Para Chloro Ortho Nitro Aniline
4-Chloro-2-nitroaniline (p-Chloro-o-nitroaniline) · CAS 89-63-4
Para Chloro Ortho Nitro Aniline (PCONA) is the diazo component behind the arylide yellows Pigment Yellow 3 and 73, the naphthol red Pigment Red 6 and the 5-chloro benzotriazole UV absorbers used in plastics. Dyers know it as Fast Red 3GL Base. Chelora Dyes supplies PCONA lot-tested with batch data and a Safety Data Sheet on every shipment, so each batch couples the way the last one did.
Also sold as: PCONA · 4-Chloro-2-nitroaniline · p-Chloro-o-nitroaniline · Fast Red 3GL Base · Azoic Diazo Component 9
- CAS number
- 89-63-4
- Molecular formula
- C6H5ClN2O2
- Molecular weight
- 172.57 g/mol
- Appearance
- Orange crystalline powder
Structure of Para Chloro Ortho Nitro Aniline
Benzene ring with NH2, NO2 and Cl substituentsWhat Para Chloro Ortho Nitro Aniline is
An orange crystalline aniline with a nitro group next to the amine and a chlorine opposite it. The ortho nitro group makes it a classic diazo component for arylide yellows and naphthol reds, and lets its azo products close into benzotriazole rings for UV absorbers.
Identification
Use these details when you match Para Chloro Ortho Nitro Aniline against your own purchase specification.
- Product name
- Para Chloro Ortho Nitro Aniline
- Chemical name
- 4-Chloro-2-nitroaniline (p-Chloro-o-nitroaniline)
- CAS number
- 89-63-4
- EC / EINECS
- 201-925-4
- Molecular formula
- C6H5ClN2O2
- Molecular weight
- 172.57 g/mol
- Product family
- Dye intermediates
- Common end use
- Arylide yellow and naphthol red pigments, UV absorbers, azoic dyeing
Physical and chemical behaviour
The points that decide how the material handles on your plant and in your reactions.
- Appearance
- Orange to orange-yellow crystalline powder.
- Melting point
- 116–118 °C. A lower or broader melt points to unreacted 2,5-dichloronitrobenzene or isomers.
- Solubility
- Practically insoluble in water — under 1 g/L. Very soluble in ethanol, ether and acetic acid; slightly soluble in acetone.
- Reactivity
- A weak base, with a conjugate-acid pKa of about −1.0. It diazotises in strong acid and couples at pH 4–5.5. The ortho nitro group lets its o-nitroazo products be reduced and cyclised into benzotriazoles.
- Stability
- Stable under normal storage conditions. Can react violently with nitric acid and strong oxidisers.
- Incompatibilities
- Strong oxidising agents, nitric acid and strong bases. Decomposition releases nitrogen oxides, hydrogen chloride and carbon oxides.
Typical specification
Every lot is tested in-house against its specification before dispatch, and the results travel with the shipment. If you work to a tighter window on any line below, send it to us and we will confirm whether we can supply to it.
| Parameter | Indicative value | Why it matters to you |
|---|---|---|
| Appearance | Orange crystalline powder | An even, bright colour is the first sign of a clean lot. Dark material carries by-products into the pigment. |
| Assay (purity) | 99.0% minby GC | Sets the stoichiometry of diazotisation and coupling. A lower assay means weaker pigment strikes and lower UV-absorber yield. |
| Melting point | 115 °C min | A quick purity check. A depressed or broad range signals feedstock or isomer contamination. |
| Moisture | 0.5% max | Affects weighing accuracy and acid strength in diazotisation. |
| 2,5-Dichloronitrobenzene | Controlledunreacted feedstock | Does not diazotise, so it lowers the effective strength and passes into the pigment or UV absorber as an impurity. |
| Isomeric chloronitroanilines | Controlled | Other isomers couple into side products of a different shade. In a greenish yellow, even small amounts show. |
| Methanol-insoluble matter | Low, reported | Insolubles cloud the diazo solution and turn up as specks in the pigment. |
| Diazo solution | Clearon test diazotisation | A clear diazo solution tells you the amine will convert fully in your plant, before you commit a full batch. |
Buying for pigments or UV absorbers? Send us your purchase specification, including assay, melting point, moisture and isomer limits, through the contact page. We will confirm what we can supply, and send a sample with its test data so you can run it beside your current material.
Where Para Chloro Ortho Nitro Aniline sits on the synthesis route
PCONA is made from 1,4-dichlorobenzene by nitration and selective ammonolysis. It then branches: into pigments and azoic dyes through diazotisation and coupling, and into UV absorbers through coupling and ring closure.
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1,4-Dichlorobenzene
The feedstock. Nitration with mixed acid gives 2,5-dichloronitrobenzene (1,4-dichloro-2-nitrobenzene).
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2,5-Dichloronitrobenzene
Only the chlorine next to the nitro group is activated. The other sits meta to it and stays put.
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4-Chloro-2-nitroaniline
Ammonia at about 165 °C replaces the activated chlorine, giving PCONA — the isolated intermediate you buy.
This product -
Diazotisation
PCONA is diazotised in strong acid. The diazonium salt couples onto acetoacetanilides, 2-naphthol or naphthol AS couplers — or onto hindered phenols for UV absorbers.
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Downstream products
Pigment Yellow 3 and 73, Pigment Red 6 and azoic reds come straight from coupling. Coupling onto phenols, then reduction, gives 5-chlorobenzotriazole UV absorbers such as UV-326.
Key derivatives of Para Chloro Ortho Nitro Aniline
PCONA is used almost entirely as an intermediate. Industry data put its main outlets as Pigment Yellow 73 and Pigment Yellow 3, with Pigment Red 6, azoic dyeing and benzotriazole UV absorbers alongside.
Pigment Yellow 3
Diazotised PCONA coupled onto 2-chloroacetoacetanilide gives this greenish-yellow arylide pigment, used in paints, inks and artists’ colours.
- C.I. No.
- 11710
- Coupler
- Acetoacet-o-chloroanilide
- Shade
- Greenish yellow
Pigment Yellow 73
With acetoacet-o-anisidide as the coupler, PCONA gives Pigment Yellow 73, one of its largest outlets. A consistent amine keeps the yellow’s strength and cleanliness steady from lot to lot.
- C.I. No.
- 11738
- Coupler
- Acetoacet-o-anisidide
- Shade
- Yellow
Pigment Red 6
Coupling onto 2-naphthol gives Pigment Red 6. It is the chlorinated relative of Pigment Orange 2, which is made the same way from ortho-nitroaniline.
- C.I. No.
- 12090
- Coupler
- 2-Naphthol
- Shade
- Red
UV-326
PCONA is diazotised and coupled onto 2-tert-butyl-4-methylphenol, then the o-nitroazo product is reduced to close the triazole ring. UV-326 protects polyolefins and other plastics; UV-327 is made the same way from 2,4-di-tert-butylphenol.
- CAS No.
- 3896-11-5
- Route
- Coupling + cyclisation
- Use
- Polymer UV stabiliser
Need a related nitroaniline? Ortho Nitroaniline is the unchlorinated version used for UV-P and Pigment Orange 2, and Ortho Chloro Para Nitro Aniline is the isomer used for red disperse dyes. Both can come on the same order.
Where the chemistry leads
Para Chloro Ortho Nitro Aniline feeds pigment, polymer-additive and textile lines. Its purity shows up in the brightness of every yellow and the colour of every UV absorber made from it.
Organic pigments
Coupled onto acetoacetanilides, PCONA gives arylide yellows such as Pigment Yellow 3 and 73; onto 2-naphthol, it gives Pigment Red 6. Pigment makers need a high-assay amine with low isomer content, because side products dull the shade.
UV absorbers
Coupling onto hindered phenols and reductive cyclisation give 5-chlorobenzotriazole UV absorbers such as UV-326 and UV-327, used to protect polyolefins and other plastics. Clean starting material keeps the absorber’s colour and assay in specification.
Azoic dyeing
As Fast Red 3GL Base (C.I. Azoic Diazo Component 9), PCONA is diazotised and developed on cotton with naphthol AS coupling components. With Naphthol AS-OL it gives a purplish red with good light fastness.
What buyers check before they switch supplier
Four parameters explain most of the shade and yield complaints when a manufacturer changes its source of Para Chloro Ortho Nitro Aniline.
Assay and residual 2,5-DCNB
Unconverted 2,5-dichloronitrobenzene does not diazotise. It lowers the effective strength of the amine and carries through as an impurity into pigment or UV absorber.
Isomer content
Other chloronitroaniline isomers couple too, giving side products of a different shade. In a greenish yellow, even small amounts show.
Melting point
A sharp melt at 116–118 °C confirms purity. A depressed or broad range is an early warning before the material reaches the diazo vessel.
Clarity of the diazo solution
A clear diazo solution in your normal time is the best predictor of a clean pigment strike. A cloudy or slow one usually means insolubles in the amine.
Tested in-house, documented in full
Consistent pigment strikes start with a consistent diazo component. Each lot of Para Chloro Ortho Nitro Aniline is checked against its specification before it leaves, and the result goes out with the material so your goods-in team can release it without a second test.
- Each lot tested against the product specification before dispatch
- Batch test report supplied with every shipment
- Safety Data Sheet supplied with the first order and on request
- Technical and specification sheets available before you order
- Samples sent with their own test data, so a trial compares like with like
- Chemists familiar with nitroaniline diazotisation, pigment coupling and benzotriazole chemistry, available to discuss results
What arrives with the material
Enough paperwork for your goods-in and quality teams to release the lot without retesting it.
- Batch test report
- The tested figures for the lot you have received, set against the specification.
- Safety Data Sheet
- Classification, protective equipment, storage conditions, first aid and spill response.
- Specification sheet
- The parameters and limits we supply against, available before you place the order.
- Sample test data
- Sent with every trial sample, so a comparison against your current material starts from the same numbers.
Packing, storage and handling
Para Chloro Ortho Nitro Aniline is a stable crystalline solid under normal conditions, but it is highly toxic. Follow all guidance in the Safety Data Sheet for protective equipment and exposure control.
How it ships
- Supplied in moisture-resistant packing, typically HDPE bags or lined fibre drums
- Bulk quantities can be discussed where your process suits larger packs
- Every pack carries the product name, lot number and hazard information
- Pack size can be matched to your diazotisation charge to minimise part-used containers
- Shipped with its batch test report and Safety Data Sheet
Storing and handling on site
- Store in a cool, dry, well-ventilated place, away from direct sunlight
- Keep containers tightly closed between uses to prevent moisture uptake
- Avoid generating dust; use closed charging or local exhaust ventilation at transfer points
- Wear the protective equipment specified in the SDS — PCONA is absorbed through the skin
- Keep apart from nitric acid, strong oxidising agents and strong bases in storage
- Rotate stock so older lots are used first
Read the Safety Data Sheet before first use. Most safety data sheets classify Para Chloro Ortho Nitro Aniline as fatal if swallowed, in contact with skin or if inhaled, with possible organ damage from repeated exposure. It can cause methaemoglobinaemia, with symptoms delayed by several hours, and it is toxic to aquatic life. The SDS sets out the required PPE, exposure limits, storage conditions, first-aid measures and spill response. If anything on it is unclear, ask our technical team.
How to order Para Chloro Ortho Nitro Aniline
Start with a sample, move to scheduled supply. Four steps from first enquiry to a delivery pattern that matches your production plan.
Send your requirement
Product name, grade or specification, quantity, packing and delivery location, through the contact page.
Get the paperwork
We come back with the specification sheet, the Safety Data Sheet and a quote against your quantity and packing.
Run a sample
A sample with its test data, so you can run it through your pigment strike or UV-absorber synthesis beside your current material.
Confirm supply
Once the trial clears, we schedule repeat supply to the same specification, lot after lot.
Para Chloro Ortho Nitro Aniline: frequently asked questions
What buyers, chemists and plant teams ask us most about this product. For anything else, get in touch.
What is Para Chloro Ortho Nitro Aniline?
Para Chloro Ortho Nitro Aniline (PCONA), or 4-chloro-2-nitroaniline (CAS 89-63-4), is an orange crystalline aromatic amine with a nitro group ortho and a chlorine para to the amino group. It is a diazo component for yellow and red pigments and an intermediate for benzotriazole UV absorbers.
What is the CAS number and molecular formula?
The CAS number is 89-63-4 and the EC (EINECS) number is 201-925-4. The molecular formula is C6H5ClN2O2 and the molecular weight is 172.57 g/mol. In the colour trade it is Fast Red 3GL Base, or C.I. Azoic Diazo Component 9 (C.I. 37040).
Is PCONA the same as OCPNA?
No. PCONA is 4-chloro-2-nitroaniline (CAS 89-63-4); OCPNA is 2-chloro-4-nitroaniline (CAS 121-87-9). They share a formula but not a substitution pattern, and they go into different products — PCONA mainly into pigments and UV absorbers, OCPNA into red disperse dyes and niclosamide.
How is Para Chloro Ortho Nitro Aniline manufactured?
By selective ammonolysis of 2,5-dichloronitrobenzene (1,4-dichloro-2-nitrobenzene) at around 165 °C. Only the chlorine next to the nitro group is activated, so ammonia replaces it and leaves the other in place. The dichloronitrobenzene comes from nitrating 1,4-dichlorobenzene. Unreacted dichloronitrobenzene is the main impurity to check.
Which pigments are made from PCONA?
The main ones are Pigment Yellow 3 (C.I. 11710), made with 2-chloroacetoacetanilide; Pigment Yellow 73 (C.I. 11738), made with acetoacet-o-anisidide; and Pigment Red 6 (C.I. 12090), made with 2-naphthol. The two yellows are its largest outlets. All three are made by diazotising PCONA and coupling onto the named component.
How is PCONA used to make UV-326?
PCONA is diazotised and coupled onto 2-tert-butyl-4-methylphenol under weakly alkaline conditions. The resulting o-nitroazo compound is then reduced, which closes the triazole ring and gives UV-326, a 5-chlorobenzotriazole UV absorber for polyolefins and other plastics. UV-327 is made the same way from 2,4-di-tert-butylphenol.
What is Fast Red 3GL Base used for?
Fast Red 3GL Base is PCONA sold as an azoic diazo component. It is diazotised and developed on cotton with naphthol AS coupling components — with Naphthol AS-OL it gives a purplish red with good light fastness. It is also used on viscose and silk.
Is Para Chloro Ortho Nitro Aniline soluble in water?
Practically not — under 1 g per litre. It dissolves well in ethanol, ether and acetic acid, and slightly in acetone. For diazotisation it is dissolved or finely dispersed in strong mineral acid, and a fine dispersion diazotises noticeably faster than coarse lumps.
What purity do you supply?
Standard material is supplied at a minimum assay of 99% by GC, with the actual figure for your lot on the batch test report. If you work to tighter limits on isomers, 2,5-dichloronitrobenzene or moisture, send your specification and we will confirm what we can supply.
What is the melting point?
About 116–118 °C. A sharp melt in that range confirms purity. A lower or broader range suggests unreacted 2,5-dichloronitrobenzene or isomers, which will show up as off-shade side products in the pigment. A capillary melting point takes minutes, so it is a sensible goods-in check alongside the batch test report.
Is Para Chloro Ortho Nitro Aniline toxic?
Yes, highly. Most safety data sheets classify it as fatal if swallowed, in contact with skin or if inhaled. It is absorbed through the skin and can cause methaemoglobinaemia, sometimes hours after exposure. Handle it only with the controls and protective equipment in our Safety Data Sheet.
How is Para Chloro Ortho Nitro Aniline transported?
It ships as UN 2237 (chloronitroanilines), Class 6.1, packing group III. The full transport details are on our Safety Data Sheet. Tell us your destination and whether it travels by sea, air or road, so we can prepare the right paperwork for each consignment.
How is Para Chloro Ortho Nitro Aniline packed and stored?
It ships as a powder in moisture-resistant packing, usually HDPE bags or lined fibre drums, labelled with the product name, lot number and hazard information. Store it cool, dry and well ventilated, away from nitric acid, oxidising agents and strong bases.
Can I get a sample, and is there a minimum order?
Yes to samples, sent with their test data so a trial compares like with like. Order quantities depend on the packing, so tell us the volume you expect through the contact page and we will confirm what is practical.
Tell us the grade and quantity of Para Chloro Ortho Nitro Aniline you need
Send your specification, the quantity and where it ships to, and our technical team will come back with the specification sheet, a quote and a sample plan. If you also buy Ortho Nitroaniline or other nitroanilines, put them on the same enquiry.