Vinyl Chloride Monomer CAS 75-01-4

What is Vinyl Chloride Monomer?

Vinyl chloride monomer is the chlorinated ethylene derivative, C₂H₃Cl, a colourless gas at ambient that liquefies at −13.4 °C or under modest pressure, with a faintly sweet odour.

Essentially all of it goes to polyvinyl chloride. PVC is the third largest commodity polymer in the world, used in pipe, profile, cable, flooring and film.

VCM is made by cracking ethylene dichloride, which in turn comes from chlorinating or oxychlorinating ethylene, with the chlorine loop balanced inside the plant.

It is a confirmed human carcinogen, causally linked to angiosarcoma of the liver. That finding in the 1970s transformed occupational exposure practice across the chemical industry, and VCM handling remains among the most tightly controlled of any monomer.

Why Vinyl Chloride Monomer specifically

• A cheap chlorinated monomer. Chlorine contributes over half the weight of PVC, which keeps the polymer economical.
• Polymerises readily. Suspension, emulsion and bulk routes all work, giving the full range of PVC grades.
• Inherent flame resistance. The chlorine content gives PVC fire performance that hydrocarbon polymers cannot match.
• Integrated chlorine balance. Oxychlorination recycles HCl from cracking, which is what makes the whole chain work.

How Vinyl Chloride Monomer is Manufactured

VCM is made by cracking ethylene dichloride, with the balanced process recycling hydrogen chloride internally.

• Direct chlorination. Ethylene reacts with chlorine to ethylene dichloride over a ferric chloride catalyst.
• Oxychlorination. Ethylene, hydrogen chloride and oxygen react over a copper chloride catalyst to make additional EDC, consuming the HCl from cracking.
• EDC purification. The dichloride is distilled to remove chlorinated by-products that would foul the cracker.
• Thermal cracking. EDC is cracked at about 500 °C to VCM and hydrogen chloride.
• HCl recovery. The hydrogen chloride is returned to oxychlorination, closing the chlorine balance.
• Purification. VCM is distilled to 99.98% or better, with acetylene and iron controlled to very low levels.

Typical Commercial Specification

Figures below are representative of commercial polymerisation-grade VCM. Tell us your PVC process and we will advise on the limits you should specify.

Physical & Chemical Properties

Behaviour in the process

VCM's hazard profile and its odour threshold together define how it must be handled:

• No useful odour warning. The odour threshold is around 3000 ppm while the exposure limit is 1 ppm, so smell gives no protection. Instrumental detection is essential.
• Heavier than air. Escaped vapour accumulates in pits, sumps and low points.
• Polymerises with peroxides and light. Storage under nitrogen away from light and oxidisers is standard.
• Forms acetylides with copper. Copper and its alloys must be excluded from VCM service.

VCM and PVC Chain Alternatives

VCM is bought only by PVC producers with full containment capability. For everyone else, the polymer is the right purchase.

Stated plainly: unless you operate a PVC polymerisation plant with full carcinogen controls, buy PVC resin. VCM is one of the few products where the containment requirement, not the price, decides whether the purchase makes sense.

Industries We Supply Vinyl Chloride Monomer To

VCM goes to PVC producers and nowhere else in meaningful volume.

Where Vinyl Chloride Monomer is Used

Polyvinyl chloride accounts for essentially all VCM consumption.

In suspension PVC manufacture

VCM is suspended as droplets in water with a protective colloid and polymerised with an organic peroxide initiator at 50 to 70 °C. The reaction is strongly exothermic and conversion is stopped at 80 to 90%, after which residual monomer must be stripped to very low levels — single-digit ppm for medical and food grades — because residual VCM in the resin is a regulated health risk.

Residual monomer control

The 1974 discovery of angiosarcoma in VCM workers led to exposure limits falling by orders of magnitude and to closed, instrumented handling throughout the chain. Modern PVC plants strip residual monomer to parts per million in the resin, and the stripping section is as important to the plant's licence to operate as the reactor itself.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis, with acetylene and iron reported alongside purity because both affect polymer molecular weight and colour.

• VCM purity — by gas chromatography, the primary grade measure.
• Acetylene — reported in ppm because it acts as a chain transfer agent.
• Iron — measured because it catalyses degradation and causes colour in PVC.
• Water and hydrogen chloride — tested for corrosion and polymerisation reasons.
• Chlorinated impurities and butadiene — measured as the characteristic process residues.
• Non-volatile residue — confirming freedom from polymer and contamination.

Common Process Problems & Likely Causes

When VCM causes trouble, it is usually acetylene, iron, water or containment. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Standard packing. Dedicated pressurised ISO tank containers and pressure vessels; pipeline supply where available.
• Pressure and temperature. Stored as a liquefied gas under its own vapour pressure, about 340 kPa at 20 °C, with temperature monitoring.
• Nitrogen blanketing. Standard, with oxygen excluded to prevent peroxide formation and polymerisation.
• Material compatibility. Carbon steel and stainless steel. Copper, brass and aluminium must be excluded.
• Detection. Continuous instrumental monitoring is essential; the odour threshold is far above the exposure limit.
• Segregation. Keep apart from oxidisers, peroxides and acids.
• Shelf life. Indefinite in a sealed, dedicated, blanketed system.
• Transport classification. UN 1086, vinyl chloride stabilised, Class 2.1 flammable gas with carcinogen labelling requirements.

Hazards & Safe Handling

Vinyl chloride is a confirmed human carcinogen and a flammable liquefied gas with no useful odour warning. It is among the most tightly controlled monomers in industry, and for good reason.

• Carcinogenicity. Classified Category 1A carcinogen, causally linked to angiosarcoma of the liver. Exposure must be kept as low as technically achievable.
• Occupational exposure. Limits are very low, commonly 1 ppm as an 8-hour average with action levels below that. Medical surveillance is typically required.
• No odour warning. The odour threshold is around 3000 ppm against an exposure limit of 1 ppm. Instrumental detection is the only protection.
• Flammability. Flammable range of roughly 3.6 to 33% in air. Control ignition sources and bond all equipment.
• Heavy vapour. Escaped gas accumulates in pits and low points. Ventilate and monitor at low level.
• Cold burns. Liquid releases flash and freeze tissue on contact.
• PPE and detection. Closed transfer, fixed and personal gas detection, and supplied-air protection for any breach of containment.
• Environment. Harmful to aquatic life and a regulated air pollutant; vent only through approved systems.

Regulatory & Compliance Notes

VCM is among the most heavily regulated industrial chemicals, with dedicated occupational standards in most jurisdictions. The notes below are orientation rather than legal advice.

• GHS classification. Flammable gas Category 1, gas under pressure, carcinogenicity Category 1A and germ cell mutagenicity.
• Occupational exposure regulation. Dedicated vinyl chloride standards with very low limits, regulated areas, monitoring and medical surveillance apply in the US, EU and elsewhere.
• Residual monomer limits. PVC for food contact and medical use is subject to strict residual VCM limits, typically 1 ppm or lower.
• Dangerous goods transport. UN 1086, Class 2.1 with carcinogen labelling. ADR, IMDG, IATA and DOT rules apply to tank design and routing.
• Emissions regulation. VCM is a regulated hazardous air pollutant with fugitive emission monitoring requirements.
• REACH and inventories. Registered under EU REACH with harmonised classification as a Category 1A carcinogen.

We Supply Vinyl Chloride Monomer Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Vinyl Chloride Monomer from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, transport paperwork 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 where routing and cargo rules allow.
• Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and the transport declaration issued as a complete set.
• Flexible volumes. From a single pressurised ISO tank up to repeat bulk shipments on a supply contract.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying Vinyl Chloride Monomer from Chelora

We are an independent sourcing and supply partner. For VCM that means settling three things before anything is nominated: your demonstrated containment and detection capability, the acetylene and iron limits your polymerisation requires, and the pressurised logistics route into your system.

• Documentation on every lot. Batch-specific COA (purity, acetylene, iron, water), plus SDS and the full transport paperwork.
• Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
• Quantities. From a single pressurised ISO tank through to full bulk shipments on contract supply.
• Grade matching. Polymerisation-grade VCM to the acetylene, iron and water limits your PVC process requires.
• Inspection. Independent third-party inspection available at loading when the contract requires it.
• Related products. Polyvinyl Chloride, Dioctyl Phthalate, Dioctyl Terephthalate and other feedstocks alongside Vinyl Chloride Monomer from one supplier.

How ordering works

• Send the enquiry. Product, grade or purity, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing format and a sample COA, normally within one working day.
• Qualify the supply. For first orders or critical applications, we share the analysis and handling documentation so your technical and safety teams can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Allocation and QC. Material allocated and released against a batch-specific COA, with an independent inspection where the contract calls for it.
• Ship and document. Filled, labelled and loaded with the full export document set, and tracked through to arrival.

Related Products

Buyers of VCM generally source PVC chain products alongside it — PVC resin, plasticisers and stabilisers are commonly bought on the same programme.