Ortho Nitrochlorobenzene
A high-purity chloronitrobenzene, supplied as 1-chloro-2-nitrobenzene for substitution and reduction routes into dyes, pigments and agrochemical intermediates.
What is Ortho Nitrochlorobenzene?
Ortho Nitrochlorobenzene, formally 1-chloro-2-nitrobenzene, is a yellow crystalline solid that melts at around 32°C — low enough that most large users take it molten and handle it as a liquid.
Its value lies in the nitro group sitting directly next to the chlorine. That neighbour pulls electron density off the ring and turns an otherwise unreactive aryl chloride into a good leaving group, so ammonia, methoxide, amines and sulphide all displace it under mild conditions. One substrate therefore opens routes to o-nitroaniline, o-nitroanisole, o-phenylenediamine and the sulphur dye range.
At Chelora Dyes, ONCB is crystallised and controlled to a high setting point with para and meta isomers held to tight limits, so substitution yields stay predictable and no isomeric by-products carry colour into the finished dye.
- Appearance
- Yellow crystals / flakes
- Odour
- Faint, aromatic
- Solubility
- Organic solvents
- Function
- Substitution substrate
- Grade
- Technical / molten
Chlorobenzene ring activated by an ortho nitro group
- Molecular formulaC6H4ClNO2
- Molecular weight157.55 g/mol
- IUPAC name1-Chloro-2-nitrobenzene
- Functional groupsNitro, aryl chloride
- CAS number88-73-3
Technical product information
Standard specification for Chelora Dyes' technical grade Ortho Nitrochlorobenzene. Custom-grade and molten bulk specifications are available on request.
| Chemical name | Ortho Nitrochlorobenzene |
|---|---|
| Synonyms | 2-Nitrochlorobenzene, o-Nitrochlorobenzene, ONCB, 1-Chloro-2-nitrobenzene |
| CAS number | 88-73-3 |
| Molecular formula | C6H4ClNO2 |
| Molecular weight | 157.55 g/mol |
| Assay (purity) | ≥ 99.5% |
| Appearance | Yellow crystalline solid or flakes; clear yellow liquid when molten |
| Setting point | ≥ 31.5°C |
| Melting point | 32–33°C |
| Boiling point | Approx. 246°C |
| Para isomer | ≤ 0.3% |
| Meta isomer | ≤ 0.2% |
| Moisture content | ≤ 0.1% |
| Solubility | Practically insoluble in water; soluble in alcohol, ether, benzene |
| Packaging | 250 kg lined MS drums; heated ISO tanks for molten supply |
| Shelf life | 24 months in sealed original packaging |
Applications of Ortho Nitrochlorobenzene
o-Nitroaniline route
Ammonolysis of the activated chlorine gives o-nitroaniline, a core diazo component in azo dye chemistry.
o-Phenylenediamine route
Ammonolysis followed by reduction supplies the diamine used in benzimidazole and dye manufacture.
Sulphur dyes
Reaction with sulphide builds the sulphur dye range used for deep blacks, browns and navy shades.
o-Anisidine and ONA route
Methoxylation displaces the chlorine to give o-nitroanisole, the feedstock for o-anisidine production.
Agrochemical intermediates
Used as a starting material in crop protection chemistry where an ortho-substituted aniline core is needed.
Rubber and specialty chemicals
Feeds antioxidant, accelerator and other specialty chemical syntheses in smaller volumes.
Why choose Chelora Dyes
Consistent purity
Assay controlled at ≥99.5% with setting point and isomers verified before dispatch.
Full documentation
COA, SDS, and regulatory data supplied with every shipment.
Flexible volumes
Drummed flake for batch users, heated bulk for continuous plants.
Technical support
Substitution, molten handling, and compliance guidance from our chemistry team.
Storage and guidelines
- Store in tightly sealed original packaging in a cool, dry, well-ventilated store.
- Keep away from heat, open flame and ignition sources, and out of direct sunlight.
- Melt drums whole in a controlled hot box — never apply direct or localised heat.
- Hold molten material at the minimum workable temperature and avoid prolonged heating.
- Segregate from strong oxidising agents, strong bases and reducing agents.
- Contain all spillage — the product is very toxic to aquatic life and must not reach drains.
Handling precautions
Ortho Nitrochlorobenzene is toxic by inhalation, ingestion and skin absorption, and its effects are cumulative. Repeated or uncontrolled exposure can cause methaemoglobinaemia.
Handle in closed systems wherever possible. Use chemically resistant gloves, chemical splash goggles and protective clothing, and provide local exhaust ventilation at every open transfer point.
Molten product adds a thermal burn risk: use insulated gloves and face protection during charging, sampling and drum melting.
Refer to the current Safety Data Sheet for exposure limits, spill containment, disposal and first-aid measures before any handling operation.
Frequently asked questions
What is Ortho Nitrochlorobenzene used for?
It is a substitution substrate. The chlorine is activated by the adjacent nitro group and is readily displaced by ammonia, methoxide, amines or sulphide, giving o-nitroaniline, o-nitroanisole, o-phenylenediamine and sulphur dye intermediates that feed azo dye, pigment and agrochemical manufacture.
How is it different from para nitrochlorobenzene?
Both isomers carry the same chlorine and nitro groups, but in the ortho isomer they are adjacent rather than opposite. That changes the reactivity of the ring and sends the two isomers down different downstream routes — the ortho grade towards ortho-substituted anilines and diamines, the para grade towards para-substituted products.
Is it supplied solid or molten?
Both. The product melts at around 32–33°C, so it is supplied as yellow flakes or solidified drums for smaller volumes and as a heated molten bulk delivery for continuous plants.
Is Ortho Nitrochlorobenzene soluble in water?
No. It is practically insoluble in water and soluble in alcohol, ether and benzene, so substitution reactions are usually run in an organic medium or as a two-phase system.
What purity do you supply?
Standard grade is supplied at a minimum assay of 99.5% with a setting point of at least 31.5°C, and para and meta isomers held to tight limits. Higher assay grades can be manufactured to order.
What packaging sizes are available?
250 kg lined mild steel drums for flake or solid material, and heated ISO tanks or road tankers for molten bulk supply.
How should it be stored, and for how long?
In sealed original packaging in a cool, dry, ventilated store away from heat, ignition sources and strong oxidisers. Shelf life is 24 months from manufacture when storage conditions are maintained.
Is it hazardous to handle?
Yes. It is toxic by inhalation, ingestion and skin absorption, can cause methaemoglobinaemia with cumulative effect, and is very toxic to aquatic life. Molten material also presents a thermal burn risk. Review the current Safety Data Sheet before any handling operation.
Do you provide a Certificate of Analysis?
Yes. Each batch ships with a Certificate of Analysis and Safety Data Sheet covering assay, setting point, isomer content, moisture and appearance.
