full production volume.
Consistent purity
Assay controlled at ≥99% with isomer content, colour, and melting range verified before dispatch.
Full documentation
COA, SDS, and regulatory data supplied with every shipment.
Flexible volumes
From 25 kg drums to jumbo bags and molten tanker supply.
Technical support
Process, handling, and compliance guidance from our chemistry team.
Storage and guidelines
- 01Store in tightly sealed original packaging under nitrogen where possible.
- 02Keep in a cool, dry, well-ventilated store, protected from air and light.
- 03Expect gradual darkening on exposure — aromatic diamines oxidise faster than monoamines.
- 04Segregate from strong oxidising agents, acids, and acid chlorides.
- 05Keep drums and bags palletised and dry; re-seal opened packaging immediately.
- 06Prevent any release to drains, surface water, or soil — the product is very toxic to aquatic life.
Handling precautions
MPDA is toxic if swallowed, in contact with skin, or if inhaled, is suspected of causing genetic defects, and may cause an allergic skin reaction. It is for industrial use by trained personnel only.
Aromatic diamines are potent skin sensitisers. Once a worker is sensitised, very low subsequent exposures can trigger a reaction, so preventing first contact matters more than tolerating small exposures.
Chemical-resistant gloves, coveralls, eye protection, and respiratory protection are required, with dust control at every bag or drum opening and charging point.
The product is very toxic to aquatic organisms with long-lasting effects. Contain all spills and dispose of waste through licensed routes.
Refer to the full Safety Data Sheet for exposure limits, health surveillance, spill response, and first-aid measures before use.
Frequently asked questions
What is Meta Phenylene Diamine used for?
Mainly as a polymer monomer: meta-aramid fibres and resins, epoxy curing agents, and high-performance polymer systems. It also serves azo dye and pigment chemistry and corrosion inhibitor synthesis.
How does MPDA differ from OPDA?
Both are C6H8N2 with a weight of 108.14, but the amines sit meta apart rather than adjacent. OPDA's adjacent amines close into benzimidazole rings; MPDA's cannot, so it builds extended polymer chains instead. The two are not interchangeable.
Why is the meta isomer used for aramid fibres?
The meta arrangement gives the polymer chain a kinked geometry rather than a straight rod. That produces the flexible, heat and flame resistant meta-aramid fibres used in protective clothing, as distinct from the rigid para-aramids used for ballistic strength.
How does it work as an epoxy curing agent?
Each amino group reacts with epoxide rings, and because there are two of them at opposite ends of a rigid aromatic ring, the resin cross-links into a dense three-dimensional network. That is what gives aromatic-amine-cured epoxies their heat resistance.
Why does the product darken so quickly?
Aromatic diamines oxidise readily in air and light. Darkening is normal and usually does not affect assay, but sealed, nitrogen-blanketed, dark storage slows it considerably and matters for colour-sensitive work.
Is it soluble in water?
Yes, unlike most aromatic amines in this range. It dissolves in water as well as alcohols and ether, which affects both its reaction chemistry and its environmental behaviour after a spill.
What does 'skin sensitiser' mean in practice?
A worker can develop an allergy after exposure and thereafter react to concentrations far below any normal exposure limit. Preventing first contact is the control strategy, which is why glove selection and dust containment are emphasised.
Can it be supplied molten?
Yes, for bulk users. With a melting point around 65°C, molten supply in heated tankers avoids dust exposure and handling losses, but requires dedicated heated lines and nitrogen blanketing at the receiving site.
What purity do you supply?
Standard technical grade is supplied at a minimum assay of 99% with isomer content at or below 0.5% and moisture at or below 0.5%. Tighter specifications can be manufactured to order.
Why is the shelf life shorter than for other solids in the range?
Because of oxidation. Twelve months is the practical window for maintaining colour and assay in sealed packaging; older material should be retested before use in a colour-sensitive or polymer-grade process.
Is MPDA hazardous?
Yes. It is acutely toxic, a skin sensitiser, suspected of causing genetic defects, and very toxic to aquatic life with long-lasting effects. Trained personnel, containment, and full PPE are required per the Safety Data Sheet.
Do you provide a Certificate of Analysis?
Yes. Every batch ships with a Certificate of Analysis and Safety Data Sheet covering assay, isomer content, melting range, moisture, colour, and appearance.