Ethyl acetate, commonly abbreviated as EA, is one of the most important ester solvents in industrial chemistry. Knowing its CAS number, physical properties, and application range is essential for formulators, procurement teams, and laboratory professionals who work with solvents on a daily basis. This article covers the identity of ethyl acetate (CAS 141-78-6), its properties, main uses, and safe handling guidance.
What Is the CAS Number of Ethyl Acetate?
Ethyl acetate is registered under CAS number 141-78-6. Its chemical formula is C4H8O2, with the structural formula CH3COOC2H5, and its molecular weight is 88.11. The compound is also listed in the European inventory as EINECS 205-500-4. These identifiers are important for regulatory compliance, safety data sheet management, and customs documentation, because they uniquely and unambiguously identify the substance regardless of the name or trade designation used.
Ethyl acetate belongs to the ester family, formed by the reaction of ethanol with acetic acid. At room temperature it is a colorless, transparent liquid with a pleasant, fruity odor reminiscent of pears, and it evaporates readily, leaving no residue.
Physical and Chemical Properties of Ethyl Acetate
The following table summarizes the key properties of ethyl acetate:
| Property | Typical Value |
| CAS number | 141-78-6 |
| Chemical formula | C4H8O2 |
| Molecular weight | 88.11 |
| Appearance | Colorless transparent liquid |
| Boiling point | 77.1 °C |
| Melting point | -83.6 °C |
| Density at 20 °C | 0.902 g/cm3 |
| Flash point | -4 °C (closed cup) |
| Vapor pressure at 20 °C | 9.7 kPa |
Ethyl acetate is highly volatile and miscible with ethanol, diethyl ether, benzene, chloroform, and most oils. It has limited miscibility with water, dissolving to roughly 8% at room temperature while also absorbing some moisture from humid air. Absorbed water slowly hydrolyzes the ester, generating acetic acid and giving the solvent an acidic reaction over time, so moisture control matters during long-term storage. At low concentrations ethyl acetate has low acute toxicity, but at high concentrations its vapors can produce anesthetic effects, and the liquid is highly flammable.
Primary Uses of Ethyl Acetate Solvent
Ethyl acetate is used in a broad range of industries because of its strong solvency and fast evaporation:
Paints, coatings, and inks: EA dissolves nitrocellulose, acrylic resins, and many other film formers, giving smooth application and rapid drying in automotive paints, printing inks, and packaging coatings.
Adhesives and synthetic leather: It is a workhorse solvent in adhesive formulations and in the production of synthetic leather and coating pastes, where its balanced evaporation rate prevents defects such as blushing.
Pharmaceutical processing: As a Class 3 residual solvent with relatively low toxicity, ethyl acetate is widely used for extraction, crystallization, and purification of active pharmaceutical ingredients.
Flavors and fragrances: Because it is a naturally occurring ester, EA serves as a flavoring ingredient and as a carrier solvent for aroma compounds.
Laboratory and cleaning applications: EA is a common mobile phase in chromatography and a fast-evaporating solvent for precision cleaning of electronic and optical components.
Safety and Handling Considerations
Ethyl acetate is highly flammable, and its vapors can form explosive mixtures with air in the range of approximately 2.0-11.5% by volume. Safe handling requires the following measures:
Keep EA away from ignition sources, sparks, and hot surfaces, and ground all containers and transfer equipment to prevent static discharge.
Use local exhaust ventilation to keep vapor concentrations below occupational exposure limits, and avoid breathing high vapor concentrations, which can cause dizziness, headache, and anesthesia.
Wear chemical-resistant gloves and safety goggles, and avoid prolonged skin contact, which can defat the skin and cause irritation.
Store in tightly sealed containers made of compatible materials, in a cool, dry, well-ventilated area separated from strong oxidizers and acids.
Dispose of waste solvent in accordance with local environmental regulations; ethyl acetate waste is typically classified as flammable hazardous waste.
Quality Considerations for Industrial Use
When specifying ethyl acetate for a process, buyers should verify the purity grade against the intended application. Standard industrial grades typically assay at 99.0-99.9% by gas chromatography, with limits on water content, acidity as acetic acid, and color. Higher-purity grades are preferred for pharmaceutical and electronics applications. Certificates of analysis should state the assay method, batch number, and the applicable specification, and packaging should protect the solvent from moisture and contamination during transport and storage.
Frequently Asked Questions
What is the CAS number of ethyl acetate?
Ethyl acetate has the CAS number 141-78-6 and the EINECS number 205-500-4. These registry numbers identify the compound internationally for regulatory and documentation purposes.
Is ethyl acetate the same as acetone?
No. Ethyl acetate (C4H8O2) is an ester of ethanol and acetic acid, while acetone (C3H6O) is a ketone. They have different boiling points, solvency profiles, and regulatory classifications, although both are fast-evaporating solvents used in similar application areas such as coatings and cleaning.
Why does ethyl acetate smell fruity?
The fruity, pear-like odor comes from the ester functional group, which is formed when ethanol and acetic acid react. Many low-molecular-weight esters have pleasant fruit-like aromas, which is why ethyl acetate is used in flavorings and fragrances as well as in industrial applications.
Is ethyl acetate safe for human consumption?
Ethyl acetate is permitted as a food additive and flavoring substance in many jurisdictions when used within regulated limits, and it is also a Class 3 residual solvent in pharmaceuticals with relatively low toxicity. However, industrial-grade solvent must never be used in food or pharmaceutical products; only grades produced and certified for those applications should be used.
How should ethyl acetate be stored to prevent degradation?
Store EA in tightly sealed containers to exclude moisture, because absorbed water slowly hydrolyzes the ester into ethanol and acetic acid, increasing acidity. Storage areas should be cool, dry, well-ventilated, and fire-protected, and containers should be kept away from direct sunlight and strong oxidizing agents.
What is the difference between ethyl acetate and butyl acetate?
Butyl acetate (C6H12O2) has a longer alkyl chain, a higher boiling point of about 126 °C, and a slower evaporation rate than ethyl acetate. This makes butyl acetate better suited to high-solids coatings and printing inks that need longer open time, while ethyl acetate is preferred where fast drying is required.
