Butyl acetate (CAS: 123-86-4) is a versatile, colorless ester solvent with a characteristic fruity odor, widely recognized for its moderate evaporation rate and high solvency power. It serves as a critical industrial chemical, with the paint and coatings sector consuming up to 90% of global production, while also finding essential applications in adhesives, printing inks, pharmaceuticals, and flavorings. This guide covers its chemical properties, production process, industrial applications, and how it compares to alternative solvents.
What Is Butyl Acetate?
Butyl acetate is an organic ester synthesized from acetic acid and n-butanol, functioning primarily as a high-performance solvent in industrial formulations. Its chemical formula is C₆H₁₂O₂, and it is identified by the CAS number 123-86-4. The molecule’s structure provides a balanced polarity that makes it highly effective at dissolving resins, nitrocellulose, and various polymers without reacting with them. It appears as a clear, colorless liquid with a sweet, fruity aroma reminiscent of pears and bananas.
Physical and Chemical Properties
The performance of butyl acetate in industrial applications is defined by specific, quantifiable physical parameters. These properties determine its evaporation profile, solubility behavior, and compatibility with other chemical systems.
| Property | Value |
|---|---|
| Chemical Formula | C₆H₁₂O₂ |
| CAS Number | 123-86-4 |
| Molecular Mass | 116.16 g/mol |
| Boiling Point | 126.1°C (259.7°F) |
| Melting Point | -78°C (-108°F) |
| Flash Point | 22°C (72°F) |
| Density (20°C) | 0.8825 g/cm³ |
| Water Solubility (20°C) | 0.68 g/100 mL |
| Vapour Pressure (20°C) | 10 mmHg |
| Industrial Purity | ≥99.0% |
| Evaporation Rate (n-BuAc=1) | 1.0 (reference) |
How Is Butyl Acetate Produced?
Industrial-grade butyl acetate is manufactured through the esterification of acetic acid with n-butanol, utilizing sulfuric acid (H₂SO₄) or ion-exchange resins as catalysts. The reaction is conducted at controlled temperatures between 100°C and 110°C to optimize yield and purity. The crude product is then distilled and purified to achieve the ≥99.0% purity standard required for industrial applications. When an isomer of butanol is used (e.g., isobutanol or sec-butanol), the corresponding isomer of butyl acetate is produced instead.
What Is Butyl Acetate Used For?
Butyl acetate is primarily utilized as a solvent in paints and coatings, which accounts for the vast majority of its global consumption. Its moderate evaporation rate prevents defects like blushing or orange peel, making it indispensable in high-quality finishing. Beyond coatings, it serves as a critical component in adhesives, inks, and specialty chemical formulations across multiple industries.
| Industry Sector | Primary Application | Key Function |
|---|---|---|
| Paints & Coatings | Lacquers, automotive finishes | Resin solvent, leveling agent |
| Adhesives | Synthetic rubber cements | Solvent carrier, viscosity control |
| Printing Inks | Flexographic & gravure inks | Ink dissolution, drying rate control |
| Automotive | OEM & refinish coatings | Durable glossy finish, fast drying |
| Pharmaceuticals | Tablet coatings, extraction | Film-forming solvent, purification agent |
| Food & Cosmetics | Flavorings, nail polishes | Fragrance carrier, fast-evaporating solvent |
| Leather Processing | Surface finishing | Topcoat solvent, tanning agent |
| Cleaning Products | Industrial degreasers | Oil, wax, and grease dissolution |
Butyl Acetate vs Common Solvents
Formulators select butyl acetate over alternatives based on specific performance metrics. The table below compares n-butyl acetate with ethyl acetate and toluene across key parameters to help procurement professionals and chemists make informed decisions.
| Parameter | n-Butyl Acetate | Ethyl Acetate | Toluene |
|---|---|---|---|
| Boiling Point | 126.1°C | 77.1°C | 110.6°C |
| Flash Point | 22°C | -4°C | 4.4°C |
| Evaporation Rate (n-BuAc=1) | 1.0 | 3.3 | 1.8 |
| Water Solubility | 0.68 g/100 mL | 8.7 g/100 mL | 0.05 g/100 mL |
| NFPA Flammability | 3 | 3 | 3 |
| NFPA Health Rating | 2 | 1 | 2 |
Safety and Handling
Butyl acetate carries an NFPA flammability rating of 3 and a health rating of 2, requiring strict adherence to safety protocols during handling and storage. With a flash point of just 22°C, it is classified as a flammable liquid and must be stored away from ignition sources in well-ventilated areas. Its vapors are heavier than air and can travel to ignition sources, forming explosive mixtures. Proper personal protective equipment (PPE), including chemical-resistant gloves and safety goggles, is mandatory during handling. Storage should be in tightly sealed containers made of stainless steel, aluminum, or carbon steel, kept in cool, dry facilities away from strong oxidizing agents.
Conclusion
Butyl acetate is a foundational industrial solvent whose balanced physical properties—moderate evaporation rate, high solvency power, and broad compatibility—make it irreplaceable in high-performance coatings, adhesives, and specialty chemical formulations. Understanding its quantified characteristics, safety parameters, and performance advantages over alternative solvents is essential for formulators and procurement professionals to optimize manufacturing processes and ensure regulatory compliance. As the paint and coatings industry continues to account for approximately 90% of global consumption, butyl acetate remains one of the most important ester solvents in the industrial chemical market.
