Isobutyric acid

Isobutyric acid

Names
IUPAC name 2-Methylpropanoic acid
Other names Isobutyric acid 2-Methylpropionic acid Isobutanoic acid
Identifiers
CAS Number	79-31-2 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:16135 Y
ChemSpider	6341 Y
DrugBank	DB02531 N
ECHA InfoCard	100.001.087
IUPHAR/BPS	1060
KEGG	C02632 Y
UNII	8LL210O1U0 Y
InChI InChI=1S/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6) Y Key: KQNPFQTWMSNSAP-UHFFFAOYSA-N Y InChI=1/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6) Key: KQNPFQTWMSNSAP-UHFFFAOYAB
SMILES O=C(O)C(C)C
Properties
Chemical formula	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)	4.86
Magnetic susceptibility (χ)	-56.06x10−6 cm3/mol
Hazards
NFPA 704	2 1 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
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), in vanilla 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 C₄H₈O₂ 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, or by the action of sodium amalgam on methacrylic acid. Isobutyric acid is a liquid under common conditions with a somewhat unpleasant smell. It boils at 155 °C and has a specific gravity is 0.9697 (0 °C). When heated with a chromic acid solution to 140 °C, it decomposes to form 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.