N-Butyl alcohol, also known as 1-butanol or n-butanol (CAS 71-36-3), is a four-carbon primary alcohol with extensive industrial applications. It is a colorless liquid with a characteristic alcoholic odor, produced mainly by the oxo synthesis from propylene or by fermentation routes. This article covers its physical and chemical properties, its major industrial uses, quality grades, and the safety measures required for handling this flammable solvent.
What Is N-Butyl Alcohol?
N-Butyl alcohol is a straight-chain primary alcohol with the molecular formula C4H10O and a molecular weight of 74.12 g/mol. It is miscible with most organic solvents and partially soluble in water. Because it combines moderate polarity with a relatively slow evaporation rate, it is a versatile solvent and chemical intermediate. Industrial n-butanol is produced on a large scale and serves as a building block for many downstream chemicals.
Key Physical and Chemical Properties
| Property | Typical Value |
|---|---|
| Molecular formula | C4H10O |
| Molecular weight | 74.12 g/mol |
| Appearance | Colorless liquid |
| Boiling point | About 117.7 °C |
| Melting point | About -89.8 °C |
| Density (20 °C) | About 0.81 g/cm3 |
| Flash point (closed cup) | About 35 °C |
| Solubility in water | About 7.7 g per 100 mL at 20 °C |
| Odor | Characteristic alcoholic, slightly sweet odor |
Major Industrial Applications
N-Butyl alcohol has a broad range of industrial uses, mainly in the following areas:
Solvent applications: Because of its excellent solubility and balanced evaporation rate, n-butanol is a key solvent in paints, coatings, printing inks and cleaning agents, effectively dissolving resins, oils and other film-forming materials.
Chemical raw material: It is used to synthesize butyl acetate, a widely used paint and coating thinner; dibutyl phthalate (DBP) and other phthalate plasticizers; and butyl acrylate for acrylic polymers.
Glycol ether production: N-butanol reacts with ethylene oxide to produce ethylene glycol butyl ethers, which are important solvents in water-based coatings and cleaners.
Plastics and resins: It participates in the production of acrylic esters and other monomers that improve the flexibility and durability of polymer materials.
Pharmaceuticals and fragrances: It serves as a solvent or intermediate in drug synthesis and is used in the manufacture of flavor and fragrance compounds.
Fuels and energy: N-butanol can be used as a biofuel additive to improve gasoline octane rating and acts as an extractant in biodiesel production.
Other applications: It is used as an auxiliary agent or reaction medium in the textile, pesticide and adhesive industries.
Quality Grades and Selection Considerations
Industrial n-butanol is available in different grades, typically with purity of 99.0% or higher. The quality of the product is usually verified against national standards such as GB/T 6027 for industrial n-butanol, which specifies limits on water content, acidity, distillation range and appearance. When selecting a grade, buyers should consider the application: solvent and extraction uses generally accept standard industrial grade, while pharmaceutical and fragrance applications may require higher purity and tighter quality control. It is also important to check the certificate of analysis, packaging integrity and supply reliability.
Safety, Storage and Transport
N-Butyl alcohol is a flammable liquid with a flash point of about 35 °C. It should be stored in a cool, dry, well-ventilated area away from ignition sources, open flames and strong oxidizers. Containers must be grounded during transfer to prevent static discharge. Vapors can form flammable mixtures with air, and prolonged exposure to high vapor concentrations may cause irritation of the eyes, nose and throat, as well as drowsiness. Appropriate personal protective equipment includes chemical-resistant gloves, safety goggles and protective clothing. In transport, n-butanol is regulated as a flammable liquid and must be carried in approved packaging with the correct hazard labeling.
Frequently Asked Questions
What are the industrial uses of n-butyl alcohol? N-Butyl alcohol is used as a solvent in paints, coatings, inks and cleaners, and as a raw material for butyl acetate, plasticizers, butyl acrylate, glycol ethers, pharmaceuticals, fragrances and biofuel additives.
Is n-butyl alcohol the same as 1-butanol? Yes. N-Butyl alcohol and 1-butanol are different names for the same straight-chain primary alcohol with CAS number 71-36-3.
Why is n-butanol used in coatings? Its balanced evaporation rate, good solvency for resins and low surface tension improve flow, leveling and film formation in solvent-based and water-based coating formulations.
Is n-butyl alcohol flammable? Yes. It has a flash point of about 35 °C and forms flammable vapor-air mixtures, so it must be kept away from ignition sources and stored with proper ventilation.
What is butyl acetate made from? Butyl acetate is produced by esterification of n-butanol with acetic acid, and it is widely used as a solvent and thinner in paints and coatings.
What personal protective equipment is needed when handling n-butanol? Chemical-resistant gloves, safety goggles, protective clothing and, where vapor concentrations are high, respiratory protection, together with good ventilation.
