2,4-Dinitrochlorobenzene
A highly activated chlorinated dinitroaromatic supplied as an intermediate for sulfur dye, dinitroaniline, and rubber chemical manufacture.
What is 2,4-Dinitrochlorobenzene?
2,4-Dinitrochlorobenzene — 24DNCB — is a yellow crystalline solid carrying two nitro groups and a chlorine on one ring. It is produced by nitrating chlorobenzene or para nitrochlorobenzene under forcing conditions.
Two nitro groups working together make the chlorine exceptionally easy to displace. Ammonia, amines, alkoxides, and sulfides all substitute it under mild conditions, which is why the compound sits at the head of several dye and specialty chemical chains, most notably sulfur dye and dinitroaniline manufacture.
At Chelora Chemicals, 24DNCB is crystallised and refined with isomer content and moisture held to specification. Because the material is both a potent skin sensitiser and an energetic dinitroaromatic, it is supplied only to industrial users equipped to handle it.
- Appearance
- Yellow crystalline flakes
- Odour
- Faint, characteristic
- Solubility
- Insoluble in water; soluble in alcohol, ether, benzene
- Function
- Chemical intermediate
- Grade
- Technical
Formula diagram
A chlorine activated by two nitro groups
- Molecular formulaC6H3ClN2O4
- Molecular weight202.55 g/mol
- IUPAC name1-Chloro-2,4-dinitrobenzene
- Functional groupsNitro, aryl chloride
- CAS number97-00-7
Technical product information
Standard specification for Chelora Chemicals' technical grade 2,4-Dinitrochlorobenzene. Custom-grade and bulk specifications are available on request.
| Chemical name | 2,4-Dinitrochlorobenzene |
|---|---|
| Synonyms | 24DNCB, DNCB, 1-Chloro-2,4-dinitrobenzene, Chlorodinitrobenzene |
| CAS number | 97-00-7 |
| Molecular formula | C6H3ClN2O4 |
| Molecular weight | 202.55 g/mol |
| Assay (purity) | ≥ 99.0% |
| Appearance | Yellow crystalline flakes |
| Melting point | 51–54°C |
| Boiling point | approx. 315°C |
| Density (25°C) | 1.68–1.70 g/cm³ |
| Isomer content | ≤ 0.5% |
| Moisture | ≤ 0.2% |
| Packaging | 25 kg bags, 200 kg drums, molten tanker |
| Shelf life | 24 months from date of manufacture |
Applications of 2,4-Dinitrochlorobenzene
Sulfur dye manufacture
Reacted with sulfur donors to build the sulfur dye systems used for deep shades on cellulosic fibres.
Dinitroaniline production
Aminated to 2,4-dinitroaniline, itself a dye and pigment intermediate.
Azo dye intermediates
Feeds dinitro-substituted colour intermediates across dye chemistry.
Rubber chemicals
Used in the synthesis of specialty rubber additives and processing chemicals.
Pharmaceutical intermediates
Applied where a doubly activated aryl chloride is needed for selective substitution.
Analytical reagents
Supplied as a derivatising reagent for thiols and amines in analytical chemistry.
Why choose Chelora Chemicals
Every batch of 2,4-Dinitrochlorobenzene is manufactured, tested, and documented to a standard that formulators and process chemists can build on with confidence — from first sample to full production volume.
Consistent purity
Assay controlled at ≥99% with isomer content and moisture verified before dispatch.
Full documentation
COA, SDS, and regulatory data supplied with every shipment.
Flexible volumes
From 25 kg bags to drums and molten tanker supply.
Technical support
Process, handling, and compliance guidance from our chemistry team.
Storage and guidelines
- 01Store in tightly closed original packaging in a cool, dry, well-ventilated store.
- 02Keep below 40°C — the product melts near 52°C and cakes in hot storage.
- 03Keep away from heat, sparks, open flame, and direct sunlight, and never heat above the recommended handling temperature.
- 04Segregate from strong bases, amines, reducing agents, and strong oxidising agents — reaction is rapid and exothermic.
- 05Control dust rigorously and avoid any skin contact at every transfer point.
- 06Store in a locked or access-controlled area with clear sensitiser warning signage.
Handling precautions
24DNCB is toxic if swallowed, in contact with skin, or if inhaled, and is a potent skin sensitiser. It is for industrial use by trained personnel only.
This material is used clinically and experimentally precisely because it sensitises skin so reliably. Once a person is sensitised, very small subsequent exposures can trigger a severe reaction, so preventing any first contact is the entire control strategy.
Double gloving with verified breakthrough resistance, coveralls, face protection, and enclosed handling or effective local exhaust are the minimum. Change gloves immediately on any suspected contact.
Dinitroaromatics store considerable energy and can decompose exothermically if overheated or contaminated. Melting, drying, and any heated processing require a documented thermal risk assessment and temperature control with independent trip protection.
Reaction with amines, alkoxides, and sulfides is rapid and strongly exothermic, requiring controlled addition, cooling, and relief provision sized for the exotherm.
The product is very toxic to aquatic life with long-lasting effects. Contain all spills and dispose of waste through licensed routes.
Refer to the full Safety Data Sheet for exposure limits, health surveillance, spill response, and first-aid measures before use.
Frequently asked questions
What is 2,4-Dinitrochlorobenzene used for?
It is an intermediate. The main outlets are sulfur dye manufacture, 2,4-dinitroaniline production, and specialty rubber and pharmaceutical intermediates. It is also used as an analytical derivatising reagent for thiols.
Why is the chlorine so reactive?
Two nitro groups, one ortho and one para, withdraw electron density powerfully and stabilise the intermediate formed when a nucleophile attacks the ring. Under that double activation the chlorine is displaced under conditions where an ordinary aryl chloride would be completely unreactive.
How does it compare with 2,4-dinitrofluorobenzene?
Both are doubly activated and displace their halogen readily. The fluoro compound reacts faster and is used as an analytical reagent, while the chloro compound is cheaper and dominates bulk dye intermediate manufacture.
Why is it such a strong sensitiser?
Its reactivity. It binds covalently to skin proteins, and the immune system responds to the modified protein. The effect is so reliable that the compound is used deliberately in dermatology and immunology, which is exactly why occupational exposure must be prevented rather than merely limited.
What PPE is required?
At minimum double gloves with verified breakthrough data, coveralls, face protection, and enclosed handling or effective local exhaust. Any suspected skin contact needs immediate washing and medical review.
What are the thermal hazards?
Dinitroaromatics store significant energy and can decompose exothermically if overheated or contaminated. Melting and drying operations need temperature control with independent trip protection and a documented thermal assessment before scale-up.
Is it soluble in water?
No. It is practically insoluble in water and dissolves in alcohols, ether, acetone, and benzene.
Can it be supplied molten?
Yes, for bulk users, since it melts near 52°C. Molten supply avoids dust exposure, but the receiving site needs dedicated heated lines with tight temperature control given the thermal sensitivity.
What purity do you supply?
Standard technical grade is supplied at a minimum assay of 99% with isomer content at or below 0.5% and moisture at or below 0.2%. Tighter specifications can be produced to order.
What packaging sizes are available?
25 kg bags, 200 kg drums, and molten product in heated tankers. Supply is subject to confirmation of the receiving site's handling capability.
Is 24DNCB regulated?
It carries transport, workplace exposure, and environmental controls in most jurisdictions, and some markets impose additional requirements on sensitising substances. Confirm your national obligations before ordering.
Do you provide a Certificate of Analysis?
Yes. Every batch is dispatched with a Certificate of Analysis and Safety Data Sheet covering assay, isomer content, melting range, moisture, and appearance.