Caproic acid

Not to be confused with Caprylic acid or Capric acid.

Caproic acid, also known as hexanoic acid, is the carboxylic acid derived from hexane with the chemical formula CH₃(CH₂)₄COOH. It is a colorless oily liquid with a fatty, cheesy, waxy odor resembling that of goats^[1] or other barnyard animals. It is a fatty acid found naturally in various animal fats and oils, and is one of the chemicals that gives the decomposing fleshy seed coat of the ginkgo its characteristic unpleasant odor.^[3] It is also one of the components of vanilla and cheese. The primary use of caproic acid is in the manufacture of its esters for use as artificial flavors, and in the manufacture of hexyl derivatives, such as hexylphenols.^[1] Salts and esters of caproic acid are known as caproates or hexanoates. Several progestin medications are caproate esters, such as hydroxyprogesterone caproate and gestonorone caproate.

Caproic acid

Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name Hexanoic acid
Other names Hexoic acid; Hexylic acid; Butylacetic acid; Pentylformic acid; 1-Pentanecarboxylic acid; C6:0 (Lipid numbers)
Identifiers
CAS Number	142-62-1 Y
3D model (JSmol)	Interactive image
Beilstein Reference	773837
ChEBI	CHEBI:30776 Y
ChEMBL	ChEMBL14184 Y
ChemSpider	8552 Y
ECHA InfoCard	100.005.046
EC Number	205-550-7
Gmelin Reference	185066
KEGG	C01585 Y
PubChem CID	8892
UNII	1F8SN134MX Y
CompTox Dashboard (EPA)	DTXSID7021607
InChI InChI=1S/C6H12O2/c1-2-3-4-5-6(7)8/h2-5H2,1H3,(H,7,8) Y Key: FUZZWVXGSFPDMH-UHFFFAOYSA-N Y InChI=1/C6H12O2/c1-2-3-4-5-6(7)8/h2-5H2,1H3,(H,7,8) Key: FUZZWVXGSFPDMH-UHFFFAOYAY
SMILES CCCCCC(=O)O
Properties
Chemical formula	C6H12O2
Molar mass	116.160 g·mol−1
Appearance	Oily liquid[1]
Odor	goat-like
Density	0.929 g/cm3[2]
Melting point	−3.4 °C (25.9 °F; 269.8 K)[1]
Boiling point	205.8 °C (402.4 °F; 478.9 K)[1]
Solubility in water	1.082 g/100 mL[1]
Solubility	soluble in ethanol, ether
Acidity (pKa)	4.88
Magnetic susceptibility (χ)	−78.55·10−6 cm3/mol
Refractive index (nD)	1.4170
Viscosity	3.1 mP
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314
Precautionary statements	P260, P264, P280, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P361, P363, P405, P501
NFPA 704 (fire diamond)	3 1 0
Flash point	103 °C (217 °F; 376 K)[2]
Autoignition temperature	380 °C (716 °F; 653 K)
Explosive limits	1.3-9.3%
Lethal dose or concentration (LD, LC):
LD50 (median dose)	3000 mg/kg (rat, oral)
Related compounds
Related compounds	Pentanoic acid, Heptanoic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Two other acids are named after goats: caprylic acid (C8) and capric acid (C10). Along with caproic acid, they account for 15% of the fat in goat's milk.

Caproic, caprylic, and capric acids (capric is a crystal- or wax-like substance, whereas the other two are mobile liquids) are not only used for the formation of esters, but also commonly used "neat" in: butter, milk, cream, strawberry, bread, beer, nut, and other flavors.

See also

• List of carboxylic acids
• List of saturated fatty acids
• Caproate fermentation