Vinyl Chloride Monomer (VCM)
One product, one destination: essentially all of it becomes PVC. It is also a confirmed human carcinogen, and the occupational limits that govern it worldwide were written in response to deaths among the men who made it.
Molecular Structure
What is Vinyl Chloride Monomer (VCM)?
Vinyl chloride is ethylene with one hydrogen replaced by chlorine, and a double bond that opens under free radical conditions to give polyvinyl chloride. At ambient temperature and pressure it is a gas, so it is handled throughout as a liquefied gas under pressure or under refrigeration. There is no bulk liquid handling of VCM in the way there is for other monomers.
Almost all of it is made by the balanced ethylene process. Half the ethylene is chlorinated directly to 1,2-dichloroethane; the other half is oxychlorinated using the hydrogen chloride recovered from the next step. The combined EDC is then thermally cracked at around 500 °C to vinyl chloride and hydrogen chloride, and that hydrogen chloride is fed back to the oxychlorination reactor. The elegance of the scheme is that chlorine enters once and leaves in the product, with no net HCl to dispose of.
Its downstream position could not be simpler. More than 98% of vinyl chloride is polymerised to PVC, with a small residue going to copolymers with vinyl acetate or vinylidene chloride. PVC is the third highest-volume polymer in the world, and vinyl chloride is the only route to it.
Vinyl chloride is a Category 1A carcinogen — established as causing cancer in humans, specifically hepatic angiosarcoma, from occupational exposure documented in the 1970s. Exposure limits are set around 1 ppm, orders of magnitude below most industrial solvents, and closed handling with monitoring is not optional.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
A two-carbon alkene carrying a single chlorine. The double bond opens under free radical initiation to give the PVC backbone; the chlorine is what makes that backbone polar, flame-retardant and receptive to the plasticisers that turn rigid PVC into flexible PVC.
Skeletal structure — chlorine on a two-carbon alkene
Structural Identity
- IUPAC NameChloroethene
- Common namesVCM, vinyl chloride, VC
- Molecular FormulaC₂H₃Cl
- Molecular Weight62.50 g/mol
- Functional groupVinyl double bond, chloro substituent
- Vapour density≈ 2.15 relative to air
- Polymerises toPVC — more than 98% of output
- Made fromEDC cracking, balanced ethylene process
- CarcinogenicityCategory 1A — known human carcinogen
- CAS Number75-01-4
- InChI KeyBZHJMEDXRYGGRV-UHFFFAOYSA-N
Product Specifications
Chelora supplies Vinyl Chloride Monomer (VCM) in standard and custom grades. Contact us for specification sheets tailored to your process.
| Chemical name | Vinyl chloride monomer |
|---|---|
| CAS Number | 75-01-4 |
| Molecular formula | C₂H₃Cl |
| Molecular weight | 62.50 g/mol |
| Purity (min) | ≥ 99.90 wt% |
| Acetylene (max) | ≤ 2.0 ppm wt |
| 1,3-Butadiene (max) | ≤ 5.0 ppm wt |
| Acetaldehyde (max) | ≤ 5.0 ppm wt |
| Hydrogen chloride (max) | ≤ 0.5 ppm wt |
| Water (max) | ≤ 200 ppm wt |
| Iron (max) | ≤ 0.50 ppm wt |
| Non-volatile residue (max) | ≤ 50 ppm wt |
| High-boiling chlorinated compounds (max) | ≤ 100 ppm wt |
| 1,2-Dichloroethane (max) | ≤ 10 ppm wt |
| Methyl chloride (max) | ≤ 100 ppm wt |
| Alkalinity as NaOH (max) | ≤ 5.0 ppm wt |
| Colour (max) | ≤ 10 Pt-Co (Hazen) |
| Flash point | −78 °C |
| Autoignition temperature | 472 °C |
| Flammable limits | 3.6 – 33% v/v in air |
| Occupational exposure | Typically 1 ppm 8-hour TWA — confirm local limit |
| Transport classification | UN 1086, Class 2.1, stabilized |
Downstream Applications & Derivatives
Key derivative chains and industrial uses of Vinyl Chloride Monomer (VCM).
Rigid PVC
Pipe, fittings, window and door profiles, cladding and rainwater goods. Rigid PVC is the largest single construction plastic by volume and takes the majority of VCM output.
Flexible PVC
Plasticised compound for cable insulation and sheathing, flooring, hose, coated fabric, roofing membrane and inflatables — the chlorine content gives inherent flame retardance.
Medical PVC
Blood bags, IV sets, tubing and catheters, where PVC's clarity, flexibility, weldability and radiation-sterilisation tolerance are difficult to match with other polymers.
PVC Film & Sheet
Calendered and extruded film for packaging, credit cards, signage, stationery and shrink sleeve labels, in both rigid and flexible formulations.
PVC Copolymers
Vinyl chloride-vinyl acetate copolymers for flooring tile, coatings and gramophone-era heritage applications, and vinylidene chloride copolymers for barrier film.
PVC Paste & Emulsion
Emulsion and microsuspension PVC for plastisols — coated fabric, wallcovering, automotive underbody sealant, dip moulding and toy manufacture.
Why source Vinyl Chloride Monomer (VCM) through Chelora Petrochem?
Verified Origin
Full origin certification and asset-backed supply chain documentation — no grey-market supply, which matters more here than for any other product we handle.
Grade Flexibility
Suspension, emulsion and copolymer grades supplied. We certify acetylene, butadiene, acetaldehyde and iron on every lot, because those are the impurities that will destroy a polymerisation batch.
Full Documentation
CoA, SDS, UN 1086 dangerous goods documentation, REACH compliance, carcinogen communication obligations, and destination-market certificates with every shipment.
Logistics Support
Experienced in liquefied gas logistics — pressurised and refrigerated ISO tanks, gas carriers and rail, with closed transfer, vapour return and leak detection provision, for Indian and international delivery.
Storage & Handling Guidelines
Always refer to the full SDS before handling. The following is a summary of key requirements.
- Handle in fully closed systems only. Vinyl chloride is a known human carcinogen with occupational limits around 1 ppm, and there is no version of open handling that is acceptable — closed transfer with vapour return is the baseline, not an enhancement.
- Install continuous or frequent atmospheric monitoring with alarms at all transfer, sampling and potential leak points, and maintain the exposure records that carcinogen regulations require.
- Store as a liquefied gas in pressure-rated vessels, either under pressure at ambient or refrigerated below −13 °C, with relief systems sized and routed to a safe location.
- Maintain the inhibitor and the storage temperature. Vinyl chloride polymerises exothermically if initiated, and a runaway in a pressure vessel is a far more serious event than in an atmospheric tank.
- Exclude air rigorously. Oxygen ingress forms peroxides in vinyl chloride, and those peroxides initiate polymerisation — this is the opposite of the requirement for vinyl acetate, and the two must not be handled on the same assumptions.
- Keep copper and copper alloys out of the wetted path. Trace acetylene in the monomer can form copper acetylide, which is shock-sensitive.
- Control ignition sources absolutely. The flammable range is exceptionally wide at 3.6% to 33%, vapour is roughly twice the density of air, and the flash point is −78 °C.
- Bond, earth and purge before every connection and disconnection, and use closed-loop sampling systems rather than open sampling under any circumstances.
- Have emergency procedures written for both the flammability and the carcinogen exposure scenario, including medical surveillance arrangements, and train on them before the first cargo arrives.
Hazard Summary
Classification: Carc. 1A (H350, may cause cancer), Flam. Gas 1 (H220), Press. Gas. Vinyl chloride is one of a small number of industrial chemicals established as carcinogenic in humans on direct epidemiological evidence rather than by extrapolation from animal data.
The carcinogenicity is not theoretical: the classification rests on clusters of hepatic angiosarcoma — a rare liver cancer — among PVC polymerisation workers, identified in the early 1970s. Occupational exposure limits worldwide were rewritten in response, typically to 1 ppm as an eight-hour average with a short-term ceiling. Prolonged exposure has also been associated with liver fibrosis, acro-osteolysis and Raynaud-type circulatory effects.
Exposure control is the whole regime: at a 1 ppm limit, ventilation and personal protective equipment are not sufficient on their own. Closed systems, vapour return, continuous monitoring, restricted access, exposure records and health surveillance are the expected controls, and most jurisdictions mandate them specifically for vinyl chloride rather than under general chemical rules.
Flammability: an extremely wide flammable range of 3.6% to 33% in air, a flash point of −78 °C and vapour about twice as dense as air. A release will find an ignition source readily and will travel at low level to do so.
Pressure: handled as a liquefied gas at roughly 3.4 bar at ambient. Vessel and hose integrity, relief sizing and the consequences of a liquid release flashing to vapour all need to be designed for, not assumed.
Peroxide formation and polymerisation: oxygen ingress produces peroxides that initiate polymerisation. In a pressure vessel, a runaway polymerisation is a rupture scenario. Air exclusion and inhibitor management are safety controls, not quality controls.
PPE minimum: appropriate to a closed system with emergency response equipment available — supplied-air respiratory protection for any breach scenario, chemical protective clothing, and cold-burn protection for liquid contact. Routine work should not require respiratory protection, and if it does, the containment has failed.
Consult the full SDS, the applicable national carcinogen regulations and the producer's handling guidance before any use. This is not a product to take on without the surveillance and monitoring regime already in place.
Frequently Asked Questions
Technical and commercial questions about Vinyl Chloride Monomer (VCM) sourcing and specifications.
What is VCM used for?
More than 98% goes to polyvinyl chloride. Within that, rigid PVC dominates — pipe, fittings, window profile, cladding and rainwater goods for construction — followed by flexible plasticised PVC for cable insulation, flooring, hose, coated fabric and roofing membrane. Medical PVC for blood bags and IV sets is a smaller but demanding segment. The remaining couple of percent goes into vinyl chloride copolymers with vinyl acetate or vinylidene chloride.
Why is vinyl chloride regulated so much more tightly than other monomers?
Because the harm was demonstrated in people, not inferred from animals. In the early 1970s, clusters of hepatic angiosarcoma — a liver cancer so rare that a handful of cases in one workforce was unmistakable — were identified among PVC polymerisation workers. That evidence led directly to vinyl chloride being classified as a human carcinogen and to occupational limits being cut to around 1 ppm, which is one to three orders of magnitude below the limits applied to most industrial solvents. The regulatory regime that followed, with mandatory monitoring, exposure records and health surveillance, became a template for how confirmed carcinogens are handled generally.
How is VCM stored and transported?
As a liquefied gas, never as an atmospheric liquid. It boils at −13.4 °C, so it is held either under its own vapour pressure of about 3.4 bar at ambient temperature, or refrigerated below its boiling point at near-atmospheric pressure. Transport is by pressurised or refrigerated ISO tank, rail tank car, or gas carrier for seaborne cargoes. Every transfer is closed with vapour return, and sampling is done through closed-loop systems. A receiving facility needs pressure-rated storage, relief routing, atmospheric monitoring and trained operators in place before the first delivery.
Why does acetylene content matter in the VCM specification?
For two separate reasons. In the polymerisation, acetylene acts as a chain transfer agent and interferes with molecular weight control, giving inconsistent PVC. More seriously, acetylene in contact with copper or copper alloys forms copper acetylide, which is shock-sensitive and can detonate. That is why the specification holds acetylene to a couple of parts per million and why copper is excluded from the wetted path throughout VCM service — a materials-of-construction requirement that is easy to violate accidentally with a brass fitting.
What is the balanced ethylene process?
It is the standard route to VCM, and the balance in the name refers to chlorine. Half the ethylene feed is chlorinated directly with chlorine to make 1,2-dichloroethane. The dichloroethane is then cracked thermally at around 500 °C into vinyl chloride and hydrogen chloride. That hydrogen chloride would be an awkward by-product, so the other half of the ethylene is reacted with it and oxygen in an oxychlorination reactor, producing more dichloroethane. The result is that chlorine enters the process once, leaves in the product, and there is no net hydrogen chloride to sell or dispose of.
What documentation does Chelora provide?
Every shipment includes a Certificate of Analysis covering purity, acetylene, 1,3-butadiene, acetaldehyde, hydrogen chloride, water, iron, non-volatile residue, high-boiling chlorinated compounds, dichloroethane and alkalinity; a Safety Data Sheet to GHS and REACH format; UN 1086 Class 2.1 dangerous goods documentation declared as stabilized; the carcinogen communication and downstream user information that REACH and equivalent regimes require; an origin certificate; and destination-market certificates including any import licensing for controlled carcinogens.
Request a quote or specification sheet
Talk to Chelora's sourcing team about Vinyl Chloride Monomer (VCM) grade, volume, logistics, documentation, and lead times. We respond within one business day.
