Para Toluidine
A high-purity methylated aromatic amine supplied as flakes for azo dye and pigment manufacture, rubber chemicals, and pharmaceutical intermediate synthesis.
What is Para Toluidine?
Para Toluidine — PT, or 4-methylaniline — is a white crystalline solid with a methyl group opposite the amino group on a benzene ring. Fresh material is close to white and develops a reddish-brown cast on exposure to air.
The methyl group is electron-donating, which makes the amine more basic than aniline and the ring more reactive toward coupling. In azo chemistry that translates into stronger, more yellow-shaded colours, and it is why para toluidine is one of the classic colour bases.
At Chelora Chemicals, PT is crystallised and refined with isomer content, melting range, and colour held to specification, giving dye and pigment manufacturers consistent diazotisation and shade reproducibility between batches.
- Appearance
- White to pale brown crystalline flakes
- Odour
- Characteristic amine odour
- Solubility
- Slightly soluble in water; soluble in alcohol, ether, dilute acid
- Function
- Chemical intermediate
- Grade
- Technical / dye
Formula diagram
Aniline ring with a methyl group in the para position
- Molecular formulaC7H9N
- Molecular weight107.15 g/mol
- IUPAC name4-Methylaniline
- Functional groupsPrimary aromatic amine, alkyl
- CAS number106-49-0
Technical product information
Standard specification for Chelora Chemicals' technical grade Para Toluidine. Custom-grade and bulk specifications are available on request.
| Chemical name | Para Toluidine |
|---|---|
| Synonyms | PT, 4-Methylaniline, p-Toluidine, 4-Aminotoluene |
| CAS number | 106-49-0 |
| Molecular formula | C7H9N |
| Molecular weight | 107.15 g/mol |
| Assay (purity) | ≥ 99.5% |
| Appearance | White to pale brown crystalline flakes |
| Melting point | 43–45°C |
| Boiling point | 200°C |
| Flash point | 87°C (closed cup) |
| Isomer content | ≤ 0.3% |
| Moisture | ≤ 0.3% |
| Packaging | 25 kg bags, 200 kg drums, molten tanker |
| Shelf life | 24 months from date of manufacture |
Applications of Para Toluidine
Azo dyes
Diazotised as a colour base for azo dyes across textile, leather, and paper applications.
Organic pigments
A classic diazo component in yellow and red pigment manufacture for inks and coatings.
Rubber chemicals
Used in the synthesis of accelerators, antioxidants, and antidegradants.
Pharmaceutical intermediates
Provides a methylated aniline core for amide and heterocyclic building blocks.
Agrochemical intermediates
Applied in herbicide and fungicide synthesis routes requiring a toluidine fragment.
Specialty chemicals
Used in optical brighteners, photographic chemicals, and analytical reagents.
Why choose Chelora Chemicals
Every batch of Para Toluidine 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 ≥99.5% 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 bags to drums and molten tanker supply.
Technical support
Process, handling, and compliance guidance from our chemistry team.
Storage and guidelines
- 01Store in tightly closed original packaging in a cool, dry, well-ventilated store.
- 02Keep below 30°C — the product melts near 44°C and cakes in warm storage.
- 03Protect from air and light; fresh white material develops a reddish-brown cast on oxidation.
- 04Segregate from strong oxidising agents, acids, and acid chlorides.
- 05Keep packaging sealed and palletised, and re-seal promptly after use.
- 06Prevent release to drains, surface water, and soil; the product is toxic to aquatic life.
Handling precautions
Para toluidine is toxic by inhalation, ingestion, and skin absorption, and is classified as a suspected carcinogen. It is for industrial use by trained personnel only.
Absorbed material forms methaemoglobin, reducing the blood's oxygen-carrying capacity. Chemical-resistant gloves, coveralls, eye protection, and respiratory protection are required.
The product melts at a low temperature, so warm-weather storage can produce partially molten material. Check packaging before opening and avoid skin contact with the liquid phase.
Control dust during bag emptying and charging, and use local exhaust ventilation at all transfer and melting points.
Refer to the full Safety Data Sheet for exposure limits, medical surveillance, spill response, and first-aid measures before use.
Frequently asked questions
What is Para Toluidine used for?
It is a dye and pigment colour base, a rubber chemical intermediate, and a building block for pharmaceutical and agrochemical synthesis. It is an intermediate, not a finished product.
What is the difference between para, ortho, and meta toluidine?
All three are C7H9N and differ only in where the methyl group sits relative to the amino group. Para toluidine is a solid melting near 44°C, while ortho and meta toluidine are liquids at room temperature. They give different shades and are not interchangeable.
Why does the methyl group matter in dye chemistry?
It donates electron density to the ring, increasing the basicity of the amine and the reactivity of the ring toward coupling. The result is stronger colour yield and a shade shift compared with plain aniline.
Why does the white flake turn pink or reddish-brown?
Air and light oxidise the amine to coloured impurities. It happens to all toluidines and does not usually affect assay, but colour matters for shade-critical work, so sealed, cool, dark storage is worth the effort.
Is Para Toluidine soluble in water?
Only slightly in neutral water. It dissolves readily in alcohols, ether, and dilute mineral acid, and acid dissolution is the usual first step before diazotisation.
Can it be supplied molten?
Yes. With a melting point around 44°C, molten supply in heated tankers is practical for bulk users and avoids dust exposure. The receiving site needs dedicated heated lines and temperature control.
What purity do you supply?
Standard technical grade is supplied at a minimum assay of 99.5% with isomer content at or below 0.3% and moisture at or below 0.3%. Tighter colour and isomer specifications can be produced to order.
What packaging sizes are available?
25 kg bags, 200 kg drums, and molten product in heated tankers. Samples are available for shade and coupling trials.
Is Para Toluidine hazardous?
Yes. It is acutely toxic by several routes, absorbed through skin, a suspected carcinogen, and toxic to aquatic life. Trained personnel, engineering controls, and full PPE are required per the Safety Data Sheet.
Why is it flagged as combustible?
Its flash point is 87°C, so the molten product and any heated operation can generate ignitable vapour. Keep melting and transfer operations away from ignition sources and ensure adequate ventilation.
Do you provide a Certificate of Analysis?
Yes. Every batch is dispatched with a Certificate of Analysis and Safety Data Sheet covering assay, isomer content, melting range, moisture, colour, and appearance.