Thionyl Chloride
Thionyl chloride is the reagent that turns a carboxylic acid into an acid chloride in one clean step — no other chlorinating agent is used at this scale across pharmaceutical and agrochemical synthesis. It is also export-controlled, and we treat that fact as part of the product, not an afterthought.
Chelora Chemicals supplies thionyl chloride to pharmaceutical, agrochemical and battery-electrolyte producers worldwide, in UN-approved packing, with a batch COA, GHS SDS and export-compliance screening on every order.
Product identity
- CAS Number
- 7719-09-7
- IUPAC name
- Thionyl chloride
- Molecular formula
- Cl₂OS
- Molecular weight
- 118.97 g/mol
- EC / EINECS
- 231-748-8
- UN Number
- 1836 · Class 8, PG I*
- SMILES
- O=S(Cl)Cl
- Export control
- CWC Sch. 3 · ECCN 1C350*
* Confirm the exact UN entry, packing group, HS heading and export-licence requirement with your freight forwarder, customs broker and our compliance desk — classification can differ by mode, destination and end use.
What Thionyl Chloride is used for
Thionyl chloride is a colourless to pale yellow, fuming, corrosive liquid with a sharp, suffocating odour. Chemically it is a specialty chlorinating agent: it converts a carboxylic acid's -OH group into -Cl, releasing only sulfur dioxide and hydrogen chloride gas as by-products — both of which leave the reaction mixture cleanly, which is exactly why it displaced older chlorinating methods across the industry decades ago.
Its dominant industrial use by volume is the manufacture of acid chlorides as reactive intermediates in pharmaceutical, agrochemical and fine-chemical synthesis, and the conversion of alcohols to alkyl chlorides. It is also the standard electrolyte and cathode-active component in lithium-thionyl-chloride primary batteries, and serves as a general dehydrating agent in inorganic and coordination chemistry.
Where it sits among chlorinating reagents
- Thionyl chloride (this product) the volume standard for acid-chloride formation; non-flammable, easy to distil off.
- Phosphorus oxychloride a related chlorinating agent used where a higher-boiling reagent is preferred; separated from thionyl chloride by distillation in mixed processes.
- Oxalyl chloride a milder, more selective alternative for acid-sensitive substrates, at higher cost per mole.
- Chloroacetyl chloride a distinct, pre-formed acid chloride rather than a chlorinating reagent. See that page.
On a controlled reagent, confirm the CAS number, your end use and your destination on the enquiry — see the full intermediate range.
Appearance and handling character
The material is a fuming liquid that reacts violently with water, releasing hydrogen chloride and sulfur dioxide gas, and it attacks many common metals in humid air. It is non-flammable but severely corrosive to skin, eyes and the respiratory tract, and long or aged storage can develop a yellow tint from trace decomposition. Moisture exclusion, sealed transfer and respiratory protection are the three practical requirements on this product.
| Parameter | Typical value |
|---|---|
| Appearance | Colourless to pale yellow fuming liquid |
| Assay (GC) | 99.0% min |
| Boiling point | 76 – 79 °C |
| Sulfuryl chloride | 0.3% max |
| Non-volatile residue | 0.1% max |
| Iron | 10 ppm max |
| Colour (APHA) | 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. Assay and colour carry straight into downstream acid-chloride purity — tell us your target and we will quote against it.
| Property | Value |
|---|---|
| Physical state | Fuming liquid at ambient |
| Melting point | −104.5 °C |
| Density | 1.64 g/cm³ (20 °C) |
| Water reaction | Violent — generates HCl + SO₂ |
| Flash point | Non-flammable |
| Incompatibilities | Water, alcohols, amines, strong oxidisers |
Physical constants compiled from public reference data for CAS 7719-09-7 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this reagent to work
One dominant reaction class and a short list of specialty uses — acid-chloride chemistry is what this reagent exists for.
Pharmaceutical acid-chloride intermediates
Converts carboxylic acid intermediates to the reactive acid chlorides used across API and advanced-intermediate synthesis.
- End-use declaration required
- Full impurity profile on request
- Low-metals grade available
Agrochemical intermediates
A core chlorinating step in the manufacture of herbicide, fungicide and insecticide active ingredients.
- Technical-grade specification
- Bulk contracted tonnage
- Second source held in reserve
Lithium-thionyl-chloride batteries
Serves as both electrolyte solvent and cathode-active material in high-energy-density primary Li-SOCl₂ cells.
- Low-moisture, battery-grade spec
- Tight metals and colour limits
- Inert-packed shipment available
Dye & pigment intermediates
Used to form sulfonyl and acid chlorides on the route to a range of dye and pigment intermediates.
- Colour-critical supply available
- Technical desk review of your route
- See our dye intermediate range
Dehydrating & inorganic chemistry
A general dehydrating reagent for preparing anhydrous metal chlorides and other inorganic synthesis steps.
- Packs from 500 mL for lab use
- Full analytical documentation available
- Retained sample held against the lot
Contract & scheduled supply
Pharma and agrochemical plants consume this continuously. We hold compliant inventory and release it against your production calendar.
- Annual contracts with scheduled call-off
- Price held across the contract period
- Export screening cleared in advance
How we supply Thionyl Chloride
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. On a CWC Schedule 3 chemical, owning no plant means every order runs through the same compliance screening regardless of volume — we route it to the producer whose licensing, packing and assay actually match a cleared, documented order.
We place your order with whichever qualified producer best matches your assay, your moisture and metals limits, your price point and your delivery window.
We keep a second qualified source on this line, because thionyl chloride capacity is concentrated among a limited number of export-licensed plants and lead times can extend quickly when one is down.
- End use and destination confirmed before we quote. This is a CWC Schedule 3 chemical, so we ask what it feeds and where it ships before pricing begins, not after.
- Assay and colour confirmed by GC before we quote. Both carry into downstream acid-chloride purity, and we state them on the COA rather than leave it to inference.
- Sulfuryl chloride and iron reported. These are the characteristic impurities that change downstream selectivity and metal-contamination risk.
- Packing specified for moisture exclusion. This is a specification point on a water-reactive liquid, not packaging detail.
- Export-control status stated up front. Said at enquiry stage so your procurement and compliance teams can plan documentation before the first order is placed.
- Export machinery handled in-house. Classification, licensing, approved packing, labelling, freight booking and customs paperwork are ours to manage.
Packed the way your plant receives it
On a water-reactive, fuming liquid the pack is doing chemistry as well as containment. Tell us how the material will be charged and we will quote the format that keeps moisture out.
Lined steel drums
UN-approved, corrosion-resistant lined drums with sealed closures — the standard commercial format for bulk transfer.
Nitrogen-blanketed packing
Available for battery-grade and moisture-critical shipments, particularly on long sea legs into humid destinations.
Bulk liquid transport
For contracted tonnage, ISO tank containers with appropriate corrosion-resistant linings reduce handling and packaging cost per tonne.
Trial / sample quantities
Small, sealed, DG-compliant containers dispatched so your R&D team can qualify the grade before committing to larger volumes.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with DG and export documentation filed before the booking is made.
Campaign despatch
We hold contracted, pre-cleared tonnage and release it against your production calendar, so each shipment is already screened before it is needed.
Moisture exclusion and respiratory protection are the controlling routes
Thionyl chloride is severely corrosive, toxic if inhaled, and reacts violently with water. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document.
Classified hazards
H314Causes severe skin burns and eye damage.H330Fatal if inhaled.H302Harmful if swallowed.EUH014Reacts violently with water.EUH029Contact with water liberates toxic gas.—Non-flammable, but corrodes many metals in the presence of moisture.
Hazard statements reflect classifications commonly published for CAS 7719-09-7. 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.
- Never apply water directly to a spill. Water reacts violently, releasing HCl and SO₂ gas — use dry sand, dry absorbent or a designated dry-quench procedure instead.
- Evacuate and ventilate before re-entry. Fuming and toxic gas release make this a respiratory hazard well beyond the immediate spill area.
- Contain, do not hose to drain. Collect the material and dispose of it as regulated chemical waste under controlled neutralisation.
- Treat contaminated clothing as waste. Remove it immediately, bag it and handle it as contaminated waste rather than sending it to an ordinary laundry.
- Treat any skin or eye contact as an emergency. H314 means irrigate immediately and seek medical attention without delay.
Storage
- Cool, dry, access-controlled store. Moisture ingress is the single biggest risk on this product — it generates gas and pressurises the container.
- Keep containers tightly closed under dry conditions. A part-used drum left open in humid air will visibly fume and corrode its own closure.
- Segregate from water, alcohols, amines and oxidisers. All react exothermically; keep them apart by distance, not just by label.
- Avoid contact with reactive metals. Corrodes many common metals in the presence of trace moisture, which is why container material matters.
- Shelf life typically 12–24 months. Re-assay and check colour before use after extended storage.
Handling & PPE
- Design vapour and skin contact out. Closed transfer under dry nitrogen, contained charging and local exhaust ventilation first; PPE last, never as the sole control.
- Acid-resistant gloves, face shield and chemical-resistant suit. With contaminated clothing removed, bagged and handled as contaminated waste.
- Supplied-air or full-face respiratory protection. Required for any operation where fuming or vapour release is possible — H330 is fatal-if-inhaled, not a minor irritant.
- Emergency shower and eyewash within reach. Given the severe-burns classification, immediate irrigation access is not optional.
- Never discharge to drain or watercourse. Contain and dispose of as regulated chemical waste under controlled neutralisation.
Transport & export control
Thionyl chloride ships as regulated cargo under UN 1836, Class 8 (Corrosive), Packing Group I, and is additionally listed under the Chemical Weapons Convention Schedule 3 and dual-use export-control regimes (such as ECCN 1C350 in several jurisdictions). We classify each consignment, screen the end user and destination, apply UN-approved packaging and labelling, and file the dangerous-goods and export declarations before the booking is made — ask us for the current compliance checklist 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 — and who is receiving it — is precisely the work you are buying from a supplier.
Certificate of Analysis
Batch-specific assay, sulfuryl chloride, non-volatile residue, iron and colour — checked against your 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, in the language your destination requires.
Dangerous Goods Declaration
UN number, hazard class and IMDG or RID/ADR declaration prepared and filed before the container is booked, with correctly marked packaging.
Export-compliance screening record
End-user, end-use and destination screening against applicable Schedule 3 and dual-use control lists, completed before the order is confirmed.
Certificate of Origin
Chamber-attested where required, plus preferential-origin forms where a trade agreement gives your import duty relief.
Retained & pre-shipment samples
Pre-shipment samples carry the same COA as the commercial lot, so what your laboratory qualifies is exactly what arrives.
A chlorinating agent that cleans up after itself
The reason thionyl chloride became the industry default is that both by-products of the reaction — sulfur dioxide and hydrogen chloride — are gases that simply leave the flask. The pattern below is general background, not a process disclosure.
React with the acid or alcohol
The substrate's hydroxyl group attacks the sulfur centre, displacing chloride and forming a reactive chlorosulfite intermediate.
Lose sulfur dioxide
The intermediate collapses with loss of SO₂, generating a chloride ion and the acylium or carbocation-like species.
Recombine to the chloride
Chloride recombines with the activated carbon centre to give the acid chloride or alkyl chloride product directly.
Strip volatiles
Excess reagent and both gaseous by-products are stripped off by distillation, leaving the product with minimal clean-up.
Why assay and moisture carry through
On this reagent, two drums at the same nominal label can give very different downstream results:
- Assay sets your stoichiometry. A reagent used off a nominal percentage will under- or over-react if the real titre has drifted from the label.
- Trace moisture self-consumes the reagent. Every trace of water reacts before your substrate gets a chance to, quietly lowering effective yield.
- Sulfuryl chloride is the characteristic co-product impurity. It can introduce unwanted chlorination side-reactions if not controlled.
- Iron and colour affect downstream product quality. Both carry into the acid chloride and, further downstream, into the finished active.
That is why we quote against your written assay and moisture limits rather than a generic "technical grade", and why the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Material | Role |
|---|---|
| Thionyl chloride CAS 7719-09-7 — this product | Acid/alcohol chlorination |
| Chloroacetyl chloride CAS 79-04-9 | Pre-formed acid chloride |
| Ethyl chloroformate CAS 541-41-3 | Carbamate / carbonate formation |
| Phosphorus oxychloride Related chlorinating agent | Higher-boiling alternative |
We supply across this reagent 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 product
Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Sulfur and chlorine feedstock
Both production routes depend on elemental sulfur or sulfur dioxide and chlorine, so sulfur and chlor-alkali markets feed through together.
- Sulfur tracks refinery and smelter output
- Chlorine follows chlor-alkali economics
- We flag feedstock-driven moves in the quote
Pharma & agrochemical demand
A very broad range of acid-chloride intermediates depends on this reagent, so demand tracks the pharma and crop-protection manufacturing cycle.
- Demand is broad-based, not single-product
- Contracted call-off smooths the exposure
- We hold a second qualified source
Export-licensing capacity
Only a limited number of plants hold the licensing and screening infrastructure to export this reagent compliantly, which constrains supply relative to raw demand.
- Compliant capacity is the real bottleneck
- Lead times extend quickly when one plant is down
- We pre-qualify a second licensed source
Freight and DG surcharges
Class 8 PG I cargo carries a significant hazardous surcharge, and inert-blanketed packing adds cost on top.
- 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
Screening and documentation lead time
Export-control screening adds a fixed step to every order's timeline, independent of production lead time.
- We run screening in parallel with sourcing
- Repeat buyers keep a standing compliance file
- Ask about pre-cleared annual contracts
Shelf life and inventory risk
A 12 to 24 month shelf life and moisture sensitivity mean stockpiling against a price move carries a real degradation cost.
- Buy to schedule rather than to price
- We hold inventory and release on call-off
- Ask about scheduled despatch
| If your end use is… | Specify |
|---|---|
| Pharma acid-chloride intermediate | Low iron, tight colour, full impurity profile |
| Li-SOCl₂ battery electrolyte | Battery grade, ultra-low moisture |
| Agrochemical intermediate | Technical grade |
| Dye / pigment intermediate | Colour-critical |
| Laboratory / reference use | Small DG-compliant pack, full COA |
Not sure which row 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 end use and destination before anything else. This is the first question on a Schedule 3 chemical, and we settle it in the first reply.
- Confirm assay and moisture limits. On this reagent both carry into downstream yield and quality, so we verify before quoting.
- Recommend packing for your climate and transit. Nitrogen-blanketed packing is worth the cost on some routes and unnecessary on others, and we will say which.
- Be straight about the export-control status. Stated at enquiry stage so your procurement and compliance teams can plan documentation before the first order.
Regulatory & compliance notes
- CWC Schedule 3 declaration obligations apply. Producers and, in some jurisdictions, large-volume buyers may face declaration requirements — ask your regulatory affairs team to confirm your position.
- Export licensing varies by destination and end use. We check applicable control lists 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. Corrosive, acidic waste streams require controlled neutralisation before discharge; check your consent against the material.
None of the above is legal advice — your own regulatory affairs and export-compliance team owns the final position for your import, export licensing and workplace. What we commit to is accurate product identity data, an honest statement of the hazard and control classification, and complete documentation to work from.
From enquiry to delivered pallet
Send the specification
Product name or CAS 7719-09-7, your assay and moisture limits, quantity, pack preference, end use and destination.
Compliance screening & quote
End-user and destination screened against Schedule 3 and dual-use lists, then pricing, lead time and packing confirmed in writing.
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
Classification filed, DG and export freight booked, export documents issued, and the consignment tracked through transit and clearance.
What buyers ask us about Thionyl Chloride
What is thionyl chloride used for?
Is thionyl chloride export-controlled?
Why does the liquid turn yellow in storage?
What purity do you normally supply?
Is it hazardous?
What is the minimum order quantity?
Is this a dangerous good? What paperwork comes with it?
Do you manufacture this yourself?
Request pricing on Thionyl Chloride
Send your required assay and moisture limits, quantity, pack format, end use and destination. Our sourcing desk is available 24 hours a day, 7 days a week, and comes back with pricing, lead time and compliance screening.