Isobutyric acid
| Isobutyric acid[1] | |
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2-Methylpropanoic acid |
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Other names
Isobutyric acid |
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| Identifiers | |
| CAS number | 79-31-2  |
| ChemSpider | 6341 |
| UNII | 8LL210O1U0 |
| DrugBank | DB04305 |
| KEGG | C02632 |
| ChEBI | CHEBI:16135 |
| ChEMBL | CHEMBL108778 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C4H8O2 |
| Molar mass | 88.11 g/mol |
| Density | 0.9697 g/cm3 at 0 °C |
| Melting point |
-47 °C, 226 K, -53 °F |
| Boiling point |
155 °C, 428 K, 311 °F |
| Acidity (pKa) | 4.86[2] |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox 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.
[edit] Production
Isobutyric acid may be artificially prepared by the hydrolysis of isobutyronitrile with alkalis, by the oxidation of isobutanol with potassium dichromate and sulfuric acid,[3] 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). 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] Biological production
Isobutyric acid can also be manufactured commercially using engineered bacteria using a sugar feedstock.[4]
Isobutyric acid is a retained trivial name under the IUPAC rules.[5]
[edit] References
- ^ Merck Index, 11th Edition, 5039
- ^ Bjerrum, J., et al. Stability Constants, Chemical Society, London, 1958.
- ^ 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.
- ^ "Biological pathways to produce methacrylate". http://www.license.umn.edu/Products/Biological-Pathways-Produce-Isobutyric-Acid-Using-Renewable-Resources__20110077.aspx.
- ^ IUPAC, the Blue Book; Oxford: Blackwell Science (1993). ISBN 0-632-03488-2. Online edition: "Recommendation R-R-9.1.".
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.
