2,4-Dinitrofluorobenzene DNFB · Sanger's Reagent · CAS 70-34-8
Chelora Chemicals is a supplier of 2,4-Dinitrofluorobenzene, the highly activated fluoroaromatic used as Sanger's reagent for amino-group derivatisation and as a building block wherever a ring-fluorine has to be displaced by an amine, alcohol or thiol. Every consignment leaves with a batch-specific COA and the current SDS.
Also known as: DNFB, Sanger's reagent, 1-Fluoro-2,4-dinitrobenzene, 2,4-Dinitro-1-fluorobenzene, FDNB
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Price, lead time and a sample COA for 2,4-Dinitrofluorobenzene, usually within one working day. We ship worldwide.
Request a Quote Email the DeskDocumentation
- Batch-specific COA (assay, melting range, appearance)
- Safety Data Sheet (SDS)
- UN 2811 dangerous-goods transport documents
- Third-party inspection on request
- Certificate of origin
What is 2,4-Dinitrofluorobenzene?
2,4-Dinitrofluorobenzene, usually shortened to DNFB and known in the laboratory as Sanger's reagent, is a benzene ring carrying a fluorine at the 1-position and nitro groups at the 2- and 4-positions, formula C₆H₃FN₂O₄. It is supplied as a yellow solid that melts just above room temperature, so drums can arrive part-liquid in warm weather.
Its value comes entirely from how activated that fluorine is. Two nitro groups pull electron density out of the ring and make the carbon bearing the fluorine unusually open to nucleophilic aromatic substitution, so amines, alcohols and thiols displace the fluoride under mild conditions where an ordinary aryl halide would not react at all.
That reactivity is what made it Frederick Sanger's reagent for labelling the free alpha-amino group of a peptide chain, and it is the same reactivity that makes it useful industrially as a building block and as a derivatising agent in analytical chemistry.
Handling demands respect. DNFB is toxic, corrosive to skin and eyes, and a potent skin sensitiser — a single careless exposure can set up a lasting allergic response. Chemical-resistant gloves, eye protection and good ventilation are not optional with this material.
Why 2,4-Dinitrofluorobenzene specifically
- An exceptionally activated leaving group. The two nitro groups make the C–F bond far more reactive to nucleophiles than the corresponding chloro compound.
- Mild reaction conditions. Substitution proceeds under conditions gentle enough for peptides and other sensitive substrates.
- Analytical workhorse. Sanger's reagent for amino-group labelling and for preparing DNP derivatives ahead of chromatographic analysis.
- A defined synthetic handle. Introduces a 2,4-dinitrophenyl group cleanly onto an amine, alcohol or thiol in one step.
How 2,4-Dinitrofluorobenzene is Manufactured
Commercially it is made by halogen exchange on 2,4-dinitrochlorobenzene — the same activation that makes the product reactive is what lets the chlorine be swapped for fluorine in the first place.
- Halogen exchange. 2,4-Dinitrochlorobenzene is treated with an alkali-metal fluoride, typically potassium fluoride, in a polar aprotic solvent at elevated temperature.
- Workup. Inorganic salts are removed and the solvent is recovered from the crude reaction mass.
- Purification. The product is purified by distillation or crystallisation to the target assay, with residual chloro compound controlled.
- Quality release and packing. Assay, melting range and residual starting material are confirmed against specification before the batch is packed and released.
Typical Commercial Specification
Figures below are representative of commercial-grade 2,4-dinitrofluorobenzene. Tell us your downstream route and the grade you need, and we will advise on the specification to order against.
| Parameter | Typical Value |
|---|---|
| Appearance | Yellow to light brown solid or melt |
| Assay | 99% min by GC |
| Residual 2,4-dinitrochlorobenzene | Trace levels to grade |
| Melting range | About 25 – 27 °C |
| Moisture | Low, to grade — the material is moisture sensitive |
Physical & Chemical Properties
| Property | Value |
|---|---|
| Chemical formula | C₆H₃FN₂O₄ |
| Molecular weight | 186.10 g/mol |
| Appearance | Yellow low-melting solid |
| Melting point | About 25 – 27 °C |
| Boiling point | About 178 °C at 13 mmHg |
| Density | About 1.48 g/mL |
| Solubility | Soluble in common organic solvents; hydrolyses in water |
| Incompatibilities | Strong bases, amines, strong reducing agents, water |
Behaviour in the process
DNFB's reactivity profile is what buyers are actually paying for:
- Nucleophilic aromatic substitution. The fluorine is displaced readily by amines, alkoxides and thiolates under mild conditions.
- Moisture sensitivity. It hydrolyses to 2,4-dinitrophenol on contact with water; keep containers sealed and solvents dry.
- Low melting point. It will soften or liquefy in a warm warehouse — plan the packing and the handling for that.
2,4-Dinitrofluorobenzene and Related Activated Aromatics
Choosing between activated halo-nitroaromatics comes down to how reactive a leaving group the route needs and what it is allowed to cost.
| Material | Leaving group | When it is the right choice |
|---|---|---|
| 2,4-Dinitrofluorobenzene | Fluoride, doubly activated | Mild conditions, sensitive substrates, analytical labelling |
| 2,4-Dinitrochlorobenzene | Chloride, doubly activated | Cost-driven routes that tolerate harder conditions |
| ortho-Fluoroaniline | Ring fluorine, not a leaving group | Routes needing a retained ring fluorine rather than a displacement |
| 2-Bromo-4-fluoroacetanilide | Bromide, for cross-coupling | Palladium-catalysed coupling rather than SNAr chemistry |
Stated plainly: if your substitution has to run under mild conditions or on a sensitive substrate, the fluoro compound earns its price premium over the chloro analogue. If the chemistry tolerates forcing conditions, it may not.
Industries We Supply 2,4-Dinitrofluorobenzene To
The same reagent serves a peptide analytics laboratory and a fine-chemical plant. What changes is the scale, the packing format and the documentation each requires.
Where 2,4-Dinitrofluorobenzene is Used
In downstream functionalisation
The practical pattern is always the same: a nucleophile attacks the carbon bearing the fluorine, fluoride leaves, and a dinitrophenyl group is installed. Because the ring is doubly activated, that happens at temperatures and pH values that leave the rest of the molecule alone — which is exactly why the reagent survived from protein sequencing into routine synthetic use.
Need a specific purity grade?
Tell us the purity grade you need, your downstream chemistry, the packing format you can receive and the annual quantity. We will come back with a price, a lead time and a sample COA.
Quality Control & Testing
Every lot is released against a batch-specific Certificate of Analysis, with residual chloro compound reported alongside the main assay because unreacted 2,4-dinitrochlorobenzene behaves very differently in your substitution step.
- Assay — by GC, the primary grade measure.
- Residual 2,4-dinitrochlorobenzene — reported because it is the carryover that costs you yield.
- Melting range — a practical purity check and a handling indicator given how low the melting point sits.
- Appearance and moisture — reported because the material hydrolyses to dinitrophenol on contact with water.
Common Process Problems & Likely Causes
| Symptom | Likely cause | What to check |
|---|---|---|
| Sluggish or incomplete substitution | Residual chloro analogue, or wet solvent consuming reagent | Residual 2,4-DNCB and moisture figures on the COA |
| Yellow phenolic by-product | Hydrolysis to 2,4-dinitrophenol from moisture ingress | Container seal, solvent dryness, age of the opened drum |
| Material liquid on arrival | Ambient temperature above the melting range | Normal for this product — confirm assay rather than rejecting on appearance |
| Darkened material | Heat exposure or prolonged storage | Storage temperature record and lot age |
Packaging, Storage & Shipping
- Standard packing. Fibre drums, HDPE drums or sealed jars, typically 1 – 50 kg net, with larger formats on contract supply.
- Moisture protection. Keep containers tightly sealed; the material hydrolyses on contact with water.
- Temperature control. Cool, dry and well ventilated, away from direct sun and heat — note the melting point sits near ambient.
- Material compatibility. Keep away from bases, amines and strong reducing agents.
- Transport classification. Commonly shipped under UN 2811, Class 6.1 — confirm the entry and packing group against your own current SDS before shipping.
Hazards & Safe Handling
2,4-Dinitrofluorobenzene is toxic, corrosive to skin and eyes, and a strong skin sensitiser. It deserves more caution than its modest molecular weight suggests, and sensitisation is the hazard people most often underestimate.
- Skin and eye contact. Corrosive and sensitising. Chemical-resistant gloves, goggles and a face shield for transfers; rinse immediately and at length on contact.
- Sensitisation. A single significant skin exposure can set up a lasting allergic response — treat even small splashes seriously.
- Inhalation. Handle in a fume hood or under local exhaust ventilation.
- Environment. Harmful to aquatic life; avoid uncontrolled release to water and follow local effluent rules.
Regulatory & Compliance Notes
2,4-Dinitrofluorobenzene is a listed specialty intermediate. Because obligations differ by territory and use, the notes below are orientation rather than legal advice.
- GHS classification. Classified as toxic, skin corrosive, seriously eye damaging and a skin sensitiser (Signal word: Danger); the SDS carries the full hazard statements for your grade.
- Chemical inventories. Listed on major chemical inventories; confirm the status for your territory before import.
- Dangerous goods transport. Commonly shipped under UN 2811, Class 6.1. Confirm the correct entry and packing group with your logistics/EHS team against your current SDS before shipping.
- HS code. Commonly declared under the halogenated and nitro derivatives headings; confirm the exact tariff line with your customs broker for your jurisdiction.
We Supply 2,4-Dinitrofluorobenzene Worldwide
Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship 2,4-Dinitrofluorobenzene from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation and freight so the material arrives ready to use.
- Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
- Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged as routing allows.
- Documentation. Commercial invoice, packing list, certificate of origin, COA and SDS issued as a complete set.
- Flexible volumes. From trial quantities up to repeat bulk shipments on a supply contract.
Buying 2,4-Dinitrofluorobenzene from Chelora
We are an independent sourcing and supply partner. For this product that means settling three things at enquiry: the assay and residual-chloride grade your application needs, the packing format given the low melting point, and the quantity you are buying.
- Documentation on every lot. Batch-specific COA with assay and impurity breakdown, plus the current SDS.
- Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
- Quantities. Laboratory and trial quantities through to larger bulk shipments on contract supply.
- Inspection. Independent third-party inspection available at loading when the contract requires it.
- Related intermediates. Fluoroanilines, bromo-fluoro intermediates and other activated aromatics alongside this product from one supplier.
How ordering works
- Send the enquiry. Assay grade, quantity, packing format, destination port and the Incoterm you buy on.
- We quote. Price, lead time, packing format and a sample COA, normally within one working day.
- Qualify the supply. For first orders or pharma-grade applications, we share the analysis so your technical team can sign off before you commit.
- Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
- Ship and document. Packed, labelled and loaded with the full export document set, and tracked through to arrival.
2,4-Dinitrofluorobenzene — Common Questions
The questions our technical desk is asked most often about 2,4-Dinitrofluorobenzene. If yours isn't here, call or email and you will reach someone who knows the chemistry.
What is the CAS number of 2,4-Dinitrofluorobenzene?
The CAS number for 2,4-Dinitrofluorobenzene (DNFB) is 70-34-8, and its EC number is 200-734-3. Its molecular formula is C₆H₃FN₂O₄ with a molecular weight of 186.10 g/mol.
What is 2,4-Dinitrofluorobenzene used for?
It is used as Sanger's reagent for labelling free amino groups in peptide analysis, as a derivatising agent for amines and thiols, and as a building block that introduces a 2,4-dinitrophenyl group under mild substitution conditions.
Why is it called Sanger's reagent?
Frederick Sanger used it to label the free terminal amino group of a peptide chain so that residue could be identified after hydrolysis — the method that underpinned the first full protein sequence.
How does it differ from 2,4-dinitrochlorobenzene?
The fluorine is a far better leaving group in this activated system, so the fluoro compound reacts under much milder conditions. The chloro analogue is cheaper but needs more forcing conditions.
How is 2,4-Dinitrofluorobenzene manufactured?
By halogen exchange on 2,4-dinitrochlorobenzene using an alkali-metal fluoride in a polar aprotic solvent, followed by purification to the target assay.
Is 2,4-Dinitrofluorobenzene hazardous?
Yes. It is toxic, corrosive to skin and eyes, and a strong skin sensitiser. Refer to the current SDS for your grade for the complete hazard classification before handling it.
What is the UN number and transport classification?
It is commonly shipped under UN 2811 (Toxic solid, organic, n.o.s.), Class 6.1. Confirm the correct entry and packing group against your own current SDS before relying on it for shipping documentation.
What are the melting point, boiling point and density?
Typical figures are a melting point around 25 – 27 °C, a boiling point around 178 °C at 13 mmHg, and a density around 1.48 g/mL. Confirm against your own supplier's COA for batch-specific figures.
Why did my drum arrive as a liquid?
Because the melting point sits just above room temperature. Material that is liquid or part-liquid on arrival in warm weather is normal — judge the lot on its assay, not its physical state.
How should 2,4-Dinitrofluorobenzene be stored?
In tightly sealed containers, cool, dry and well ventilated, away from direct sun, heat, bases, amines and strong reducing agents. It hydrolyses on contact with water.
What purity grades do you offer?
Standard commercial grade is 99% minimum by GC, with residual 2,4-dinitrochlorobenzene and melting range reported on the COA.
What packing sizes and order quantities are available?
Fibre drums, HDPE drums or sealed jars, typically 1–50 kg net, with larger formats available on contract supply. Orders run from laboratory quantities up to repeat bulk loads.
Ready to source 2,4-Dinitrofluorobenzene?
Send us your purity requirement and annual volume. You will get a price, a realistic lead time and a sample COA from someone who understands what the material has to do in your process — delivered anywhere in the world.