Isobutyric acid
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| Names | |
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| IUPAC name
2-Methylpropanoic acid
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| Other names
Isobutyric acid
2-Methylpropionic acid Valerianic acid | |
| Identifiers | |
3D model (JSmol)
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| ECHA InfoCard | 100.001.087 |
CompTox Dashboard (EPA)
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| Properties | |
| C4H8O2 | |
| Molar mass | 88.11 g/mol |
| Density | 0.9697 g/cm3 at 0 °C |
| Melting point | −47 °C (−53 °F; 226 K) |
| Boiling point | 155 °C (311 °F; 428 K) |
| Acidity (pKa) | 4.84 at 20 °C |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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 isobutanol with potassium dichromate and sulfuric acid,[2] 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.
References
- ^ Merck Index, 11th Edition, 5039
- ^ I. Pierre and E. Puchot (1873). "New Studies on Valerianic Acid and its Preparation on a Large Scale". Ann. de chim. et de phys. 28: 366.
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press. {{cite encyclopedia}}: Missing or empty |title= (help)
