Vinyl Acetate Monomer (VAM)
The monomer behind wood glue, emulsion paint and laminated windscreens. It is also the rare monomer that must be stored with oxygen present, because its inhibitor stops working without it.
Molecular Structure
What is Vinyl Acetate Monomer (VAM)?
Vinyl acetate is the ester of acetic acid with vinyl alcohol — in practice, an acetate group carrying a polymerisable vinyl double bond. That double bond is what the whole product does: it opens under free radical conditions and links into polyvinyl acetate, or copolymerises with ethylene, vinyl chloride or acrylic esters to give a family of soft, adhesive, film-forming polymers.
Modern production runs ethylene, acetic acid and oxygen together over a palladium-gold catalyst on silica in the vapour phase. The older acetylene route, adding acetic acid across acetylene over zinc acetate, survives where acetylene from coal is cheaper than ethylene, which is why it remains in use in parts of China.
Roughly two-thirds of output is polymerised directly into polyvinyl acetate emulsions and ethylene-vinyl acetate copolymers. Most of the rest is hydrolysed to polyvinyl alcohol, which in turn is the route to polyvinyl butyral — the interlayer that holds a shattered windscreen together.
VAM is inhibited with hydroquinone, and hydroquinone only works in the presence of dissolved oxygen. Blanketing a VAM tank with pure nitrogen, which is correct practice for most monomers, disables the inhibitor and can allow an uncontrolled exothermic polymerisation. Storage requires air or a controlled oxygen content in the vapour space.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
An acetate ester carrying a vinyl group. The ester end is unreactive under polymerisation conditions and stays intact in the polymer backbone as a pendant group; the vinyl double bond is what opens and links, and what has to be kept from doing so in storage.
Skeletal structure — acetate ester with a polymerisable vinyl group
Structural Identity
- IUPAC NameEthenyl acetate
- Common namesVAM, vinyl acetate, VA
- Molecular FormulaC₄H₆O₂
- Molecular Weight86.09 g/mol
- Functional groupsVinyl double bond, acetate ester
- ReactivityFree radical polymerisation and copolymerisation
- InhibitorHydroquinone — requires dissolved oxygen
- Made fromEthylene + acetic acid + O₂ over Pd/Au
- Legacy routeAcetylene + acetic acid over zinc acetate
- CAS Number108-05-4
- InChI KeyXTXRWKRVRITETP-UHFFFAOYSA-N
Product Specifications
Chelora supplies Vinyl Acetate Monomer (VAM) in standard and custom grades. Contact us for specification sheets tailored to your process.
| Chemical name | Vinyl acetate monomer |
|---|---|
| CAS Number | 108-05-4 |
| Molecular formula | C₄H₆O₂ |
| Molecular weight | 86.09 g/mol |
| Purity (min) | ≥ 99.90 wt% |
| Hydroquinone inhibitor | 3 – 5 ppm wt (low) or 12 – 17 ppm wt (standard) |
| Acetaldehyde (max) | ≤ 50 ppm wt |
| Acetic acid (max) | ≤ 50 ppm wt |
| Methyl acetate (max) | ≤ 200 ppm wt |
| Water (max) | ≤ 0.040 wt% |
| Colour (max) | ≤ 10 Pt-Co (Hazen) |
| Non-volatile residue (max) | ≤ 0.010 wt% |
| Distillation range | 72 – 73 °C |
| Specific gravity | 0.930 – 0.935 at 20/20 °C |
| Acidity as acetic acid (max) | ≤ 0.005 wt% |
| Suspended matter | Free of suspended matter |
| Polymer content | Nil |
| Flash point | −8 °C (closed cup) |
| Autoignition temperature | 402 °C |
| Flammable limits | 2.6 – 13.4% v/v in air |
| Transport classification | UN 1301, Class 3, PG II, stabilized |
Downstream Applications & Derivatives
Key derivative chains and industrial uses of Vinyl Acetate Monomer (VAM).
PVAc Adhesives
Polyvinyl acetate emulsions are the standard wood glue and the binder in paper, packaging and bookbinding adhesives — low odour, water-based and easy to formulate.
Emulsion Paints
Vinyl acetate-ethylene and vinyl acetate-acrylic copolymer emulsions as binders in interior and exterior architectural coatings, and in construction mortars and tile adhesives.
Polyvinyl Butyral
Hydrolysis to polyvinyl alcohol and reaction with butyraldehyde gives PVB — the tough, adhesive interlayer in laminated windscreens and architectural safety glass.
EVA Copolymers
Ethylene vinyl acetate for flexible film, footwear foam, hot melt adhesives, cable compounds and the encapsulant layer in crystalline silicon solar modules.
Polyvinyl Alcohol
PVAc hydrolysed to PVOH — a water-soluble polymer used as a textile sizing agent, paper coating, emulsion stabiliser and the film in detergent pods.
EVOH Barrier Resin
Ethylene vinyl alcohol copolymer, made by hydrolysing EVA, gives one of the best oxygen barriers available in a melt-processable resin for multilayer food packaging.
Why source Vinyl Acetate Monomer (VAM) through Chelora Petrochem?
Verified Origin
Full origin certification and asset-backed supply chain documentation — no grey-market supply.
Grade Flexibility
Low-inhibitor and standard-inhibitor grades supplied. We certify the actual hydroquinone content on despatch, not a nominal figure, because your safe storage window depends on knowing it.
Full Documentation
CoA, SDS, UN 1301 transport documents, REACH compliance, and destination-market certificates with every shipment.
Logistics Support
Experienced in inhibited flammable monomer logistics — dedicated road tankers and ISO tanks with bonding, earthing and controlled vapour-space provision, plus drums and IBCs, for Indian and international delivery.
Storage & Handling Guidelines
Always refer to the full SDS before handling. The following is a summary of key requirements.
- Maintain oxygen in the vapour space. Hydroquinone inhibitor is only effective with dissolved oxygen present, so VAM is stored under air or under nitrogen with a controlled oxygen content — never under a pure nitrogen blanket, which is the correct practice for most other monomers and the wrong one here.
- Store cool and out of sunlight, ideally below 30 °C. Polymerisation rate rises steeply with temperature and inhibitor is consumed faster the warmer the tank runs.
- Test inhibitor level and monitor storage temperature on a defined schedule. Falling inhibitor or a rising tank temperature with no external cause are the two warning signs of an incipient polymerisation, and both are only useful if someone is actually looking.
- Observe the shelf life. VAM is not indefinitely stable in storage; rotate stock, record receipt dates, and re-test rather than assuming a long-held tank is still on specification.
- Exclude peroxides, strong oxidisers, strong acids and strong bases, and keep the material away from anything that could initiate free radicals.
- Treat every transfer as a static ignition hazard. Flash point is −8 °C, so ignitable vapour is present at all normal ambient temperatures — bond and earth all connections and avoid splash filling.
- Ventilate to keep vapour well below the lower flammable limit of 2.6%, and classify the area for electrical equipment.
- Keep water out. Water hydrolyses VAM slowly to acetaldehyde and acetic acid, both of which appear on the specification and both of which accelerate further degradation.
- Provide eyewash and safety showers, use non-sparking tools, and have a plan for what to do if a tank does begin to polymerise — including shortstop capability and the decision to evacuate.
Hazard Summary
Classification: Flam. Liq. 2 (H225), Carc. 2 (H351, suspected of causing cancer), STOT SE 3 (H335, respiratory irritation). VAM's carcinogenicity classification is based on respiratory tract effects at high inhalation exposure.
Runaway polymerisation is the defining process hazard: VAM polymerises exothermically once initiated, and in a bulk tank the reaction is self-accelerating because the heat released raises the rate further. The consequences include vessel overpressure and rupture. Inhibitor management, temperature monitoring and stock rotation are the controls, and none of them work without someone checking.
The inhibitor needs oxygen: hydroquinone requires dissolved oxygen to scavenge radicals. Applying a pure nitrogen blanket — normal good practice on most flammable liquids — removes that oxygen and disables the protection. This is the single most commonly misapplied piece of VAM handling knowledge and it is worth confirming explicitly with anyone who will operate the storage.
Flammability: a flash point of −8 °C means ignitable vapour at all ambient temperatures, with a flammable range from 2.6% to 13.4%. Vapour is heavier than air and accumulates at low level.
Health: irritating to the eyes, skin and respiratory tract. The odour is detectable well below harmful concentrations, which gives useful warning but should not be relied on as an exposure control since olfactory fatigue sets in.
Environmental: harmful to aquatic life. Contain releases; do not discharge to drains or surface water.
PPE minimum: chemical goggles, resistant gloves, antistatic clothing and footwear at transfer points, with respiratory protection where vapour concentrations cannot be controlled by ventilation.
Consult the full SDS and the producer's safe handling guidance for inhibitor management, exposure limits, spill containment and emergency response before any use.
Frequently Asked Questions
Technical and commercial questions about Vinyl Acetate Monomer (VAM) sourcing and specifications.
What is VAM used for?
Around two-thirds is polymerised into polyvinyl acetate emulsions for wood, paper and packaging adhesives, and into vinyl acetate-ethylene copolymer emulsions used as binders in emulsion paints, tile adhesives and construction mortars. Most of the remainder is hydrolysed to polyvinyl alcohol — which leads on to polyvinyl butyral for laminated safety glass, and to EVOH barrier resin — or copolymerised with ethylene to make EVA for film, footwear foam, hot melt adhesives and solar module encapsulant.
Why must VAM be stored with oxygen present rather than under nitrogen?
Because of how the inhibitor works. VAM is stabilised with hydroquinone, and hydroquinone scavenges free radicals only when dissolved oxygen is available to it — the two work as a pair. A pure nitrogen blanket strips the dissolved oxygen out of the liquid over time and leaves the hydroquinone unable to function, so the monomer is effectively uninhibited while the paperwork still says it is stabilised. Standard practice is therefore to store VAM under air, or under nitrogen with a deliberately controlled oxygen content in the vapour space. This runs against the instinct of anyone used to handling other flammable monomers, which is exactly why it causes incidents.
What happens if VAM begins to polymerise in storage?
The reaction is exothermic and self-accelerating: heat released raises the temperature, which raises the rate, which releases more heat. In a bulk tank this can progress to boiling, overpressure and vessel rupture, and the polymer left behind fouls the tank and lines beyond easy recovery. The warning signs are a rising tank temperature with no external explanation, and a falling inhibitor level on routine test. Both are detectable well before the situation becomes dangerous, provided monitoring is actually in place and someone reviews the readings.
What inhibitor levels are available and which should I buy?
Two grades are common: low-inhibitor VAM at roughly 3–5 ppm hydroquinone and standard at roughly 12–17 ppm. Low-inhibitor material suits polymerisers who feed it into reaction quickly and do not want to strip or overcome inhibitor at the front of the process. Standard inhibitor suits longer supply chains, warmer climates and anyone holding stock for a period. The trade-off is straightforward — more inhibitor means a longer safe storage window and more work to initiate polymerisation. Match the grade to how fast you will actually consume the material, not to how fast you plan to.
Why does the acetaldehyde specification matter?
Acetaldehyde is the main hydrolysis and degradation product of VAM, and it is both a symptom and a cause. Its presence indicates water ingress or thermal history in the supply chain, and it also acts as a chain transfer agent in the polymerisation, which caps molecular weight and changes emulsion properties. A rising acetaldehyde figure on incoming material is a good early indicator that the storage or transport chain has a problem, which is why it is worth testing on receipt rather than accepting the despatch certificate.
What documentation does Chelora provide?
Every shipment includes a Certificate of Analysis covering purity, hydroquinone inhibitor content as actually measured, acetaldehyde, acetic acid, methyl acetate, water, colour, non-volatile residue, distillation range and specific gravity; a Safety Data Sheet to GHS and REACH format; UN 1301 Class 3 dangerous goods documentation declared as stabilized; an origin certificate; and destination-market or food-contact certificates where the downstream application requires them.
Request a quote or specification sheet
Talk to Chelora's sourcing team about Vinyl Acetate Monomer (VAM) grade, volume, logistics, documentation, and lead times. We respond within one business day.
