Iso Butyric Acid

Cas Number


Other Names

Isobutyl alcohol



2-methylpropyl alcohol


The formula



Isobutyric acid, also known as 2-methylpropanoic acid, is a carboxylic acid with structural formula (CH3)2CHCO2H. It is a colorless liquid with a somewhat unpleasant odor. It is soluble in water and organic solvents. Isobutyric acid is an isomer of n-butyric acid. Deprotonation or esterification of isobutyric acid gives derivatives called isobutyrates. Isobutyric acid is found in the free state in carobs (Ceratonia siliqua), in vanilla, and in the root of Arnica dulcis, and as an ethyl ester in croton oil.

Physical and Chemical Properties
Physical state and appearance Clear Colorless Liquid
Odor Pungent, like rancid butter
Molecular Weight 88.1g/mole
Boiling Point 154°C (309.2°F)
Critical Temperature 336.11°C (637°F)
Flash point 55°C
Melting Point -47°C (-52.6°F)
Specific Gravity 0.95 (Water = 1)
Water/Oil Dist. Coefficient The product is more soluble in oil; log (oil/water) = 0.
Dispersion Properties See solubility in water, diethyl ether
Isobutyric Acid 99
Specific Gravity @ 20 / 20 C 0.951
Water, % 0.1
Visual Colour, pcs 10

1. Isobutanol has a variety of technical and industrial applications

2. Feedstock in the manufacture of isobutyl acetate, which is used in the production of lacquer and similar coatings, and in the food industry as a flavouring agent

3. Precursor of derivative esters; isobutyl esters such as diisobutyl phthalate (DIBP) are used as plasticizer agents in plastics, rubbers, and other dispersions

4. Paint solvent

5. Varnish remover

6. Ink ingredient

7. Paint additive, to reduce viscosity, improve brush flow, and retard formation of oil residues (blush) on painted surfaces

8. Gasoline additive, to reduce carburetor icing

9. Automotive polish additive

10. Automotive paint cleaner additive

11. Chemical extractant in production of organic compounds

12. Mobile phase in thin layer chromatography

Isobutanol could possibly serve as an alternative to gasoline to fuel combustion engines and it is being produced by companies such as Gevo for this use in a joint venture with Cargill.A 1993 SAE technical paper addresses blending methanol, ethanol and isobutanol with unleaded gasoline for use as a motor fuel. A similar mixture is being used by Dyson Racing in the 2010 American LeMans Series. Gevo intends to acquire Agri-Energy's Luverne, Minnesota, ethanol production facility to retrofit it to produce commercial quantities of isobutanol for motor fuel.