{{not to be confused|Caprylic acid|Capric acid}} {{Chembox | Watchedfields = changed | verifiedrevid = 443856741 | ImageFile_Ref = {{chemboximage|correct|??}} | ImageFile = Caproic acid acsv.svg | ImageClass = skin-invert | ImageName = Skeletal formula | ImageFile1 = Caproic-acid-3D-balls.png | ImageClass1 = bg-transparent | ImageName1 = Ball-and-stick model | PIN = Hexanoic acid | OtherNames = Hexoic acid<br />Hexylic acid<br />Butylacetic acid<br />Pentylformic acid<br />1-Pentanecarboxylic acid<br />C6:0 (Lipid numbers) | IUPACName = Hexanoic acid | Section1 = {{Chembox Identifiers |ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |ChemSpiderID = 8552 |UNII_Ref = {{fdacite|correct|FDA}} |UNII = 1F8SN134MX |Gmelin = 185066 |Beilstein = 773837 |EC_number = 205-550-7 |KEGG_Ref = {{keggcite|correct|kegg}} |KEGG = C01585 |InChI = 1/C6H12O2/c1-2-3-4-5-6(7)8/h2-5H2,1H3,(H,7,8) |InChIKey = FUZZWVXGSFPDMH-UHFFFAOYAY |ChEMBL_Ref = {{ebicite|correct|EBI}} |ChEMBL = 14184 |StdInChI_Ref = {{stdinchicite|correct|chemspider}} |StdInChI = 1S/C6H12O2/c1-2-3-4-5-6(7)8/h2-5H2,1H3,(H,7,8) |StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |StdInChIKey = FUZZWVXGSFPDMH-UHFFFAOYSA-N |CASNo_Ref = {{cascite|correct|CAS}} |CASNo = 142-62-1 |PubChem = 8892 |ChEBI_Ref = {{ebicite|correct|EBI}} |ChEBI = 30776 |SMILES = CCCCCC(=O)O }} | Section2 = {{Chembox Properties |C=6 | H=12 | O=2 |Appearance=Oily liquid<ref name=Merck>{{Merck11th}}</ref> |Odor = goat-like |Density=0.929 g/cm<sup>3</sup><ref name=GESTIS>{{GESTIS|ZVG=28160}}</ref> |MeltingPtC=−3.4 |MeltingPt_ref = <ref name=Merck/> |BoilingPtC=205.8 |BoilingPt_ref = <ref name=Merck/> |Solubility=1.082 g/100 mL<ref name=Merck/> |SolubleOther = soluble in ethanol, ether |pKa = 4.88 |RefractIndex = 1.4170 |Viscosity = 3.1 mP |MagSus = −78.55·10<sup>−6</sup> cm<sup>3</sup>/mol }} | Section3 = {{Chembox Hazards |NFPA-H = 3 | NFPA-F = 1 | NFPA-R = 0 |FlashPtC =103 |FlashPt_ref = <ref name=GESTIS/> |AutoignitionPtC =380 |ExploLimits = 1.3-9.3% |LD50 = 3000 mg/kg (rat, oral) |GHSPictograms = {{GHS05}} |GHSSignalWord = Danger |HPhrases = {{H-phrases|314}} |PPhrases = {{P-phrases|260|264|280|301+330+331|302+352|303+361+353|304+340|305+351+338|310|312|321|322|361|363|405|501}} }} | Section4 = {{Chembox Related |OtherCompounds = Pentanoic acid, Heptanoic acid }} }}
'''Caproic acid''', also known as '''hexanoic acid''', is the carboxylic acid derived from hexane with the chemical formula {{chem2|CH3(CH2)4COOH}}. It is a colorless oily liquid with a fatty, cheesy, waxy odor resembling that of goats<ref name=Merck/> 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.<ref>{{Cite web |url=http://scidiv.bcc.ctc.edu/rkr/Ginkgo/Ginkgo.html |title=Ginkgo.html<!-- Bot generated title --> |access-date=2007-03-08 |archive-date=2008-12-26 |archive-url=https://web.archive.org/web/20081226065433/http://scidiv.bcc.ctc.edu/rkr/ginkgo/Ginkgo.html |url-status=live }}</ref> It is also one of the components of vanilla and cheese. Salts and esters of caproic acid are known as '''caproates''' or '''hexanoates'''.
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 used for the formation of esters, and also commonly used "neat" in: butter, milk, cream, strawberry, bread, beer, nut, and other flavors.
== Properties == Caproic acid is a 6-Carbon saturated fatty acid. It occurs in a white crystalline solid form or a colorless to pale yellow liquid state, accompanied by a strong and unpleasant odor. It has limited solubility in water, although it is soluble in dimethyl ether, benzene and other organic solvents.<ref>{{Cite web |title=What is Caproic Acid? Cosmetic usage, alternatives, and regulatory insights |url=https://slate.greyb.com/ingredients/caproic-acid/ |access-date=2026-01-07 |website=Slate |language=en-US}}</ref><ref>{{Cite web |last=PubChem |title=Hexanoic Acid |url=https://pubchem.ncbi.nlm.nih.gov/compound/8892 |access-date=2026-01-07 |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref>
It may be prepared by fractionation of the volatile fatty acids of coconut oil.<ref>{{Cite web |title=Hexanoic acid {{!}} 142-62-1 |url=https://amp.chemicalbook.com/ChemicalProductProperty_EN_CB3224164.htm?N=India |access-date=2026-01-07 |website=amp.chemicalbook.com}}</ref> Caproic acid belongs to the family of medium chain fatty acids (MCFAs) which can be used to synthesize Medium-chain triglycerides.
== Uses == 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.<ref name="Merck" /> Several progestin medications are caproate esters, such as hydroxyprogesterone caproate and gestonorone caproate. Its derivatives are also used in soaps, shampoos, conditioners and gels.
Caproic acid is also used as a component in varnish driers, as well as a lubricant. Its derivatives can also be incorporated to modify the elasticity, strength, and resilience of rubber products.<ref>{{Cite web |title=Industrial Applications of Hexanoic Acid (CAS 142-62-1) |url=https://www.nbinno.com/article/other-organic-chemicals/industrial-applications-of-hexanoic-acid-cas-142-62-1-rh#:~:text=In%20the%20realm%20of%20rubber,all%20your%20hexanoic%20acid%20needs. |access-date=2026-01-07 |website=www.nbinno.com}}</ref>
DHEA-caproate ester (#121) has a IC50 of 0.049nM for the 5-alpha-reductase enzyme.<ref>Salvador, Jorge A.R.; Pinto, Rui M.A.; Silvestre, Samuel M. . (2013). Steroidal 5α-reductase and 17α-hydroxylase/17,20-lyase (CYP17) inhibitors useful in the treatment of prostatic diseases. The Journal of Steroid Biochemistry and Molecular Biology, 137(), 199–222. doi:10.1016/j.jsbmb.2013.04.006 </ref><ref>Yazmín Arellano; Eugene Bratoeff; Mariana Garrido; Juan Soriano; Yvonne Heuze; Marisa Cabeza. (2011). New ester derivatives of dehydroepiandrosterone as 5α-reductase inhibitors. , 76(12), 0–1246. doi:10.1016/j.steroids.2011.05.015 </ref>
==See also== * List of carboxylic acids * List of saturated fatty acids * Caproate fermentation
==References== {{Reflist}}
{{Fatty acids}} {{Authority control}}
Category:Fatty acids Category:Alkanoic acids