Para Fluoro Nitro Benzene
Para Fluoro Nitro Benzene — PFNB or 1-fluoro-4-nitrobenzene — pairs a reactive fluorine with a strongly activating nitro group on the same ring. That combination makes it one of the more versatile fluoroaromatic building blocks in the intermediate trade: reduce the nitro group and you reach 4-fluoroaniline; leave it in place and the fluorine itself becomes a leaving group for nucleophilic aromatic substitution chemistry.
Chelora Chemicals supplies PFNB to pharmaceutical, agrochemical and specialty polymer manufacturers worldwide, in drums and container quantities, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 350-46-9
- IUPAC name
- 1-Fluoro-4-nitrobenzene
- Molecular formula
- C6H4FNO2
- Molecular weight
- 141.10 g/mol
- EC / EINECS
- 206-502-8
- MDL number
- MFCD00007282
- SMILES
- Fc1ccc([N+](=O)[O-])cc1
- HS Code
- 2904 99*
* Confirm the exact HS heading with your customs broker — classification of fluoro-nitro aromatic derivatives varies between destination tariffs.
What Para Fluoro Nitro Benzene is used for
Para Fluoro Nitro Benzene carries a fluorine and a nitro group on opposite ends of the same benzene ring. On its own, an aromatic C–F bond is one of the strongest and least reactive bonds in organic chemistry. Put a strongly electron-withdrawing nitro group directly across the ring from it, and the picture changes entirely: the ring becomes activated toward nucleophilic aromatic substitution, and fluorine — despite the strength of the C–F bond — becomes the fastest-leaving halogen in that reaction because of how strongly it polarises the ring. That single quirk of physical organic chemistry is the reason this molecule has a market at all.
In practice PFNB is a dual-purpose intermediate: reduce the nitro group and you reach 4-fluoroaniline; leave the nitro group in place and react a nucleophile onto the ring and you reach a fluorine-free aryl ether, amine or thioether carrying the nitro group for further chemistry.
Why the isomer matters
The fluoronitrobenzene isomers are separate molecules with separate chemistry, and the position of the fluorine relative to the nitro group is not recoverable once the wrong isomer has entered a synthesis:
- 4-Fluoronitrobenzene (CAS 350-46-9) — this product. Fluorine para to the nitro group, the arrangement that activates SNAr most cleanly and gives 4-fluoroaniline on reduction.
- 2-Fluoronitrobenzene (CAS 1493-27-2) — the ortho isomer, used where a 2-fluoroaniline or ortho-substituted SNAr product is required.
- 3-Fluoronitrobenzene (CAS 402-67-5) — the meta isomer, where the fluorine sits outside the nitro group's strongest activating positions, giving very different reactivity.
If your purchase order simply says "fluoronitrobenzene", quote us the CAS number and we will confirm the correct material before the order is placed. We source the sister isomers and related fluoroaromatic and chloroaromatic intermediates as well — see our full product range for the current list.
Appearance and handling character
PFNB melts at roughly 21–24 °C — essentially room temperature — so the same drum can arrive as a pale yellow to greenish-yellow crystalline solid in a cool store and as a clear liquid on a warm loading dock. Neither state means the material is off specification; it simply means pack format and stowage need planning around your climate. It is insoluble in water but dissolves readily in ethers, alcohols and chlorinated solvents. Read the safety section before planning handling: this material is classified as acutely toxic by ingestion, skin contact and inhalation, and that should shape your PPE and ventilation from the outset.
| Parameter | Typical value |
|---|---|
| Appearance | Pale yellow to greenish-yellow solid / liquid |
| Assay (GC) | 98.0% min |
| Moisture (KF) | 0.3% max |
| Freezing range | 20 – 24 °C |
| Total isomeric impurities | 1.5% max |
| Refractive index (n20/D) | Reported per batch |
Important: the figures above are indicative of commercial grade material and are offered for planning only. The batch certificate of analysis is the governing document. If your process needs a tighter assay, a specific isomer limit, or a controlled moisture figure for a downstream SNAr step, send us the specification and we will quote against it rather than against a generic grade.
| Property | Value |
|---|---|
| Physical state | Solid to liquid near ambient |
| Melting point | ≈ 21 – 24 °C |
| Boiling point | ≈ 205 °C @ 760 mmHg |
| Flash point | ≈ 83 °C |
| Relative density | ≈ 1.33 |
| Refractive index | ≈ 1.531 (n20/D) |
| Partition coeff. (log P) | ≈ 1.8 |
| Water solubility | Insoluble |
| Organic solubility | Soluble in ether, alcohols & chlorinated solvents |
Physical constants compiled from public reference data for CAS 350-46-9 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
PFNB earns its place through reactivity, not volume alone. Its value sits in the two doors it opens: reduction of the nitro group, and displacement of the fluorine.
4-Fluoroaniline precursor
Catalytic or chemical reduction of the nitro group gives 4-fluoroaniline, a major fluorinated aniline used across fluoroquinolone-adjacent chemistry, phenylurea and sulfonylurea herbicides, and azo dye synthesis.
- Hydrogenation or Fe/Sn-mediated reduction
- Isomer content carries through to the aniline
- See our full aniline range
SNAr fluorine displacement
The nitro group activates the ring so strongly that amines, phenoxides and thiolates displace the fluorine directly, building aryl ethers, aryl amines and aryl sulfides while the nitro group is retained for downstream chemistry.
- No transition-metal catalyst required
- Moisture-sensitive nucleophile steps
- Ask about grade for SNAr-grade reactivity
Pharmaceutical intermediates
The 4-fluorophenyl fragment appears across several established drug families. PFNB is a common way to install it via SNAr etherification or amination, followed by nitro reduction where an amine handle is also required.
- Amide, ether and amine formation
- Heterocyclic ring construction
- See our pharma intermediate range
Agrochemical building block
Downstream 4-fluoroaniline and 4-fluorophenoxy fragments feed into substituted urea and diphenyl-ether herbicide chemistry, and PFNB is the usual entry point into that fluorinated aromatic chain.
- Substituted urea & ether herbicide chemistry
- Moisture critical at the SNAr step
- See our agrochemical intermediate range
Aromatic polyimides & polymers
SNAr etherification of PFNB with bisphenol-type diols is a known route into soluble aromatic polyimides and other high-performance engineering polymers that need a fluorinated ether linkage in the backbone.
- Nitro-activated ether-forming step
- Specialty polymer & coatings chemistry
- Available in trial and laboratory quantities
Contract & scheduled supply
Pharma and agro intermediate plants run to campaign, not to a calendar month. Most PFNB buyers want tonnage released against a production plan rather than in one shipment. We hold inventory and release it to your schedule.
- Annual contracts with scheduled call-off
- Price held across the contract period
- Second source held in reserve
How we supply Para Fluoro Nitro Benzene
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. We own no fluorination plant — and for a specification-sensitive intermediate like this one, that independence works in your favour. We are never obliged to push you whatever a captive unit happens to be running that month.
Instead we place your order with whichever qualified producer best matches your assay, your isomer tolerance, your price point and your delivery window.
We keep a second qualified source on this line. When a fluorination unit goes down for maintenance, or a feedstock disruption hits one plant, your campaign switches source rather than stalling.
- Specification read against the CAS first. We confirm you need 350-46-9 and not the ortho or meta isomer before we quote a price.
- Batch COA shared before dispatch. You approve the assay, moisture and impurity profile against your own spec while the material is still in our warehouse.
- Hazard status stated up front. This material is toxic by ingestion, skin contact and inhalation, and we say so at enquiry stage — not in the small print of a document pack that arrives with the goods.
- Pre-shipment samples for qualification. New account or new source, your R&D team runs a lab batch before the full quantity ever moves.
- Packing chosen for your climate. With a melting point around 22 °C, whether the drum arrives solid or liquid depends on your routing — we plan both with you.
- Export machinery handled in-house. Hazard classification, UN-approved packing, labelling, freight booking and customs paperwork are ours to manage.
- Consolidation onto one bill of lading. Ship PFNB alongside other intermediates from our range — one invoice, one shipment, one counterparty.
Packed the way your plant receives it
A material that sits right at room temperature needs packing chosen with the routing in mind, not just the destination. Tell us how it will be charged at your end and we will quote the format that suits your operation.
Lined MS / HDPE drums
UN-certified drums with an inert liner, the default format regardless of whether the material arrives solid or liquid. Better vapour containment than an open bag format.
Laminated multi-wall bags
For consignments held below 20 °C for the full transit, where the material stays reliably solid. We advise against this format on tropical or unrefrigerated ocean routings.
IBC totes & jumbo drums
For high-volume buyers taking material as a melted liquid. Fewer container movements, lower packing cost per kilo and reduced operator contact on charging.
Samples & trial packs
Laboratory samples and pilot quantities dispatched by courier so your R&D team can qualify the grade before committing to campaign volume.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to. Ocean, air and road freight arranged end-to-end with documentation filed before booking.
Campaign despatch
Pharma and agro intermediate production runs to campaign. We hold contracted tonnage and release it against your production calendar instead of landing it all at once.
Handle this as an acute toxicant by every route
Para fluoro nitro benzene is classified as toxic if swallowed, toxic in contact with skin and toxic if inhaled — all three routes at once — alongside a skin sensitisation entry and a warning on organ damage from repeated exposure. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document and should govern your risk assessment, PPE selection, exposure monitoring and emergency planning.
Classified hazards
H301Toxic if swallowed.H311Toxic in contact with skin.H331Toxic if inhaled.H317May cause an allergic skin reaction.H373May cause damage to organs through prolonged or repeated exposure.H412Harmful to aquatic life with long lasting effects.
Hazard statements reflect the harmonised GHS classification commonly published for CAS 350-46-9. Supplier classifications may differ in detail; always read the SDS issued with your specific batch, and treat the acute-toxicity entries as the ones that shape your controls.
Spill & emergency orientation
Plan your response before the drum arrives, not after it splits or melts across a warm floor. The points below are orientation for your emergency planners — sections 4, 5 and 6 of the SDS are the authoritative instructions and should be posted at the point of use.
- Contain, do not hose. The material is harmful to aquatic life. Collect a spill mechanically or with absorbent into a labelled container; never wash it to a drain.
- Assume skin absorption. This is toxic on contact with skin as well as by ingestion — remove contaminated clothing immediately and wash the skin thoroughly.
- Treat vapour and dust the same way. Whether the spill is molten liquid or crystalline solid, avoid breathing vapour or dust and ventilate the area.
- Have the SDS with the casualty. Fluoronitrobenzenes can affect the blood's oxygen-carrying capacity, and the treating clinician needs the product identity and CAS number in hand.
- Record the exposure. For a triple-route acute toxicant, an exposure record is worth creating and retaining — a decision for your EHS function, easier made before an incident than after one.
Storage
- Cool, dry, well-ventilated store, ideally held below the 21–24 °C melting range so the material stays solid and predictable to handle.
- Keep containers tightly closed. A nitroaromatic slowly darkens and can lose light volatile fractions if left open, and an open container also picks up moisture.
- Segregate from reducing agents, strong bases and combustible materials. Nitroaromatics can react exothermically under the wrong conditions.
- Access-controlled storage. A triple-route acute toxicant deserves the same restricted access as any other classified toxic intermediate.
- Shelf life is typically 12–24 months in sealed original packing under these conditions. Re-assay before use after long storage.
Handling & PPE
- Design exposure out, do not manage it down. Closed transfer and mechanical charging first, ventilation second, PPE last.
- Skin protection is the priority. This material is toxic through skin contact — chemical-resistant gloves and coveralls, not just splash protection. H317 also applies, so repeat handlers should watch for sensitisation.
- Respiratory protection where vapour or dust may be generated — particularly when charging a warm, partly molten drum — per your own exposure assessment.
- Health surveillance and exposure records for a classified acute toxicant are a decision for your occupational health provider and EHS function; we flag the classification, the programme is yours to run.
- Never discharge to drain or watercourse. H412 applies — collect spills as solid or liquid waste and dispose of them as regulated chemical waste.
Transport
PFNB moves as regulated cargo. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. The applicable UN number, class and packing group are stated on your shipping documents and SDS — ask us for the current DG paperwork when you plan the shipment.
What travels with every consignment
A chemical shipment is only as good as the file that travels with it. Verifying what the source plant sends is precisely the work you are buying from a supplier.
Certificate of Analysis
Batch-specific assay by GC, moisture by Karl Fischer, appearance, melting range and impurity profile — checked against your purchase specification before we release the goods.
GHS Safety Data Sheet
Full 16-section SDS in GHS format covering hazards, exposure controls, handling, storage, spill response, toxicology and disposal — issued in the language your destination requires.
Dangerous Goods Declaration
UN number, hazard class, packing group and IMDG or IATA declaration prepared and filed before the container is booked, with correctly marked and labelled packaging.
Certificate of Origin
Chamber-attested where required, plus preferential-origin forms where a trade agreement gives your import duty relief at the destination.
Third-party inspection
SGS, Intertek or Bureau Veritas sampling and inspection arranged on request before loading, giving you independent verification of what actually ships.
Retained & pre-shipment samples
Pre-shipment samples carry the same COA as the commercial lot, so what your laboratory qualifies is exactly what arrives. Retention samples held against the batch.
The two routes out of this molecule
Almost everything made from PFNB leaves by one of two doors: reduce the nitro group, or displace the fluorine. Understanding which one you are using explains why the moisture content and isomer purity matter as much as they do. The routes below are the general industrial pattern, not a process disclosure.
Start with the ring
PFNB provides a fluorine and a nitro group in a para relationship — the nitro group activates the ring, and the fluorine sits at the most reactive position for what follows.
Door one — reduce
Catalytic hydrogenation, or a classical Fe/HCl or Sn/HCl reduction, converts the nitro group to an amine, giving 4-fluoroaniline with the ring fluorine untouched.
Door two — displace
An amine, phenoxide or thiolate nucleophile attacks the ring and pushes out the fluoride ion, building an aryl ether, amine or thioether while the nitro group stays in place.
Finish to grade
The crude product is purified by distillation, crystallisation or extraction, then standardised to whatever the end market demands — pharma intermediate spec, agro spec or polymer-grade purity.
Why the fluorine is the fast-leaving group here
This is the one fact about PFNB worth understanding before you specify a grade. In an ordinary aliphatic substitution, fluorine is a poor leaving group because the C–F bond is so strong. In nitro-activated nucleophilic aromatic substitution the mechanism is different: the rate-determining step is nucleophilic attack on the ring, not the bond breaking, and fluorine's high electronegativity makes that ring carbon unusually electrophilic. The result is counter-intuitive but well established — fluorine is typically the fastest-displaced halogen in nitro-activated SNAr, faster than chlorine, bromine or iodine.
- Isomeric fluoronitrobenzenes react at very different rates and give structurally different products — off-target substitution here means a hard-to-remove impurity downstream.
- Residual moisture competes with the intended nucleophile in an SNAr step, wasting reagent and generating hydrolysis by-products.
- Reduction catalysts can be poisoned by trace sulfur or halide impurities carried over from an under-specified batch, cutting yield on the aniline route.
- Colour bodies from oxidative degradation during storage can carry through crystallisation and show up in a finished pharma intermediate.
That chain of consequences is the reason we quote against your written specification rather than a generic "98% technical" grade, and the reason the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Intermediate | Principal outlet |
|---|---|
| Para Fluoro Nitro Benzene CAS 350-46-9 — this product | 4-Fluoroaniline SNAr aryl ethers & amines Polyimide chemistry |
| 2-Fluoronitrobenzene CAS 1493-27-2 | 2-Fluoroaniline Ortho-substituted SNAr targets |
| 3-Fluoronitrobenzene CAS 402-67-5 | 3-Fluoroaniline Meta-pattern dye & agro chemistry |
If your route calls for one of the others, we source those as well — see our full product range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this intermediate
PFNB is not a commodity with a screen price. Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Fluorination feedstock
The route back to PFNB runs through a halogen-exchange fluorination step on a chloronitrobenzene precursor. Fluorinating agent cost and availability move directly into the quote in a way a chlorinated-only intermediate does not experience.
- Fluorinating agent cost sets a floor
- Fewer qualified fluorination producers than chlorination
- We flag feedstock-driven moves in the quote
Pharma & agro demand cycles
Demand tracks the production campaigns of the fluoroaniline and SNAr-derived actives built downstream, so enquiries often cluster around known campaign windows rather than running level through the year.
- Quote early for campaign tonnage
- Spot buying at peak costs materially more
- Contracted call-off smooths the exposure
Handling & hazard cost
A triple-route acute toxicant carries real occupational handling cost at the producing plant — closed transfer systems and monitored ventilation are not optional extras, and that cost sits inside the price.
- Closed-system producers command a premium
- PPE and monitoring shape plant overheads
- We check destination handling rules before quoting
Pack format & climate
Because the melting point sits at room temperature, pack format is a genuine cost and risk decision, not just a preference — drummed liquid transfer is cheaper per kilo than bagged solid but needs the right stowage on a hot routing.
- Drums cost less per kilo at volume
- Bagged format needs a cool, controlled transit
- We plan stowage against your destination climate
Freight & DG surcharges
This is regulated cargo, so ocean freight carries a hazardous surcharge and space is tighter than for general cargo. Destination and Incoterm move landed cost as much as the ex-works price does.
- Compare on landed cost, not ex-works
- DG space books out ahead of peak season
- We quote FOB, CIF, CFR or DDP as you prefer
Source availability
A plant turnaround or a fluorinating-agent supply disruption can take capacity offline at short notice. Single-sourced buyers feel this hardest.
- We hold a second qualified source on this line
- Qualify the alternate before you need it
- Ask us about dual-source contracts
| If your end use is… | Specify |
|---|---|
| Reduction to 4-fluoroaniline | High assay, low sulfur & halide (catalyst-friendly) |
| SNAr ether / amine formation | Low moisture, tight isomer limit |
| Polyimide / polymer chemistry | Colour ceiling, very low metals |
| Pharmaceutical chain | Tight isomer limit; metals and residues reported |
| Laboratory / R&D | Small pack, high purity, full analytical pack |
Not sure which column you are in? Describe the reaction you are running and our technical desk will recommend the grade — including telling you when a cheaper specification would do the job just as well.
Support that goes beyond shipping the drum
What our technical desk will do
- Match a grade to your reaction. Tell us whether you are reducing or displacing, and we will recommend the specification — and say so plainly when a tighter, costlier grade would add nothing.
- Be straight about the hazard profile. We state the acute-toxicity classification at enquiry stage so your EHS team can price the controls into the decision, rather than meeting it for the first time on the label.
- Advise on handling and storage for your site conditions — a warehouse in a Gulf summer is a different problem from one in northern Europe for a material that melts at room temperature.
- Review your specification before it goes into a contract, so you are not locked into a limit that no plant can consistently hit.
Regulatory & compliance notes
- Acute-toxicant obligations are jurisdiction-specific. Several regimes impose exposure monitoring, health surveillance and record retention for triple-route acute toxicants. Confirm what applies at your site before the first delivery.
- Import controls vary by destination. Some jurisdictions apply registration or licensing requirements to nitroaromatic intermediates. We check the destination rules before quoting, not after you have raised the PO.
- Chemical inventory listings differ between regions. Confirm your obligations under the applicable inventory regime for your import volume — we will supply the identity data you need for that filing.
- Downstream residue limits in pharma and agro chains can be stricter than the commercial COA reports. Your regulatory team should confirm the finished-product position for the end use you have in mind.
None of the above is legal advice — your own regulatory affairs team owns the final compliance position for your import and your workplace. What we commit to is giving you accurate product identity data, an honest statement of the hazard classification and complete documentation to work from.
From enquiry to delivered pallet
Send the specification
Product name or CAS 350-46-9, the assay and impurity limits you work to, quantity, pack preference and destination port.
Receive a firm quote
Pricing, lead time, packing and Incoterm confirmed in writing within 24 hours — our sourcing desk is staffed around the clock.
Qualify and approve
Sample dispatched if you are qualifying a new source. Batch COA shared for your approval before the material is released.
Ship and track
DG classification filed, freight booked, export documents issued, and the consignment tracked through transit and clearance to your plant.
Often bought alongside this grade
Consolidate several intermediates onto one shipment and one invoice. These are the fluoroaromatic and nitroaromatic building blocks our pharma, agro and specialty polymer customers most often order in the same programme. Every name below sits within our full product range — enquire with the CAS number for current availability and specification.
What buyers ask us about Para Fluoro Nitro Benzene
Is this material classified as a carcinogen?
Can I use the ortho or meta isomer instead?
Why does the material arrive as a liquid sometimes and a solid other times?
What purity do you normally supply?
What is the minimum order quantity?
How long does delivery take?
Why does the solid darken in storage?
How should we store it, and what is the shelf life?
Is this a dangerous good? What paperwork comes with it?
- Batch certificate of analysis
- GHS-format safety data sheet
- Dangerous-goods declaration with UN number, class and packing group
- Commercial invoice, packing list and bill of lading or airway bill
- Certificate of origin and any destination-specific forms
Do you supply to my country?
Do you manufacture this yourself?
Can you hold stock against a production plan?
Request pricing on Para Fluoro Nitro Benzene
Send your required assay, quantity, pack format and destination port. Our sourcing desk is available 24 hours a day, 7 days a week, and comes back with pricing, lead time and packing options — whether that is a single trial drum or a contracted container programme for the year.