Isobutyric acid
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| Isobutyric acid | |
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| Chemical name | 2-Methylpropanoic acid |
| Other names | Isobutyric acid 2-Methylpropionic acid |
| Chemical formula | C4H8O2 |
| Molecular mass | 88.10 g/mol |
| CAS number | [79-31-2] |
| Density | 0.9697 g/cm3 at 0 °C |
| Melting point | -47 °C |
| Boiling point | 155 °C |
| SMILES | CC(C)C(=O)O |
| Disclaimer and references | |
Isobutyric acid, also known as 2-methylpropanoic acid, is a carboxylic acid with structural formula (CH3)2-CH-COOH. It is found in the free state in carobs (Ceratonia siliqua) and in the root of Arnica dulcis, and as an ethyl ester in croton oil.
Isobutyric acid is an isomer of n-butyric acid; they have the same chemical formula C4H8 O2 but a different structure.
Isobutyric acid may be artificially prepared by the hydrolysis of isobutyronitrile with alkalis, by the oxidation of isobutyl alcohol with potassium dichromate and sulfuric acid,[1] or by the action of sodium amalgam on methacrylic acid. It is a liquid of somewhat unpleasant smell, boiling at 155 °C. Its specific gravity is 0.9697 (0 °C) and pKa is 4.84 (20 °C). Heated with chromic acid solution to 140 °C, it gives carbon dioxide and acetone. Alkaline potassium permanganate oxidizes it to α-hydroxyisobutyric acid, (CH3)2-C(OH)-COOH. Its salts are more soluble in water than those of butyric acid.
[edit] References
- ^ I. Pierre and E. Puchot, Ann. de chim. et de phys., 1873, 28, p. 366
- Merck Index, 11th Edition, 5039.
- This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.
