Para Toluidine
Para Toluidine — PT or 4-methylaniline — is one of the foundation stones of the colour industry. Diazotised and coupled, it builds the toluidine reds and yellows that have anchored printing ink and coatings ranges for a century, and it carries on into dyes, optical brighteners, rubber chemicals and agrochemical intermediates.
Chelora Chemicals supplies Para Toluidine to pigment houses, dye manufacturers, agrochemical producers and fine chemical plants worldwide, in bags, drums and container quantities, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 106-49-0
- IUPAC name
- 4-Methylaniline
- Molecular formula
- C7H9N
- Molecular weight
- 107.15 g/mol
- EC / EINECS
- 203-403-1
- MDL number
- MFCD00007906
- SMILES
- Cc1ccc(N)cc1
- HS Code
- 2921 43*
* Confirm the exact HS heading with your customs broker — toluidines sit under a different subheading from the simple anilines, and destination tariffs vary.
What Para Toluidine is used for
Para Toluidine is aniline with a methyl group para to the amine. The methyl is electron-donating, which makes the ring slightly more reactive than plain aniline and — more importantly for colour chemistry — shifts the absorption of any chromophore built from it toward a warmer, more yellow-red shade. That shade shift is the commercial point of the molecule.
In practice PT is a captive intermediate: pigment and dye plants buy it to diazotise and couple, or to nitrate and reduce on the way to a more elaborate coupling component. Beyond colour, it turns up as an aryl amine building block in agrochemical, rubber and pharmaceutical synthesis wherever a 4-methylphenyl fragment is wanted on the finished molecule.
Why the isomer matters
The three toluidine isomers look alike on a packing list and behave nothing alike in a reactor. In colour work the substitution is particularly unforgiving, because the wrong isomer still couples — it simply gives the wrong shade:
- Para toluidine (CAS 106-49-0) — this product. Methyl para to the amine. The classic pigment and dye diazo base.
- Ortho toluidine (CAS 95-53-4) — methyl adjacent to the amine, with a very different steric profile and its own dye and agro routes. Note that it carries a stricter carcinogenicity classification than the para isomer.
- Meta toluidine (CAS 108-44-1) — the 1,3 pattern, used in dye and specialty synthesis.
If your purchase order simply says "toluidine", quote us the CAS number and we will confirm the correct material before the order is placed. We supply the sister isomers as well — see the full intermediate range.
Appearance and handling character
PT ships as white to light brown lustrous crystals, flakes or plates melting around 44 °C — low enough that an uncooled container on a tropical routing will very likely soften or fuse the contents. Material that has melted and re-set is chemically unchanged but can arrive as a single cake, so pack format and stowage are worth planning rather than leaving to the freight desk. It is only slightly soluble in water and dissolves readily in alcohols and ether. Like all primary aromatic amines it darkens on exposure to air and light, and in colour work that drift is not purely cosmetic — specify a colour ceiling if your shade is tightly standardised.
| Parameter | Typical value |
|---|---|
| Appearance | White to light brown crystals / flakes |
| Assay (GC) | 99.0% min |
| Moisture (KF) | 0.3% max |
| Melting range | 43 – 46 °C |
| Total isomeric impurities | 0.5% max |
| Insolubles / residue | Reported per batch |
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. If your process demands a tighter assay, a specific ortho-isomer limit, a colour ceiling or a controlled moisture figure, 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 | ≈ 43 – 46 °C |
| Boiling point | ≈ 200 °C @ 760 mmHg |
| Flash point | ≈ 87 °C |
| Relative density | ≈ 1.05 @ 20 °C |
| Auto-ignition temperature | ≈ 480 °C |
| Water solubility | ≈ 6.6 – 7.5 g/L @ 20 °C |
| Organic solubility | Freely soluble in alcohols, ether, dilute acids |
| Stability | Light, air and heat sensitive; colours on storage |
Physical constants compiled from public reference data for CAS 106-49-0 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
Colour chemistry takes the bulk of global para toluidine consumption. The balance runs through agrochemical, rubber and fine chemical synthesis.
Azo pigments
The dominant outlet. Nitrated to 4-methyl-2-nitroaniline and then diazotised and coupled onto a naphthol, PT builds the classic toluidine reds — the bright, economical monoazo pigments that still anchor printing ink, coating and coloured-plastic ranges worldwide.
- Toluidine red and related monoazo shades
- Isomer content shows up directly as off-shade
- Largest single source of PT demand
Dyes & optical brighteners
A long-established diazo and coupling component across azo dye ranges for textiles, paper and leather, and a building block in the stilbene and triazine chemistry behind fluorescent whitening agents.
- Azo dyes for textile and paper
- Brightener and whitening agent chains
- Shade consistency batch to batch matters
Agrochemical intermediates
Acylated, or converted to the corresponding isocyanate and reacted onward, PT provides the 4-methylphenyl fragment in anilide and substituted-urea chemistry used across crop protection.
- Anilide and urea formation
- Custom intermediate synthesis
- See our agrochemical intermediate range
Pharmaceutical & fine chemicals
A cheap, well-behaved aryl amine handle for amide, sulfonamide and Schiff base formation, and a starting point for substituted toluidine derivatives used across medicinal and specialty chemistry.
- Amide and sulfonamide formation
- Heterocyclic ring construction
- Available in trial and laboratory quantities
Rubber & polymer chemistry
Aryl amines feed the accelerator and antioxidant chains that protect elastomers against heat and oxidative ageing. A steady, lower-visibility outlet running at technical rather than pigment-grade purity.
- Accelerator and antioxidant synthesis
- Tyre and technical rubber compounding
- Looser colour tolerance acceptable
Contract & scheduled supply
Pigment plants run shade campaigns rather than continuous single-product output. Most PT 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 Toluidine
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. We own no toluidine plant — and for a colour-critical 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 isomer tolerance, your colour requirement, your price point and your delivery window.
We keep a second qualified source on this line. When a plant goes down for maintenance, or a monsoon disrupts a road corridor, your shade campaign switches source rather than stalling mid-programme.
- Specification read against the CAS first. We confirm you need 106-49-0 and not the ortho or meta isomer before we quote a price — and the ortho isomer carries a different hazard profile, so the distinction matters twice over.
- Batch COA shared before dispatch. You approve the assay, moisture, colour and impurity profile against your own spec while the material is still in our warehouse.
- Shade continuity taken seriously. Where a colour house has qualified a source, we work to keep you on it rather than rotating suppliers batch to batch.
- Pre-shipment samples for qualification. New account or new source, your laboratory runs a coupling trial before the full quantity ever moves.
- Packing chosen for your climate. With a melting point near 44 °C, pack format and stowage matter on a tropical routing. We plan both with you.
- 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 PT 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 and your handling effort. Tell us how the material will be charged at your end and we will quote the format that suits your operation — not just the one that suits ours.
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 for longer sea transits and humid destinations. Better protection against moisture pick-up, air ingress and colour drift than bagged material.
Jumbo / FIBC bags
Bulk bags with liner for high-volume users 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 colour laboratory can run a coupling 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
Pigment plants run to shade campaigns. We hold contracted tonnage and release it against your production calendar instead of landing it all at once.
Handle this as a toxic, absorbable amine
PT is not a benign solid. It is acutely toxic by all three routes, readily absorbed through intact skin, a skin sensitiser, and carries a suspected carcinogenicity entry. It is also very toxic to aquatic life. 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 and emergency planning.
Classified hazards
H301Toxic if swallowed.H311Toxic in contact with skin.H331Toxic if inhaled.H317May cause an allergic skin reaction.H319Causes serious eye irritation.H351Suspected of causing cancer.H410Very toxic to aquatic life with long lasting effects.
Hazard statements reflect the GHS classification commonly published for CAS 106-49-0. Some suppliers additionally assign organ-toxicity statements; always read the SDS issued with your specific batch.
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. 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. Contaminated clothing is a continuing exposure route — remove it immediately and wash the skin thoroughly.
- Have the SDS with the casualty. Toluidines can cause methaemoglobinaemia, and the treating clinician needs the product identity and CAS number in hand.
- Dispose as regulated waste through a licensed contractor, in line with your local chemical waste regulations.
Storage
- Cool, dry, dark, well-ventilated store. The melting point is only about 44 °C, so an uncooled store in a hot climate will fuse the contents — and heat accelerates the colour drift as well.
- Keep containers tightly closed. This product is light, air and heat sensitive; an open bag picks up both moisture and colour.
- Segregate from oxidising agents, strong acids, nitrites and acid chlorides. As a primary aromatic amine it reacts exothermically with acylating and oxidising reagents.
- Bunded, sealed-floor storage. The compound is very toxic to aquatic life — containment matters more than dilution in a spill scenario.
- Shelf life is typically 24 months in sealed original packing under these conditions. Re-assay and re-check colour before use after long storage.
Handling & PPE
- Skin protection is the priority. Toluidines are absorbed through intact skin — chemical-resistant gloves and coveralls, not just splash protection. H317 applies, so sensitisation is a real risk for repeat handlers.
- Engineering controls first. Charge under local exhaust ventilation or in a closed transfer system; with a suspected carcinogen, the hierarchy of control matters.
- Respiratory protection where dust or vapour may be generated — particularly when breaking a caked drum — per your own exposure assessment.
- Eye protection and an accessible eyewash and safety shower at all charging points — H319 applies.
- Never discharge to drain or watercourse. H410 applies — collect spills as solid waste and dispose of them as regulated chemical waste.
Transport
PT moves as regulated cargo. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. The applicable UN number, 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, moisture by Karl Fischer, appearance, melting range and impurity 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 number, 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.
How this toluidine becomes a pigment
Understanding what happens to PT downstream explains why the specification matters so much — and why an apparently small isomer impurity in the aniline shows up as an off-shade batch three steps later. The route below is the general industrial pattern, not a process disclosure.
Start with the methylated aniline
The para methyl group donates electron density into the ring, warming the shade of any chromophore built from it and raising reactivity relative to plain aniline.
Nitrate or acylate
For the classic reds the ring is nitrated to 4-methyl-2-nitroaniline. For anilide and urea chemistry the amine is acylated directly instead.
Diazotise
Sodium nitrite in acid at low temperature converts the amine to the diazonium salt. Temperature and acid strength govern the yield and the impurity burden.
Couple, finish and standardise
Coupling onto a naphthol gives the pigment, which is filtered, washed, dried, milled and standardised to shade — the point where any isomer-driven drift becomes visible.
Why aniline quality carries through the whole route
Every step acts on the nitrogen or on the ring beside it. Anything in the feed that competes for that nitrogen, or that carries its own reactive functionality, follows the material down the line:
- Isomeric toluidines nitrate at different positions and couple to different chromophores. The result is a shade that cannot be corrected by standardisation alone.
- Oxidation products — the coloured species responsible for the brown drift — dull the finished shade and cost you tinting strength.
- Residual water dilutes the acid charge and shifts the nitrite stoichiometry in diazotisation, and destroys acid chloride on an acylation route.
- Insolubles and heavy residues add filtration load, lengthen the batch cycle and can show as specks in a let-down.
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 Toluidine CAS 106-49-0 — this product | Toluidine red pigments Azo dyes & brighteners Agro and rubber intermediates |
| Ortho Toluidine CAS 95-53-4 | Dye intermediates Agrochemical actives Stricter hazard classification |
| Meta Toluidine CAS 108-44-1 | Dye and specialty synthesis |
If your route calls for a different isomer or a related aromatic amine, we supply those as well — see the full intermediate range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this intermediate
PT 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.
Downstream colour demand
Pigment demand tracks coatings, packaging ink and plastics output, so construction and consumer packaging cycles reach back to the toluidine within a quarter or two.
- Ink and coatings cycles drive volume
- Shade campaigns concentrate demand
- Contracted call-off smooths the exposure
Upstream feedstock
The route back to PT runs through toluene, nitration and hydrogenation. Movements in toluene, nitric acid and hydrogen feed through to the toluidine within a quarter or so.
- Toluene and nitration set the floor
- Energy cost weighs on distillation
- We flag feedstock-driven moves in the quote
Specification tier
Pigment-grade material with a colour ceiling and a tight ortho-isomer limit prices above technical grade destined for rubber or general synthesis. Paying for a spec you do not need is a common and avoidable cost.
- Tell us the end use, not just the purity
- Technical grade suits non-colour outlets
- We will say when a tighter spec is unnecessary
Pack format
Cost per kilo falls from 25 kg bags to drums to jumbo bags. If your charging system can take a bulk bag, the saving over a campaign usually dwarfs the handling change.
- Small bags carry the highest packing cost
- FIBC is cheapest per kilo at volume
- Disposal of packing is a hidden cost at your end
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, an environmental inspection or a monsoon disruption can take capacity offline at short notice. Single-sourced buyers feel this hardest — and a source change mid-shade is its own problem.
- 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 |
|---|---|
| Toluidine red pigments | Colour ceiling, tight ortho-isomer limit, low insolubles |
| Dyes & optical brighteners | As above, with shade consistency batch to batch |
| Agrochemical intermediates | High assay with controlled moisture |
| Rubber chemicals | Technical grade; looser colour tolerance acceptable |
| Laboratory / R&D | Small pack, high purity, full analytical pack |
Not sure which column you are in? Describe the reaction 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 reaction. Tell us the step you are running and we will recommend the specification — and say so plainly when a tighter, costlier grade would add nothing.
- Protect your shade continuity. Where a colour house has qualified a particular source, we work to keep you on it and flag in advance when a switch is unavoidable.
- Advise on handling and storage for your site conditions — a bagged store in a Gulf summer is a different problem from one in northern Europe, especially for a solid melting near 44 °C.
- 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
- Suspected carcinogen classification. Where that triggers obligations at your site — exposure monitoring, health surveillance, record retention — confirm what applies before the first delivery. The related ortho isomer is classified more strictly still, so do not carry assumptions across.
- Import controls vary by destination. Some jurisdictions apply registration, licensing or end-use declaration requirements to aromatic amines. 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.
- Textile and article restrictions can apply downstream of azo colourants depending on the end market. Your regulatory team should confirm the finished-article position for the shade you are building.
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 and complete documentation to work from.
From enquiry to delivered pallet
Send the specification
Product name or CAS 106-49-0, the assay, colour and impurity 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 for your coupling trial 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.
What buyers ask us about Para Toluidine
Is para toluidine interchangeable with ortho toluidine?
What purity do you normally supply?
Will a source change affect my shade?
What is the minimum order quantity?
How long does delivery take?
The material arrived caked or partly fused. Is it off-spec?
Why does the solid darken in storage, and does it matter?
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 Toluidine
Send your required assay, colour ceiling, 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.