Ortho Dichloro Benzene 1,2-Dichlorobenzene · ODCB · CAS 95-50-1
Chelora Chemicals is a supplier of Ortho Dichloro Benzene (ODCB), used both as a high-boiling industrial solvent and as the starting material for 3,4-dichloroaniline, a key diazo-component precursor for azo dyes, pigments and agrochemical intermediates. Every consignment leaves with a batch-specific COA and the current SDS.
Also known as: 1,2-Dichlorobenzene, o-DCB, o-Dichlorobenzol, Orthosol
Request a quotation
Price, lead time and a sample COA for Ortho Dichloro Benzene, usually within one working day. We ship worldwide.
Request a Quote Email the DeskDocumentation
- Batch-specific COA (GC assay, isomer purity, colour)
- Safety Data Sheet (SDS)
- UN 1591 dangerous-goods transport documents
- Third-party inspection on request
- Certificate of origin
What is Ortho Dichloro Benzene?
Ortho Dichloro Benzene (ODCB) is a benzene ring carrying two chlorine atoms on adjacent carbons — chemical name 1,2-dichlorobenzene, formula C₆H₄Cl₂. It is supplied as a colourless to pale yellow liquid with a mild aromatic odour.
Its value is two-fold: on its own it is a high-boiling, low-reactivity solvent used in degreasing and as a process solvent; as a building block it is the raw material for 3,4-dichloroaniline, the diazo component behind a wide range of azo dyes, pigments and phenylurea/anilide herbicide intermediates.
Commercially it is produced by the catalysed chlorination of benzene, which gives a mixture of the ortho- and para-isomers (chlorine is an ortho/para director) that is separated by fractional distillation.
Handling follows standard precautions for a chlorinated aromatic solvent — chemical-resistant gloves and eye protection, adequate ventilation, and storage away from strong oxidisers and open flame given its combustibility.
Why ODCB specifically
- Adjacent di-chlorine substitution. The 1,2- (ortho) chlorine pattern is what the downstream amination to 3,4-dichloroaniline depends on.
- Dye-intermediate feedstock. The main route to 3,4-dichloroaniline, used throughout azo dye and pigment synthesis.
- High-boiling solvent. Used as a process solvent and degreasing agent where a stable, high-boiling chlorinated solvent is needed.
- Distinct from the para-isomer. Para-Dichlorobenzene has different reactivity and different end uses and is not interchangeable with ODCB in most syntheses.
How ODCB is Manufactured
ODCB is produced by the direct chlorination of benzene.
- Catalysed chlorination. Benzene is reacted with chlorine gas in the presence of a Lewis-acid catalyst, giving mainly a mixture of the ortho- and para-dichlorobenzene isomers.
- Isomer separation. The crude mixture is separated by fractional distillation to isolate ortho-dichlorobenzene from the para-isomer and residual mono- and tri-chlorobenzenes.
- Purification. The isolated ODCB is further distilled to the target assay specification.
- Quality release and packing. Assay, isomer purity and colour are confirmed against specification before the batch is packed and released.
Typical Commercial Specification
Figures below are representative of commercial-grade ODCB. Tell us your downstream route and the grade you need, and we will advise on the specification to order against.
| Parameter | Typical Value |
|---|---|
| Appearance | Colourless to pale yellow liquid |
| ODCB content | 99% min by GC assay |
| Isomer purity | Para-dichlorobenzene, trace levels to grade |
| Moisture | 0.1% max |
Physical & Chemical Properties
| Property | Value |
|---|---|
| Chemical formula | C₆H₄Cl₂ |
| Molecular weight | 147.00 g/mol |
| Appearance | Colourless to pale yellow liquid |
| Melting / freezing point | About -17 to -18 °C |
| Boiling point | About 178 – 180 °C |
| Density | About 1.30 – 1.31 g/mL (20 – 25 °C) |
| Flash point | About 66 °C (closed cup) |
| Water solubility | Practically insoluble |
| Incompatibilities | Strong oxidisers, open flame |
Behaviour in the process
ODCB's properties are what dye-intermediate producers and solvent users are buying:
- Amination reactivity. The activated ring positions allow conversion to 3,4-dichloroaniline under catalytic amination/reduction conditions.
- Thermal and chemical stability. Stable, high-boiling liquid suited to use as a process solvent away from strong oxidisers.
- Low water solubility. Practically insoluble in water, which governs effluent handling and spill response.
ODCB and Related Chlorinated Benzenes
Choosing between dichlorobenzene isomers and related chlorinated benzenes comes down to the substitution pattern the target synthesis — or the solvent application — needs.
| Material | Substitution | When it is the right choice |
|---|---|---|
| Ortho Dichloro Benzene | 1,2-diCl | Routes needing the adjacent-chlorine pattern, or a high-boiling chlorinated solvent |
| Para Dichloro Benzene | 1,4-diCl | Routes needing the para-chlorine pattern instead, or moth-repellent/deodorant-block use |
| Monochlorobenzene | 1-Cl | Routes needing a single, less-hindered ring chlorine |
| 1,2,4-Trichlorobenzene | 1,2,4-triCl | Routes or solvent uses needing a third ring chlorine |
Stated plainly: a synthesis built around the adjacent-chlorine pattern needs ODCB specifically — the para-isomer has different reactivity and is not a drop-in substitute for amination to 3,4-dichloroaniline.
Industries We Supply ODCB To
The same ODCB feeds a dye-intermediate manufacturer and an industrial-solvent buyer. What changes is the downstream processing and the documentation each requires.
Where ODCB is Used
In downstream functionalisation
ODCB's two adjacent ring chlorines set up the catalytic amination to 3,4-dichloroaniline, which is then diazotised and coupled to build the target dye, pigment or herbicide intermediate. The ortho substitution pattern is often exactly why a route is designed around ODCB specifically rather than the para-isomer.
Need a specific purity grade?
Tell us whether you need solvent-grade or dye-intermediate-grade ODCB, your downstream chemistry, the packing format you can receive and the annual quantity. We will come back with a price, a lead time and a sample COA.
Quality Control & Testing
Every lot is released against a batch-specific Certificate of Analysis, with isomer purity reported alongside the main assay because para-dichlorobenzene carryover affects both downstream amination yield and solvent performance.
- ODCB content — by GC assay, the primary grade measure.
- Isomer purity — para-dichlorobenzene and other chlorobenzene carryover, reported because it affects downstream chemistry.
- Colour and moisture — reported because both affect solvent and process performance.
Common Process Problems & Likely Causes
| Symptom | Likely cause | What to check |
|---|---|---|
| Off-target amination product | Para-dichlorobenzene isomer carryover | Isomer purity figure on the COA |
| Lower boiling range than expected | Co-eluting monochlorobenzene or moisture | GC assay and moisture figures on the COA |
| Darkened material on receipt | Oxidation or contamination during storage or transit | Colour specification and storage conditions |
Packaging, Storage & Shipping
- Standard packing. Drums or ISO tanks, typically 200 L drums up to tank-container bulk formats on contract supply.
- Container compatibility. Use compatible gaskets and linings; ODCB can attack some plastics and rubbers over time.
- Temperature control. Store in a cool, dry, well-ventilated area away from direct sun, heat and ignition sources given the flash point.
- Material compatibility. Avoid contact with strong oxidisers and open flame.
- Transport classification. Commonly shipped under UN 1591, Class 6.1, Packing Group III — confirm the correct entry against your own current SDS before shipping.
Hazards & Safe Handling
ODCB is harmful if swallowed and if inhaled, causes skin and eye irritation, and is harmful to aquatic life with long-lasting effects. Standard precautions for a chlorinated aromatic solvent and good laboratory and plant practice apply throughout handling.
- Skin and eye contact. Chemical-resistant gloves and goggles are standard practice; rinse thoroughly with water on contact.
- Inhalation. Use adequate ventilation or local exhaust when handling, given the material's volatility.
- PPE. Chemical-resistant gloves, safety goggles and, where vapour exposure is a concern, a suitable respirator.
- Environment. Harmful to aquatic life with long-lasting effects; avoid uncontrolled release to water and follow local effluent rules.
Regulatory & Compliance Notes
ODCB is a well-established, widely registered industrial chemical. Because obligations differ by territory and use, the notes below are orientation rather than legal advice.
- GHS classification. Commonly classified as harmful if swallowed and if inhaled, an irritant to skin and eyes, and hazardous to the aquatic environment; the SDS carries the full hazard statements for your grade.
- REACH and chemical inventories. Registered under EU REACH and listed on major chemical inventories.
- Dangerous goods transport. Commonly shipped under UN 1591 (o-Dichlorobenzene), Class 6.1, Packing Group III. Confirm the correct entry with your logistics/EHS team against your current SDS before shipping.
- HS code. Commonly declared under the chlorobenzene/dichlorobenzene heading; confirm the exact tariff line with your customs broker for your jurisdiction.
We Supply ODCB Worldwide
Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Ortho Dichloro Benzene from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation and freight so the material arrives ready to use.
- Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
- Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged as routing allows.
- Documentation. Commercial invoice, packing list, certificate of origin, COA and SDS issued as a complete set.
- Flexible volumes. From drum quantities up to ISO-tank bulk shipments on a supply contract.
Buying ODCB from Chelora
We are an independent sourcing and supply partner. For this product that means settling three things at enquiry: whether you need solvent-grade or dye-intermediate-grade material, the packing format, and the quantity you are buying.
- Documentation on every lot. Batch-specific COA with GC assay and isomer breakdown, plus the current SDS.
- Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
- Quantities. Drum quantities through to larger ISO-tank shipments on contract supply.
- Inspection. Independent third-party inspection available at loading when the contract requires it.
- Related dye intermediates. Para Chloro Ortho Nitro Aniline, meta-Chloroaniline and other dye and pigment intermediates alongside this product from one supplier.
How ordering works
- Send the enquiry. Grade (solvent or dye-intermediate), quantity, destination port and the Incoterm you buy on.
- We quote. Price, lead time, packing format and a sample COA, normally within one working day.
- Qualify the supply. For first orders or dye-grade applications, we share the analysis so your technical team can sign off before you commit.
- Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
- Ship and document. Packed, labelled and loaded with the full export document set, and tracked through to arrival.
Ortho Dichloro Benzene — Common Questions
The questions our technical desk is asked most often about ODCB. If yours isn't here, call or email and you will reach someone who knows the chemistry.
What is the CAS number of Ortho Dichloro Benzene?
The CAS number for Ortho Dichloro Benzene (1,2-dichlorobenzene) is 95-50-1, and its EC number is 202-425-9. Its molecular formula is C₆H₄Cl₂ with a molecular weight of 147.00 g/mol.
What is ODCB used for?
It is used as the feedstock for 3,4-dichloroaniline, a key diazo component in azo dye, pigment and herbicide intermediate synthesis, and on its own as a high-boiling industrial solvent and degreasing agent.
Do you supply ODCB worldwide?
Yes. Chelora Chemicals supplies and exports ODCB worldwide — across Asia Pacific, Europe, the Middle East, Africa and the Americas, as well as throughout India. Every consignment carries the COA and SDS.
How does it differ from para-dichlorobenzene?
The chlorine positions are different — adjacent (1,2-) for ODCB versus opposite (1,4-) for the para-isomer — which changes the reactivity, the physical properties and the typical end use of each.
How is ODCB manufactured?
By the catalysed chlorination of benzene, which gives a mixture of the ortho- and para-isomers that is then separated by fractional distillation.
Is ODCB hazardous?
It is harmful if swallowed and if inhaled, causes skin and eye irritation, and is harmful to aquatic life with long-lasting effects. Refer to the current SDS for your grade for the complete hazard classification.
What is the UN number and transport classification?
ODCB is commonly shipped under UN 1591 (o-Dichlorobenzene), Class 6.1, Packing Group III, and is also marked as a marine pollutant/environmentally hazardous substance under several transport modes. Confirm against your own current SDS before relying on it for shipping documentation.
What are the melting point, boiling point and density?
Typical figures are a melting/freezing point around -17 to -18 °C, a boiling point around 178–180 °C, and a density around 1.30–1.31 g/mL. Confirm against your own supplier's COA for batch-specific figures.
How should ODCB be stored?
In sealed, compatible containers, cool, dry and away from direct sun, heat, ignition sources and strong oxidisers, given its flash point of around 66 °C.
What purity grades do you offer?
Standard commercial grade is 99% minimum by GC assay, with isomer purity (versus para-dichlorobenzene) and moisture reported on the COA.
What packing sizes and order quantities are available?
Drums, typically 200 L, up to ISO-tank bulk formats available on contract supply. Orders run from trial quantities up to repeat bulk loads.
Ready to source Ortho Dichloro Benzene?
Send us your purity requirement and annual volume. You will get a price, a realistic lead time and a sample COA from someone who understands what the material has to do in your process — delivered anywhere in the world.