Para Phenylene Diamine
A high-purity aromatic diamine supplied for para-aramid fibre, rubber antidegradant, and dye intermediate manufacture.
What is Para Phenylene Diamine?
Para Phenylene Diamine — PPD — is a white to light purple crystalline solid with amino groups at opposite ends of the ring. It darkens rapidly on exposure to air, often within minutes of opening a container.
The straight, symmetrical geometry is what makes it valuable. Polymerised with terephthaloyl chloride it gives para-aramid, whose rod-like chains align into the exceptionally strong fibres used in ballistic and cut protection. The same difunctional structure feeds rubber antidegradants and oxidative dye chemistry.
At Chelora Chemicals, PPD is crystallised and packaged with assay, melting range, and colour held to specification, and handled to limit the rapid oxidation to which para diamines are especially prone.
- Appearance
- White to light purple crystalline solid
- Odour
- Faint amine odour
- Solubility
- Soluble in water, alcohol, and ether
- Function
- Monomer / chemical intermediate
- Grade
- Technical / polymer
Formula diagram
Two amino groups at opposite ends of the ring
- Molecular formulaC6H8N2
- Molecular weight108.14 g/mol
- IUPAC name1,4-Phenylenediamine
- Functional groupsTwo primary aromatic amines
- CAS number106-50-3
Technical product information
Standard specification for Chelora Chemicals' technical grade Para Phenylene Diamine. Custom-grade and bulk specifications are available on request.
| Chemical name | Para Phenylene Diamine |
|---|---|
| Synonyms | PPD, PPDA, 1,4-Phenylenediamine, p-Phenylenediamine |
| CAS number | 106-50-3 |
| Molecular formula | C6H8N2 |
| Molecular weight | 108.14 g/mol |
| Assay (purity) | ≥ 99.0% |
| Appearance | White to light purple crystalline solid |
| Melting point | 139–143°C |
| Boiling point | 267°C |
| Flash point | > 150°C (closed cup) |
| Isomer content | ≤ 0.5% |
| Moisture | ≤ 0.5% |
| Packaging | 25 kg drums, 500 kg jumbo bags |
| Shelf life | 12 months in sealed original packaging |
Applications of Para Phenylene Diamine
Para-aramid fibre
Polymerised with terephthaloyl chloride to give the rigid-chain polymer behind high-strength aramid fibres.
Rubber antidegradants
The amine component of phenylenediamine antiozonants used in tyre and technical rubber compounds.
Azo & oxidative dyes
Used as a coupling and oxidation base in dye chemistry, including hair colourant systems where permitted.
Polymer intermediates
Applied as a chain extender and monomer in polyimide and high-performance resin systems.
Antioxidants
Feeds the synthesis of amine antioxidants for polymers and lubricants.
Specialty chemicals
Used in corrosion inhibitor and specialty amine derivative manufacture.
Why choose Chelora Chemicals
Every batch of Para 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 500 kg jumbo bags and full container loads.
Technical support
Process, handling, and compliance guidance from our chemistry team.
Storage and guidelines
- 01Store in tightly sealed original packaging under nitrogen — this product oxidises faster than almost anything else in the range.
- 02Keep cool, dry, and completely protected from air and light.
- 03Expect rapid darkening once a container is opened; re-seal and re-blanket immediately after each withdrawal.
- 04Segregate from strong oxidising agents, acids, and acid chlorides.
- 05Keep drums and bags palletised and dry, with dust control at every transfer point.
- 06Prevent any release to drains, surface water, or soil — the product is very toxic to aquatic life.
Handling precautions
PPD is toxic if swallowed, in contact with skin, or if inhaled, and is a potent skin sensitiser. It is for industrial use by trained personnel only.
Sensitisation is the defining occupational hazard here. PPD is one of the most significant contact allergens in industrial use, and once a worker is sensitised, very low subsequent exposures provoke reactions. Preventing first contact is the control strategy, not limiting dose.
Chemical-resistant gloves with verified breakthrough data, coveralls, eye protection, and respiratory protection are required, with rigorous dust control at every drum or bag opening.
The substance is absorbed through intact skin and can affect the blood by forming methaemoglobin.
The product is very toxic to aquatic organisms with long-lasting effects. Contain all spills and dispose of waste through licensed routes.
Some jurisdictions restrict PPD concentrations in consumer products, particularly cosmetic and hair colourant applications. Confirm the requirements for your finished product before formulating.
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 Para Phenylene Diamine used for?
Its largest outlets are para-aramid fibre manufacture and rubber antidegradants. It is also used in dye chemistry, including oxidative hair colourants where permitted, and in high-performance polymer systems.
How does PPD differ from MPDA and OPDA?
All three are C6H8N2 with a weight of 108.14, differing only in where the second amine sits. PPD's straight, symmetrical geometry gives rigid-rod polymers; MPDA's kinked geometry gives flexible meta-aramids; OPDA's adjacent amines close into benzimidazole rings. They are not interchangeable.
Why does para geometry give stronger fibre?
Because the polymer chains come out straight rather than kinked. Straight chains pack and align closely, letting hydrogen bonding between them carry load efficiently, which is what produces the tensile strength para-aramids are known for.
Why does the product darken so fast?
Para diamines oxidise very readily, and PPD is among the fastest. Material can visibly darken within minutes of air exposure. This is normal and does not necessarily indicate assay loss, but it makes nitrogen blanketing essential for colour-sensitive use.
How serious is the sensitisation risk?
It is the main reason this product is handled the way it is. PPD is a well-documented and potent contact allergen. Sensitised individuals react to very low exposures thereafter, so exposure prevention rather than exposure limitation is the correct approach.
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 chemistry and its environmental behaviour after a spill.
Are there restrictions on PPD in consumer products?
Yes, in many jurisdictions, particularly for cosmetic and hair colourant use where maximum concentrations and labelling requirements apply. Confirm the rules for your finished product and market before formulating.
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%. Polymer-grade specifications with tighter colour and metals limits can be manufactured to order.
What packaging sizes are available?
25 kg drums and 500 kg jumbo bags under nitrogen, with full container loads for bulk users.
Why is the shelf life only twelve months?
Oxidation. Twelve months is the practical window for holding colour and assay in sealed, blanketed packaging. Older stock should be re-assayed before use in polymer or colour-critical work.
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.