Ortho Dichlorobenzene
Most chemicals are bought for what they become. This one is largely bought for where it boils. At around 180 °C, ortho dichlorobenzene lets a reactor run hot at atmospheric pressure while staying chemically indifferent to phosgene, isocyanates and hot polycondensation chemistry — which is why it sits inside isocyanate and engineering polymer plants rather than in the finished product.
The second stream of demand is synthetic: nitrated, it gives 3,4-dichloronitrobenzene and from there 3,4-dichloroaniline, the backbone of a large family of herbicides. Chelora Chemicals supplies ODCB in drums, IBCs, ISO tanks and road tankers worldwide, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 95-50-1
- IUPAC name
- 1,2-Dichlorobenzene
- Molecular formula
- C6H4Cl2
- Molecular weight
- 147.00 g/mol
- EC / EINECS
- 202-425-9
- UN Number
- 1591 · Class 6.1 · PG III
- SMILES
- Clc1ccccc1Cl
- HS Code
- 2903 91*
* Confirm the exact HS heading with your customs broker — the chlorinated benzene subheadings separate the individual isomers in several tariff schedules, and declaring the wrong one on a bulk movement is an expensive correction at the port.
What Ortho Dichlorobenzene is used for
Ortho dichlorobenzene is a colourless to pale yellow liquid with a faint aromatic odour, practically insoluble in water and miscible with most organic solvents. It is denser than water at about 1.31, which matters more than it sounds: a spill or a phase separation puts the ODCB layer at the bottom, not the top, and plant drawings drawn for a lighter solvent get this wrong.
Commercially it arrives from two directions. Benzene chlorination produces mono-, di- and polychlorinated products together, and the dichloro cut is separated into ortho and para isomers by distillation. The ortho isomer stays liquid and goes to solvent and synthesis markets; the para isomer crystallises and goes elsewhere entirely. Because they come off the same column, ODCB availability tracks what the chlorination plants are running for the para isomer — a supply fact worth knowing before you single-source it.
The two demand streams
- As a solvent that does not react. Phosgenation of amines to isocyanates, polyphenylene sulphide and polysulphone polymerisation, high-temperature degreasing and heat transfer duty — all cases where you need a liquid that holds temperature and then strips off cleanly.
- As a feedstock that does react. Nitration gives 3,4-dichloronitrobenzene, reduced to 3,4-dichloroaniline, which carries into a long list of herbicides and into dye and pigment chemistry.
- As a formulation solvent. Crop-protection concentrates use it where the active needs a high-boiling, water-immiscible carrier that will not flash off in a hot warehouse.
The upstream of all of this is mono chlorobenzene and the chlor-alkali cycle — see the full intermediate range.
Appearance and handling character
The material ships as a clear mobile liquid with a flash point near 66 °C. That keeps it out of the flammable-liquid transport classes, but a jacketed vessel or a steam-traced line will sit well above it, so the fire classification of your installation has to be made on the operating temperature rather than on the drum label. It is harmful if swallowed, irritating to skin, eyes and respiratory tract, and very toxic to aquatic life with long-lasting effects. The safety section below should be read before any handling is planned.
| Parameter | Typical value |
|---|---|
| Appearance | Clear colourless to pale yellow liquid |
| Assay (o-DCB) | 99.0% min |
| Para isomer | Reported per batch |
| Monochlorobenzene | Reported per batch |
| Trichlorobenzenes | Reported per batch |
| Moisture | 0.05% max |
| Colour (APHA) | 20 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. Solvent users should tell us their colour and water ceilings; nitration users should tell us their isomer and trichloro ceilings. The two ask for different things from the same product.
| Property | Value |
|---|---|
| Physical state | Liquid at ambient |
| Boiling point | ≈ 180 °C |
| Melting point | ≈ −17 °C |
| Flash point | ≈ 66 °C (closed cup) |
| Relative density | ≈ 1.306 @ 20 °C |
| Vapour density | ≈ 5.1 (air = 1) |
| Water solubility | Practically insoluble (~0.01%) |
| Organic solubility | Miscible with most organic solvents |
Physical constants compiled from public reference data for CAS 95-50-1 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
Half the demand wants it to do nothing but hold temperature. The other half wants it to be nitrated. Both are quoted from the same tank, but not against the same specification.
Isocyanate manufacture
The phosgenation of amines to TDI and MDI runs in a solvent that must be inert to phosgene, stable at reaction temperature and separable from the product. ODCB is the classic answer and remains a large consumer of the molecule.
- Inert to phosgene and isocyanate
- Recovered and recycled on plant
- Low water and colour normally specified
Engineering polymer synthesis
Polyphenylene sulphide, polysulphones and related high-performance polymers are built in high-boiling polar or chlorinated media. ODCB appears as reaction medium, wash solvent and recovery stream.
- High-temperature polycondensation
- Consistency between lots matters
- Bulk delivery normally preferred
Herbicide intermediate chain
Nitration gives 3,4-dichloronitrobenzene, reduced to 3,4-dichloroaniline — the starting point for a long list of crop-protection actives. The isomer and trichloro content of the feed carries directly into that chain.
- See 3,4-Dichloronitrobenzene
- Tight isomer ceilings available
- End-use declaration may be required
Agrochemical formulation
Emulsifiable concentrates and other liquid formulations use ODCB where the active needs a high-boiling, water-immiscible carrier that survives storage in hot climates without flashing off.
- High boiling point, low volatility
- Colour specification often tight
- Drum and IBC packs typical
Degreasing & heat transfer
Industrial cleaning of heavy residues, wax and carbon deposits, and closed-loop heat transfer duty where a high boiling point at atmospheric pressure is worth more than a low viscosity.
- Dissolves heavy organic residues
- Check seal and elastomer compatibility
- Vapour control essential indoors
Contract & bulk supply
Solvent consumers buy to a make-up rate rather than a campaign, so predictability beats opportunism. We contract annual tonnage with scheduled ISO tank or tanker call-off and hold the price across the period.
- ISO tank and road tanker programmes
- Price held across the contract
- Second source held in reserve
How we supply Ortho Dichlorobenzene
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. On a co-product like ODCB that is an advantage rather than a disclaimer: the ortho cut is available in whatever quantity the chlorination plant's para-isomer economics allow, and holding no plant of our own means we are not trying to push you the isomer we happen to be long on.
We place your order with whichever qualified producer best matches your assay, your colour and water ceilings, your pack format and your delivery window.
We keep a second qualified source on this line. A solvent make-up stream that stops is a plant that stops, so the alternate is qualified before you need it rather than after.
- Isomer confirmed before we quote. Ortho, meta and para dichlorobenzene are three different products at three different prices — we settle which one you mean in the first reply.
- Quoted against your actual use. A phosgenation solvent and a nitration feed need different numbers tightened. Tell us which you are, and we quote the right grade instead of the generic one.
- Batch COA shared before dispatch. You approve assay, colour, moisture and isomer profile against your own spec while the material is still in our warehouse or at the loading point.
- Bulk handled properly. ISO tank and road tanker movements are quoted with the cleaning certificate, the previous cargo history and the discharge arrangements settled up front.
- 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 1591 classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
Packed the way your plant receives it
On a solvent, the pack format is usually the biggest single line in the landed cost. Tell us how the material enters your process and we will quote the format that suits it.
MS & HDPE drums
UN-approved drums, the standard commercial format for plants that charge by drum pump and do not hold dedicated tankage.
IBC totes
Fewer handling movements than drums and easier to meter into a batch. Note the density — a cubic metre of ODCB is about 1.3 tonnes, so check your rack rating.
ISO tank containers
The usual export format for solvent consumers. Quoted with cleaning certificate and previous cargo history, and booked against your discharge window.
Road tankers
Where the distance and the receiving tankage allow it, tanker delivery is the lowest landed cost per tonne and removes drum disposal from your site entirely.
Samples & trial packs
Laboratory and pilot quantities dispatched so your plant can qualify the grade first — subject to DG rules for your destination and courier.
Contracted call-off
Solvent make-up is a continuous need. We hold contracted tonnage and release it against your consumption rate instead of landing it all at once.
Combustible, not flammable — and that distinction misleads people
Ortho dichlorobenzene is harmful if swallowed, irritating to skin, eyes and the respiratory tract, and very toxic to aquatic life with long-lasting effects. Its flash point near 66 °C keeps it out of the flammable transport classes — but most of the processes that use it run hotter than that, so the fire case has to be made on your operating temperature. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document.
Classified hazards
H302Harmful if swallowed.H315Causes skin irritation.H319Causes serious eye irritation.H335May cause respiratory irritation.H410Very toxic to aquatic life with long lasting effects.
Hazard statements reflect classifications commonly published for CAS 95-50-1. Transport classification is UN 1591, Class 6.1, Packing Group III, which is a toxicity-based class rather than a flammability one. Always read the SDS issued with your specific batch.
Spill & emergency orientation
Plan your response before the tanker arrives. Sections 4, 5 and 6 of the SDS are the authoritative instructions and should be posted at the point of use.
- It sinks. At density 1.31 a spill into water goes to the bottom, not the surface. Booms and skimmers designed for a floating hydrocarbon will not recover it.
- Never allow it to reach drain or watercourse. H410 applies. Bunding, interceptors and a closed drainage policy matter more here than almost any other control.
- Absorb and collect. Contain with inert absorbent, collect into labelled closed containers and dispose of as regulated chemical waste. Ventilate the area.
- Watch vapour in confined spaces. Vapour is around five times heavier than air and will collect in pits, sumps and the bottom of tanks. Confined-space entry procedures apply.
- Above 66 °C it is a fire risk. Hot process leaks, steam-traced lines and heated storage change the case completely from what the transport class implies.
Storage
- Cool, dry, well-ventilated store away from heat and ignition sources, in tightly closed original packing, on a sealed and bunded floor sized for the largest container plus a margin.
- Materials of construction. Mild steel, stainless steel and lined tanks are all in service. Check elastomers and gaskets — chlorinated aromatics swell many common seal materials, and a weeping flange on an H410 product is a reportable event.
- Segregate from strong oxidisers and from aluminium and other reactive metals in contact with hot material.
- Account for the density when sizing racking, bunds and tank foundations. A 1000 L IBC holds about 1.3 tonnes rather than one.
- Shelf life is typically 24 months or more in sealed packing. Re-check colour and moisture after long storage.
Handling & PPE
- Closed transfer first. Pump from drum or IBC rather than decanting, and vent through a scrubber or carbon filter where the receiving vessel breathes into an occupied area.
- Chemical-resistant gloves, goggles and coveralls. Select glove material against the SDS breakthrough data rather than by habit — nitrile performance against chlorinated aromatics is limited.
- Respiratory protection for drumming, tank cleaning and any hot work, per your own exposure assessment.
- Confined-space controls for tank entry — the vapour is heavy and will not clear by itself.
- Never discharge to drain or watercourse. H410 applies — contain and dispose of as regulated chemical waste.
Transport
Ortho dichlorobenzene moves as regulated cargo under UN 1591, Class 6.1, Packing Group III. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. For bulk movements the tank cleaning certificate and previous cargo history are provided with the nomination — 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, isomer profile, monochlorobenzene and trichlorobenzene content, moisture and colour — 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 1591, Class 6.1, Packing Group III and the IMDG or IATA declaration prepared and filed before the container is booked, with correctly marked and labelled packaging.
Tank cleaning & cargo history
For ISO tank and tanker movements, the cleaning certificate and previous cargo record travel with the nomination so your QA can accept the equipment before it loads.
Third-party inspection
SGS, Intertek or Bureau Veritas sampling and inspection arranged on request before loading, giving you independent verification of what actually ships.
Certificate of Origin
Chamber-attested where required, plus preferential-origin forms where a trade agreement gives your import duty relief at the destination.
A co-product you cannot make on its own
Nobody builds a plant to make ortho dichlorobenzene by itself. It comes off a chlorination train alongside its isomers, and that single fact explains most of its commercial behaviour. The routes below are the general industrial pattern, not a process disclosure.
Chlorinate benzene
Benzene is chlorinated over a Lewis acid catalyst, giving monochlorobenzene first and then the dichloro products as chlorination proceeds.
Separate the cuts
Distillation removes unreacted benzene and the monochloro product, leaving the dichlorobenzene fraction — overwhelmingly the ortho and para isomers.
Split ortho from para
Distillation and crystallisation separate the liquid ortho isomer from the solid para isomer. Residual para content is the figure that shows up on your COA.
Use it or nitrate it
From here it either goes to a solvent user unchanged, or into mixed-acid nitration to give 3,4-dichloronitrobenzene for the aniline chain.
What the impurities actually do to you
The impurity list on a dichlorobenzene COA looks dull until you map each line to the process it damages:
- Para isomer is the main one. In a solvent it is mostly harmless until the solvent is cooled or concentrated, at which point it can crystallise out and foul exchangers and filters. In a nitration feed it produces a different nitro isomer that follows you all the way to the aniline.
- Monochlorobenzene boils 48 °C lower and will distil overhead ahead of your product, upsetting recovery column balances and reducing the effective boiling point of the solvent charge.
- Trichlorobenzenes boil higher and accumulate in the recycle loop of a recovered-solvent system. Plants that recycle care about this figure far more than plants that use once-through.
- Water and colour are the two numbers an isocyanate plant usually fixes first, because moisture consumes phosgene and colour carries into the product.
That is why we ask what the solvent is doing in your process before quoting, and why the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Product | Character & main use |
|---|---|
| Mono Chlorobenzene CAS 108-90-7 | Flammable liquid, bp 132 °C Nitration feed, solvent |
| Ortho Dichlorobenzene CAS 95-50-1 — this product | Liquid, bp 180 °C Process solvent, 3,4-DCNB feed |
| Meta Dichlorobenzene CAS 541-73-1 | Liquid, bp 173 °C Scarce; agro intermediates |
| Para Dichlorobenzene CAS 106-46-7 | Solid, mp ≈ 53 °C PPS, deodorant blocks |
We supply across the chlorinated aromatic family — see mono chlorobenzene, meta dichlorobenzene and the full intermediate range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this solvent
Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
It is a co-product, so it follows
Chlorination plants run for the whole slate. When para dichlorobenzene demand is strong the ortho cut is plentiful and soft; when it is weak the ortho cut tightens even though nothing changed on your side of the market.
- Isomer prices move together, not alone
- Ask us what the para market is doing
- Contracted call-off smooths the exposure
Benzene and chlorine
The cost floor is benzene plus chlorine plus energy. Benzene tracks crude and naphtha; chlorine tracks the chlor-alkali cycle and therefore caustic soda demand, which has nothing to do with you at all.
- Benzene moves with the aromatics complex
- Chlorine economics follow caustic demand
- We flag feedstock-driven moves in the quote
Pack format and tank equipment
Bulk is materially cheaper per tonne than drums, but only if you have tankage, a bunded discharge point and the tank equipment is available on your lane. ISO tank availability swings with trade flows.
- Compare on landed cost, not ex-works
- Drum disposal is a real cost at your end
- We quote drum, IBC and bulk side by side
Environmental regulation
Chlorinated aromatics carry emissions, effluent and reporting obligations that have consolidated capacity into fewer, larger plants and pushed some solvent users to substitute. Both effects sit inside the price.
- Discharge rules vary by jurisdiction
- Solvent recovery changes your net cost
- 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. On a product this dense, freight is quoted on weight rather than volume — which changes the comparison.
- Density 1.31 fills weight limits first
- DG space books out ahead of peak season
- We quote FOB, CIF, CFR or DDP as you prefer
Solvent recovery changes the maths
A plant that recovers 95% of its solvent buys make-up, not charge. Your real exposure to the price is your loss rate, and improving recovery is often cheaper than negotiating the quote.
- Trichloro build-up limits recycle life
- Make-up volumes suit contracted call-off
- Ask us about dual-source contracts
| If your end use is… | Specify |
|---|---|
| Isocyanate phosgenation | Very low moisture; tight colour; low MCB |
| Polymer reaction medium | Low water; consistent assay lot to lot |
| Nitration to 3,4-DCNB | Tight para isomer; low trichlorobenzenes |
| Agrochemical formulation | Colour ceiling; low odour; residue limit |
| Degreasing / heat transfer | Commercial grade; confirm seal compatibility |
Not sure which column you are in? Describe what the solvent is doing in your process 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 first. Ortho, meta and para are three different products with three different prices and three different physical forms. We settle it in the first reply.
- Ask what the solvent is doing. A phosgenation charge, a polymerisation medium and a nitration feed want different numbers tightened on the same COA.
- Flag the density and the sink behaviour. Racking, bunding and spill response all need to account for a liquid heavier than water — it catches people out regularly.
- 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
- Aquatic toxicity drives the obligations. The H410 classification shapes your discharge consent, your bunding requirement and your waste route. Check it against the material before introducing it.
- Emission reporting for chlorinated solvents applies in several jurisdictions, often with a threshold tied to annual throughput rather than to a single use.
- Chemical inventory listings differ between regions — we will supply the identity data you need for that filing.
- Bulk receipt rules. Tanker and ISO tank discharge is often licensed separately from drum storage at the destination site. Confirm before you switch pack format to save money.
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 tank
Send the specification
Product name or CAS 95-50-1, your assay, colour, moisture and isomer limits, quantity, pack format 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, and for bulk the tank cleaning certificate, shared for your approval before release.
Ship and track
UN 1591 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 Dichlorobenzene
Why ODCB rather than another chlorinated solvent?
How is it different from the para and meta isomers?
What purity do you normally supply?
Is it flammable?
How is it packed and shipped?
What is the minimum order quantity?
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 Ortho Dichlorobenzene
Send your required assay, colour and moisture ceilings, 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 drum or a contracted ISO tank programme for the year.