Lauric acid

Lauric acid or systematically, dodecanoic acid, is a saturated fatty acid with a 12-carbon atom chain, thus having many properties of medium-chain fatty acids, is a bright white, powdery solid with a faint odor of bay oil or soap. The salts and esters of lauric acid are known as laurates.

Lauric acid
Names
IUPAC name
Dodecanoic acid
Other names
n-Dodecanoic acid, Dodecylic acid, Dodecoic acid, Laurostearic acid, Vulvic acid, 1-Undecanecarboxylic acid, Duodecylic acid, C12:0 (Lipid numbers)
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.005.075
EC Number
  • 205-582-1
KEGG
UNII
Properties
C12H24O2
Molar mass 200.322 g·mol−1
Appearance White powder
Odor Slight odor of bay oil
Density 1.007 g/cm3 (24 °C)[1]
0.8744 g/cm3 (41.5 °C)[2]
0.8679 g/cm3 (50 °C)[3]
Melting point 43.8 °C (110.8 °F; 316.9 K)[3]
Boiling point 297.9 °C (568.2 °F; 571.0 K)
282.5 °C (540.5 °F; 555.6 K)
at 512 mmHg[1]
225.1 °C (437.2 °F; 498.2 K)
at 100 mmHg[3][4]
37 mg/L (0 °C)
55 mg/L (20 °C)
63 mg/L (30 °C)
72 mg/L (45 °C)
83 mg/L (100 °C)[5]
Solubility Soluble in alcohols, diethyl ether, phenyls, haloalkanes, acetates[5]
Solubility in methanol 12.7 g/100 g (0 °C)
120 g/100 g (20 °C)
2250 g/100 g (40 °C)[5]
Solubility in acetone 8.95 g/100 g (0 °C)
60.5 g/100 g (20 °C)
1590 g/100 g (40 °C)[5]
Solubility in ethyl acetate 9.4 g/100 g (0 °C)
52 g/100 g (20°C)
1250 g/100 g (40°C)[5]
Solubility in toluene 15.3 g/100 g (0 °C)
97 g/100 g (20°C)
1410 g/100 g (40°C)[5]
log P 4.6[6]
Vapor pressure 2.13·10−6 kPa (25 °C)[6]
0.42 kPa (150 °C)[4]
6.67 kPa (210 °C)[7]
Acidity (pKa) 5.3 (20 °C)[6]
Thermal conductivity 0.442 W/m·K (solid)[2]
0.1921 W/m·K (72.5 °C)
0.1748 W/m·K (106 °C)[1]
1.423 (70 °C)[1]
1.4183 (82 °C)[3]
Viscosity 6.88 cP (50 °C)
5.37 cP (60 °C)[2]
Structure
Monoclinic (α-form)[8]
Triclinic, aP228 (γ-form)[9]
P21/a, No. 14 (α-form)[8]
P1, No. 2 (γ-form)[9]
2/m (α-form)[8]
1 (γ-form)[9]
a = 9.524 Å, b = 4.965 Å, c = 35.39 Å (α-form)[8]
α = 90°, β = 129.22°, γ = 90°
Thermochemistry
404.28 J/mol·K[4]
−775.6 kJ/mol[6]
7377 kJ/mol
7425.8 kJ/mol (292 K)[4]
Hazards
GHS pictograms
GHS Signal word Danger
H412[7]
P273[7]
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
1
1
1
Flash point > 113 °C (235 °F; 386 K)[7]
Related compounds
Related compounds
 Glyceryl laurate
Related compounds
Related compounds
 Undecanoic acid
Tridecanoic acid
Dodecanol
Dodecanal
Sodium lauryl sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Occurrence

Lauric acid, as a component of triglycerides, comprises about half of the fatty-acid content in coconut milk, coconut oil, laurel oil, and palm kernel oil (not to be confused with palm oil),[10][11] Otherwise, it is relatively uncommon. It is also found in human breast milk (6.2% of total fat), cow's milk (2.9%), and goat's milk (3.1%).[10]

In various plants

In Insects

Properties

Although 95% of medium-chain triglycerides are absorbed through the portal vein, only 25–30% of lauric acid is absorbed through it.[15]

Like many other fatty acids, lauric acid is inexpensive, has a long shelf-life, is nontoxic, and is safe to handle. It is used mainly for the production of soaps and cosmetics. For these purposes, lauric acid is reacted with sodium hydroxide to give sodium laurate, which is a soap. Most commonly, sodium laurate is obtained by saponification of various oils, such as coconut oil. These precursors give mixtures of sodium laurate and other soaps.[11]

Laboratory use

In the laboratory, lauric acid may be used to investigate the molar mass of an unknown substance via the freezing-point depression. The choice of lauric acid is convenient because the melting point of the pure compound is relatively high (43.8°C). Its cryoscopic constant is 3.9°C·kg/mol. By melting lauric acid with the unknown substance, allowing it to cool, and recording the temperature at which the mixture freezes, the molar mass of the unknown compound may be determined.[16]

Potential medicinal properties

Lauric acid increases total serum cholesterol more than many other fatty acids, but mostly high-density lipoprotein (HDL) (the "good" blood cholesterol). As a result, lauric acid has been characterized as having "a more favorable effect on total HDL cholesterol than any other fatty acid [examined], either saturated or unsaturated".[17] In general, a lower total/HDL serum cholesterol ratio correlates with a decrease in atherosclerotic risk.[18] Nonetheless, an extensive meta-analysis on foods affecting the total LDL/serum cholesterol ratio found in 2003 that the net effects of lauric acid on coronary artery disease outcomes remained uncertain.[19] A 2016 review of coconut oil (which is nearly half lauric acid) was similarly inconclusive about the effects on cardiovascular disease risk.[15]

References
  1. G., Chuah T.; D., Rozanna; A., Salmiah; Y., Thomas Choong S.; M., Sa'ari (2006). "Fatty acids used as phase change materials (PCMs) for thermal energy storage in building material applications" (PDF). University Putra Malaysia. Archived from the original (PDF) on 2014-11-03. Retrieved 2014-06-22.
  2. Mezaki, Reiji; Mochizuki, Masafumi; Ogawa, Kohei (2000). Engineering data on mixing (1st ed.). Elsevier Science B.V. p. 278. ISBN 0-444-82802-8.
  3. Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
  4. Dodecanoic 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), http://webbook.nist.gov (retrieved 2014-06-14)
  5. Seidell, Atherton; Linke, William F. (1952). Solubilities of inorganic and organic compounds (3rd ed.). New York: D. Van Nostrand Company. pp. 742–743.
  6. CID 3893 from PubChem
  7. Sigma-Aldrich Co., Lauric acid. Retrieved on 2014-06-14.
  8. Vand, V.; Morley, W. M.; Lomer, T. R. (1951). "The crystal structure of lauric acid". Acta Crystallographica. 4 (4): 324–329. doi:10.1107/S0365110X51001069.
  9. Sydow, Erik von (1956). "On the structure of the crystal form A of lauric acid" (PDF). actachemscand.org. Acta Chemica Scandinavica. Retrieved 2014-06-14.
  10. Beare-Rogers, J.; Dieffenbacher, A.; Holm, J.V. (2001). "Lexicon of lipid nutrition (IUPAC Technical Report)". Pure and Applied Chemistry. 73 (4): 685–744. doi:10.1351/pac200173040685. S2CID 84492006.
  11. David J. Anneken, Sabine Both, Ralf Christoph, Georg Fieg, Udo Steinberner, Alfred Westfechtel "Fatty Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim. doi:10.1002/14356007.a10_245.pub2
  12. Nasaruddin, Mohd hanif; Noor, Noor Qhairul Izzreen Mohd; Mamat, Hasmadi (2013). "Komposisi Proksimat dan Komponen Asid Lemak Durian Kuning (Durio graveolens) Sabah" [Proximate and Fatty Acid Composition of Sabah Yellow Durian (Durio graveolens)] (PDF). Sains Malaysiana (in Malay). 42 (9): 1283–1288. ISSN 0126-6039. OCLC 857479186. Retrieved 28 November 2017.
  13. Zarifikhosroshahi; Tugba Murathan; Kafkas; Okatan (2019). "Variation in volatile and fatty acid contents among Viburnum opulus L. Fruits growing different locations". Scientia Horticulturae. 264: 109160. doi:10.1016/j.scienta.2019.109160.
  14. Montevecchi, G.; Zanasi, L.; Masino, F.; Maistrello, L.; Antonelli, A. (2019). "Black soldier fly (Hermetia illucens L.): effect on the fat integrity using different approaches to the killing of the prepupae". Journal of Insects as Food and Feed. 6 (2): 121–131. doi:10.3920/JIFF2019.0002.
  15. Eyres L, Eyres MF, Chisholm A, Brown RC (2016). "Coconut oil consumption and cardiovascular risk factors in humans". Nutrition Reviews. 74 (4): 267–280. doi:10.1093/nutrit/nuw002. PMC 4892314. PMID 26946252.
  16. http://faculty.sites.uci.edu/chem1l/files/2015/04/Freezing-Point-Depression.pdf
  17. Mensink RP, Zock PL, Kester AD, Katan MB (May 2003). "Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials". American Journal of Clinical Nutrition. 77 (5): 1146–1155. doi:10.1093/ajcn/77.5.1146. ISSN 0002-9165. PMID 12716665.
  18. Thijssen, M.A. and R.P. Mensink. (2005). Fatty Acids and Atherosclerotic Risk. In Arnold von Eckardstein (Ed.) Atherosclerosis: Diet and Drugs. Springer. pp. 171–172. ISBN 978-3-540-22569-0.
  19. Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials

Further reading
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