Ortho Nitrochlorobenzene
Here the nitro group is not the part that changes — it is the part that makes everything else possible. Sitting ortho to the chlorine, it pulls electron density out of the ring and turns an otherwise inert aryl chloride into a leaving group you can displace with methoxide, ammonia or hydroxide. That single property is the reason this molecule exists commercially.
Chelora Chemicals supplies o-NCB to dye and pigment houses, agrochemical plants, rubber chemical producers and fine chemical manufacturers worldwide, in UN-approved packing, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 88-73-3
- IUPAC name
- 1-Chloro-2-nitrobenzene
- Molecular formula
- C6H4ClNO2
- Molecular weight
- 157.55 g/mol
- EC / EINECS
- 201-854-9
- UN Number
- 1578 · Class 6.1
- SMILES
- O=[N+]([O-])c1ccccc1Cl
- 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 Ortho Nitrochlorobenzene is used for
Ortho nitrochlorobenzene is a yellow crystalline solid melting at about 32 °C — close enough to ambient that it arrives as crystals in a cool store and as a soft cake in a hot one. Almost all commercial demand is for one reaction type: nucleophilic aromatic substitution of the chlorine.
Methoxide gives o-nitroanisole, ammonia gives o-nitroaniline, hydroxide gives o-nitrophenol, and aniline gives 2-nitrodiphenylamine for rubber chemicals. Reduce the nitro group instead and you get o-chloroaniline; reduce an o-nitroaniline and you reach o-phenylenediamine, the benzimidazole building block behind several fungicides. One intermediate, five established downstream chains.
Why the isomer decides the chemistry
- Ortho nitrochlorobenzene (CAS 88-73-3) — this product. Chlorine activated by the ortho nitro group; the substitution workhorse.
- Para nitrochlorobenzene — also activated, also displaced readily, but gives the para-substituted products and separates from the same nitration mixture.
- Meta nitrochlorobenzene (CAS 121-73-3) — the nitro group cannot activate from the meta position, so the chlorine stays put and the material is used for reduction to m-chloroaniline. See that page.
- Dichloronitrobenzenes — two chlorines, one nitro group, and a completely different downstream chain. See 2,5-DCNB.
On this product family the CAS number is not a formality. Always state it on the purchase order — see the full intermediate range.
Appearance and handling character
The material ships as a yellow crystalline solid or flake, practically insoluble in water and freely soluble in alcohol, benzene and ether. It is absorbed through intact skin, is a methaemoglobin former and is also a skin sensitiser — so repeated small contacts matter here as much as a single large one. The safety section below should be read before any handling is planned.
| Parameter | Typical value |
|---|---|
| Appearance | Yellow crystalline solid / flake |
| Assay | 99.5% min |
| Crystallising point | 31.5 °C min |
| Para isomer | Reported per batch |
| Dinitro content | Reported per batch |
| Moisture | 0.1% 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. On this product the crystallising point and the para figure together tell you more than the assay alone — tell us your ceilings and we will quote against them rather than against a generic grade.
| Property | Value |
|---|---|
| Physical state | Crystalline solid at ambient |
| Melting point | ≈ 32 – 34 °C |
| Boiling point | ≈ 245 – 246 °C @ 760 mmHg |
| Flash point | ≈ 127 °C |
| Relative density | ≈ 1.37 (solid) |
| Water solubility | Practically insoluble |
| Organic solubility | Soluble in alcohol, benzene, ether |
| Chlorine reactivity | High — activated for SNAr displacement |
Physical constants compiled from public reference data for CAS 88-73-3 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
One activated chlorine, several nucleophiles, several industries. The reaction is almost always the same; what changes is what you put on the ring in its place.
o-Nitroanisole & o-anisidine
Methoxide displaces the chlorine to give o-nitroanisole, reduced onward to o-anisidine — a long-established diazo component in azo dye and pigment manufacture.
- Methanol / sodium methoxide route
- Para isomer carries through as by-product
- See Ortho Nitroanisole
o-Nitroaniline & o-phenylenediamine
Ammonolysis gives o-nitroaniline; reduction of that gives o-phenylenediamine, the benzimidazole building block used in fungicide and speciality synthesis.
- Pressure ammonolysis route
- Dye, pigment and agrochemical chains
- End-use declaration may be required
o-Nitrophenol
Alkaline hydrolysis gives o-nitrophenol, used in dye and pigment chemistry and as a feedstock for further substitution and reduction steps.
- Caustic hydrolysis route
- Also reached from nitration of phenol
- See Para Nitrophenol
o-Chloroaniline
Catalytic reduction of the nitro group leaves the chlorine in place, giving o-chloroaniline for dye, pigment and agrochemical synthesis.
- Catalytic hydrogenation route
- Low moisture protects catalyst life
- Reduction is strongly exothermic
Rubber chemicals
Condensation with aniline gives 2-nitrodiphenylamine, the precursor to diphenylamine-type antioxidants and antiozonants used across tyre and rubber compounding.
- Aniline condensation route
- Consistent assay matters for yield
- Contract volumes available
Contract & scheduled supply
Downstream plants run to campaign and Class 6.1 freight needs planning. Most 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 Ortho Nitrochlorobenzene
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. On a product where the ortho and para isomers come off the same nitration line and look identical on a drum label, owning no plant means we can route your order to the producer whose isomer separation actually matches your tolerance.
We place your order with whichever qualified producer best matches your assay, your crystallising point, 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.
- Isomer confirmed before we quote. Ortho, para or meta — three different reactivity profiles, and this is where orders on this product line go wrong most often.
- Crystallising point reported on every batch. It is the quickest honest read on how clean a lot really is, and it appears as its own figure on the COA.
- Batch COA shared before dispatch. You approve assay, crystallising point and para content against your own spec while the material is still in our warehouse.
- Skin absorption and sensitisation stated up front. We say so at enquiry stage so your EHS team can plan the right controls, not after the pallet lands.
- 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 1578 classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
Packed the way your plant receives it
With a melting point near ambient, pack format is not cosmetic on this product. Tell us how the material will be charged at your end and we will quote the format that suits it.
UN bags / fibre drums
Lined, UN-approved 25 kg packs for Class 6.1 solids — the standard commercial format and the easiest for manual charging.
HDPE drums
Sealed drums with inner liner for longer storage, humid destinations or warehouses that run warm enough to soften the product in a bag.
Low-dust & molten options
Flaked product reduces airborne fines during charging. Where you charge molten and have heated receipt facilities, molten movement can be arranged subject to the DG position.
Samples & trial packs
Laboratory and pilot quantities dispatched so your R&D team can qualify the grade first — subject to DG 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.
Skin absorption is the controlling route
Ortho nitrochlorobenzene is toxic by the oral, dermal and inhalation routes, is a skin sensitiser, is very toxic to aquatic life and is a methaemoglobin former. On a low-volatility solid the exposure that actually hurts people is usually dermal rather than inhaled — which should shape your controls. 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.H373May cause damage to organs through prolonged or repeated exposure.H410Very toxic to aquatic life with long lasting effects.
Hazard statements reflect classifications commonly published for CAS 88-73-3. Chloronitrobenzenes as a class are methaemoglobin formers and are associated with effects on blood and liver on repeated exposure. Always read the SDS issued with your specific batch.
Spill & emergency orientation
Plan your response before the pallet arrives. Sections 4, 5 and 6 of the SDS are the authoritative instructions and should be posted at the point of use.
- Contain, do not hose to drain. H410 applies — collect spilled solid mechanically, avoid raising dust and dispose of it as regulated chemical waste.
- Assume skin absorption. Contaminated clothing is a continuing exposure route — remove it immediately and wash the skin thoroughly with soap and water.
- Expect delayed presentation. Methaemoglobinaemia may appear some hours after exposure. A casualty who feels fine should still be assessed, with the SDS in hand.
- Watch the melt. A spill in a warm area can liquefy, spread and wet surfaces that then stay contaminated. Treat warm spills as larger than they look.
- Substitution and reduction are exothermic. Both the SNAr step and catalytic reduction release substantial heat — calorimetry and properly sized relief belong in the process design.
Storage
- Cool, dry, well-ventilated and access-controlled store, away from direct sunlight and heat sources. The melting point near 32 °C is a genuine constraint in a tropical warehouse.
- Keep containers tightly closed on a sealed and bunded floor. Dust and fines from a damaged pack are the most likely route to an unplanned exposure.
- Segregate from reducing agents, alkalis and strong oxidisers.
- Restrict access. With a toxic-by-skin-contact and sensitising classification, controlling who enters the store is a genuine control measure.
- Shelf life is typically 24 months or more in sealed original packing. Re-assay before use after long storage.
Handling & PPE
- Design skin contact out. Closed transfer, contained charging and dust suppression first; ventilation second; PPE last.
- Chemical-resistant gloves and coveralls, with contaminated clothing removed, bagged and handled as contaminated waste rather than sent to an ordinary laundry.
- Sensitisation changes the calculus. Once a worker is sensitised, exposures that previously caused nothing can provoke a reaction — so even minor repeated contact is worth engineering out.
- Health surveillance. Where repeated-exposure organ toxicity triggers obligations at your site, your occupational health provider owns the detail.
- Never discharge to drain or watercourse. H410 applies — contain and dispose of as regulated chemical waste.
Transport
Chloronitrobenzenes move as regulated cargo under UN 1578, 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, crystallising point, para isomer, dinitro content and moisture — checked against your purchase specification before release.
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 1578, 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.
The nitro group stays; the chlorine leaves
An unactivated aryl chloride barely reacts with a nucleophile. Put a nitro group ortho to it and the picture changes completely. The routes below are the general industrial pattern, not a process disclosure.
Nitrate chlorobenzene
Mixed-acid nitration of mono chlorobenzene gives mainly the ortho and para isomers, with a little meta.
Separate the isomers
Crystallisation and distillation split ortho from para. What is left shows up as the para figure and the crystallising point on the COA.
Displace the chlorine
Methoxide, ammonia, hydroxide or an amine attacks the activated ring position and the chloride leaves — the step most buyers purchase this product for.
Reduce where required
Catalytic reduction of the nitro group gives the aniline — either o-chloroaniline directly, or the diamine after a substitution step.
Why feed quality carries through the whole route
In a substitution chemistry an impurity does not sit quietly in the pot — it reacts alongside your intended molecule:
- Para isomer is activated exactly like the ortho, so it is displaced in the same step and arrives as a para-substituted by-product in your product stream. This is the single most consequential impurity on the product.
- Dinitro by-products from over-nitration are far more reactive again and can cause runaway behaviour as well as colour and yield problems.
- Moisture consumes alkoxide, hydrolyses the chloride to the phenol and shortens catalyst life in the reduction step.
- Crystallising point is the quick practical read on all of the above, which is why buyers watch it as closely as the assay figure.
That is why we quote against your written limits rather than a generic "technical" grade, and why the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Intermediate | Downstream chain |
|---|---|
| Ortho nitrochlorobenzene CAS 88-73-3 — this product | o-Nitroanisole, o-nitroaniline, o-nitrophenol, o-chloroaniline |
| Meta nitrochlorobenzene CAS 121-73-3 | m-Chloroaniline Dyes, agro, pharma |
| 2,5-Dichloronitrobenzene CAS 89-61-2 | 2,5-Dichloroaniline Pigments & dyes |
We supply across the chloronitrobenzene family — 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
Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Ortho / para balance
One nitration line produces both isomers, and the plant's economics depend on selling both. If para demand softens, ortho carries more of the overhead — which is why these two prices move together rather than independently.
- Ask us what the para market is doing
- Separation cost sits in the price
- Contracted call-off smooths the exposure
Upstream feedstock
The route runs back through benzene, chlorination to chlorobenzene and mixed-acid nitration. Benzene, chlorine and acid economics all feed through within a quarter or so.
- See Mono Chlorobenzene
- Oleum and nitric acid cost feeds in
- We flag feedstock-driven moves in the quote
Downstream demand cycles
Dye, pigment, rubber chemical and agrochemical seasons do not peak together. When two of them want material in the same quarter, lead times stretch before prices do.
- Book ahead of the agrochemical season
- Lead time moves before price moves
- Scheduled release protects your campaign
Regulatory pressure
Chloronitroaromatic production carries effluent, emissions and occupational health obligations that have consolidated capacity into fewer, larger plants. That cost sits inside the price.
- Handling obligations vary by jurisdiction
- Effluent rules shape plant economics
- We check destination rules before quoting
Freight & DG surcharges
Class 6.1 cargo carries a hazardous surcharge and space is tighter than for general cargo. 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. 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 |
|---|---|
| Methoxylation to o-nitroanisole | Low moisture; tight para ceiling |
| Ammonolysis to o-nitroaniline | High assay; low dinitro content |
| Caustic hydrolysis | Consistent crystallising point |
| Catalytic reduction | Low moisture for catalyst life; consistent assay |
| Laboratory / reference | Highest available purity, small DG-compliant pack |
Not sure which column you are in? Describe what you make from it 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
- Confirm the isomer before anything else. Ortho, para and meta behave differently in your reactor, and we settle which one you need in the first reply.
- Set the para ceiling with you. It is the number that decides how much by-product your downstream step has to deal with, and the one most often left vague on a purchase order.
- Be straight about the hazard profile. Toxic by all three routes, skin-absorbed, sensitising, very toxic to aquatic life — stated at enquiry stage so your EHS team can plan.
- 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
- Chloronitroaromatic obligations are jurisdiction-specific. Several regimes impose exposure monitoring, health surveillance and record retention for this class. Confirm what applies at your site before the first delivery.
- Import controls vary by destination. We check the destination rules before quoting, not after you have raised the PO.
- Chemical inventory listings differ between regions — we will supply the identity data you need for that filing.
- Effluent and waste rules matter because of the H410 classification. Check your discharge consent against the material before introducing it.
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 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 88-73-3, your assay, crystallising point and para limits, 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 1578 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 Ortho Nitrochlorobenzene
How is this different from the para and meta isomers?
What purity do you normally supply?
Why does para isomer content matter?
Is it absorbed through the skin?
What is the minimum order quantity?
How long does delivery take?
It melts near room temperature — how should we store it?
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 Ortho Nitrochlorobenzene
Send your required assay, crystallising point, para ceiling, 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.