Stearic acid

Stearic acid[1]
Skeletal formula of stearic acid
Ball-and-stick model of stearic acid
Stearic acid
Names
Preferred IUPAC name
Octadecanoic acid
Other names
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.285 Edit this at Wikidata
EC Number
  • 200-313-4
KEGG
RTECS number
  • WI2800000
UNII
  • CCCCCCCCCCCCCCCCCC(=O)O
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]
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°
Thermochemistry
501.5 J/mol·K[2][6]
435.6 J/mol·K[2]
−947.7 kJ/mol[2]
−11342.4 kJ/mol[9]
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
1
0
Flash point 205 °C (401 °F; 478 K)
Lethal dose or concentration (LD, LC):
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).

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]

  1. ^ Susan Budavari, ed. (1989). Merck Index (11th ed.). Rahway, New Jersey: Merck & Co., Inc. p. 8761. ISBN 978-0-911910-28-5.
  2. ^ 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.
  3. ^ 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.
  4. ^ a b c d "stearic acid". Chemister.ru. 2007-03-19. Retrieved 2017-06-30.
  5. ^ a b c Seidell, Atherton; Linke, William F. (1919). Solubilities of Inorganic and Organic Compounds (2nd ed.). D. Van Nostrand Company. p. 677.
  6. ^ 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)
  7. ^ 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.
  8. ^ 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.
  9. ^ a b c d e f g "Stearic acid". PubChem, US National Library of Medicine. 29 April 2023. Retrieved 5 May 2023.
  10. ^ Science Lab.com. "Stearic acid MSDS" (PDF). Retrieved 2020-09-30.
  11. ^ 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.
  12. ^ 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.
  13. ^ 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