Ethyl Acetate CAS 141-78-6

Introduction to Ethyl Acetate

Ethyl Acetate is a clear, highly volatile ester solvent. A polar ester group attaches to a short ethyl chain in the molecule. It dissolves many synthetic resins and natural polymers. Formulators use it mostly for surface coatings, gravure inks, and liquid-liquid extraction of active pharmaceutical ingredients.

Compared to acetone, Ethyl Acetate evaporates slower (roughly 4 on a butyl acetate=1 scale vs. 6 for acetone) and smells better, giving coatings more leveling time. The main trap on the factory floor is water ingress. If a drum is left open or poorly sealed, the liquid absorbs ambient humidity and slowly hydrolyzes into acetic acid and ethanol. The acid value goes up, ruining moisture-sensitive systems like two-component polyurethanes. Test moisture (Karl Fischer) and acid value before using old stock.

Key Features of Ethyl Acetate

• Fast evaporation: Evaporates quickly at room temperature, giving adhesives fast tack-free times and allowing higher press speeds in gravure printing.
• Broad solvency: The polar ester group easily dissolves nitrocellulose, acrylics, vinyls, and epoxies, acting as the main active solvent.
• Low toxicity: Exempt from many Hazardous Air Pollutant (HAP) rules, making it a top choice to replace toluene or MEK in compliant formulas.
• Azeotropic behavior: Forms an azeotrope with water and ethanol. Distillation columns use the trait to reach high purity, but the product needs careful drying afterward.

Ethyl Acetate Chemical & Physical Properties

Applications of Ethyl Acetate

Coatings and paints: Dissolves acrylic and alkyd resins, controlling the initial evaporation phase. It leaves the film quickly to prevent sagging, leaving slower solvents to handle leveling. Typical usage is 15–30% of the total solvent blend in wood and industrial topcoats.

Gravure and flexographic inks: Dissolves polyurethane and nitrocellulose binders. Fast evaporation ensures quick drying on non-porous substrates like PET and BOPP films at high press speeds. Formulators usually put 40–60% EtOAc in the blend to hit target speeds without blocking on the rewind roll.

Pharmaceutical extraction: Slightly water-miscible and low in toxicity, so plants use it for liquid-liquid extraction of active ingredients. It pulls polar to semi-polar compounds out of aqueous reaction mixtures. As a Class 3 solvent under ICH Q3C guidelines, residual limits are generally acceptable up to 5000 ppm.

Adhesives and sealants: Lowers the viscosity of neoprene and acrylic contact adhesives. The solvent flashes off right after application, giving immediate grab and green strength. Solvent-based contact cements often contain 50–70% Ethyl Acetate.

Storage & Safety Precautions for Ethyl Acetate

• Storage conditions: Keep in closed, grounded steel drums or IBC totes. Store in a cool, well-ventilated warehouse away from direct sunlight. Keep temperature below 35 °C (95 °F).
• Moisture control: Hydrolyzes slowly into acetic acid and ethanol when exposed to water. Keep drums tightly sealed when not in use. Never leave partially empty drums open in a humid shop.
• Incompatible materials: Keep away from strong oxidizers, strong alkalis, and strong acids. Mixing them accelerates hydrolysis or causes violent reactions.
• Flammability: Highly flammable liquid and vapor (Flash point -4 °C / 25 °F). Use explosion-proof equipment. Bond and ground containers during transfer to prevent static sparks.
• PPE & Spill: Wear splash goggles, nitrile gloves, and an organic vapor respirator in poorly ventilated areas. Contain spills with inert absorbents like sand or earth; never use combustible sawdust.
• Transport: UN 1173, Class 3 Flammable Liquid, Packing Group II.

Ethyl Acetate FAQ

Q: How does moisture in CAS 141-78-6 Ethyl Acetate affect two-component polyurethane coatings?

A: Water reacts with isocyanate in 2K PU, causing CO2 pinholes and tackiness. Keep moisture <0.05% (ASTM E1064). Downgrade wet drums.

Q: Why does Ethyl Acetate smell sour after sitting in an open drum for six months?

A: Sourness is acetic acid from moisture hydrolysis, which poisons catalysts. Reseal drums tightly. Reject sour batches (ASTM D1613) for sensitive uses.

Q: How should I blend Ethyl Acetate with Butyl Acetate for gravure printing inks?

A: EtOAc dries 3x faster. Use 40-60% to prevent blocking, plus 20-30% Butyl Acetate to solvate resin. Reduce EtOAc if high humidity causes film blushing.