Para Chloro Ortho Amino Phenol
A high-purity chlorinated aminophenol, supplied as 4-chloro-2-aminophenol for metal-complex and azo dye manufacture.
What is Para Chloro Ortho Amino Phenol?
PCOAP, formally 2-amino-4-chlorophenol, is a grey to light brown crystalline powder carrying a hydroxyl group at C-1, an amino group on the adjacent carbon and a chlorine para to the hydroxyl.
The amino and hydroxyl pair is what the dye chemistry is built around. Sitting side by side they form a chelating pocket, so once the molecule has been carried into an azo dye that dye can bind chromium or cobalt and form a metal complex — the family that gives wool, polyamide and leather their high light and wet fastness. The chlorine deepens the shade and pulls solubility down, which reinforces that fastness.
At Chelora Dyes, PCOAP is crystallised and dried to a controlled melting range and low moisture, and packed sealed to limit oxidation, so the coupled shade stays consistent batch to batch.
- Appearance
- Grey to light brown
- Odour
- Faint, phenolic
- Solubility
- Alcohol, alkali, acid
- Function
- Coupling component
- Grade
- Technical / dye
Phenol ring with adjacent amino group and para chlorine
- Molecular formulaC6H6ClNO
- Molecular weight143.57 g/mol
- IUPAC name2-Amino-4-chlorophenol
- Functional groupsPhenol, aromatic amine, aryl chloride
- CAS number95-85-2
Technical product information
Standard specification for Chelora Dyes' technical grade Para Chloro Ortho Amino Phenol. Custom-grade and low-colour specifications are available on request.
| Chemical name | Para Chloro Ortho Amino Phenol |
|---|---|
| Synonyms | 4-Chloro-2-aminophenol, 2-Amino-4-chlorophenol, PCOAP |
| CAS number | 95-85-2 |
| Molecular formula | C6H6ClNO |
| Molecular weight | 143.57 g/mol |
| Assay (purity) | ≥ 98.0% |
| Appearance | Grey to light brown crystalline powder; darkens on exposure |
| Melting range | 140–145°C |
| Moisture content | ≤ 1.0% |
| Ash content | ≤ 0.3% |
| Insoluble matter | ≤ 0.5% |
| Solubility | Sparingly soluble in water; soluble in alcohol, dilute alkali and dilute acid |
| Packaging | 25 kg / 50 kg lined fibre or HDPE drums, nitrogen blanketed on request |
| Shelf life | 12 months in sealed original packaging |
Applications of Para Chloro Ortho Amino Phenol
Metal-complex dyes
The chelating aminophenol site binds chromium or cobalt to give 1:2 complex dyes with high fastness.
Azo dye manufacture
Serves as a partner in azo coupling chemistry for bronze, olive and brown shade ranges.
Wool and polyamide dyes
Feeds acid and premetallised dye ranges where wet and light fastness on protein fibres is critical.
Leather dyes
Applied in leather finishing formulations that call for deep, fast brown and bronze shades.
Pigment intermediates
Used as an intermediate in pigment and colourant syntheses requiring a chelating aminophenol core.
Fine chemical intermediates
Supplies an aminophenol building block for benzoxazole and other heterocycle chemistry.
Why choose Chelora Dyes
Consistent purity
Assay controlled at ≥98% with melting range and colour verified before dispatch.
Full documentation
COA, SDS, and regulatory data supplied with every shipment.
Protective packing
Sealed lined drums with nitrogen blanketing available to limit oxidation.
Technical support
Coupling, metallisation, and compliance guidance from our chemistry team.
Storage and guidelines
- Store in tightly sealed original packaging in a cool, dry, well-ventilated store.
- Keep in the dark — light and air both drive discolouration.
- Re-blanket part-used drums with nitrogen and re-seal them promptly.
- Protect from moisture pickup; the powder can cake if exposed to humid air.
- Segregate from oxidising agents, strong acids and alkalis.
- Contain spillage and keep it out of drains and surface water.
Handling precautions
Para Chloro Ortho Amino Phenol is harmful if swallowed and irritating to skin, eyes and the respiratory tract. It is also a potential skin sensitiser, so contact should be avoided rather than simply limited.
It is toxic to aquatic organisms, and spillage must be contained rather than washed away.
Control dust at weighing, charging and any bulk handling point. Use chemically resistant gloves, eye protection and protective clothing, with local exhaust ventilation where dust may be generated.
Refer to the full Safety Data Sheet for exposure limits, spill containment, disposal and first-aid measures before use.
Frequently asked questions
What is Para Chloro Ortho Amino Phenol used for?
It is used in azo dye chemistry, most importantly for metal-complex dyes. The amino and hydroxyl groups sit next to each other and form a chelating site, so once the molecule is built into an azo dye it can bind chromium or cobalt to give complexes with high light and wet fastness for wool, polyamide and leather.
What does the chlorine contribute?
Chlorine para to the hydroxyl deepens the shade and lowers solubility in the finished dye, which improves wet fastness. It also stabilises the ring against oxidation relative to the unsubstituted aminophenol.
Why does the powder darken in storage?
Aminophenols oxidise slowly on contact with air and light, and the oxidation products are strongly coloured. Some darkening from grey towards brown is normal. Keep drums sealed, cool and dark, and re-seal part-used containers promptly.
Is it soluble in water?
Only sparingly. It dissolves readily in alcohol, in dilute alkali as the phenolate and in dilute acid as the amine salt, which is how it is normally taken into solution for reaction.
What purity do you supply?
Standard technical grade is supplied at a minimum assay of 98%, with moisture and ash held within tight limits. Higher assay and low-colour grades can be manufactured to order for shade-sensitive applications.
What packaging sizes are available?
25 kg and 50 kg lined fibre or HDPE drums, nitrogen blanketed on request, with larger volumes available on a scheduled supply basis.
How should it be stored, and for how long?
In sealed original packaging in a cool, dry, dark and ventilated store away from oxidising agents and strong acids. Shelf life is 12 months from manufacture when storage conditions are maintained.
Is it hazardous to handle?
It is harmful if swallowed, irritating to skin and eyes, a potential skin sensitiser and toxic to aquatic life. Control dust during weighing and charging, avoid skin contact, and review the current Safety Data Sheet before any handling operation.
Do you provide a Certificate of Analysis?
Yes. Each batch ships with a Certificate of Analysis and Safety Data Sheet covering assay, melting range, moisture, ash and appearance.
