Para Anisidine
A high-purity methoxy-substituted aniline, supplied as 4-methoxyaniline for diazotization into azo dyes and pigments and for fine chemical synthesis.
What is Para Anisidine?
Para Anisidine, formally 4-methoxyaniline, is a white to light brown crystalline solid with an amino group at C-1 and a methoxy group directly opposite at C-4. It melts at around 57°C, low enough that flake will soften in a hot warehouse, and it darkens on exposure to air and light.
The methoxy group is the reason the molecule earns its place. It is a strong electron donor sitting para to the amine, so once the amine is diazotized the resulting chromophore absorbs further into the spectrum than aniline would: the same coupling partner gives bordeaux, violet and navy instead of orange and red.
At Chelora Dyes, PA is crystallised and dried to a controlled melting range and low moisture, and packed sealed under nitrogen on request, so the material arrives light in colour and couples to a consistent shade batch to batch.
- Appearance
- White to light brown
- Odour
- Faint, amine-like
- Solubility
- Alcohol, dilute acid
- Function
- Diazo component
- Grade
- Technical / reagent
Aniline ring with a para methoxy substituent
- Molecular formulaC7H9NO
- Molecular weight123.15 g/mol
- IUPAC name4-Methoxyaniline
- Functional groupsPrimary aromatic amine, methoxy ether
- CAS number104-94-9
Technical product information
Standard specification for Chelora Dyes' technical grade Para Anisidine. Reagent-grade and low-colour specifications are available on request.
| Chemical name | Para Anisidine |
|---|---|
| Synonyms | 4-Methoxyaniline, p-Anisidine, PA, 4-Aminoanisole |
| CAS number | 104-94-9 |
| Molecular formula | C7H9NO |
| Molecular weight | 123.15 g/mol |
| Assay (purity) | ≥ 99.0% |
| Appearance | White to light brown crystalline flakes; darkens on exposure |
| Melting range | 57–60°C |
| Boiling point | 243–246°C |
| Moisture content | ≤ 0.5% |
| Ash content | ≤ 0.1% |
| Solubility | Sparingly soluble in cold water; soluble in hot water, alcohol, ether 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 Anisidine
Azo dye manufacture
Diazotized as a diazo component for bordeaux, violet and navy shades across textile and leather dyeing.
Organic pigments
Feeds pigment intermediates where a deeper, bluer coupled shade is required in inks and coatings.
Azoic and direct dyes
Used in azoic dyeing systems and direct dye chemistry for cellulosic substrates.
Pharmaceutical intermediates
A methoxy-aniline building block for amide, heterocycle and condensation chemistry.
Agrochemical intermediates
Applied where a para-methoxy aniline core is required in crop protection synthesis.
Analytical reagents
Supplied as a laboratory reagent for derivatisation and quality-control test methods.
Why choose Chelora Dyes
Consistent purity
Assay controlled at ≥99% 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 hold colour.
Technical support
Diazotization, storage, and compliance guidance from our chemistry team.
Storage and guidelines
- Store in tightly sealed original packaging in a cool, dry, well-ventilated store.
- Keep below 30°C where possible — flake softens and cakes as it approaches its melting range.
- Keep in the dark; light and air both drive discolouration.
- Re-blanket part-used drums with nitrogen and re-seal them promptly.
- Segregate from oxidising agents, acids and acid chlorides.
- Contain spillage and keep it out of drains and surface water.
Handling precautions
Para Anisidine is toxic by inhalation, ingestion and skin absorption. Repeated or uncontrolled exposure can cause methaemoglobinaemia.
Control dust at weighing, charging and any bulk handling point, and prevent all skin contact.
Use chemically resistant gloves, chemical splash goggles and protective clothing, with local exhaust ventilation where dust or vapour may be generated. Molten or warmed material adds a thermal burn risk.
Refer to the current Safety Data Sheet for exposure limits, spill containment, disposal and first-aid measures before any handling operation.
Frequently asked questions
What is Para Anisidine used for?
It is diazotized and coupled as a diazo component in azo dye and pigment manufacture, where the methoxy group deepens the shade towards bordeaux, violet and navy. It also serves as a building block in pharmaceutical and agrochemical synthesis and as a laboratory reagent.
How is it different from ortho anisidine?
Both carry an amine and a methoxy group, but in the para isomer they sit opposite each other rather than adjacent. That symmetry gives a higher melting solid and a diazonium salt that couples to bluer, deeper shades, while the ortho isomer is used where a different shade and crystal behaviour are wanted.
Why has the material darkened?
Aromatic amines oxidise slowly on contact with air and light, and the oxidation products are strongly coloured. A shift from white towards light brown or pink is normal and does not by itself indicate loss of assay. Keep drums sealed, cool and dark, and use nitrogen blanketing on part-used containers.
Is Para Anisidine soluble in water?
Only sparingly in cold water. It dissolves better in hot water and freely in alcohol, ether and dilute mineral acid, and the acid solution is the normal starting point for diazotization.
It has softened or fused in the drum. Is it still usable?
The product melts at around 57–60°C, so flake can soften or cake in a hot warehouse. This does not affect assay. Store below 30°C where possible, and break up or re-melt the whole drum under controlled heating rather than applying localised heat.
What purity do you supply?
Standard grade is supplied at a minimum assay of 99%, with moisture and ash held within tight limits. Higher assay and low-colour grades can be manufactured to order.
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 acids. Shelf life is 12 months from manufacture when storage conditions are maintained.
Is it hazardous to handle?
Yes. It is toxic by inhalation, ingestion and skin absorption and can cause methaemoglobinaemia. Control dust at weighing and charging, prevent skin contact, and review the current Safety Data Sheet before any handling operation.
