2-Methylbutanoic acid

2-Methylbutanoic acid
Names
	Preferred IUPAC name 2-Methylbutanoic acid
	Other names 2-Methylbutyric acid; Methylethylacetic acid
Identifiers
CAS Number	R/S: 116-53-0 ; R: 32231-50-8 ; S: 1730-91-2 ;
3D model (JSmol)	R/S: Interactive image;
Beilstein Reference	1098537
ChEBI	R/S: CHEBI:37070; R: CHEBI:45525; S: CHEBI:38655;
ChEMBL	R/S: ChEMBL1160012;
ChemSpider	R/S: 8012 ; R: 5323416; S: 395556;
ECHA InfoCard	100.003.769
EC Number	R/S: 204-145-2;
KEGG	R/S: C18319;
PubChem CID	R/S: 8314; R: 6950479; S: 448893;
UNII	R/S: PX7ZNN5GXK ; S: 5N31513I0N ;
CompTox Dashboard (EPA)	R/S: DTXSID5021621;
	InChI R/S: InChI=1S/C5H10O2/c1-3-4(2)5(6)7/h4H,3H2,1-2H3,(H,6,7) Key: WLAMNBDJUVNPJU-UHFFFAOYSA-N; R: Key: WLAMNBDJUVNPJU-SCSAIBSYSA-N; S: Key: WLAMNBDJUVNPJU-BYPYZUCNSA-N;
	SMILES R/S: CCC(C)C(=O)O;
Properties
Chemical formula	C5H10O2
Appearance	Clear colorless liquid
Density	0.94 g/cm3 (20 °C)
Melting point	−90 °C (−130 °F; 183 K)
Boiling point	176 °C (349 °F; 449 K)
log P	1.18
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H312, H314
Precautionary statements	P260, P264, P270, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P363, P405, P501
Flash point	83 °C (181 °F; 356 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

2-Methylbutanoic acid, also known as 2-methylbutyric acid is a branched-chain alkyl carboxylic acid with the chemical formula CH₃CH₂CH(CH₃)CO₂H, classified as a short-chain fatty acid. It exists in two enantiomeric forms, (R)- and (S)-2-methylbutanoic acid. (R)-2-methylbutanoic acid occurs naturally in cocoa beans and (S)-2-methylbutanoic occurs in many fruits such as apples and apricots,^[2]^[3] as well as in the scent of the orchid Luisia curtisii.^[4]

^ ^a ^b Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
^ Rettinger, Klaus; Burschka, Christian; Scheeben, Peter; Fuchs, Heike; Mosandl, Armin (1991). "Chiral 2-alkylbranched acids, esters and alcohols. Preparation and stereospecific flavour evaluation" (PDF). Tetrahedron: Asymmetry. 2 (10): 965–968. doi:10.1016/S0957-4166(00)86137-6.
^ Karl A. D. Swift (1999). Current Topics in Flavours and Fragrances: Towards a New Millennium of Discovery. Springer. p. 52. ISBN 0-7514-0490-X.
^ Genera Orchidacearum Vol 6, Ed. Alec M. Pridgeon et al., p. 207 (LUISIA).

[GESTIS-1] Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health

[Tet-2] Rettinger, Klaus; Burschka, Christian; Scheeben, Peter; Fuchs, Heike; Mosandl, Armin (1991). "Chiral 2-alkylbranched acids, esters and alcohols. Preparation and stereospecific flavour evaluation" (PDF). Tetrahedron: Asymmetry. 2 (10): 965–968. doi:10.1016/S0957-4166(00)86137-6.

[Karl_A._D._Swift-3] Karl A. D. Swift (1999). Current Topics in Flavours and Fragrances: Towards a New Millennium of Discovery. Springer. p. 52. ISBN 0-7514-0490-X.

[4] Genera Orchidacearum Vol 6, Ed. Alec M. Pridgeon et al., p. 207 (LUISIA).

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