Isobutyric acid

Isobutyric acid^[1]
Names
	Preferred IUPAC name 2-Methylpropanoic acid
	Other names Isobutyric acid; 2-Methylpropionic acid; Isobutanoic acid
Identifiers
CAS Number	79-31-2 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:16135 ;
ChEMBL	ChEMBL108778 ;
ChemSpider	6341 ;
DrugBank	DB02531 ;
ECHA InfoCard	100.001.087
EC Number	201-195-7;
IUPHAR/BPS	1060;
KEGG	C02632 ;
PubChem CID	6590;
RTECS number	NQ4375000;
UNII	8LL210O1U0 ;
UN number	2529
CompTox Dashboard (EPA)	DTXSID4021636 ;
	InChI InChI=1S/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6) Key: KQNPFQTWMSNSAP-UHFFFAOYSA-N ; 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 (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)	−56.06×10−6 cm3/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H302, H311, H314
Precautionary statements	P210, P280, P301+P312+P330, P303+P361+P353, P305+P351+P338+P310
NFPA 704 (fire diamond)	3 2 0
Flash point	55 °C (131 °F; 328 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Isobutyric acid, also known as 2-methylpropanoic acid or isobutanoic acid, is a carboxylic acid with structural formula (CH₃)₂CHCOOH. It is an isomer of butyric acid. It is classified as a short-chain fatty acid. Deprotonation or esterification gives derivatives called isobutyrates.

Isobutyric acid is a colorless liquid with a somewhat unpleasant odor. It is soluble in water and organic solvents. It is found naturally in carobs (Ceratonia siliqua), in vanilla, and in the root of Arnica dulcis, and as an ethyl ester in croton oil.^[6]

^ Merck Index, 11th Edition, 5039
^ "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 748. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
^ Bjerrum, J.; et al. (1958). Stability Constants. London: Chemical Society.
^ Sigma-Aldrich. "Isobutyric acid". Retrieved 2020-10-03.
^ "NFPA Hazard Classification". Retrieved 2020-10-03.
^ Chisholm, Hugh, ed. (1911). "Butyric Acid" . Encyclopædia Britannica. Vol. 4 (11th ed.). Cambridge University Press. p. 892.

[1] Merck Index, 11th Edition, 5039

[iupac2013-2] "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 748. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.

[3] Bjerrum, J.; et al. (1958). Stability Constants. London: Chemical Society.

[sigma-4] Sigma-Aldrich. "Isobutyric acid". Retrieved 2020-10-03.

[5] "NFPA Hazard Classification". Retrieved 2020-10-03.

[EB1911-6] Chisholm, Hugh, ed. (1911). "Butyric Acid" . Encyclopædia Britannica. Vol. 4 (11th ed.). Cambridge University Press. p. 892.

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