2,4-Dinitrochlorobenzene
On an ordinary chlorobenzene the chlorine is almost inert. Put a nitro group ortho to it and another para to it, and that same chlorine becomes one of the most readily displaced leaving groups in aromatic chemistry — amines, alkoxides, phenoxides, thiolates and hydroxide all substitute it under mild conditions. That single property is why DNCB has been a backbone intermediate of the dye and fine chemical industries for more than a century.
Chelora Chemicals supplies DNCB to dye manufacturers, rubber chemical producers, agrochemical plants and fine chemical houses worldwide, in UN-approved packing, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 97-00-7
- IUPAC name
- 1-Chloro-2,4-dinitrobenzene
- Molecular formula
- C6H3ClN2O4
- Molecular weight
- 202.55 g/mol
- EC / EINECS
- 202-551-4
- UN Number
- 1577 · Class 6.1
- SMILES
- Clc1ccc(cc1[N+](=O)[O-])[N+](=O)[O-]
- HS Code
- 2904 99*
* Confirm the exact HS heading with your customs broker — compounds carrying both chloro and nitro substituents can sit under a different subheading from the simple nitroaromatics depending on the destination tariff schedule.
What 2,4-Dinitrochlorobenzene is used for
DNCB is a yellow crystalline solid that melts just above ambient, around 52 °C. Its commercial value comes entirely from the electronic effect of its two nitro groups: both withdraw electron density from the ring, both stabilise the negatively charged intermediate formed when a nucleophile attacks the carbon bearing the chlorine, and between them they turn an unreactive aryl chloride into an exceptionally good substrate for nucleophilic aromatic substitution.
Practically, that means DNCB is the standard way to attach a 2,4-dinitrophenyl group onto almost anything that has a lone pair. Treat it with ammonia or an amine and you get 2,4-dinitroaniline and its N-substituted relatives; with hydroxide, 2,4-dinitrophenol; with an alkoxide, the corresponding ether; with a thiolate, the aryl sulphide. Those products in turn feed azo and sulphur dye manufacture, rubber accelerators and antidegradants, agrochemical actives and pharmaceutical intermediates.
Why the isomer matters
- 2,4-Dinitrochlorobenzene (CAS 97-00-7) — this product. Nitro groups ortho and para to the chlorine, both activating it. The commercially dominant isomer.
- 2,6- and 3,4-dinitro isomers — the activation pattern differs, and so does the rate and selectivity of substitution.
- Mononitrochlorobenzenes — only one activating group, so substitution needs much harder conditions. See meta nitrochlorobenzene.
- Dichloronitrobenzenes — two chlorines, one nitro; the question becomes which chlorine goes first. See 3,4-dichloronitrobenzene.
Always quote the CAS number on your purchase order. We supply across the nitro and chloro aromatic range — see the full intermediate range.
Appearance and handling character
DNCB ships as a yellow crystalline solid or flake, practically insoluble in water and soluble in hot alcohol, benzene, ether and other organic solvents. Two handling facts dominate everything else. It is toxic by all three exposure routes, and it is one of the most potent contact sensitisers known to occupational medicine — a single significant skin exposure can sensitise a worker for life. The safety section below should be read before any handling is planned.
| Parameter | Typical value |
|---|---|
| Appearance | Yellow crystalline solid / flake |
| Assay | 99.0% min |
| Melting range | 51 – 53 °C |
| Isomer content | Reported per batch |
| Residual chloronitrobenzene | Reported per batch |
| Moisture | 0.2% max |
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. Melting range is the practical purity indicator buyers watch on this product — a depressed or broad range usually means isomer or residual mononitro content, so it is worth reading alongside the assay figure rather than instead of it.
| Property | Value |
|---|---|
| Physical state | Solid at ambient; melts just above |
| Melting point | ≈ 51 – 53 °C |
| Boiling point | ≈ 315 °C @ 760 mmHg |
| Flash point | ≈ 194 °C |
| Relative density | ≈ 1.69 (solid) |
| Water solubility | Practically insoluble |
| Organic solubility | Soluble in hot alcohol, benzene, ether, acetone |
| Stability | Stable in storage; exothermic with nucleophiles |
Physical constants compiled from public reference data for CAS 97-00-7 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
Nearly every industrial use of DNCB is the same reaction with a different nucleophile. What changes is the product and the market it serves.
Dye & pigment intermediates
DNCB is a long-standing feedstock for sulphur and azo dye chemistry, and the route to 2,4-dinitroaniline — itself a widely used diazo component. The dinitrophenyl group also appears directly in a range of disperse and acid dye structures.
- Sulphur black and azo dye routes
- 2,4-Dinitroaniline production
- See our dye intermediate range
2,4-Dinitrophenol & derivatives
Hydrolysis of the activated chlorine gives 2,4-dinitrophenol, the gateway to a family of phenolic derivatives and onward chemistry, including picramic and picric routes.
- Controlled hydrolysis route
- Phenolic derivative chemistry
- End-use declaration required
Rubber chemicals
Thiolate and amine substitution routes from DNCB lead into rubber accelerator and antidegradant chemistry, where aryl sulphide and aryl amine fragments are standard structural motifs.
- Aryl sulphide intermediates
- Accelerator and antidegradant routes
- Technical desk review of your step
Agrochemical intermediates
Dinitrophenyl ethers and amines built from DNCB appear across several agrochemical synthesis routes, where the activated substitution step is the cleanest way to install the fragment.
- Dinitrophenyl ether chemistry
- Custom synthesis quantities available
- See our agrochemical intermediate range
Analytical & biochemical reagent
The dinitrophenyl group is a classic derivatising label in analytical and protein chemistry, and DNCB and its relatives remain standard reagents in laboratory procedures built around that chemistry.
- Reagent-grade material on request
- Small pack sizes, subject to DG rules
- Full analytical documentation available
Contract & scheduled supply
Nitration plants run to campaign and dangerous-goods freight needs planning. Most DNCB 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 2,4-Dinitrochlorobenzene
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. We own no nitration plant — and on a potent sensitiser that moves as Class 6.1 dangerous goods, that independence means we can route your order to a producer whose handling, packing and documentation standards actually match what your site needs.
We place your order with whichever qualified producer best matches your assay, your isomer requirement, your price point and your delivery window.
We keep a second qualified source on this line. When a plant goes down for maintenance, your campaign switches source rather than stalling.
- Sensitisation stated at enquiry stage. We tell you this is a potent contact sensitiser before you quote the job internally — not in the small print of a document pack that arrives with the goods.
- Packing integrity checked, not assumed. On a solid sensitiser, drum closure and liner quality are a safety control. We inspect before release rather than trusting the loading note.
- Batch COA shared before dispatch. You approve assay, melting range and isomer profile against your own spec while the material is still in our warehouse.
- Reactivity flagged for your process safety team. Exothermic reaction with amines and alkalis is a known hazard on this molecule, and we say so in writing.
- Pre-shipment samples for qualification. New account or new source, your laboratory runs a trial before the full quantity ever moves.
- Export machinery handled in-house. UN 1577 classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
Packed the way your plant receives it
On a solid sensitiser, pack format is a handling decision before it is a cost decision. Tell us how the material will be charged at your end and we will quote accordingly.
UN-approved drums
Fibre or HDPE drums with inner liner, UN-certified for Class 6.1 solids — the standard commercial format and the easiest to handle without generating dust.
Large drums
Larger UN drums for high-volume users with mechanical handling and closed charging, cutting cost per kilo and the number of openings your operators make.
Molten movement
Where you charge molten and have heated receipt facilities, molten bulk movement is possible in suitable equipment, subject to the DG position for your destination.
Samples & trial packs
Laboratory and pilot quantities dispatched so your R&D team can qualify the grade first — subject to the dangerous-goods rules for your destination and courier.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with DG documentation filed before the booking is made rather than chased afterwards.
Campaign despatch
Dangerous-goods space needs planning. We hold contracted tonnage and release it against your production calendar instead of landing it all at once.
Handle this as a potent skin sensitiser
2,4-Dinitrochlorobenzene is toxic by all three routes of exposure, very toxic to aquatic life, and one of the most powerful contact sensitisers in industrial use. Sensitisation is effectively permanent, which changes the logic of your controls: the goal is zero skin contact, not acceptable skin contact. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document.
Classified hazards
H301Toxic if swallowed.H311Toxic in contact with skin.H331Toxic if inhaled.H317May cause an allergic skin reaction.H315Causes skin irritation.H319Causes serious eye irritation.H410Very toxic to aquatic life with long lasting effects.
Hazard statements reflect the GHS classification commonly published for CAS 97-00-7. Some suppliers additionally list organ-toxicity entries, and nitroaromatics as a class are associated with methaemoglobin formation on significant exposure. Always read the SDS issued with your specific batch — and treat the sensitisation entry as the one that shapes your controls most.
Reactivity & thermal stability
This is a polynitroaromatic. Under ordinary storage it is stable, but the reactivity that makes it useful also makes it energetic. Your own process safety study and the SDS govern — the points below are orientation for your planners.
- Reactions with nucleophiles are exothermic. Ammonia, amines, alkalis and alkoxides all react readily, and runaway incidents are documented in industry. Calorimetry and relief sizing are not optional on this chemistry.
- Do not overheat. Decomposition of polynitroaromatics above their normal operating range can be rapid and self-accelerating. Control melt temperature and avoid local hot spots on jacketed vessels.
- Segregate strictly from amines, ammonia, alkalis, reducing agents and strong oxidisers in storage, not just in process.
- Contain, do not hose to drain. H410 applies — collect spilled solid mechanically, avoid raising dust and dispose of it as regulated chemical waste.
- Record the exposure. With a sensitisation classification, most occupational regimes expect an exposure record and health surveillance — a decision made more easily before an incident than after one.
Storage
- Cool, dry, well-ventilated and access-controlled store, away from direct sunlight, heat sources and ignition sources. Note the low melting point — a hot warehouse can soften or cake the product.
- Keep containers tightly closed on a sealed and bunded floor. Dust and fines from a damaged drum are the most likely route to an unplanned skin exposure.
- Segregate from amines, ammonia, alkalis, reducing agents and oxidisers — this is a reactivity control, not a housekeeping preference.
- Restrict access. Given the sensitisation classification, limiting who can enter the store is a genuine control measure.
- Shelf life is typically 24 months or more in sealed original packing under these conditions. Re-assay before use after long storage.
Handling & PPE
- Design skin contact out entirely. Closed transfer, contained charging and dust suppression first; ventilation second; PPE last. With a sensitiser, PPE is the weakest line of defence.
- Chemical-resistant gloves and coveralls, changed and disposed of properly — contaminated clothing is a continuing exposure route for the wearer and for anyone handling the laundry.
- Respiratory protection during drum opening, charging and any operation that can generate dust, per your own exposure assessment.
- Health surveillance. Where a sensitisation classification triggers obligations at your site, your occupational health provider and EHS function own the detail.
- Never discharge to drain or watercourse. H410 applies — contain and dispose of as regulated chemical waste.
Transport
DNCB moves as regulated cargo under UN 1577, Class 6.1. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. The applicable packing group is 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, melting range, isomer and residual mononitro content and moisture — 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 1577, 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.
Two nitro groups make one chlorine leave
Everything industrial about DNCB follows from a single mechanism. The routes below are the general industrial pattern, not a process disclosure.
Activate the ring
Nitro groups ortho and para to the chlorine withdraw electron density and, critically, stabilise the negative charge that builds up when a nucleophile attacks that carbon.
Attack and add
The nucleophile adds to the carbon bearing the chlorine, forming the stabilised anionic intermediate that gives this reaction class its name.
Eliminate the chloride
Chloride leaves, aromaticity is restored, and the nucleophile is now attached — as an amine, an ether, a phenol or a sulphide, depending on what you charged.
Carry forward
The dinitro product is then reduced, diazotised, condensed or coupled onward into the dye, rubber chemical or agrochemical structure it was destined for.
Why feed quality carries through the whole route
Because the substitution step is fast and fairly indiscriminate, whatever arrives in the drum reacts alongside the molecule you wanted:
- Isomeric dinitrochlorobenzenes substitute at different rates and give products with the nitro groups in the wrong places — which then carry all the way to the finished shade or active.
- Residual mononitrochlorobenzene is far less activated, so it largely survives your substitution step and reports as unreacted material or as a difficult impurity downstream.
- Moisture competes as a nucleophile in alkaline conditions, consuming reagent and generating phenolic by-product you then have to separate.
- Melting range is the quick practical read on all of the above — a depressed or broad range tells you something is present that the assay figure alone may not reveal.
That is why the batch COA on this product reports melting range and isomer content alongside the assay, and why we share it for approval before dispatch rather than sending it with the invoice.
| Intermediate | Principal character |
|---|---|
| 2,4-Dinitrochlorobenzene CAS 97-00-7 — this product | Highly activated chlorine Substitution under mild conditions |
| Meta dinitrobenzene CAS 99-65-0 | No leaving group Route to m-phenylenediamine |
| Meta nitrochlorobenzene CAS 121-73-3 | Single nitro, meta Harder substitution conditions |
We supply across the nitro and chloro aromatic range — see the full intermediate range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this intermediate
DNCB 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.
Compliance cost is built in
A potent sensitiser that is also a polynitroaromatic carries heavy compliance cost at every stage — containment, health surveillance, effluent treatment, DG handling. That cost sits inside the price and is one reason capacity has consolidated.
- Few plants carry the full control set
- Obligations vary by jurisdiction
- We check destination rules before quoting
Upstream feedstock
The route runs back through benzene, chlorobenzene and mixed-acid nitration. Benzene and chlorine economics, plus nitric and sulphuric acid cost, feed through within a quarter or so.
- Chlorobenzene availability sets the floor
- Nitration energy and acid recovery weigh heavily
- We flag feedstock-driven moves in the quote
Campaign production
Nitration lines are campaigned and changeover is expensive. If your enquiry lands between campaigns the honest answer is a longer lead time — and we will give you that answer rather than a date nobody can hold.
- Quote early for campaign tonnage
- Spot buying off-campaign costs more
- Contracted call-off smooths the exposure
Pack format
Smaller drums cost more per kilo and, on a sensitiser, also mean more openings and more handling events. Larger units are usually cheaper and safer at once — if your charging arrangement can take them.
- Fewer openings means less exposure risk
- Packing disposal is a hidden cost at your end
- We will advise on the trade-off honestly
Freight & DG surcharges
Class 6.1 cargo carries a hazardous surcharge, space is tighter than for general cargo, and some carriers restrict polynitroaromatics outright. 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, an environmental inspection or a monsoon disruption can take capacity offline at short notice. On a product with a short producer list, 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 |
|---|---|
| Dye & pigment synthesis | Tight isomer limit; narrow melting range |
| Amination to dinitroaniline | Low moisture; low residual mononitro |
| Rubber chemical route | Consistent assay; sulphur-compatible impurity profile |
| Agrochemical chain | Full impurity profile; retention sample held |
| Laboratory / reagent | Highest available purity, small DG-compliant pack |
Not sure which column you are in? Describe the substitution 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 substitution. An amination and a hydrolysis are sensitive to different impurities — tell us which you run and we will specify accordingly.
- Be straight about the hazard profile. Potent sensitiser, toxic by all routes, very toxic to aquatic life — all stated at enquiry stage so your EHS team can price the controls into the decision.
- Flag the reactivity for your process safety team. Exothermic reaction with amines and alkalis is a documented industrial hazard on this molecule, and we put it in writing rather than assume you know.
- 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
- Sensitiser obligations are jurisdiction-specific. Several regimes impose substitution reviews, exposure monitoring, health surveillance and record retention for respiratory and skin sensitisers. Confirm what applies at your site before the first delivery.
- Polynitroaromatics attract additional scrutiny. Some destinations apply import notification or end-use declaration requirements to this class. We check 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.
- Effluent and waste rules matter because of the H410 classification. Your site's discharge consent should be checked against the material before it is introduced.
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 97-00-7, the assay, melting range and isomer 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
UN 1577 classification filed, DG freight booked, export documents issued, and the consignment tracked through transit and clearance to your plant.
Others in the Chelora range
What buyers ask us about 2,4-Dinitrochlorobenzene
Why is this such a strong skin sensitiser?
Is DNCB thermally stable?
What purity do you normally supply?
In what form does it ship — solid or molten?
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 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?
Request pricing on 2,4-Dinitrochlorobenzene
Send your required assay, melting range, isomer limits, 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 pack or a contracted programme for the year.