Octadecanoic Acid - The NIST WebBook

Octadecanoic acid

• Formula: C18H36O2
• Molecular weight: 284.4772
• IUPAC Standard InChI: InChI=1S/C18H36O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h2-17H2,1H3,(H,19,20) Copy
• IUPAC Standard InChIKey: QIQXTHQIDYTFRH-UHFFFAOYSA-N Copy
• CAS Registry Number: 57-11-4
• Chemical structure: This structure is also available as a 2d Mol file
• Other names: Stearic acid; n-Octadecanoic acid; Humko Industrene R; Hydrofol Acid 150; Hystrene S-97; Hystrene T-70; Hystrene 80; Industrene R; Kam 1000; Kam 2000; Kam 3000; Neo-Fat 18; Neo-Fat 18-53; Neo-Fat 18-54; Neo-Fat 18-55; Neo-Fat 18-59; NAA 173; PD 185; Stearex Beads; Stearophanic acid; Steric acid; Vanicol; 1-Heptadecanecarboxylic acid; Heptadecanecarboxylic acid; Neo-fat 18-61; Pearl stearic; Century 1240; Dar-chem 14; Emersol 120; Emersol 132; Emersol 150; Formula 300; Glycon DP; Glycon TP; Glycon S-70; Glycon S-80; Glycon S-90; Groco 54; Groco 55; Groco 55L; Groco 58; Groco 59; Hy-phi 1199; Hy-phi 1205; Hy-phi 1303; Hy-phi 1401; Hydrofol acid 1655; Hydrofol acid 1855; Hydrofol 1895; Hystrene 4516; Hystrene 5016; Hystrene 7018; Hystrene 9718; Industrene 5016; Neo-Fat 18-S; Tegostearic 254; Tegostearic 255; Tegostearic 272; Cetylacetic acid; Industrene 8718; Industrene 9018; Barolub FTA; Loxiol G 20; Lunac S 20; Emersol 153; Century 1210; Century 1220; Century 1230; Emersol 6349; Hystrene 7018 FG; Hystrene 9718 NF FG; Industrene 4518; Industrene 7018 FG; n-Octadecylic acid; Pristerene 4904; Promulsin; Proviscol wax; Stearex; Tsubaki; Vis-Plus; Prifac 2918; Adeka Fatty Acid SA 910; Century 1224; Edenor C18; Hydrofol Acid 1895; Kiri stearic acid; Lunac S 40; SA 400 (fatty acid); WO 2 (fatty acid); Octadecanoic acid (stearic acid); Emersol 110 (Salt/Mix); Emery 400 (Salt/Mix)
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• Information on this page:
  • Condensed phase thermochemistry data
  • References
  • Notes
• Other data available:
  • Phase change data
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Gas Chromatography
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• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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Condensed phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments: ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity	Value	Units	Method	Reference	Comment
ΔfH°liquid	-891. ± 2.	kJ/mol	Ccb	Lebedeva, 1964	Hfusion =10.81±0.10 kcal/mol; ALS
Quantity	Value	Units	Method	Reference	Comment
ΔcH°liquid	-11280.1 ± 1.9	kJ/mol	Ccb	Adriaanse, Dekker, et al., 1965	Reanalyzed by Cox and Pilcher, 1970, Original value = -11279.4 ± 1.9 kJ/mol; Hfusion=63.0 kJ/mol; Corresponding ΔfHºliquid = -948.0 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
ΔcH°liquid	-11336.8 ± 2.1	kJ/mol	Ccb	Lebedeva, 1964	Hfusion =10.81±0.10 kcal/mol; Corresponding ΔfHºliquid = -891.28 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
ΔfH°solid	-912. ± 11.	kJ/mol	Ccb	Medard and Thomas, 1952	Reanalyzed by Cox and Pilcher, 1970, Original value = -897.9 kJ/mol; Author's hf291_condensed=-223.8 kcal/mol; ALS
Quantity	Value	Units	Method	Reference	Comment
ΔcH°solid	-11290.79	kJ/mol	Ccb	Shkaraputa, Danilenko, et al., 1984	Corresponding ΔfHºsolid = -937.33 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
ΔcH°solid	-11271. ± 13.	kJ/mol	Ccb	Swain, Silbert, et al., 1964	Corresponding ΔfHºsolid = -956.9 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
ΔcH°solid	-11316. ± 11.	kJ/mol	Ccb	Medard and Thomas, 1952	Reanalyzed by Cox and Pilcher, 1970, Original value = -11331.9 kJ/mol; Author's hf291_condensed=-223.8 kcal/mol; Corresponding ΔfHºsolid = -912.07 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
ΔcH°solid	-11298.	kJ/mol	Ccb	Emery and Benedict, 1911	Corresponding ΔfHºsolid = -930. kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°solid,1 bar	435.6	J/mol*K	N/A	Singleton, Ward, et al., 1950	Extrapolation below 90 K, 64.4 J/mol*K.; DH

Constant pressure heat capacity of solid

Cp,solid (J/mol*K)	Temperature (K)	Reference	Comment
501.55	298.15	Schaake, van Miltenburg, et al., 1982	T = 80 to 355 K.; DH
561.9	298.15	Singleton, Ward, et al., 1950	T = 154 to 350 K.; DH

References

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Lebedeva, 1964 Lebedeva, N.D., Heats of combustion of monocarboxylic acids, Russ. J. Phys. Chem. (Engl. Transl.), 1964, 38, 1435-1437. [all data]

Adriaanse, Dekker, et al., 1965 Adriaanse, N.; Dekker, H.; Coops, J., Heats of combustion of normal saturated fatty acids and their methyl esters, Rec. Trav. Chim. Pays/Bas, 1965, 84, 393-407. [all data]

Cox and Pilcher, 1970 Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Medard and Thomas, 1952 Medard, L.; Thomas, M., Determination des chaleurs de combustion de douze composes organiques utilises dans les poudres et enplosies, Mem. Poudres, 1952, 34, 421-442. [all data]

Shkaraputa, Danilenko, et al., 1984 Shkaraputa, L.N.; Danilenko, V.V.; Sklyar, V.T.; Kendis, M.Sh.; Ratushnaya, V.I., Changes in enthalpy in the reaction of stearic acid with dextramine, Neftepererab. Neftekhim. (Moscow), 1984, 27, 31-32. [all data]

Swain, Silbert, et al., 1964 Swain, H.A., Jr.; Silbert, L.S.; Miller, J.G., The heats of combustion of aliphatic long chain peroxyacids, t-butyl peroxyesters, and related acids and esters, J. Am. Chem. Soc., 1964, 86, 2562-2566. [all data]

Emery and Benedict, 1911 Emery, A.G.; Benedict, F.G., The heat of combustion of compounds of physiological importance, Am. J. Physiol., 1911, 28, 301-307. [all data]

Singleton, Ward, et al., 1950 Singleton, W.S.; Ward, T.L.; Dollear, F.G., Physical properties of fatty acids. I. Some dilatometric and thermal properties of stearic acid in two polymorphic forms, J. Am. Oil Chem. Soc., 1950, 27, 143-146. [all data]

Schaake, van Miltenburg, et al., 1982 Schaake, R.C.F.; van Miltenburg, J.C.; De Kruif, C.G., Thermodynamic properties of the normal alkanoic acids. II. Molar heat capacities of seven even-numbered normal alkanoic acids, J. Chem. Thermodynam., 1982, 14, 771-778. [all data]

Notes

Go To: Top, Condensed phase thermochemistry data, References

• Symbols used in this document:

  Cp,solid	Constant pressure heat capacity of solid
  S°solid,1 bar	Entropy of solid at standard conditions (1 bar)
  ΔcH°liquid	Enthalpy of combustion of liquid at standard conditions
  ΔcH°solid	Enthalpy of combustion of solid at standard conditions
  ΔfH°liquid	Enthalpy of formation of liquid at standard conditions
  ΔfH°solid	Enthalpy of formation of solid at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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