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Isobutanol Isobutanol
Systematic name 2-Methyl-1-propanol
Other names Isobutyl alcohol, IBA,
2-methylpropyl alcohol
Molecular formula C4H10O
Molar mass 74.12 g/mol
Appearance Colorless liquid
CAS number [78-83-1]
Density and phase 0.802 g/cm³, liquid
Solubility in water Limited miscibility
In ethanol, ether
In acetone, toluene
Fully miscible
Melting point -108 °C (165 K)
Boiling point 108 °C (380 K)
Acidity (pKa) ?
Viscosity 3.95 centipoise at 20°C
Dipole moment ?
MSDS External MSDS
Main hazards Flammable
NFPA 704
NFPA 704.svg
Flash point 28 °C
R/S statement R: 10-20-22-36-37-38
S: 7-16-24/25-26
RTECS number NP9625000
Supplementary data page
Structure and
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related alcohols Isopropyl alcohol,
ethanol, 2-butanol
Other compounds acetone, propylene,

diisopropyl ether

Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
Infobox disclaimer and references

Isobutanol (IUPAC nomenclature: 2-methyl-propan-1-ol; also known as 2-methylpropyl alcohol, among other names) is a colorless, flammable, organic compound with a characteristic smell. Its isomers are 1-butanol, 2-butanol and tert-butanol. It is classified as an alcohol and as such it is widely used as a solvent in chemical reactions, as well as being a useful starting material for organic synthesis.

Isobutanol is produced naturally during the fermentation of carbohydrates. It may also be a by-product of the decay process of organic matter.


The main use of isobutanol is as starting material in the manufacture of isobutyl acetate, which is mostly used in the production of lacquer and similar coatings. Isobutyl acetate is also used in the food industry as flavouring agent.

Isobutanol is also used in the industrial synthesis of derivative esters. Isobutyl esters such as diisobutyl phthalate (DIBP) are used as plasticizer agents in plastics, rubbers and other dispersions.

Other applications of isobutanol include its use as a solvent in paint, varnish removers and inks. Its addition in small amounts into paints reduces their viscosity, improves brush flow, and retards the formation of oil residues (known as blush) on painted surfaces.

Minor uses include its inclusion as gasoline additive for spark-ignition engines where it helps to prevent carburettor icing, polishers and cleaners. It is used as chemical extractant in the production of organic compounds, and as mobile phase in thin layer chromatography.


Isobutanol is a volatile, flammable, liquid that should be stored and used in well-ventilated areas. It is moderately irritating to the skin and greatly irritating to the eyes, mucous membranes and respiratory tract. Exposure to high concentrations of its vapour can cause temporary narcosis.

Isobutanol is considered to be slightly toxic and it has been shown to cause liver damage in mice and humans. Ingestion may also lead to alcohol poisoning.


External links

de:2-Methyl-1-propanol it:2-metil-1-propanolo nl:2-methyl-1-propanol fi:Isobutanoli