Ortho Nitroaniline
A high-purity nitro-substituted aniline, supplied as Ortho Nitroaniline (ONA), used as a diazo component and dyestuff intermediate across the dye, pigment and pharmaceutical industries.
What is Ortho Nitroaniline?
Ortho Nitroaniline, abbreviated ONA, is an orange crystalline solid built on a benzene ring carrying a nitro group ortho to the primary amino group, with a musty odour characteristic of nitroaniline isomers.
Its primary industrial role is as a dyestuff intermediate and diazo component, and it is also the main precursor to phenylenediamines, which are converted into benzimidazoles, a family of heterocycles that are key components in pharmaceutical manufacture, placing ONA alongside other anilines used across dye and pharma intermediate chemistry.
At Chelora Dyes, ortho nitroaniline is crystallised and dried to a controlled melting point and colour specification, so downstream diazotisation, reduction and coupling reactions run cleanly and give a consistent, reproducible feedstock batch to batch.
- Appearance
- Orange solid
- Odour
- Musty
- Solubility
- Ethanol, ether, acetone, benzene
- Function
- Diazo component
- Grade
- Technical / dye grade
Benzene ring with ortho amino and nitro groups
- Molecular formulaC6H6N2O2
- Molecular weight138.13 g/mol
- IUPAC name2-Nitroaniline
- Functional groupsPrimary amine, nitro
- CAS number88-74-4
Technical product information
Standard specification for Chelora Dyes' technical grade Ortho Nitroaniline. Custom-grade and bulk specifications are available on request.
| Chemical name | Ortho Nitroaniline |
|---|---|
| Synonyms | ONA, o-Nitroaniline, 2-Nitrobenzenamine, 1-Amino-2-nitrobenzene |
| CAS number | 88-74-4 |
| Molecular formula | C6H6N2O2 |
| Molecular weight | 138.13 g/mol |
| Assay (purity) | ≥ 99.0% |
| Appearance | Orange solid |
| Melting point | 71–72°C |
| Boiling point | 284°C |
| Density | 1.44 g/mL |
| Moisture content | ≤ 0.2% |
| Solubility | Slightly soluble in water; soluble in ethanol; very soluble in ether, acetone, benzene and chloroform |
| Packaging | 25 kg / 50 kg multi-wall bags, fibre drums, bulk pallet packs |
| Shelf life | 24 months in sealed original packaging |
Applications of Ortho Nitroaniline
Dyestuff intermediate
Used directly as a diazo component in the manufacture of azo dyes and pigments.
Phenylenediamine production
Reduced to phenylenediamines, key building blocks for a range of downstream chemistries.
Benzimidazole / pharma intermediates
Phenylenediamine derivatives are converted into benzimidazoles used in pharmaceutical manufacture.
Pigment intermediates
Feeds azo and heterocyclic pigment routes used across coatings and printing inks.
Sulfur dye synthesis
Used as an intermediate in some sulfur dye and vat dye manufacturing routes.
Analytical reagents
Used as a reference reagent in analytical and research-scale organic chemistry.
Why choose Chelora Dyes
Consistent purity
Assay controlled at ≥99% with melting point and colour verified before dispatch.
Full documentation
COA, SDS, and regulatory data supplied with every shipment.
Flexible volumes
From bags to fibre drums and bulk pallet packs.
Technical support
Process, diazotisation, and compliance guidance from our chemistry team.
Storage and guidelines
- Store in tightly sealed original bags or drums in a dry environment.
- Keep in a cool, dry, well-ventilated area away from direct sunlight and heat sources.
- Keep containers closed when not in use to prevent moisture uptake and caking.
- Segregate from strong oxidising agents, reducing agents and combustible materials.
- Use compatible packaging: lined multi-wall bags and fibre drums.
- Re-seal containers promptly after use and follow site procedures for toxic-solid handling.
Handling precautions
Ortho Nitroaniline is toxic if swallowed, inhaled or absorbed through the skin, so it should be handled only with appropriate PPE and dust control.
Use chemically resistant gloves, eye and face protection, and adequate ventilation during weighing, charging, and any bulk handling operation.
Keep away from open flame and sources of ignition, and away from strong oxidisers. The substance is also classified as hazardous to aquatic life, so avoid release to drains or watercourses.
Refer to the full Safety Data Sheet for exposure limits, monitoring requirements, spill containment, disposal, and first-aid measures before use.
Frequently asked questions
What is Ortho Nitroaniline used for?
Ortho Nitroaniline is chiefly used as a dyestuff intermediate and diazo component, and as the main precursor to phenylenediamines, which are converted to benzimidazoles used in pharmaceuticals.
Is Ortho Nitroaniline soluble in water?
It is only slightly soluble in water, but is soluble in ethanol and very soluble in ether, acetone, benzene and chloroform.
What purity do you supply?
Standard technical grade is supplied at a minimum assay of 99.0%, with melting point and colour held within tight limits.
How is Ortho Nitroaniline packaged and shipped?
As a solid, it is supplied in 25 kg / 50 kg multi-wall paper or plastic-lined bags, with bulk supply available on fibre drums or pallet-packed cartons for large volumes.
How should it be stored, and for how long?
In tightly sealed original bags or drums in a cool, dry, well-ventilated store away from direct sunlight, heat, and strong oxidising or reducing agents. Shelf life is 24 months from manufacture when storage conditions are maintained.
Is it hazardous to handle?
Ortho Nitroaniline is toxic if swallowed, inhaled or absorbed through the skin, and is classified as hazardous to aquatic life. It should be handled only with appropriate PPE, dust control, and adequate ventilation. Review the 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, melting point, moisture and colour.
