Methyl Acetate Storage & Tank Compatibility

Storing Methyl Acetate? Start Here

Methyl acetate (C₃H₆O₂, CAS 79-20-9) is a clear, colorless ester solvent with a sweet, fruity odor, widely used as a fast-evaporating alternative to acetone in paints, coatings, adhesives, nail-care products and as a process solvent. With a boiling point near 57 C and a flash point of about -10 C, it is highly volatile and highly flammable, and its vapor readily forms ignitable mixtures with air. As a small ester molecule it is an aggressive solvent toward many plastics: it swells, softens and permeates polyethylene, which makes HDPE and crosslinked polyethylene tanks unsuitable for bulk storage. Engineers handling methyl acetate should plan for stainless steel, lined steel or fluoropolymer containment, robust vapor control, grounding and bonding, and tight closure to limit losses and exposure.

Is Methyl Acetate Compatible with Polyethylene (HDPE / XLPE) Tanks?

No. Methyl acetate is an ester solvent, and esters are a class that polyethylene does not resist well. Published chemical resistance charts for HDPE and crosslinked polyethylene rate ester solvents as not recommended: the solvent is absorbed into the polymer, causing swelling, softening, loss of mechanical strength and measurable permeation through the wall over time. Even where short-term contact appears acceptable, long-term storage leads to stress, weight gain and vapor loss through the tank wall. For these reasons HDPE and XLPE rotomolded tanks should not be used for methyl acetate storage. Select stainless steel (304 or 316), properly grounded carbon steel, or PTFE-lined vessels, and use PTFE or other ester-compatible gaskets and seals rather than FKM. If you are evaluating a blend or a dilute aqueous stream, confirm the specific formulation against the manufacturer resistance data before committing to any plastic.

Material compatibility at a glance

Methyl acetate is a fast-evaporating ester solvent that swells and permeates polyethylene, so HDPE and XLPE tanks are not suitable for storage. Specify stainless steel (304 or 316), suitably grounded carbon steel, or PTFE-lined equipment, and pair them with PTFE seals. Always design for a flammable, low-flash-point liquid.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Highly flammable (flash point about -10 C): keep away from heat, sparks, open flame and static; bond and ground all transfer equipment.
• Vapors are heavier than air and can travel to an ignition source and flash back; use explosion-proof electrical and adequate ventilation.
• Store in a cool, well-ventilated, fire-rated area away from oxidizers and strong bases; keep containers tightly closed.
• Avoid breathing vapor; overexposure can cause headache, drowsiness, dizziness and organ effects, including reports of optic-nerve injury.
• Wear chemical splash goggles and ester-resistant gloves; methyl acetate causes serious eye irritation.
• Have appropriate fire extinguishing media available (dry chemical, carbon dioxide, alcohol-resistant foam); do not use a straight water stream.

Common questions

Can I store methyl acetate in an HDPE or poly tank?

No. Methyl acetate is an ester solvent that swells, softens and permeates polyethylene. HDPE and XLPE tanks are rated not recommended for esters. Use stainless steel, lined steel, or PTFE-lined equipment instead.

What tank or vessel material is best for methyl acetate?

Stainless steel 304 or 316 is the preferred choice, with properly grounded carbon steel and PTFE-lined vessels also suitable. Pair them with PTFE seals; avoid FKM (Viton), which esters attack.

Is methyl acetate flammable?

Yes. It is highly flammable with a flash point near -10 C and a low boiling point of about 57 C, so it evaporates quickly and forms ignitable vapor. Handle it with grounding, bonding, and explosion-proof equipment.

What is the NFPA 704 rating for methyl acetate?

Per CAMEO Chemicals and the PubChem safety summary, methyl acetate is Health 1, Flammability 3, Instability 0, with no special hazard symbol.