2,4-Dinitrofluorobenzene
2,4-Dinitrofluorobenzene — DNFB, universally known as Sanger's Reagent — is the aryl fluoride whose two nitro groups turn an otherwise unremarkable carbon–fluorine bond into one of the most reliable electrophiles in organic and biological chemistry. It is the reagent Frederick Sanger used to determine the first complete protein sequence, and it remains a working tool for N-terminal amino acid analysis, hapten synthesis, amine derivatisation and fine chemical nucleophilic-aromatic-substitution chemistry today.
Chelora Chemicals supplies DNFB to life-science reagent houses, immunology and dermatology research groups, and fine chemical manufacturers worldwide, in light-protected, cold-chain packaging as well as bulk drums, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 70-34-8
- IUPAC name
- 1-Fluoro-2,4-dinitrobenzene
- Molecular formula
- C6H3FN2O4
- Molecular weight
- 186.10 g/mol
- EC / EINECS
- 200-734-3
- MDL number
- MFCD00007056
- SMILES
- O=[N+]([O-])c1ccc(F)c([N+]([O-])=O)c1
- HS Code
- 2904 20*
* Confirm the exact HS heading with your customs broker — classification of dinitro aromatic derivatives varies between destination tariffs.
What 2,4-Dinitrofluorobenzene is used for
2,4-Dinitrofluorobenzene is an aryl fluoride activated by two nitro groups positioned ortho and para to the fluorine. That arrangement stabilises the anionic intermediate formed when a nucleophile attacks the ring, making the fluorine an unusually fast and reliable leaving group despite the strength of the carbon–fluorine bond itself. The result is a compound that reacts cleanly and selectively with primary and secondary amines, alcohols and thiols under mild conditions — exactly the property that made it useful to Frederick Sanger in 1945, and that keeps it in routine use across biochemistry and fine chemical synthesis today.
In practice DNFB serves two quite different customer bases from the same drum: life-science and analytical laboratories buying it in small, light-protected packs as a labelling and derivatisation reagent, and fine chemical and dye manufacturers buying it in bulk as an SNAr electrophile for custom synthesis.
Sanger's Reagent — a brief history
DNFB owes its common name to Frederick Sanger, who used it in the 1940s to react with the free α-amino group at the N-terminus of a protein. Acid hydrolysis of the tagged protein released a yellow DNP-amino acid that could be identified by chromatography, revealing which amino acid sat at the chain's start. That technique — predating both Edman degradation and modern mass-spectrometric sequencing — let Sanger determine the complete amino acid sequence of insulin, work for which he received the 1958 Nobel Prize in Chemistry. The reagent, and the dinitrophenylation chemistry it performs, is still in active laboratory use.
Related electrophiles exist with a different leaving group — most notably 2,4-dinitrochlorobenzene (DNCB), which reacts more slowly because chloride is a poorer leaving group than fluoride in this activated system. If your protocol or process specifies one and not the other, quote us the CAS number and we will confirm the correct material before the order is placed — browse the full product range for the sister electrophiles we can source.
Appearance and handling character
DNFB ships as an off-white to pale yellow low-melting solid, or as a liquid depending on ambient temperature — its melting point of roughly 24–27 °C sits right at typical room temperature, so the same drum can arrive solid in a cool climate and liquid in a warm one. It darkens toward yellow, orange or brown on prolonged exposure to light and heat. It is practically insoluble in water and dissolves readily in ether, benzene, ethanol and acetone. Read the safety section before planning any handling: this material is a well-documented, potent skin sensitiser — a property researchers deliberately exploit to induce experimental contact dermatitis — and that should shape your controls from the outset.
| Parameter | Typical value |
|---|---|
| Appearance | Off-white to pale yellow solid or low-melting liquid |
| Assay (GC/HPLC) | 98.0% min |
| Melting range | 24 – 27 °C |
| Moisture (KF) | 0.3% max |
| Colour | Reported per batch |
| Non-volatile residue | 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. Analytical and immunology customers in particular should send their purity, colour and endotoxin-free packaging requirements — we source against a written specification rather than a generic grade.
| Property | Value |
|---|---|
| Physical state | Low-melting solid / liquid near ambient |
| Melting point | ≈ 24 – 27 °C |
| Boiling point | ≈ 178 °C @ 25 mmHg (reduced pressure) |
| Flash point | ≈ 110 °C |
| Relative density | ≈ 1.48 (25 °C) |
| Refractive index | ≈ 1.567 – 1.570 |
| Water solubility | Practically insoluble (≈ 400 mg/L, 25 °C) |
| Organic solubility | Soluble in ether, benzene, ethanol, acetone |
| Odour | Faint, characteristic aromatic odour |
Physical constants compiled from public reference data for CAS 70-34-8 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
DNFB sells into two distinct worlds from the same specification — life-science reagent use in small, light-protected packs, and bulk fine-chemical electrophile use in drums.
N-terminal amino acid analysis
The classical Sanger method: DNFB tags the free α-amino group of a protein or peptide, and acid hydrolysis followed by chromatographic identification of the resulting DNP-amino acid reveals the N-terminal residue.
- Foundational protein sequencing chemistry
- Still used in teaching labs and reference protocols
- See our analytical reagent range
DNP hapten & immunology reagents
Dinitrophenylation of carrier proteins builds DNP-conjugates used as model haptens in immunogenicity research, anti-DNP antibody generation and ELISA/immunoassay development.
- Hapten-carrier conjugate chemistry
- Model antigen for immunology research
- Small, light-protected research packs
Dermatology & sensitisation research
DNFB is the standard contact-sensitiser used to induce experimental allergic and atopic-dermatitis-like skin responses in preclinical models, and to benchmark anti-inflammatory and anti-allergic candidate compounds against it.
- Reference contact-hypersensitivity reagent
- Widely cited in dermatology pharmacology literature
- Research-grade small packs with full CoA
HPLC / GC amine derivatisation
A reliable pre-column labelling reagent for primary and secondary amines — including volatile amines such as propylamine and diethylamine — converting them into UV-detectable DNP-amine derivatives for chromatographic quantification.
- Pre-column derivatisation chemistry
- Consistent, reproducible tagging yield
- Available in analytical-grade small packs
Fine chemical & dye intermediate synthesis
The same activated fluorine that makes DNFB a good labelling reagent makes it a reliable bulk SNAr electrophile — building N-aryl and O-aryl linkages, diarylamines and dinitrophenyl ether/thioether intermediates for dye and specialty chemistry.
- Nucleophilic aromatic substitution chemistry
- Bulk commercial-grade pack sizes
- See our fine chemical intermediate range
Contract & scheduled supply
Fine-chemical buyers running an SNAr campaign want tonnage released against a production plan; reagent houses want a reliable cold-chain trickle of small packs. We hold inventory for both 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 2,4-Dinitrofluorobenzene
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. We own no dinitration or fluorination plant — and for a product bought by two very different customer types from the same specification, that independence works in your favour. We are never obliged to push you whatever a captive unit happens to be running that month, whether you need five grams for a bench protocol or five hundred kilograms for a synthesis campaign.
Instead we place your order with whichever qualified producer best matches your assay, your pack size, your price point and your delivery window.
We keep a second qualified source on this line. When a plant goes down for maintenance, or a cold-chain routing is disrupted, your order switches source rather than stalling.
- Specification read against the CAS first. We confirm you need 70-34-8 and not DNCB or another dinitroaromatic electrophile before we quote a price.
- Batch COA shared before dispatch. You approve the assay, melting range and colour against your own spec while the material is still in our warehouse.
- Sensitisation risk stated up front. This material is a documented potent skin sensitiser, 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.
- Cold-chain packing chosen for your use. With a melting point right around room temperature, analytical customers get light-protected, insulated small packs; bulk buyers get drums stowed for their climate.
- 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 DNFB alongside other intermediates from our range — one invoice, one shipment, one counterparty.
Packed for the lab bench or the reactor
Because this product's melting point sits at room temperature and it darkens with light and heat, pack format is chosen to protect quality as much as to control cost. Tell us which type of buyer you are and we will quote accordingly.
Amber glass, light-protected
Amber glass bottles for analytical, immunology and R&D buyers, cold-chain couriered with ice packs to preserve colour and purity in transit.
Fibre & HDPE drums, lined
UN-approved lined drums for fine-chemical and dye-intermediate buyers, shipped by refrigerated container or with insulated liners depending on route and season.
Bulk drums / campaign lots
For contracted SNAr synthesis programmes, bulk drummed material lowers packing cost per kilo while keeping the same cold-chain quality controls.
Samples & trial packs
Gram-scale samples dispatched by cold-chain courier so your laboratory can qualify the grade before committing to a larger pack size or campaign volume.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to. Air freight with cold-chain handling for reagent packs, ocean freight for bulk drums, documented end-to-end.
Campaign despatch
Fine-chemical production runs to campaign; reagent demand runs as a steady trickle. We hold contracted volume for both and release against your calendar.
Handle this as a potent, well-documented sensitiser
This is the point on the page that matters most. DNFB is acutely toxic by all three exposure routes and carries a May cause damage to organs through prolonged or repeated exposure notation — but its most operationally important property is that it is a strong, well-characterised skin sensitiser: the very reactivity that makes it useful as a research reagent for inducing contact dermatitis in animal models is the same reactivity that puts unprotected handlers at real risk. 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
H301+H311+H331Toxic if swallowed, in contact with skin or if inhaled.H315Causes skin irritation.H317May cause an allergic skin reaction.H319Causes serious eye irritation.H373May cause damage to organs through prolonged or repeated exposure.H410Very toxic to aquatic life with long lasting effects.
Hazard statements reflect the harmonised GHS classification commonly published for CAS 70-34-8. Supplier classifications may differ in detail; always read the SDS issued with your specific batch, and treat the sensitisation entry (H317) as the one that shapes your controls, alongside the acute toxicity profile.
Spill & emergency orientation
Plan your response before the pack arrives, not after a bottle breaks. 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.
- Assume any skin contact is sensitising. Even a trace amount can trigger an allergic response on repeat exposure — remove contaminated clothing and wash the skin thoroughly and immediately, every time.
- Contain, do not hose to drain. The material is very toxic to aquatic life. Collect spilled solid or liquid into a labelled container; never wash it to a drain.
- Work in a fume hood or with local exhaust. Whether solid or liquid on the day, avoid generating dust or mist — both are inhalation and sensitisation risks.
- Have the SDS with the casualty. The treating clinician needs the product identity, CAS number and its known sensitising properties in hand.
- Record every meaningful exposure. For a potent contact sensitiser, most occupational regimes expect an exposure record to be created and retained, and repeat exposure without proper controls can build sensitisation over time. That is a decision for your EHS function, and it is easier made before an incident than after one.
Storage
- Refrigerated storage, 2–8 °C, is recommended. With a melting point around room temperature, cool storage both prevents unwanted melting/caking and slows the light- and heat-driven colour drift.
- Protect from light as well as heat — amber or opaque packaging and a dark store both help preserve purity and colour for analytical use.
- Keep containers tightly closed. This limits moisture pickup and slows oxidative darkening.
- Segregate from amines, bases and reducing agents. DNFB is a reactive electrophile by design and can react exothermically with primary and secondary amines — never store it alongside amine-based reagents.
- Access-controlled storage. For a potent sensitiser, restricting who can reach the store is part of the control, not an administrative nicety.
- Shelf life is typically around 24 months in sealed original packing under refrigerated, dark conditions. Re-assay before use after long storage.
Handling & PPE
- Design exposure out, do not manage it down. Closed transfer and mechanical charging first, local exhaust ventilation second, PPE last — this compound is not one to handle casually with gloves alone.
- Skin protection is the absolute priority. Use chemical-resistant gloves and full-coverage protective clothing rated for the specific compound — the H317 sensitisation entry is not a minor footnote here.
- Respiratory protection where dust or mist may be generated — for example when the material is being weighed at room temperature near its melting point — per your own exposure assessment.
- Health surveillance and exposure records. Where a sensitiser classification triggers obligations at your site, your occupational health provider and EHS function own the detail. We flag the classification; the programme is yours to run.
- Never discharge to drain or watercourse. H410 applies — collect spills and residues as regulated chemical waste.
Transport
DNFB moves as regulated cargo, typically under UN 2811, Class 6.1, Packing Group II. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. The exact packing instruction and quantity limits 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
Whether you are qualifying a reagent for an analytical protocol or a bulk feedstock for a synthesis campaign, the file that travels with the shipment is exactly what you are buying from a supplier.
Certificate of Analysis
Batch-specific assay by GC/HPLC, melting range, moisture and colour — 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 shipment 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.
Why the fluorine leaves so readily
Almost everything DNFB does traces back to one reaction: nucleophilic aromatic substitution (SNAr) at the carbon bearing the fluorine. Understanding that mechanism explains both why it is such a useful labelling reagent and why it must be handled with real respect.
Start with the activated ring
Two nitro groups, ortho and para to the fluorine, withdraw electron density from the ring and stabilise a negative charge at the carbon under nucleophilic attack.
Nucleophile attacks
An amine, alcohol or thiol nucleophile adds to the ring carbon bearing fluorine, forming a resonance-stabilised anionic Meisenheimer intermediate.
Fluoride leaves
Fluoride is expelled to restore aromaticity — counter-intuitively fast in this activated system, because the addition step, not the C–F bond strength, controls the rate.
Finish to the DNP derivative
The product — a DNP-amine, DNP-amino acid, DNP-ether or DNP-thioether — is isolated, purified and, for reagent use, identified against a reference standard.
Why purity and colour carry through every downstream use
Because the same electrophilic carbon is doing the work in every application, anything that competes for it — or contaminates the batch — follows the material into the result:
- Residual DNCB or other dinitrohalobenzenes react at a different rate and can distort quantitative amino-acid or amine derivatisation work.
- Colour bodies from oxidative darkening in storage can interfere with the colourimetric or chromatographic detection steps that many DNFB-based methods rely on.
- Moisture is generally well tolerated but can slow the SNAr reaction and promote hydrolysis side-products in sensitive synthesis work.
- Trace metal or ionic residues matter disproportionately in immunology and hapten-conjugation work, where a clean analytical-grade pack is worth paying for.
That is the reason we quote against your written specification — reagent-grade or bulk fine-chemical grade — rather than against a single generic grade, and the reason the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Electrophile | Principal outlet |
|---|---|
| 2,4-Dinitrofluorobenzene CAS 70-34-8 — this product | N-terminal amino acid analysis DNP hapten & immunology reagents SNAr fine chemical synthesis |
| 2,4-Dinitrochlorobenzene (DNCB) Slower SNAr electrophile | Reference contact-sensitisation standard Slower-reacting SNAr chemistry |
| 2,3,4-Trifluoronitrobenzene Fluoroquinolone-route electrophile | Pharmaceutical intermediate chemistry |
If your protocol calls for one of the others, we can source those as well — browse the full electrophile & intermediate range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this reagent
DNFB is not a commodity with a screen price, and its two very different buyer bases move the quote in different ways. Knowing what drives it helps you time a purchase and read whether an offer is realistic.
Two demand profiles, one product
Life-science reagent demand is a steady year-round trickle of small packs; fine-chemical SNAr demand arrives in campaign-sized blocks. The two rarely move together.
- Small-pack pricing reflects handling, not just raw cost
- Bulk campaign pricing tracks feedstock and capacity
- Tell us which type of buyer you are when you enquire
Fluorobenzene & dinitration feedstock
The route back to DNFB runs through fluorobenzene and a controlled dinitration step. Movements in fluorine and nitric acid chemistry feed through to the finished reagent within a quarter or so.
- Dinitration is a tightly controlled, specialist step
- Few producers run it at analytical-reagent quality
- We flag feedstock-driven moves in the quote
Sensitiser classification
The H317 skin-sensitisation entry raises the compliance and handling cost of producing, storing and moving this material, and that cost sits inside the price you are quoted.
- Handling obligations vary by jurisdiction
- Occupational exposure limits apply in several markets
- We check destination rules before quoting
Cold-chain & light-protection cost
Refrigerated, light-protected packaging for reagent-grade material costs noticeably more per kilo than ambient bulk drums — a small pack for a lab is a different economic product from a drum for a plant.
- Small analytical packs carry the highest cost per gram
- Bulk ambient drums are cheapest per kilo
- We quote each format on its own basis
Freight & DG surcharges
This is regulated cargo with occasional cold-chain requirements, so both ocean and air freight carry hazardous and, for small packs, temperature-control surcharges.
- Compare on landed cost, not ex-works
- Air freight suits urgent small-pack reagent orders
- We quote FOB, CIF, CFR or DDP as you prefer
Source availability
A limited number of plants run dinitration and fluorination to analytical-reagent quality at the same time as bulk fine-chemical grade. Single-sourced buyers feel a disruption 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 |
|---|---|
| N-terminal amino acid analysis | HPLC-grade purity, tight melting range, low colour |
| DNP hapten / immunology work | High purity, low ionic residue, analytical CoA |
| HPLC/GC amine derivatisation | Research-grade small pack, batch-consistent purity |
| Dermatology / sensitisation research | Research-grade, light-protected small pack |
| Dye / fine-chemical SNAr synthesis | Standard 98% commercial grade, bulk pack |
Not sure which column you are in? Describe the assay or 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 bottle
What our technical desk will do
- Match a grade to your use. Tell us whether you are running an analytical protocol or a bulk SNAr synthesis and we will recommend the specification — and say so plainly when a tighter, costlier grade would add nothing.
- Be straight about the sensitisation risk. We state the H317 classification at enquiry stage so your EHS or lab safety officer can price the controls into the decision, rather than meeting it for the first time on the label.
- Advise on cold-chain and light protection for your site conditions — a research lab's fridge storage is a different problem from a bulk plant's drummed warehouse.
- Review your specification before it goes into a contract, so you are not locked into a purity or colour limit that no plant can consistently hit.
Regulatory & compliance notes
- Sensitiser obligations are jurisdiction-specific. Several regimes impose occupational exposure limits, health surveillance and record retention for classified skin sensitisers. Confirm what applies at your site before the first delivery.
- Import controls vary by destination. Some jurisdictions apply registration, licensing or end-use declaration requirements to dinitroaromatic reagents. 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.
- Life-science reagent buyers should confirm their own institutional biosafety/chemical-safety committee requirements for a documented sensitiser before the first shipment arrives on site.
None of the above is legal advice — your own regulatory affairs or laboratory safety 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 pack
Send the specification
Product name or CAS 70-34-8, the assay and colour limits you work to, quantity, pack preference and destination.
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 cold-chain 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 address.
Often bought alongside this grade
Consolidate reagent and fine-chemical orders onto one shipment and one invoice. These are the activated aryl halides and nitroaromatics our analytical, immunology and fine chemical customers most often order in the same programme. Every card below opens our full product range — contact us with the CAS number for a dedicated quote on any of them.
What buyers ask us about 2,4-Dinitrofluorobenzene
Is this really "Sanger's Reagent"?
Is this the same as DNCB (2,4-dinitrochlorobenzene)?
Is this a solid or a liquid?
Why is it dangerous to handle?
What purity do you normally supply?
What is the minimum order quantity?
How long does delivery take?
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 airway bill or bill of lading
- Certificate of origin and any destination-specific forms
Do you supply to my country, and can you handle small research orders?
Do you manufacture this yourself?
Can you hold stock against a production or research plan?
Request pricing on 2,4-Dinitrofluorobenzene
Send your required assay, pack size (gram-scale reagent or bulk drum), colour specification and destination. 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 cold-chain research sample or a contracted campaign volume for the year.