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Stearic acid
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| Names | |
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| Preferred IUPAC name
Octadecanoic acid | |
Other names
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| Identifiers | |
3D model (JSmol)
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| ChEMBL | |
| ChemSpider | |
| DrugBank | |
| ECHA InfoCard | 100.000.285 |
| EC Number |
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| KEGG | |
PubChem CID
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| RTECS number |
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C18H36O2 | |
| Molar mass | 284.484 g·mol−1 |
| Appearance | White solid |
| Odor | Pungent, oily |
| Density | 0.9408 g/cm3 (20 °C)[2] 0.847 g/cm3 (70 °C) |
| Melting point | 69.3 °C (156.7 °F; 342.4 K)[2] |
| Boiling point | 361 °C (682 °F; 634 K) decomposes 232 °C (450 °F; 505 K) at 15 mmHg[2] |
| 0.00018 g/100 g (0 °C) 0.00029 g/100 g (20 °C) 0.00034 g/100 g (30 °C) 0.00042 g/100 g (45 °C) 0.00050 g/100 g (60 °C)[3] | |
| Solubility | Soluble in [4] |
| Solubility in dichloromethane | 3.58 g/100 g (25 °C) 8.85 g/100 g (30 °C) 18.3 g/100 g (35 °C)[4] |
| Solubility in hexane | 0.5 g/100 g (20 °C) 4.3 g/100 g (30 °C) 19 g/100 g (40 °C) 79.2 g/100 g (50 °C) 303 g/100 g (60 °C)[4] |
| Solubility in ethanol | 1.09 g/100 mL (10 °C) 2.25 g/100 g (20 °C) 5.42 g/100 g (30 °C) 22.7 g/100 g (40 °C) 105 g/100 g (50 °C) 400 g/100 g (60 °C)[3] |
| Solubility in acetone | 4.73 g/100 g[5] |
| Solubility in chloroform | 15.54 g/100 g[5] |
| Solubility in toluene | 13.61 g/100 g[5] |
| Vapor pressure | 0.01 kPa (158 °C)[2] 0.46 kPa (200 °C) 16.9 kPa (300 °C)[6] |
| −220.8·10−6 cm3/mol | |
| Thermal conductivity | 0.173 W/m·K (70 °C) 0.166 W/m·K (100 °C)[7] |
Refractive index (nD)
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1.4299 (80 °C)[2] |
| Structure | |
| B-form = Monoclinic[8] | |
| B-form = P21/a[8] | |
| B-form = Cs 2h[8] | |
a = 5.591 Å, b = 7.404 Å, c = 49.38 Å (B-form)[8] α = 90°, β = 117.37°, γ = 90°
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| Thermochemistry | |
Heat capacity (C)
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501.5 J/mol·K[2][6] |
Std molar
entropy (S⦵298) |
435.6 J/mol·K[2] |
Std enthalpy of
formation (ΔfH⦵298) |
−947.7 kJ/mol[2] |
Std enthalpy of
combustion (ΔcH⦵298) |
−11342.4 kJ/mol[9] |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Flash point | 205 °C (401 °F; 478 K) |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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4640 mg/kg (rats, oral)[10] 21.5 mg/kg (rats, intravenous)[4] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Stearic acid (/ˈstɪərɪk/ STEER-ik, /stiˈærɪk/ stee-ARR-ik) is a saturated fatty acid with an 18-carbon chain.[9] The IUPAC name is octadecanoic acid.[9] It is a soft waxy solid with the formula CH3(CH2)16CO2H.[9] The triglyceride derived from three molecules of stearic acid is called stearin.[9] Stearic acid is a prevalent fatty-acid in nature, found in many animal and vegetable fats, but is usually higher in animal fat than vegetable fat. It has a melting point of 69.4 °C (156.9 °F) °C and a pKa of 4.50.[11]
Its name comes from the Greek word στέαρ "stéar", which means tallow. The salts and esters of stearic acid are called stearates.[9] As its ester, stearic acid is one of the most common saturated fatty acids found in nature and in the food supply, following palmitic acid.[12][13] Dietary sources of stearic acid include meat, poultry, fish, eggs, dairy products, and foods prepared with fats; beef tallow, lard, butterfat, cocoa butter, and shea butter are rich fat sources of stearic acid.[9][12]
- ^ Susan Budavari, ed. (1989). Merck Index (11th ed.). Rahway, New Jersey: Merck & Co., Inc. p. 8761. ISBN 978-0-911910-28-5.
- ^ a b c d e f g h Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
- ^ a b Ralston, A.W.; Hoerr, C.W. (1942). "The Solubilities of the Normal Saturated Fatty Acids". The Journal of Organic Chemistry. 7 (6): 546–555. doi:10.1021/jo01200a013. PMID 20280727.
- ^ a b c d "stearic acid". Chemister.ru. 2007-03-19. Retrieved 2017-06-30.
- ^ a b c Seidell, Atherton; Linke, William F. (1919). Solubilities of Inorganic and Organic Compounds (2nd ed.). D. Van Nostrand Company. p. 677.
- ^ a b Octadecanoic acid in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2014-06-15)
- ^ Vargaftik, Natan B.; et al. (1993). Handbook of Thermal Conductivity of Liquids and Gases (illustrated ed.). CRC Press. p. 318. ISBN 978-0-8493-9345-7.
- ^ a b c d von Sydow, E. (1955). "On the structure of the crystal form B of stearic acid". Acta Crystallographica. 8 (9): 557–560. Bibcode:1955AcCry...8..557V. doi:10.1107/S0365110X55001746.
- ^ a b c d e f g "Stearic acid". PubChem, US National Library of Medicine. 29 April 2023. Retrieved 5 May 2023.
- ^ Science Lab.com. "Stearic acid MSDS" (PDF). Retrieved 2020-09-30.
- ^ Loften, J.R.; Linn, J.G.; Drackley, J.K.; Jenkins, T.C.; Soderholm, C.G.; Kertz, A.F. (August 2014). "Invited review: Palmitic and stearic acid metabolism in lactating dairy cows". Journal of Dairy Science. 97 (8): 4661–4674. doi:10.3168/jds.2014-7919. ISSN 0022-0302. PMID 24913651.
- ^ a b Hunter, J. E.; Zhang, J.; Kris-Etherton, P. M. (2009). "Cardiovascular disease risk of dietary stearic acid compared with trans, other saturated, and unsaturated fatty acids: A systematic review". American Journal of Clinical Nutrition. 91 (1): 46–63. doi:10.3945/ajcn.2009.27661. PMID 19939984.
- ^ Gunstone, F. D., John L. Harwood, and Albert J. Dijkstra "The Lipid Handbook with Cd-Rom. 3rd ed. Boca Raton: CRC Press, 2007. ISBN 0849396883 | ISBN 978-0849396885
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