Para Fluoro Aniline
A high-purity fluorinated aromatic amine supplied for pharmaceutical and agrochemical intermediate synthesis, liquid crystal materials, and fine chemical manufacture.
What is Para Fluoro Aniline?
Para Fluoro Aniline — PFA, or 4-fluoroaniline — is a colourless to amber liquid carrying a fluorine atom directly opposite the amino group on a benzene ring.
A single fluorine changes a molecule's behaviour out of proportion to its size. It blocks metabolic oxidation at that ring position, raises lipophilicity, and subtly shifts electron density, which is why fluorinated anilines appear so often in modern drug and crop-protection molecules.
At Chelora Chemicals, PFA is distilled to low colour and controlled isomer content, with moisture held tight, so that acylation, coupling, and heterocycle-forming steps downstream run reproducibly at pharmaceutical intermediate quality.
- Appearance
- Colourless to amber liquid
- Odour
- Characteristic amine odour
- Solubility
- Slightly soluble in water; soluble in organic solvents
- Function
- Chemical intermediate
- Grade
- Technical / pharma intermediate
Formula diagram
Aniline ring with fluorine in the para position
- Molecular formulaC6H6FN
- Molecular weight111.12 g/mol
- IUPAC name4-Fluoroaniline
- Functional groupsPrimary aromatic amine, aryl fluoride
- CAS number371-40-4
Technical product information
Standard specification for Chelora Chemicals' technical and pharma-intermediate grade Para Fluoro Aniline. Custom-grade and bulk specifications are available on request.
| Chemical name | Para Fluoro Aniline |
|---|---|
| Synonyms | PFA, 4-Fluoroaniline, p-Fluoroaniline, 4-Aminofluorobenzene |
| CAS number | 371-40-4 |
| Molecular formula | C6H6FN |
| Molecular weight | 111.12 g/mol |
| Assay (purity) | ≥ 99.5% |
| Appearance | Clear, colourless to amber liquid |
| Density (20°C) | 1.168–1.178 g/cm³ |
| Boiling point | 186–188°C |
| Melting point | −2°C |
| Flash point | 78°C (closed cup) |
| Refractive index (20°C) | 1.537–1.541 |
| Water content | ≤ 0.2% |
| Packaging | 200 kg drums, 1000 kg IBC |
| Shelf life | 12 months in sealed original packaging |
Applications of Para Fluoro Aniline
Pharmaceutical intermediates
A core building block in fluorinated API synthesis, including kinase inhibitor and antimicrobial routes.
Agrochemicals
Used to introduce a fluorinated aniline fragment into insecticide and herbicide actives.
Liquid crystal materials
Feeds fluorinated intermediates used in display-grade liquid crystal manufacture.
Dyes & pigments
Diazotised to give fluorinated colour components with distinctive shade and fastness.
Heterocyclic synthesis
Condensed into quinolines, benzimidazoles, and related fluorinated ring systems.
Fine chemicals
Applied as a research and custom-synthesis building block where a para-fluorine is required.
Why choose Chelora Chemicals
Every batch of Para Fluoro Aniline is manufactured, tested, and documented to a standard that formulators and process chemists can build on with confidence — from first sample to full production volume.
Consistent purity
Assay controlled at ≥99.5% with colour, isomer profile, and water content verified before dispatch.
Full documentation
COA, SDS, and regulatory data supplied with every shipment.
Flexible volumes
From 200 kg drums to IBC quantities, with laboratory samples on request.
Technical support
Process, handling, and compliance guidance from our chemistry team.
Storage and guidelines
- 01Store in tightly sealed original containers under nitrogen where possible.
- 02Keep in a cool, dry, well-ventilated area away from heat and direct sunlight.
- 03Protect from air and light — the product darkens on oxidation.
- 04Segregate from strong oxidising agents, acids, and acid chlorides.
- 05Use compatible containers: lined steel, stainless steel, or HDPE.
- 06Re-seal drums promptly after use and maintain nitrogen blanketing on bulk storage.
Handling precautions
PFA is a toxic aromatic amine that is harmful in contact with skin, by inhalation, and if swallowed. It is for industrial use by trained personnel only.
Aromatic amines are readily absorbed through intact skin and can affect the blood by forming methaemoglobin. Chemical-resistant gloves, coveralls, and eye protection are required.
Use local exhaust ventilation for drum decanting, charging, and any heated operation; avoid breathing vapour or mist.
The product is combustible above its flash point of 78°C. Keep away from ignition sources and earth equipment during transfer.
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 Fluoro Aniline used for?
It is an intermediate for fluorinated pharmaceuticals and agrochemicals, liquid crystal materials, and specialty dyes. The para-fluoroaniline fragment appears in a wide range of modern API and crop-protection structures.
Why is fluorine added to aromatic intermediates?
Fluorine is small enough to replace hydrogen without changing the molecule's shape, but it blocks metabolic oxidation at that position, increases lipophilicity, and alters electron distribution. In drug design this often improves stability and potency.
Is the fluorine reactive?
Not under ordinary conditions. An aryl fluorine on a ring without strong activating groups is very stable, so the amino group is the reactive handle in most syntheses. Nucleophilic displacement of aryl fluorine requires strongly activated systems and forcing conditions.
Why does the liquid turn amber or brown?
Aromatic amines oxidise slowly on contact with air and light, producing coloured impurities. Assay is usually unaffected, but keeping drums sealed, cool, dark, and nitrogen-blanketed preserves colour for pharmaceutical intermediate use.
Is it soluble in water?
Only slightly. It is readily soluble in alcohols, ethers, esters, and aromatic hydrocarbons, so reactions are normally run in organic media.
What purity do you supply?
Standard grade is supplied at a minimum assay of 99.5% with water content at or below 0.2%. Higher assay and low-colour specifications for pharmaceutical intermediate use can be manufactured to order.
What packaging sizes are available?
200 kg drums and 1000 kg IBCs, with laboratory and pilot samples available for development work.
How does PFA differ from 2-fluoroaniline and 3-fluoroaniline?
All three share the formula C6H6FN but place the fluorine ortho, meta, or para to the amino group. That position changes basicity, reactivity, and the geometry of the final molecule, so the isomers are not interchangeable.
How long can it be stored?
12 months from manufacture in sealed original packaging under the recommended conditions. Nitrogen blanketing and cool, dark storage materially extend colour stability.
Is PFA hazardous?
Yes. It is toxic, skin-absorbable, combustible above 78°C, and hazardous to aquatic life. Engineering controls, PPE, and the Safety Data Sheet should be reviewed 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, colour, refractive index, density, water content, and appearance.