What Is Normal Butanol?
Normal butanol, also called n-butanol or n-butyl alcohol, is the straight-chain C4 primary alcohol with the formula CH3CH2CH2CH2OH (C4H10O, molecular weight 74.12 g/mol). It is a colourless liquid of medium volatility with a characteristic banana-like odour. n-Butanol has limited miscibility in water (about 7.7 g per 100 mL at 20 °C) but dissolves readily in ethers, alcohols, glycols and hydrocarbons. It is flammable, with a closed-cup flash point of about 35 °C.
Main Uses of Normal Butanol
As a solvent
n-Butanol is extensively used in the coatings industry for lacquers, varnishes, enamels and acrylic paints. It improves film formation, flow and gloss, and prevents the whitish haze known as blushing in nitrocellulose lacquers. It is also a solvent in printing inks, cleaning formulations and textile dye systems.
As a chemical intermediate
The largest application of n-butanol is as a starting material for other chemicals:
Butyl acrylate - the biggest derivative, used to make acrylic polymers for paints, adhesives, textiles and sealants.
Butyl acetate - an important solvent with a fruity odour, used in coatings and inks.
Glycol ethers and plasticiser esters such as dibutyl phthalate (DBP), used to impart flexibility to plastics; DBP is subject to strict EU authorisation requirements.
Amino resins and other speciality intermediates.
Other applications
n-Butanol is also used in the manufacture of pharmaceuticals and herbicides, as an extraction solvent in mineral processing, and in rubber and cosmetic formulations.
Key Properties
| Property | Value |
|---|---|
| Molecular formula | C4H10O |
| CAS / EINECS | 71-36-3 / 200-751-6 |
| Boiling point | ≈117.7 °C |
| Melting point | ≈−89.8 °C |
| Density | ≈0.810 g/mL at 20 °C |
| Flash point (closed cup) | ≈35 °C |
| Auto-ignition temperature | ≈343 °C |
| UN number | 1120 (class 3, packing group III) |
How n-Butanol Is Produced
Most commercial n-butanol is made by the oxo process: propylene is hydroformylated to n-butyraldehyde, which is then hydrogenated to n-butanol. Fermentation routes (biobutanol) are also commercialised as renewable alternatives.
Safety and Buying
n-Butanol is classified as a flammable liquid (H226) and causes serious eye damage (H318), skin irritation (H315) and respiratory irritation (H335); it is harmful if swallowed (H302). It is transported under UN 1120, class 3, packing group III. Store in tightly closed containers in a cool, ventilated area away from ignition sources and oxidisers. When buying, specify the grade and purity, request the batch COA and SDS, and confirm the packaging format - typically 160 kg drums, 800 kg IBC totes or ISO tanks (about 12.8 MT, 16 MT and 18.5 MT per 20-foot container respectively).
Frequently Asked Questions
What is normal butanol used for? n-Butanol is used mainly as a coatings solvent and as an intermediate for butyl acrylate, butyl acetate, glycol ethers and plasticiser esters, with additional uses in pharmaceuticals, herbicides and extraction processes.
Is normal butanol the same as 1-butanol? Yes. Normal butanol, n-butanol and 1-butanol all refer to the straight-chain C4 alcohol, CAS 71-36-3.
Is n-butanol miscible with water? Only partially. n-Butanol dissolves in water to about 7.7 g/100 mL at 20 °C and, conversely, absorbs water; it is not fully miscible like the lower alcohols.
What is the flash point of n-butanol? The closed-cup flash point is about 35 °C, which places n-butanol in the flammable liquid class (UN 1120, packing group III).
What are the main derivatives of n-butanol? Butyl acrylate is the largest derivative, followed by butyl acetate, glycol ethers and phthalate plasticiser esters.
How is n-butanol produced? Predominantly by the oxo process from propylene via n-butyraldehyde hydrogenation; renewable fermentation routes are also available.