2,4-Dinitrochlorobenzene 1-Chloro-2,4-dinitrobenzene · CAS 97-00-7
Chelora Chemicals is a supplier of 2,4-Dinitrochlorobenzene (DNCB), a reactive chloronitroaromatic used as a precursor for azo dye and pigment building blocks and as a key reagent in biochemical research. Every consignment leaves with a batch-specific COA and the current SDS.
Also known as: DNCB, CDNB, 1-Chloro-2,4-dinitrobenzene, 2,4-Dinitrophenyl chloride, 1,3-Dinitro-4-chlorobenzene
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Price, lead time and a sample COA for 2,4-Dinitrochlorobenzene, 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 3441 dangerous-goods transport documents
- Third-party inspection on request
- Certificate of origin
What is 2,4-Dinitrochlorobenzene?
2,4-Dinitrochlorobenzene (DNCB), also known as 1-chloro-2,4-dinitrobenzene or CDNB, is a benzene ring carrying a chlorine atom and two nitro groups at the 2- and 4-positions, formula C₆H₃ClN₂O₄. It is supplied as pale yellow to green crystals or crystalline powder with a faint almond-like odour, insoluble in water but soluble in alcohol, benzene and ether.
Its value as an intermediate comes from the chlorine atom, which is strongly activated toward nucleophilic aromatic substitution by the two flanking nitro groups. This makes DNCB a highly reactive building block for azo dye and pigment intermediates, and the same reactivity is why it is widely used as a standard reagent in biochemical research — most notably as the substrate in glutathione S-transferase (GST) activity assays.
Commercially it is produced by nitrating 2-chloronitrobenzene (or chlorobenzene, in a two-step nitration), introducing the second nitro group at the 4-position.
Handling requires more caution than most chloronitroaromatics: DNCB is fatal in contact with skin and a strong skin sensitiser, so chemical-resistant gloves, full-coverage clothing and eye protection, adequate ventilation, and storage away from strong oxidisers, ammonia and hydrazine hydrate are essential.
Why 2,4-Dinitrochlorobenzene specifically
- Activated chlorine leaving group. The two ortho/para-positioned nitro groups make the chlorine highly reactive toward amines, thiols and other nucleophiles.
- Dye and pigment intermediate. A precursor for azo dye and pigment building blocks used across textiles, coatings and inks.
- Standard biochemical reagent. The reference substrate for glutathione S-transferase (GST) activity assays in research laboratories worldwide.
- Distinct from mono-nitro analogues. The reactivity is much higher than ortho- or para-nitrochlorobenzene alone, because the two nitro groups activate the ring together.
How 2,4-Dinitrochlorobenzene is Manufactured
2,4-Dinitrochlorobenzene is produced commercially by nitrating 2-chloronitrobenzene with a mixed-acid nitrating system (nitric acid/sulfuric acid), introducing the second nitro group at the 4-position.
- Nitration. 2-Chloronitrobenzene is nitrated under controlled temperature with mixed nitric/sulfuric acid, installing the second nitro group para to the chlorine.
- Workup. The crude product is washed free of spent acid and by-product isomers, including the related 2,6-dinitrochlorobenzene formed in smaller amount.
- Crystallisation. The product is crystallised and dried to the target melting-range specification.
- Quality release and packing. Assay, melting range and appearance are confirmed against specification before the batch is packed and released.
Typical Commercial Specification
Figures below are representative of commercial-grade 2,4-Dinitrochlorobenzene. Tell us your downstream route and the grade you need, and we will advise on the specification to order against.
| Parameter | Typical Value |
|---|---|
| Appearance | Pale yellow to green crystals or crystalline powder |
| DNCB content | 99% min by GC/HPLC assay |
| Melting range | About 48 – 54 °C, as a purity indicator |
| Isomer purity | 2,6-Dinitrochlorobenzene, trace levels to grade |
Physical & Chemical Properties
| Property | Value |
|---|---|
| Chemical formula | C₆H₃ClN₂O₄ |
| Molecular weight | 202.55 g/mol |
| Appearance | Pale yellow to green crystals/powder, almond-like odour |
| Melting point | About 48 – 54 °C |
| Boiling point | About 315 °C |
| Density | About 1.7 g/cm³ |
| Flash point | About 186 °C (367 °F) |
| Water solubility | Insoluble (about 8 mg/L) |
| Incompatibilities | Strong oxidisers, ammonia; reacts violently with hydrazine hydrate |
Behaviour in the process
DNCB's reactivity pattern is what dye-intermediate producers and research buyers are paying for:
- Activated nucleophilic substitution. The chlorine is readily displaced by amines, thiols and other nucleophiles under mild conditions, driven by the two nitro groups.
- Combustibility. Classified as combustible with a defined explosive limit range; avoid ignition sources and strong oxidisers.
- Thermal stability. Stable under normal storage conditions away from incompatible materials, but reacts violently with hydrazine hydrate and strong reducing/oxidising agents.
2,4-DNCB and Related Chloronitrobenzenes
Choosing between chloronitrobenzene intermediates comes down to how many nitro groups are needed, and where, for the target synthesis.
| Material | Substitution | When it is the right choice |
|---|---|---|
| 2,4-Dinitrochlorobenzene | 1-Cl, 2,4-diNO₂ | Routes needing a highly activated, readily displaceable chlorine |
| 2,6-Dinitrochlorobenzene | 1-Cl, 2,6-diNO₂ | Routes needing the symmetrical 2,6-dinitro pattern instead |
| ortho-Nitrochlorobenzene | 1-Cl, 2-NO₂ | Routes needing a single, less-activated nitro group |
| 2,4-Dinitroaniline | 1-NH₂, 2,4-diNO₂ | Routes needing the amine rather than the chloro leaving group |
Stated plainly: a synthesis that depends on a fast, mild nucleophilic displacement needs DNCB's specific activation pattern — the mono-nitro and 2,6-isomer analogues react far more slowly and are not drop-in substitutes.
Industries We Supply 2,4-Dinitrochlorobenzene To
The same DNCB feeds a dye-intermediate manufacturer and a biochemistry research lab. What changes is the downstream substitution chemistry and the documentation each requires.
Where 2,4-Dinitrochlorobenzene is Used
In downstream functionalisation
DNCB's chlorine is displaced by amines, thiols and other nucleophiles under comparatively mild conditions, driven by the two flanking nitro groups. This is exactly why it is reached for both in dye-intermediate synthesis, where speed and conversion matter, and in biochemistry, where a fast, well-characterised reaction with glutathione is the basis of the GST assay itself.
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 melting range reported alongside the main assay because it is a fast, reliable purity indicator for this product.
- DNCB content — by GC/HPLC assay, the primary grade measure.
- Melting range — a narrow range close to the literature value confirms low isomer/acid-residue carryover.
- Isomer purity — 2,6-dinitrochlorobenzene carryover, reported because it affects downstream reaction selectivity.
Common Process Problems & Likely Causes
| Symptom | Likely cause | What to check |
|---|---|---|
| Slow or incomplete substitution reaction | Isomer carryover reducing the effective reactive fraction | Isomer purity and assay figures on the COA |
| Depressed or wide melting range on receipt | Acid-residue or isomer impurities from the nitration step | Melting-range figure on the COA against the lot's history |
| Off-target GST assay readings | Trace impurities affecting the DNCB-glutathione reaction rate | Assay purity and storage history of the lot |
Packaging, Storage & Shipping
- Standard packing. Fibre drums, HDPE drums or bags, typically 25 – 200 kg net, with larger bulk formats on contract supply.
- Temperature control. Store below about 30 °C, in a cool, dry, well-ventilated area away from direct sun, heat and ignition sources.
- Material compatibility. Keep strictly away from strong oxidisers, ammonia and hydrazine hydrate, which reacts violently with DNCB.
- Combustibility. Classified as combustible; store away from flames and other ignition sources and follow local fire-code segregation requirements.
- Transport classification. Commonly shipped under UN 3441 (Chlorodinitrobenzenes, solid), Class 6.1, Packing Group II — confirm the correct entry and packing group against your own current SDS before shipping.
Hazards & Safe Handling
2,4-Dinitrochlorobenzene is fatal in contact with skin, toxic if inhaled, harmful if swallowed, causes skin and eye irritation, and is a strong skin sensitiser that may cause an allergic reaction. This is a more demanding hazard profile than most chloronitroaromatics, and handling should be planned accordingly.
- Skin contact. Treated as a potentially fatal exposure route — chemical-resistant gloves, full-coverage protective clothing and immediate, thorough washing on any contact are standard practice.
- Eye contact. Causes serious eye damage; tightly fitting chemical safety goggles are required, not just general eyewear.
- Inhalation. Use adequate ventilation or local exhaust; avoid generating or inhaling dust.
- Sensitisation. Repeated or even brief skin contact can sensitise; once sensitised, individuals may react to very low exposures — this is a key reason DNCB is used as a reference sensitiser in toxicology research.
- PPE. Chemical-resistant gloves, tightly fitting safety goggles, full-coverage protective clothing and a suitable respirator where dust or vapour exposure is possible.
Regulatory & Compliance Notes
2,4-Dinitrochlorobenzene is a long-established, widely registered specialty intermediate. Because obligations differ by territory and use, the notes below are orientation rather than legal advice.
- GHS classification. Signal word Danger, with hazard statements including H310 (fatal in contact with skin), H301/H302 (toxic/harmful if swallowed), H331 (toxic if inhaled), H315 (causes skin irritation), H318 (causes serious eye damage) and H317 (may cause an allergic skin reaction); the SDS carries the full hazard statements for your grade.
- REACH and chemical inventories. Registered under EU REACH and listed on major chemical inventories.
- Dangerous goods transport. Commonly shipped under UN 3441 (Chlorodinitrobenzenes, solid), 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 nitro-derivative heading; confirm the exact tariff line with your customs broker for your jurisdiction.
We Supply 2,4-Dinitrochlorobenzene Worldwide
Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship 2,4-Dinitrochlorobenzene 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-Dinitrochlorobenzene from Chelora
We are an independent sourcing and supply partner. For this product that means settling three things at enquiry: the purity grade your application needs, the packing format, and the quantity you are buying.
- Documentation on every lot. Batch-specific COA with assay, melting range and isomer breakdown, plus the current SDS.
- Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
- Quantities. Trial quantities through to larger bulk shipments on contract supply.
- Inspection. Independent third-party inspection available at loading when the contract requires it.
- Related chloronitrobenzenes. 2,6-Dinitrochlorobenzene, ortho- and para-nitrochlorobenzene alongside this product from one supplier.
How ordering works
- Send the enquiry. Purity grade, quantity, 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 dye-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-Dinitrochlorobenzene — Common Questions
The questions our technical desk is asked most often about 2,4-Dinitrochlorobenzene (DNCB). 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-Dinitrochlorobenzene?
The CAS number for 2,4-Dinitrochlorobenzene (DNCB, 1-chloro-2,4-dinitrobenzene) is 97-00-7, and its EC number is 202-551-4. Its molecular formula is C₆H₃ClN₂O₄ with a molecular weight of 202.55 g/mol.
What is 2,4-Dinitrochlorobenzene used for?
It is used as a reactive intermediate for azo dye and pigment synthesis, and separately as the standard substrate reagent for glutathione S-transferase (GST) activity assays in biochemical research.
Do you supply 2,4-Dinitrochlorobenzene worldwide?
Yes. Chelora Chemicals supplies and exports 2,4-Dinitrochlorobenzene worldwide — across Asia Pacific, Europe, the Middle East, Africa and the Americas, as well as throughout India. Every consignment carries the COA and SDS.
How does it differ from 2,6-dinitrochlorobenzene?
The two nitro groups sit in different positions relative to the chlorine — 2,4- versus 2,6- — which changes the symmetry and reactivity. Routes designed around the 2,4-pattern need this isomer specifically.
How is 2,4-Dinitrochlorobenzene manufactured?
By nitrating 2-chloronitrobenzene with a mixed nitric/sulfuric acid system, which introduces the second nitro group at the 4-position, followed by workup and crystallisation.
Is 2,4-Dinitrochlorobenzene hazardous?
Yes — it is fatal in contact with skin, toxic if inhaled, harmful if swallowed, causes serious eye damage, and is a strong skin sensitiser. This is a more demanding hazard profile than most chloronitrobenzenes. Refer to the current SDS for your grade for the complete hazard classification.
What is the UN number and transport classification?
2,4-Dinitrochlorobenzene is commonly shipped under UN 3441 (Chlorodinitrobenzenes, solid), Class 6.1, Packing Group II. 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 48–54 °C, a boiling point around 315 °C, and a density around 1.7 g/cm³. Confirm against your own supplier's COA for batch-specific figures.
How should 2,4-Dinitrochlorobenzene be stored?
In sealed containers, below about 30 °C, cool, dry and away from direct sun, heat, ignition sources, strong oxidisers, ammonia and hydrazine hydrate (which reacts violently with it).
What purity grades do you offer?
Standard commercial grade is 99% minimum by GC/HPLC assay, with melting range and isomer purity (versus 2,6-dinitrochlorobenzene) reported on the COA.
What packing sizes and order quantities are available?
Fibre drums, HDPE drums or bags, typically 25–200 kg net, with larger bulk formats available on contract supply. Orders run from trial quantities up to repeat bulk loads.
Ready to source 2,4-Dinitrochlorobenzene?
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.