Meta Dichloro Benzene
Meta Dichloro Benzene — 1,3-dichlorobenzene, commonly traded as MDCB — is the meta isomer of dichlorobenzene and a specialty halogenated-aromatic building block. Its two chlorines sitting 1,3 to each other make it the specific isomer that triazole fungicide and several herbicide and dye syntheses are built around, a role the ortho and para isomers cannot substitute for.
Chelora Chemicals supplies MDCB to agrochemical technical manufacturers, dye houses and fine chemical producers worldwide, in drums and bulk tanker quantities, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 541-73-1
- IUPAC name
- 1,3-Dichlorobenzene
- Molecular formula
- C6H4Cl2
- Molecular weight
- 147.00 g/mol
- EC / EINECS
- 208-792-1
- MDL number
- MFCD00000573
- SMILES
- Clc1cccc(Cl)c1
- HS Code
- 2903 92*
* Confirm the exact HS heading with your customs broker — classification of halogenated benzene derivatives varies between destination tariffs.
What Meta Dichloro Benzene is used for
Meta Dichloro Benzene is a benzene ring carrying two chlorine atoms in the 1,3 relationship. That specific geometry — neither adjacent (ortho) nor opposite (para) — sets the substitution pattern for everything built from it downstream. It is the molecule of choice wherever a synthesis route needs chlorines positioned meta to each other, most importantly across the triazole fungicide family that protects cereals, fruit and vegetable crops worldwide.
In practice MDCB is a specialty, lower-volume halogenated intermediate rather than a bulk commodity solvent. Buyers value consistent isomer purity above almost everything else, because the ortho and para isomers it is made alongside cannot be substituted into a meta-specific synthesis without changing the product.
Why the isomer matters
The three dichlorobenzene isomers are separate molecules with almost entirely separate uses, and none of them is interchangeable with another downstream:
- 1,3-Dichlorobenzene (CAS 541-73-1) — this product. Chlorines meta to each other. The specialty, higher-value isomer of the three.
- 1,2-Dichlorobenzene (o-DCB, CAS 95-50-1) — the ortho isomer, widely used as an industrial solvent and degreaser and as an intermediate in its own right.
- 1,4-Dichlorobenzene (p-DCB, CAS 106-46-7) — the para isomer, best known as a moth-repellent and toilet-deodoriser block, and a feedstock for its own polymer and intermediate chemistry.
If your purchase order simply says "dichlorobenzene", quote us the CAS number and we will confirm the correct isomer before the order is placed. Isomer mix-ups are the single most common costly mistake in this product family — an ortho or para batch will not perform the same chemistry as the meta isomer, however similar the drum label looks.
Appearance and handling character
MDCB ships as a colourless to pale yellow liquid with a mild, sweet aromatic odour. It is a liquid across a wide ambient range — its melting point sits well below freezing, so unlike some solid aniline intermediates it does not cake or fuse in a hot container. It is practically insoluble in water and miscible with alcohols, ketones, aromatic and chlorinated solvents. It is combustible rather than highly flammable, and — a point worth stating plainly given how often chlorinated aromatics are assumed to be carcinogens by default — IARC classifies this substance in Group 3: not classifiable as to its carcinogenicity to humans. Read the safety section below for the hazards that do apply.
| Parameter | Typical value |
|---|---|
| Appearance | Colourless to pale yellow clear liquid |
| Assay (GC) | 99.0% min |
| Moisture (KF) | 0.1% max |
| Isomeric purity (o- / p-DCB content) | 1.0% max, reported per batch |
| Colour (APHA) | Reported per batch |
| Non-volatile residue | Reported per batch |
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. If your synthesis is sensitive to trace ortho or para isomer, or needs a colour ceiling for a light-sensitive downstream step, send us your specification and we will quote against it rather than against a generic grade.
| Property | Value |
|---|---|
| Physical state | Liquid at ambient |
| Melting point | ≈ −24.8 °C |
| Boiling point | 172 – 173 °C @ 760 mmHg |
| Flash point | ≈ 63 – 67 °C (closed cup) |
| Relative density | ≈ 1.288 at 25 °C |
| Refractive index | n20/D ≈ 1.546 |
| Partition coeff. (log P) | ≈ 3.53 |
| Water solubility | Practically insoluble (≈ 125 mg/L @ 25 °C) |
| Organic solubility | Miscible with alcohols, ketones, aromatic & chlorinated solvents |
| Odour | Mild, sweet aromatic |
Physical constants compiled from public reference data for CAS 541-73-1 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this molecule to work
MDCB's value is concentrated where the 1,3-chlorine pattern is specifically required — above all in triazole fungicide manufacture — with meaningful secondary demand in dyes, other agrochemicals and as an industrial process solvent.
Triazole fungicides
The largest single outlet. MDCB is a key building block for triazole fungicides including Propiconazole, Difenoconazole, Hexaconazole, Epoxiconazole and Imazalil — broad-spectrum actives that protect cereals, fruit and vegetable crops worldwide.
- Isomeric purity is the buyer's first check
- Demand tracks the global crop-protection calendar
- See our agrochemical intermediate range
Other agrochemical actives
Beyond the triazole family, MDCB also feeds selected herbicide chemistries and has been used historically in the synthesis of certain insecticide intermediates, where the meta chlorine pattern sets up the required ring substitution.
- Confirm your exact downstream active with our technical desk
- Isomer and moisture limits are usually the critical parameters
- Small-volume, high-specification orders welcome
Dyes & pigment chemistry
MDCB is used as an intermediate and reaction solvent in dye and pigment manufacture, where its aromatic ring and inert chlorine substituents make it a stable participant in demanding condensation and coupling chemistry.
- Colour ceiling on the COA matters more here than elsewhere
- See our full dye intermediate range
Pharmaceutical intermediates
The meta-disubstituted ring is a useful building block across several established drug families, installed through halogen-selective coupling, amide formation or ring construction chemistry.
- Amide, ether and cross-coupling chemistry
- Trial and laboratory quantities available
Industrial process solvent
A non-polar, high-boiling solvent used as a processing medium or diluent in coatings, inks, adhesives and rubber and plastics processing, and occasionally as a heat-transfer or dielectric-fluid component in specialty electrical applications.
- Confirm compatibility with your process equipment
- Available in bulk for solvent-grade use
Contract & scheduled supply
Fungicide manufacturers run to a crop-protection production plan, not a calendar month. Most MDCB buyers want tonnage released against that 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 Meta Dichloro Benzene
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. We own no chlorobenzene plant — and for an isomer-sensitive intermediate like this one, that independence works in your favour. We are never obliged to push you whatever a captive unit happens to be running that month.
Instead we place your order with whichever qualified producer best matches your isomeric purity requirement, your price point and your delivery window.
We keep a second qualified source on this line. When a plant goes down for maintenance, or a feedstock disruption hits, your production schedule switches source rather than stalling.
- Specification read against the CAS first. We confirm you need 541-73-1 (the meta isomer) and not the ortho or para dichlorobenzene, before we quote a price.
- Batch COA shared before dispatch. You approve the assay, isomeric purity and colour profile against your own spec while the material is still in our warehouse.
- Hazard status stated plainly. We tell you what is and is not classified for this material at enquiry stage — including the IARC Group 3 position — rather than leaving you to infer it from a generic chlorinated-aromatic reputation.
- Pre-shipment samples for qualification. New account or new source, your R&D team runs a lab batch before the full quantity ever moves.
- Packing chosen for your process. Whether you need drummed material for a batch reactor or bulk liquid for continuous processing, we plan the format with you.
- Export machinery handled in-house. Hazard classification, UN-approved packing, labelling, freight booking and customs paperwork are ours to manage.
- Consolidation onto one bill of lading. Ship MDCB alongside other intermediates from our range — one invoice, one shipment, one counterparty.
Packed the way your plant receives it
As a liquid intermediate, pack format is mainly a question of volume and your charging method. Tell us how it will be handled at your end and we will quote the format that suits your operation.
Mild steel / lined drums
UN-certified drums, the standard format for LCL movements and for plants charging batch-wise by hand or drum pump.
IBC totes
Intermediate bulk containers for customers taking a pallet at a time — fewer handling movements and a lower packing cost per litre than drums.
Bulk liquid transport
For contracted campaign tonnage, flexitank or ISO tank movement cuts packing cost and handling to a minimum on high-volume orders.
Samples & trial packs
Laboratory samples and pilot quantities dispatched by courier so your R&D team can qualify the isomeric purity before committing to volume.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to. Ocean, air and road freight arranged end-to-end with documentation filed before booking.
Campaign despatch
Fungicide production runs to a crop-protection plan. We hold contracted tonnage and release it against your production calendar instead of landing it all at once.
Handle it as a combustible, aquatic-toxic liquid
MDCB is not classified as a carcinogen — IARC places it in Group 3, not classifiable as to carcinogenicity to humans — but it is still a hazardous material that deserves proper controls: it is combustible, harmful if swallowed, capable of organ effects on repeated exposure, and toxic to aquatic life with long-lasting effects. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document and should govern your risk assessment, PPE selection, exposure monitoring and emergency planning.
Classified hazards
H227Combustible liquid.H302Harmful if swallowed.H373May cause damage to organs through prolonged or repeated exposure.H411Toxic to aquatic life with long lasting effects.
Hazard statements reflect the classification commonly published on reagent-grade safety data sheets for CAS 541-73-1 (GHS pictograms GHS07, GHS09). Supplier classifications may differ in detail; always read the SDS issued with your specific batch. IARC Group 3 — not classifiable as to carcinogenicity to humans — is stated explicitly here because this class of chlorinated aromatic is often assumed to carry a cancer hazard it does not have; confirm the current position for your own regulatory filing independently.
Spill & emergency orientation
Plan your response before the drum arrives, not after it leaks. The points below are orientation for your emergency planners — 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. The material is toxic to aquatic life with long-lasting effects. Bund and collect a liquid spill into a labelled container; never wash it to a drain or watercourse.
- Use inert absorbent. Sand, vermiculite or a commercial spill granule for a liquid spill; the material floats on and is insoluble in water.
- Remove ignition sources. It is combustible with a flash point in the low 60s °C — keep it away from open flame, sparks and hot surfaces during cleanup.
- Wash skin and eyes promptly after contact, and remove contaminated clothing without delay.
- Have the SDS with the casualty. H373 flags organ effects from prolonged or repeated exposure; the treating clinician needs the product identity and CAS number in hand.
Storage
- Cool, dry, well-ventilated store, away from direct sunlight, open flame and other ignition sources given its combustible classification.
- Keep containers tightly closed to limit vapour loss and moisture pick-up, and to slow the slight colour drift some batches show on long storage.
- Segregate from strong oxidising agents and from aluminium and its alloys, which can react with chlorinated aromatics under some conditions.
- Bunded, access-controlled storage. Standard good practice for a liquid organic classified as toxic to aquatic life.
- Shelf life is typically 24 months or more in sealed original packing under these conditions. Re-assay before use after long storage.
Handling & PPE
- Closed transfer where practical. Pump or gravity-feed from drum or IBC rather than open pouring, to limit vapour exposure.
- Chemical-resistant gloves and splash-proof eye protection as a baseline for any liquid chlorinated aromatic, regardless of its favourable carcinogenicity position.
- Local exhaust ventilation at any point where the drum or reactor is opened, particularly in a warm climate where vapour pressure rises.
- Control ignition sources around bulk transfer and tank operations given the combustible-liquid classification.
- Never discharge to drain or watercourse. H411 applies — collect spills and rinse water as regulated chemical waste.
Transport
MDCB moves as regulated cargo in most jurisdictions. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made. The applicable UN number, class and packing group are 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 by GC, moisture by Karl Fischer, isomeric purity, colour and non-volatile residue — checked against your purchase specification before we release the goods.
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 number, 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.
Why the meta pattern is worth paying for
Dichlorobenzene is produced industrially as a mixture of isomers, and separating the meta fraction to high purity is materially harder than isolating the ortho or para isomer. That separation cost is a real part of what you are paying for in a specification-grade MDCB drum. The pattern below is the general industrial picture, not a process disclosure.
Start with chlorobenzene
Further chlorination of chlorobenzene, or diazotisation-based routes from a chloroaniline precursor, produce a mixture of dichlorobenzene isomers.
Separate the isomers
Ortho, meta and para dichlorobenzene have close but distinguishable boiling points and physical properties, separated by careful fractional distillation and, where needed, crystallisation.
Polish to specification
The meta cut is polished to remove trace ortho and para carry-over and colour bodies, since even small isomer contamination can show up in a sensitive downstream synthesis.
Build the finished active
Triazole ring construction, etherification or further halogenation installs the rest of the target molecule — a fungicide, dye or pharmaceutical intermediate — onto the meta-substituted ring.
Why isomeric purity carries through the whole route
Because the three isomers behave so similarly in bulk physical properties, a downstream chemist relies on the isomer assay on the COA rather than on anything they can easily verify visually:
- Ortho or para carry-over reacts in parallel through the same chemistry and gives a structurally similar but functionally different by-product that is often hard to separate from the target molecule.
- Colour bodies from an oxidised or poorly polished batch can carry through into a finished dye or fungicide, showing up as an off-spec appearance in the final product.
- Residual moisture matters wherever the next step involves an acid chloride, chlorinating agent or other moisture-sensitive reagent.
- Heavy residues from an incomplete distillation concentrate in still bottoms and reduce the number of passes a plant gets from its purification train.
That chain of consequences is the reason we quote against your written specification rather than a generic "99% technical" grade, and the reason the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Isomer | Principal outlet |
|---|---|
| 1,3-Dichlorobenzene (meta) CAS 541-73-1 — this product | Triazole fungicides Dyes & pigments Pharmaceutical intermediates |
| 1,2-Dichlorobenzene (ortho) CAS 95-50-1 | Industrial solvent Degreasing Own intermediate chemistry |
| 1,4-Dichlorobenzene (para) CAS 106-46-7 | Moth repellent / deodoriser blocks Polymer & intermediate feedstock |
If your route calls for one of the other isomers, we supply those as well — see our full chlorinated benzene range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this intermediate
MDCB is a specialty, lower-volume isomer rather than a bulk commodity. Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Crop-protection demand cycle
Triazole fungicide manufacture, the largest outlet for this molecule, tracks the global crop-protection production and application calendar rather than running flat through the year.
- Quote ahead of the season your customer serves
- Spot buying at peak season costs materially more
- Contracted call-off smooths the exposure
Upstream feedstock
The route back to MDCB runs through benzene and chlorine chemistry. Movements in benzene and chlor-alkali economics, and the isomer-separation cost specifically, feed through to the quoted price within a quarter or so.
- Chlorine and benzene set the floor
- Isomer-separation capacity is the real constraint
- We flag feedstock-driven moves in the quote
Narrow supply base
Because separating the meta isomer to high purity is harder than isolating ortho or para dichlorobenzene, fewer plants worldwide produce specification-grade MDCB at volume than produce the other two isomers.
- We hold a second qualified source on this line
- Qualify the alternate before you need it
- Ask us about dual-source contracts
Regulatory pressure on chlorinated solvents
Some jurisdictions apply tightening restrictions to chlorinated aromatic solvents in general, even where a specific substance — like this one — carries a favourable carcinogenicity position. That regulatory direction affects long-term investment in capacity.
- Solvent-use restrictions vary by jurisdiction
- Agrochemical-intermediate use is generally unaffected
- We check destination rules before quoting
Pack format
Cost per kilo falls from drums to IBCs to bulk liquid transport as order size grows. Choosing the right format for your storage and charging capacity keeps landed cost sensible.
- Drums suit trial and smaller orders
- IBC or bulk liquid suits contracted campaign tonnage
- We help you choose based on your tankage
Freight & DG surcharges
This is regulated cargo, so ocean freight 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
| If your end use is… | Specify |
|---|---|
| Triazole fungicide manufacture | High assay with tight ortho/para isomer limits |
| Dyes & pigments | Colour ceiling, tight isomer limit, low insolubles |
| Pharmaceutical chain | Tight isomer limit; metals and residues reported |
| Industrial solvent use | Standard commercial assay; isomer limit usually secondary |
| Laboratory / R&D | Small pack, high purity, full analytical pack |
Not sure which column you are in? Describe the reaction or process you are running 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
- Match a grade to your reaction. Tell us the step you are running and we will recommend the specification — and say so plainly when a tighter, costlier grade would add nothing.
- Be straight about the hazard profile, both ways. We flag the combustible and aquatic-toxicity classifications at enquiry stage, and we are equally clear that IARC does not classify this substance as a carcinogen — neither overstating nor understating the picture.
- Advise on handling and storage for your site conditions, including ignition-source control given the combustible-liquid classification.
- Review your specification before it goes into a contract, so you are not locked into an isomer limit that no plant can consistently hit.
Regulatory & compliance notes
- Solvent-use restrictions are jurisdiction-specific. Several regimes are tightening rules on chlorinated aromatic solvents generally; confirm what applies to your intended use at your site before the first delivery.
- Import controls vary by destination. Some jurisdictions apply registration or licensing requirements to chlorinated aromatics. We check destination rules before quoting, not after you have raised the PO.
- Chemical inventory listings differ between regions. Confirm your obligations under the applicable inventory regime for your import volume — we will supply the identity data you need for that filing.
- Downstream active registration — if you are building a fungicide or other agrochemical active from this intermediate, your regulatory team should confirm the registration position for the finished active in your target market.
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 giving you 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 541-73-1, the assay and isomeric-purity limits you work to, 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
DG classification filed, freight booked, export documents issued, and the consignment tracked through transit and clearance to your plant.
Often bought alongside this grade
Consolidate several intermediates onto one shipment and one invoice. These are the chlorinated aromatics and agrochemical intermediates our fungicide, dye and fine chemical customers most often order in the same programme. Browse the full range for current CAS numbers and specifications.
What buyers ask us about Meta Dichloro Benzene
Is this material classified as a carcinogen?
Can I use the ortho or para isomer instead?
What purity do you normally supply?
What is the minimum order quantity?
How long does delivery take?
Is it flammable or just combustible?
Why does purity specification focus on the isomer content?
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?
Can you hold stock against a production plan?
Request pricing on Meta Dichloro Benzene
Send your required assay, isomeric-purity limit, 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 drum or a contracted container programme for the year.