Ortho Chloro Para Nitro Aniline OCPNA · 2-Chloro-4-nitroaniline · CAS 121-87-9

What is Ortho Chloro Para Nitro Aniline?

Ortho Chloro Para Nitro Aniline, formally 2-chloro-4-nitroaniline, is a chlorinated nitroaniline, formula C₆H₅ClN₂O₂, that carries a chlorine ortho to the amine and a nitro group para to it. It is sold as a yellow to orange crystalline powder with a weak, characteristic odour, and melts in the region of 105–110 °C.

Its value as a dye intermediate comes from the combination of a reactive amine, an electron-withdrawing nitro group and a displaceable ortho-chlorine on the same ring, which lets it be diazotised and coupled to build azo chromophores, or used as a precursor to other chloronitroaniline and diaminobenzene derivatives, in a reliable and well-characterised sequence.

Commercially, it is produced by the ammonolysis of 2,4-dichloronitrobenzene (DCNB), in which ammonia selectively displaces the chlorine ortho to the nitro group under pressure, leaving the chlorine para to the nitro group intact on the ring.

It ships as a Class 6.1 toxic solid rather than a flammable-liquid classification, so transport and storage planning should centre on the toxicity and environmental hazard statements on the SDS rather than on fire risk.

Why Ortho Chloro Para Nitro Aniline specifically

• A proven diazo component. The aromatic amine diazotises cleanly and couples to give the azo dyes and pigments this intermediate is best known for.
• A displaceable chlorine. The ortho-chlorine, activated by the para-nitro group, is a handle for further nucleophilic substitution toward other fine-chemical and dye intermediates.
• The specific substitution pattern dye chemistry needs. The 2-chloro-4-nitro pattern on the aniline ring is specified by name in numerous azo dye and pigment synthesis routes.
• Established supply chain. As a long-established dye intermediate, OCPNA is produced at commercial scale with a mature, well-documented quality profile.

How Ortho Chloro Para Nitro Aniline is Manufactured

Ortho Chloro Para Nitro Aniline is made through a dedicated ammonolysis sequence from a dichloronitrobenzene feedstock, so supply tracks installed amination capacity rather than a generic aromatics stream.

• Feedstock preparation. 2,4-Dichloronitrobenzene (DCNB) is sourced or produced as the starting aromatic.
• Ammonolysis. The DCNB is reacted with ammonia under pressure and controlled temperature, selectively displacing the chlorine activated by the ortho-nitro group.
• Isolation. The crude amination product is separated from unreacted ammonia and by-product ammonium chloride.
• Purification. The crude solid is purified by recrystallisation or similar finishing steps to the target purity, typically 98–99% by GC/HPLC.
• Quality release. Assay, isomer-impurity content (notably the para-chloro ortho-nitro isomer, PCONA) and melting range are confirmed against specification before the batch is released.

Typical Commercial Specification

Figures below are representative of commercial-grade Ortho Chloro Para Nitro Aniline. 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

Ortho Chloro Para Nitro Aniline's reactivity pattern is what dye and pigment chemists are buying:

• Diazotisation and coupling. The primary aromatic amine diazotises under standard conditions and couples with naphthol, aniline and pyrazolone couplers to build azo dyes and pigments.
• Activated nucleophilic substitution. The ortho-chlorine, activated by the para-nitro group, can be displaced by amines and other nucleophiles en route to further intermediates.
• Electron-poor ring. The nitro group makes the ring electron-poor, which affects the rate of diazotisation and the stability of the diazonium salt formed.
• Low volatility solid. Decomposes rather than boiling cleanly, so processing is generally done in solution rather than by distillation.

Ortho Chloro Para Nitro Aniline and Related Chloronitroaniline Intermediates

OCPNA is one of several chloronitroaniline isomers used as dye intermediates, and the choice between them depends on the exact substitution pattern the target chromophore needs.

Stated plainly: the choice of chloronitroaniline is dictated by the target dye's exact substitution pattern — a route built around 2-chloro-4-nitroaniline needs this specific isomer, and a transposed pattern needs PCONA instead.

Industries We Supply Ortho Chloro Para Nitro Aniline To

The same chloronitroaniline intermediate feeds an azo dye house, a pigment manufacturer and a basic pharmaceutical intermediate producer. What changes is the downstream coupling chemistry and the documentation each requires.

Where Ortho Chloro Para Nitro Aniline is Used

Ortho Chloro Para Nitro Aniline is bought almost entirely as a dye and pigment synthesis building block. These are the downstream chemistries our customers use it for.

In dye and pigment synthesis

The amine is diazotised under standard cold conditions and coupled with the chosen partner to give the finished azo colourant. Isomer purity matters because a PCONA or DCNB carry-over shifts shade and can complicate purification of the final dye or pigment.

In pharma and agrochemical synthesis

Outside colourants, the same chloro-nitroaniline fragment, and the activated chlorine it carries, is used in routes toward basic pharmaceutical intermediates and selected agrochemical actives where this exact substitution pattern is specified.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis, with isomer content reported alongside assay because both affect downstream shade and coupling performance.

• OCPNA content — by gas chromatography or HPLC, the primary grade measure.
• PCONA isomer content — reported because this transposed isomer carries over into shade variation in the finished dye.
• 3,4-Dichloronitrobenzene residual — monitored as the characteristic feedstock-related impurity.
• Melting range — a fast purity and identity check against specification.

Common Process Problems & Likely Causes

When this intermediate causes trouble, it is usually isomer carry-over or moisture pick-up. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Standard packing. HDPE drums or multi-wall paper/poly-lined bags, typically 25 – 50 kg net, with bulk bags on contract supply.
• Moisture exclusion. Keep sealed and dry; moisture pick-up affects diazotisation performance and flow characteristics.
• Temperature control. Store at room temperature, away from direct sun and heat sources.
• Material compatibility. Standard practice for a toxic solid; avoid contact with strong oxidisers and reducing agents.
• Shelf life. Stable in sealed, dry containers under normal storage conditions.
• Transport classification. UN 1993*, toxic solid, organic, n.o.s., Class 6.1, Packing Group III. ADR, IMDG, IATA and DOT requirements apply to packing, labelling and routing — confirm the exact UN entry and shipping name with your forwarder for your lane.

Hazards & Safe Handling

Ortho Chloro Para Nitro Aniline is classified as a toxic solid, harmful if swallowed and toxic to aquatic life with long-lasting effects. Standard toxic-solid handling practice and good laboratory and plant hygiene apply.

• Ingestion. Harmful if swallowed; good hygiene practice (no eating, drinking or smoking in the work area) is essential.
• Skin and eye contact. Standard practice is chemical-resistant gloves and goggles; rinse thoroughly with water on contact.
• Inhalation. Prevent dust dispersion and use adequate ventilation or local exhaust when handling powder.
• PPE. Chemical-resistant gloves, safety goggles and a dust-rated respirator as a baseline for routine handling of the powder.
• Environment. Do not let this chemical enter waterways or the environment; follow local effluent and waste-disposal rules.

Regulatory & Compliance Notes

Ortho Chloro Para Nitro Aniline is a long-established dye intermediate 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. Typically classified as acute toxic (oral) and hazardous to the aquatic environment; 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. Toxic solid, organic, n.o.s., Class 6.1, Packing Group III. ADR, IMDG, IATA and DOT requirements apply to packing, labelling and routing.
• HS code. Commonly declared under the chloronitroaniline / halogenated amine derivatives heading; confirm the exact tariff line with your customs broker for your jurisdiction.
• National specifications. Several markets, including India, publish a formal specification standard for this intermediate covering assay and named isomer impurities — tell us if your order needs to be certified against one.

We Supply Ortho Chloro Para Nitro Aniline Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Ortho Chloro Para Nitro Aniline 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 sample and drum 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 Ortho Chloro Para Nitro Aniline from Chelora

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

• Documentation on every lot. Batch-specific COA with assay, isomer content and melting range, plus the current SDS.
• Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
• Quantities. Sample and drum trial quantities through to larger bulk shipments on contract supply.
• Inspection. Independent third-party inspection available at loading when the contract requires it.
• Related dye intermediates. Para Chloro Ortho Nitro Aniline and other chloronitroaniline intermediates alongside this product from one supplier.

How ordering works

• Send the enquiry. Purity, 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, 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 Dye Intermediates

Buyers of Ortho Chloro Para Nitro Aniline often source other chloroaniline and nitroaniline building blocks alongside it. Consolidating them cuts freight cost and gives you a single point of contact for documentation.