Caproic acid
Chemical compound
From Wikipedia, the free encyclopedia
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. Salts and esters of caproic acid are known as caproates or hexanoates.
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| Names | |
|---|---|
| IUPAC name
Hexanoic acid | |
| Preferred IUPAC name
Hexanoic acid | |
| Other names
Hexoic acid Hexylic acid Butylacetic acid Pentylformic acid 1-Pentanecarboxylic acid C6:0 (Lipid numbers) | |
| Identifiers | |
3D model (JSmol) |
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| 773837 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.005.046 |
| EC Number |
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| 185066 | |
| KEGG | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| 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] |
| 1.082 g/100 mL[1] | |
| Solubility | soluble in ethanol, ether |
| Acidity (pKa) | 4.88 |
| −78.55·10−6 cm3/mol | |
Refractive index (nD) |
1.4170 |
| Viscosity | 3.1 mP |
| Hazards | |
| GHS labelling: | |
 | |
| Danger | |
| H314 | |
| 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) | |
| Flash point | 103 °C (217 °F; 376 K)[2] |
| 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).
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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.[4][5]
It may be prepared by fractionation of the volatile fatty acids of coconut oil.[6] 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.[1] 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.[7]
DHEA-caproate ester (#121) has a IC50 of 0.049nM for the 5-alpha-reductase enzyme.[8][9]