Isobutyric acid is a colorless oily liquid with a pungent smell similar to butyric acid. Relative density 0.949 (20°C), melting point -47°C, boiling point 152~155°C, flash point (closed cup) 7Chemicalbook 6.67°C, refractive index 1.3930 (20°C). It is easily soluble in water and miscible with ethanol, ether, chloroform, etc. Isobutyric acid exists in a free state in rice, beans and the roots of Arnica montana.