Para Toluidine 4-Methylaniline (p-Toluidine) · CAS 106-49-0

What is Para Toluidine?

Para Toluidine, formally 4-methylaniline, is a toluene ring carrying a single amine group para to the methyl substituent, formula C₇H₉N. At room temperature it is a colourless to pale flake solid that darkens progressively on exposure to air and light, melting around 44–45 °C.

Its value as an intermediate comes from the aromatic amine's reactivity: it diazotises cleanly for azo-dye coupling, acylates to give rubber-accelerator intermediates, and condenses in a range of pharmaceutical and agrochemical syntheses.

Commercially, it is produced from toluene by nitration followed by selective hydrogenation, or by reduction of p-nitrotoluene, with isomer separation from the ortho- and meta-toluidines carried out during purification.

It ships as a toxic solid (Class 6.1) rather than under flammable-liquid classifications — handling follows standard toxic-solid precautions, with particular attention to dust control and skin contact.

Why Para Toluidine specifically

• A clean diazotisation substrate. The para-methyl, para-amine arrangement gives predictable, high-yield diazo coupling for azo-dye manufacture.
• An established rubber-chemical intermediate. Acylation and condensation chemistry built from this amine feeds vulcanisation-accelerator synthesis.
• A pharmaceutical and agrochemical building block. Used across a range of active-ingredient and intermediate syntheses that specifically call for the para-substituted toluidine.
• The specific isomer the route needs. The para- pattern is distinct from ortho- and meta-toluidine, and routes built around it need this isomer specifically, not a mixture.

How Para Toluidine is Manufactured

Para Toluidine is made through a controlled nitration and selective reduction sequence from toluene, so supply tracks installed nitrotoluene and hydrogenation capacity rather than a generic aromatics feedstock stream.

• Nitration of toluene. Mixed nitration gives a blend of ortho-, meta- and para-nitrotoluene isomers.
• Isomer separation. The para-nitrotoluene fraction is separated by distillation or crystallisation ahead of reduction.
• Catalytic hydrogenation. The nitro group is reduced to an amine, giving crude para-toluidine.
• Purification. The crude amine is purified by distillation or crystallisation to the target purity, typically 98% or better.
• Quality release and packing. Melting point, assay and colour are confirmed against specification, and the flaked solid is packed promptly to limit air exposure.

Typical Commercial Specification

Figures below are representative of commercial-grade para toluidine. Tell us your downstream route and the grade you need, and we will advise on the specification to order against.

Physical & Chemical Properties

Behaviour in the process

Para Toluidine's reactivity pattern is what dye, rubber-chemical and pharma intermediate producers are buying:

• Diazotisation. Reacts cleanly with nitrous acid to form a diazonium salt for azo-dye coupling reactions.
• Acylation. Reacts with acid chlorides and anhydrides to give amide intermediates used in rubber-chemical and pharma synthesis.
• Alkylation and condensation. The aromatic amine undergoes standard N-alkylation and condensation reactions common to primary aromatic amines.
• Base reactivity. As a weak aromatic amine base, it readily neutralises acids in exothermic reactions to form salts.

Para Toluidine and Related Toluidines

Para Toluidine is one of three toluidine isomers, and the choice between them depends entirely on the substitution pattern the target synthesis needs.

Stated plainly: the choice of toluidine isomer is dictated by the target dye or intermediate's exact substitution pattern — a route designed around para-substituted chemistry needs this isomer, and a different pattern requires a different starting material.

Industries We Supply Para Toluidine To

The same amine building block feeds an azo-dye manufacturer, a rubber-chemical producer, and a pharmaceutical intermediate plant. What changes is the downstream condensation chemistry and the documentation each requires.

Where Para Toluidine is Used

Para Toluidine is bought for several distinct downstream chemistries. These are the applications our customers use it for.

In dye and pigment synthesis

Para Toluidine is diazotised under controlled, low-temperature acidic conditions, and the resulting diazonium salt is coupled to a second aromatic component to build the azo chromophore. Isomer and colour-grade quality are what determine final dye shade consistency.

In rubber and pharmaceutical intermediates

In rubber chemistry, acylated derivatives of this amine feed accelerator intermediate synthesis; in pharmaceutical and agrochemical routes, it serves as a building block condensed or coupled into the target active ingredient.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis, with isomeric purity and colour grade reported alongside the main assay because both affect downstream diazotisation and coupling performance.

• p-Toluidine content — by GC assay, the primary grade measure.
• Melting point — a fast purity and identity check.
• Isomeric purity — ortho- and meta-toluidine carryover, reported because it affects dye-coupling shade consistency.
• Colour grade — reported because oxidative discolouration is a practical indicator of handling quality since manufacture.

Common Process Problems & Likely Causes

When this amine causes trouble, it is usually isomer carryover or oxidative discolouration. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Standard packing. Fibre drums or HDPE bags, typically 25 – 200 kg net, with larger bulk formats on contract supply.
• Oxidation protection. Keep sealed and protected from air and light; the amine darkens progressively on exposure, affecting colour grade.
• Temperature control. Store in a cool, dry, well-ventilated area away from direct sun and heat sources.
• Material compatibility. Avoid contact with strong oxidisers and strong acids.
• Shelf life. Best used within a reasonable period of manufacture; colour grade degrades gradually even in sealed storage.
• Transport classification. UN 3451, Toluidines, solid, Class 6.1, Packing Group II. ADR, IMDG, IATA and DOT requirements apply to packing, labelling and routing.

Hazards & Safe Handling

Para Toluidine is toxic if swallowed, in contact with skin or if inhaled, and is very toxic to aquatic life. As a Packing Group II toxic solid, it carries a more severe hazard rating than many other toluidine-family amines, so standard toxic-solid precautions and good laboratory and plant practice apply throughout handling.

• Skin and eye contact. Chemical-resistant gloves and goggles are standard practice; rinse thoroughly with water on contact and seek medical advice for eye exposure.
• Inhalation. Use adequate ventilation and dust control when handling the flaked solid; avoid breathing dust or fumes.
• Ingestion risk. Classified toxic if swallowed; treat as a higher-severity toxic solid than many related amines given its Packing Group II rating.
• PPE. Chemical-resistant gloves, safety goggles and, where dust is generated, a suitable respirator.
• Environment. Very toxic to aquatic organisms; avoid uncontrolled release to water and follow local effluent rules.

Regulatory & Compliance Notes

Para Toluidine is a registered specialty amine shipped as a Class 6.1 toxic solid. Because obligations differ by territory and use, the notes below are orientation rather than legal advice — confirm your own position with your regulatory adviser.

• GHS classification. Classified as toxic if swallowed, in contact with skin or if inhaled, and very toxic to aquatic life; the SDS carries the full hazard statements for your grade.
• REACH and chemical inventories. Registered under EU REACH and listed on major chemical inventories.
• Dangerous goods transport. UN 3451, Toluidines, solid, Class 6.1, Packing Group II. ADR, IMDG, IATA and DOT requirements apply to packing, labelling and routing.
• HS code. Commonly declared under the toluidine derivatives heading; confirm the exact tariff line with your customs broker for your jurisdiction.
• Quality agreements. Dye, rubber-chemical and pharma producers commonly expect documented purity, isomeric purity and change control. Tell us what your agreement requires.

We Supply Para Toluidine Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Para Toluidine from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged as routing allows.
• Documentation. Commercial invoice, packing list, certificate of origin, COA and SDS issued as a complete set.
• Flexible volumes. From trial quantities up to repeat bulk shipments on a supply contract.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying Para Toluidine from Chelora

We are an independent sourcing and supply partner. For this product that means settling three things at enquiry: the purity and isomer-purity grade your application needs, the packing format, and the quantity you are buying.

• Documentation on every lot. Batch-specific COA with assay, isomer breakdown and colour, plus the current SDS.
• Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
• Quantities. Trial quantities through to larger bulk shipments on contract supply.
• Inspection. Independent third-party inspection available at loading when the contract requires it.
• Related amines. Ortho- and meta-toluidine alongside this product from one supplier.

How ordering works

• Send the enquiry. Purity, isomer-purity grade, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing format and a sample COA, normally within one working day.
• Qualify the supply. For first orders or dye- and pharma-grade applications, we share the analysis so your technical team can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Allocation and QC. Material allocated and released against a batch-specific COA, with an independent inspection where the contract calls for it.
• Ship and document. Packed, labelled and loaded with the full export document set, and tracked through to arrival.

Related Aromatic Amine Intermediates

Buyers of para toluidine often source other aromatic amine intermediates alongside it. Consolidating them cuts freight cost and gives you a single point of contact for documentation.