Para Phenylenediamine
Para Phenylenediamine — PPD or 1,4-diaminobenzene — is the essential building block of two very different, high-value markets: para-aramid fibre (the polymer family used in ballistic and cut-resistant textiles and reinforcement), and oxidative hair-colour and fur-dye chemistry. It is also a core precursor for rubber antiozonant and antioxidant chemistry.
Chelora Chemicals supplies PPD to fibre and polymer manufacturers, hair-colour and cosmetic-ingredient producers, and rubber-chemical formulators worldwide, in bags, drums and container quantities, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 106-50-3
- IUPAC name
- Benzene-1,4-diamine
- Molecular formula
- C6H8N2
- Molecular weight
- 108.14 g/mol
- EC / EINECS
- 203-404-7
- UN Number
- 1673
- SMILES
- Nc1ccc(N)cc1
- HS Code
- 2921 51*
* Confirm the exact HS heading with your customs broker — classification of phenylenediamine isomers varies between destination tariffs.
What Para Phenylenediamine is used for
Para Phenylenediamine is benzene carrying two amino groups in the 1,4 (para) pattern — the two amines sit directly opposite one another across the ring. That linear geometry is exactly what step-growth polymerisation needs to build fully extended, rigid polymer chains, and PPD's condensation with terephthaloyl chloride gives poly(p-phenylene terephthalamide), the para-aramid polymer spun into some of the highest tensile-strength fibres commercially produced, used in ballistic protection, tyre reinforcement, ropes and composite structures.
The same molecule, in an entirely different reaction, oxidises to a coloured quinonediimine species that couples with modifier compounds to build the permanent dark shades used across oxidative hair colourants and fur dyes — the highest-visibility use of PPD, and the one behind most of the consumer-facing regulatory attention this molecule receives.
Why the isomer matters
The three phenylenediamine isomers have distinct chemistry, hazard profiles and end-markets, and a substitution downstream is not recoverable:
- 1,4-Diaminobenzene / para phenylenediamine (CAS 106-50-3) — this product. The linear-geometry isomer: para-aramid fibre and oxidative hair-dye chemistry.
- 1,3-Diaminobenzene / meta phenylenediamine (CAS 108-45-2) — the meta isomer, used for meta-aramid fibre and epoxy curing. See our meta phenylenediamine page.
- 1,2-Diaminobenzene / ortho phenylenediamine (CAS 95-54-5) — the ortho isomer, the benzimidazole-chemistry workhorse. See our ortho 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
PPD ships as a white to light purple crystalline solid melting around 140–147 °C, which turns purple, then black, on exposure to air — this oxidation is not subtle, and is one reason the material is normally handled and stored under inert atmosphere. It is soluble in water, alcohol and most polar organic solvents. Read the safety section before planning any handling: PPD is a strong, well-documented skin sensitiser and can cause severe allergic reactions, and the fine powder is also a dust-explosion hazard — both facts should shape your controls from the outset.
| Parameter | Typical value |
|---|---|
| Appearance | White to light purple crystalline solid |
| Assay (GC/titration) | 99.0% min |
| Moisture (KF) | 0.3% max |
| Melting range | 138 – 147 °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 and cosmetic-ingredient manufacture are both 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 | ≈ 140 – 147 °C |
| Boiling point | ≈ 267 °C |
| Flash point | ≈ 156 °C |
| Water solubility | Freely soluble |
| Organic solubility | Soluble in alcohol & most polar organic solvents |
| Dust hazard | Finely powdered material poses a dust-explosion risk |
| Odour | Faint, amine-like |
Physical constants compiled from public reference data for CAS 106-50-3 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
PPD's volume splits across two very different, high-value markets, with rubber-chemical demand as a significant third outlet.
Para-aramid fibre
The defining high-performance outlet. PPD condenses with terephthaloyl chloride to give poly(p-phenylene terephthalamide), spun into extremely high tensile-strength fibres used in ballistic protection, tyre reinforcement and composite structures.
- Polymerisation-grade purity and colour are critical
- Trace-metal control matters for fibre performance
- See our full aromatic diamine range
Oxidative hair & fur dye chemistry
PPD oxidises and couples with modifier compounds to build the permanent dark shades used across the hair-colourant and fur-dye industries — the highest-visibility, and most tightly regulated, use of this molecule.
- Primary intermediate in oxidative colour systems
- Cosmetic-grade purity and regulatory documentation available
- See also meta phenylenediamine
Rubber antiozonants & antioxidants
PPD is the aromatic core of the p-phenylenediamine-class antiozonants and antioxidants that protect tyre and technical rubber compounds from ozone cracking and oxidative degradation.
- Antiozonant intermediate chemistry
- Tyre and technical rubber goods sector
- Tight isomer limits usually apply
Photographic & analytical chemistry
PPD derivatives are used as colour photographic developing agents, and the parent compound serves as an analytical reagent for detecting trace iron and copper, and in select polymer synthesis for covalent organic frameworks.
- Colour photographic developer chemistry
- Analytical/diagnostic reagent chemistry
- Reagent-grade purity available
Fine & specialty synthesis
A well-characterised diamine building block for custom polyamides, polyimides and heterocyclic chemistry where the 1,4-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 cosmetic-ingredient plants run to campaign, not to a calendar month. Most PPD 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 Para Phenylenediamine
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. We own no phenylenediamine plant — and for a polymer-grade and cosmetic-adjacent, 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 106-50-3 and not the ortho or meta 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 is a strong, well-documented skin sensitiser and a dust-explosion hazard in fine powder form, 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 polymerisation or formulation trial before the full quantity ever moves.
- Packing chosen to limit oxidation and dust. Given how visibly and quickly this material darkens in air, and its dust-explosion profile, we arrange sealed, nitrogen-blanketed packing on request.
- 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 PPD 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 — given the material's sensitisation potential, dust-explosion profile, and oxidation sensitivity — your operator exposure and finished colour alike. 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-critical fibre and cosmetic-grade material.
Jumbo / FIBC bags
Bulk bags with liner for high-volume fibre and rubber-chemical producers with closed, dust-controlled mechanical charging. Fewer handling movements and materially lower operator contact.
Samples & trial packs
Laboratory samples and pilot quantities dispatched by courier so your R&D team can run a polymerisation or formulation 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 cosmetic-ingredient 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 strong, well-documented sensitiser
This is the point on the page that matters most. Para phenylenediamine is one of the most clinically well-documented skin sensitisers among aromatic amines — it causes allergic contact dermatitis, and cross-reacts with other para-amino compounds. It is also toxic by ingestion, skin contact and inhalation, and finely powdered material poses a dust-explosion hazard. 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
H317May cause an allergic skin reaction.H301Toxic if swallowed.H311Toxic in contact with skin.H319Causes serious eye irritation.H331Toxic if inhaled.H410Very toxic to aquatic life with long lasting effects.
Hazard statements reflect the harmonised GHS classification commonly published for CAS 106-50-3 (GHS06 Toxic, GHS07 Exclamation mark, GHS09 Environmental hazard). PPD is widely recognised clinically as a marker of group sensitivity to para-amino compounds such as benzocaine and certain azo dyes. Supplier classifications may differ in detail; always read the SDS issued with your specific batch, and treat the sensitisation entry as the one that shapes 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.
- Control ignition sources around dust. Finely powdered material poses a dust-explosion hazard — eliminate ignition sources and use appropriately rated equipment when handling a significant spill.
- Assume skin absorption and treat every exposure as a sensitisation risk. Contaminated clothing is a continuing exposure route — remove it immediately and wash the skin thoroughly.
- Have the SDS with the casualty. PPD can cause severe allergic and anaphylactoid reactions in sensitised individuals; the treating clinician needs the product identity and CAS number in hand.
- Record the exposure. For a strong sensitiser with a well-documented clinical history, exposure records should be created and retained as a matter of course. That is a decision for your EHS function, made before an incident rather than after one.
Storage
- Cool, dry, well-ventilated store, away from direct sunlight and heat sources. The melting point sits around 140–147 °C, comfortably above ordinary storage and transit temperatures.
- Keep containers tightly closed, and blanket with nitrogen where practical. This material oxidises rapidly and visibly on air exposure, turning purple then black — an open drum will change colour within hours to days.
- Segregate from oxidising agents, strong acids and acid chlorides. As a diamine it reacts exothermically with acylating and oxidising reagents.
- Control dust and ignition sources. Fine powder poses a dust-explosion hazard — bond and earth equipment used for transfer, and control static.
- Shelf life is typically 6–12 months in sealed original packing under these conditions — shorter than many anilines given its rapid oxidation. 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 — the standard hierarchy of control for a strong sensitiser.
- Skin protection is the absolute priority. PPD is one of the best-documented skin sensitisers among aromatic amines — chemical-resistant gloves, coveralls and full-face protection are the baseline, not the exception.
- Respiratory protection wherever dust may be present, particularly when breaking a caked drum or emptying a bulk bag.
- Previously sensitised individuals should not handle this material. Given how well-documented PPD sensitisation is, screen regular handlers and remove anyone showing signs of a reaction from further exposure.
- Never discharge to drain or watercourse. H410 applies — collect spills as solid waste and dispose of them as regulated chemical waste.
Transport
PPD 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.
Two reactions, two entirely different industries
PPD's linear, 1,4-diamine geometry supports two commercially important but unrelated reactions: polycondensation into an extended-chain polymer, and oxidative coupling into a coloured dye. The routes below are the general industrial pattern, not a process disclosure.
Start with the diamine
PPD provides two primary aromatic amine groups directly opposite one another on the ring — a linear geometry that favours fully extended, rigid polymer chains.
Door one — polycondense
Low-temperature solution polycondensation with terephthaloyl chloride builds poly(p-phenylene terephthalamide), which is wet-spun into para-aramid fibre.
Door two — oxidise and couple
In oxidative hair-dye and fur-dye systems, PPD is oxidised to a reactive quinonediimine intermediate, which couples with modifier compounds to build the final permanent dark shade.
Door three — build antiozonant chemistry
Substitution reactions on the nitrogen atoms build the p-phenylenediamine-class antiozonants and antioxidants used in rubber compounding.
Why feed quality carries through the whole route
All three doors depend on both amine groups being free, clean 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 oxidise differently and give different chain geometries or shade characters — a real defect risk in fibre-grade polymer work and a shade-consistency risk in dye work.
- Residual moisture can hydrolyse the acid chloride comonomer in fibre polymerisation, reducing molecular weight and fibre strength.
- Premature oxidation — the purple-to-black drift that gives PPD its distinctive storage behaviour — consumes reactive material before it reaches the intended reaction, reducing yield in both fibre and dye applications.
- Trace metals can catalyse unwanted oxidation during storage and processing, and are tightly controlled in both fibre-grade and cosmetic-ingredient 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 |
|---|---|
| Para Phenylenediamine CAS 106-50-3 — this product | Para-aramid fibre Oxidative hair & fur dyes Rubber antiozonants |
| Meta Phenylenediamine CAS 108-45-2 | Meta-aramid fibre Epoxy curing agents |
| Ortho Phenylenediamine CAS 95-54-5 | Benzimidazole chemistry Fungicide & pharma intermediates |
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
PPD 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.
Two independent demand cycles
High-performance fibre demand (defence, industrial, automotive) and hair-colourant demand (cosmetics, seasonal consumer trends) pull on the same molecule through different, largely uncorrelated 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 PPD runs through p-dinitrobenzene or 4-nitroaniline 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
PPD's clinically well-documented sensitisation profile attracts significant regulatory attention in the cosmetics sector specifically, and its dust-explosion and toxicity profile raises compliance cost across all applications.
- Cosmetic-use regulation is unusually detailed in many markets
- Handling obligations vary by jurisdiction and application
- We check destination rules before quoting
Pack format
Cost per kilo falls from 25 kg bags to drums to jumbo bags — and given the dust and sensitisation profile, sealed, dust-tight drums also directly reduce operator exposure.
- 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 cosmetics 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 |
|---|---|
| Para-aramid fibre | Polymerisation grade, tight colour and trace-metal limits |
| Oxidative hair/fur dyes | Cosmetic-grade purity, batch-certified colour and assay |
| Rubber antiozonant chemistry | High assay with tight isomer limits |
| Photographic/analytical reagent use | Very high purity, low metals |
| Laboratory / R&D | Small pack, high purity, full analytical pack |
Not sure which column you are in? Describe the reaction or formulation 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 or formulating a dye system, 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 sensitisation classification and its clinical significance 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 — controlling dust and oxidation both need particular attention on this product.
- 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
- Cosmetic-use regulation of PPD is unusually detailed in many jurisdictions. If your end use is a hair or fur dye product, confirm current permitted concentration limits and labelling requirements with your regulatory team before finalising a formulation — these rules change periodically.
- Sensitiser obligations apply broadly. Several regimes impose exposure monitoring and health surveillance for chemicals with this hazard profile, regardless of end use. 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. 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.
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 106-50-3, 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, cosmetics and rubber 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 Para Phenylenediamine
Is PPD safe to use in cosmetic products?
Can I use the ortho or meta 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 Para 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.