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)
IUPAC Standard InChIKey: QIQXTHQIDYTFRH-UHFFFAOYSA-N
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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Condensed phase thermochemistry data

Go To: Top, Phase change data, References, Notes

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
Δ_fH°_liquid	-891. ± 2.	kJ/mol	Ccb	Lebedeva, 1964	Hfusion =10.81±0.10 kcal/mol; ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_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 Δ_fHº_liquid = -948.0 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-11336.8 ± 2.1	kJ/mol	Ccb	Lebedeva, 1964	Hfusion =10.81±0.10 kcal/mol; Corresponding Δ_fHº_liquid = -891.28 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_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
Δ_cH°_solid	-11290.79	kJ/mol	Ccb	Shkaraputa, Danilenko, et al., 1984	Corresponding Δ_fHº_solid = -937.33 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_solid	-11271. ± 13.	kJ/mol	Ccb	Swain, Silbert, et al., 1964	Corresponding Δ_fHº_solid = -956.9 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_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 Δ_fHº_solid = -912.07 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_solid	-11298.	kJ/mol	Ccb	Emery and Benedict, 1911	Corresponding Δ_fHº_solid = -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

C_p,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

Phase change data

Go To: Top, Condensed phase thermochemistry data, References, Notes

Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
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
T_boil	634.2	K	N/A	Aldrich Chemical Company Inc., 1990	BS
T_boil	631.15	K	N/A	Krafft, 1880	Uncertainty assigned by TRC = 5. K; TRC
Quantity	Value	Units	Method	Reference	Comment
T_fus	341. ± 3.	K	AVG	N/A	Average of 31 out of 32 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_triple	342.49	K	N/A	Schaake, van Miltenburg, et al., 1982, 2	Uncertainty assigned by TRC = 0.02 K; TRC
T_triple	341.85	K	N/A	Spizzichino, 1956	Uncertainty assigned by TRC = 0.5 K; TRC
T_triple	342.65	K	N/A	Singleton, Ward, et al., 1950, 2	Uncertainty assigned by TRC = 0.01 K; TRC
Quantity	Value	Units	Method	Reference	Comment
P_triple	4.2663×10^-8	bar	N/A	Spizzichino, 1956	Uncertainty assigned by TRC = 1.9998×10^-8 bar; TRC
Quantity	Value	Units	Method	Reference	Comment
T_c	805.09	K	N/A	D'Souza and Teja, 1987	Uncertainty assigned by TRC = 3.5 K; Ambrose's procedure; TRC
Quantity	Value	Units	Method	Reference	Comment
P_c	13.2658	bar	N/A	D'Souza and Teja, 1987	Uncertainty assigned by TRC = 0.85 bar; Ambrose's procedure; TRC
Quantity	Value	Units	Method	Reference	Comment
Δ_subH°	204. ± 9.	kJ/mol	TPD	Cappa, Lovejoy, et al., 2008	AC

Enthalpy of vaporization

Δ_vapH (kJ/mol)	Temperature (K)	Method	Reference	Comment
124.3	364.	A	Stephenson and Malanowski, 1987	Based on data from 349. to 415. K.; AC
100.6	472.	A	Stephenson and Malanowski, 1987	Based on data from 457. to 649. K.; AC
118.9 ± 2.0	379.	ME,TE	de Kruif, Schaake, et al., 1982	Based on data from 366. to 389. K.; AC
79.8	515.	I	Cramer, 1943	AC

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
P = vapor pressure (bar)
T = temperature (K)

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Temperature (K)	A	B	C	Reference	Comment
446.9 to 643.	5.72544	3348.131	-57.825	Stull, 1947	Coefficents calculated by NIST from author's data.

Enthalpy of sublimation

Δ_subH (kJ/mol)	Temperature (K)	Method	Reference	Comment
158.5	291. to 309.	TPTD	Chattopadhyay and Ziemann, 2005	AC
158.	296. to 319.	TPTD	Chattopadhyay, Tobias, et al., 2001	Experimental values based on the TPTD method are often inconsistent with values determined using other experimental methods; AC
166.5 ± 4.2	336.	ME	Davies and Malpass, 1961	Based on data from 331. to 340. K. See also Cox and Pilcher, 1970, 2.; AC
167. ± 4.2	330.89	V	Davies and Malpass, 1961, 2	ALS

Enthalpy of fusion

Δ_fusH (kJ/mol)	Temperature (K)	Method	Reference	Comment
61.300	342.75	N/A	Sato, Yoshimoto, et al., 1990	DH
60.4	338.3	N/A	Moore, Koelmel, et al., 2007	AC
63.2	342.8	DSC	Moreno, Cordobilla, et al., 2007	AC
57.8	344.1	DSC	Teixeira, Gonçalves da Silva, et al., 2006	AC
50.93	340.2	AC	Yu, Meng, et al., 2000	AC
61.21	342.5	N/A	Domalski and Hearing, 1996	AC
68.450	342.65	N/A	Singleton, Ward, et al., 1950	DH
64.643	326.1	N/A	Eykman, 1889	DH

Entropy of fusion

Δ_fusS (J/mol*K)	Temperature (K)	Reference	Comment
178.8	342.75	Sato, Yoshimoto, et al., 1990	DH
1998.	342.65	Singleton, Ward, et al., 1950	DH
198.	326.1	Eykman, 1889	DH

Enthalpy of phase transition

ΔH_trs (kJ/mol)	Temperature (K)	Initial Phase	Final Phase	Reference	Comment
61.208	342.49	crystaline, I	liquid	Schaake, van Miltenburg, et al., 1982	DH

Entropy of phase transition

ΔS_trs (J/mol*K)	Temperature (K)	Initial Phase	Final Phase	Reference	Comment
178.12	342.49	crystaline, I	liquid	Schaake, van Miltenburg, et al., 1982	DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:

References

Go To: Top, Condensed phase thermochemistry data, Phase change data, Notes

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]

Aldrich Chemical Company Inc., 1990
Aldrich Chemical Company Inc., Catalog Handbook of Fine Chemicals, Aldrich Chemical Company, Inc., Milwaukee WI, 1990, 1. [all data]

Krafft, 1880
Krafft, F., The production of laurinaldehyde c(12)h(24)o, myristinaldehyde c(14)h(28)o, palmitinaldehyde c(16)h(32)o, stearinaldehyde c(18)h(36)o: I investigation of aldehydes, Ber. Dtsch. Chem. Ges., 1880, 13, 1413-8. [all data]

Schaake, van Miltenburg, et al., 1982, 2
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. Thermodyn., 1982, 14, 771-8. [all data]

Spizzichino, 1956
Spizzichino, C., Contribution a l'etude des tensions de vapeur et des chaleurs de vaporisation des acides gras, esters methyliques et alcools gras a des pressions inferieures a 1 mm de mercure, J. des Recherches du C.N.R.S., 1956, 34, 1-24. [all data]

Singleton, Ward, et al., 1950, 2
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. [all data]

D'Souza and Teja, 1987
D'Souza, R.; Teja, A.S., The prediction of the vapor pressures of carboxylic acids, Chem. Eng. Commun., 1987, 61, 13. [all data]

Cappa, Lovejoy, et al., 2008
Cappa, Christopher D.; Lovejoy, Edward R.; Ravishankara, A.R., Evaporation Rates and Vapor Pressures of the Even-Numbered C ₈ -C ₁₈ Monocarboxylic Acids, J. Phys. Chem. A, 2008, 112, 17, 3959-3964, https://doi.org/10.1021/jp710586m . [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

de Kruif, Schaake, et al., 1982
de Kruif, C.G.; Schaake, R.C.F.; van Miltenburg, J.C.; van der Klauw, K.; Blok, J.G., Thermodynamic properties of the normal alkanoic acids III. Enthalpies of vaporization and vapour pressures of 13 normal alkanoic acids, The Journal of Chemical Thermodynamics, 1982, 14, 8, 791-798, https://doi.org/10.1016/0021-9614(82)90176-8 . [all data]

Cramer, 1943
Cramer, K.S.N., Chem. Zentr. II, 1943, 2234. [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Chattopadhyay and Ziemann, 2005
Chattopadhyay, Sulekha; Ziemann, Paul J., Vapor Pressures of Substituted and Unsubstituted Monocarboxylic and Dicarboxylic Acids Measured Using an Improved Thermal Desorption Particle Beam Mass Spectrometry Method, Aerosol Science and Technology, 2005, 39, 11, 1085-1100, https://doi.org/10.1080/02786820500421547 . [all data]

Chattopadhyay, Tobias, et al., 2001
Chattopadhyay, Sulekha; Tobias, Herbert J.; Ziemann, Paul J., A Method for Measuring Vapor Pressures of Low-Volatility Organic Aerosol Compounds Using a Thermal Desorption Particle Beam Mass Spectrometer, Anal. Chem., 2001, 73, 16, 3797-3803, https://doi.org/10.1021/ac010304j . [all data]

Davies and Malpass, 1961
Davies, Mansel; Malpass, V.E., 212. Heats of sublimation of straight-chain monocarboxylic acids, J. Chem. Soc., 1961, 1048, https://doi.org/10.1039/jr9610001048 . [all data]

Cox and Pilcher, 1970, 2
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press Inc., London, 1970, 643. [all data]

Davies and Malpass, 1961, 2
Davies, M.; Malpass, V.E., Heats of sublimation of straight-chain monocarboxylic acids, J. Chem. Soc., 1961, 1048-10. [all data]

Sato, Yoshimoto, et al., 1990
Sato, K.; Yoshimoto, N.; Suzuki, M.; Kobayashi, M.; Kaneko, F., Structure and transformation in polymorphism of petroselinic acid (cis-w-12-octadecenoic acid), J. Phys. Chem., 1990, 94, 3180-3185. [all data]

Moore, Koelmel, et al., 2007
Moore, David J.; Koelmel, Donald; Laura, Donna; Bedford, Eilidh, Infrared spectroscopy and differential scanning calorimetry studies of binary combinations of cis-6-octadecenoic acid and octadecanoic acid, Chemistry and Physics of Lipids, 2007, 150, 1, 109-115, https://doi.org/10.1016/j.chemphyslip.2007.06.217 . [all data]

Moreno, Cordobilla, et al., 2007
Moreno, Evelyn; Cordobilla, Raquel; Calvet, Teresa; Cuevas-Diarte, M.A.; Gbabode, Gabin; Negrier, Philippe; Mondieig, Denise; Oonk, Harry A.J., Polymorphism of even saturated carboxylic acids from n-decanoic to n-eicosanoic acid, New J. Chem., 2007, 31, 6, 947, https://doi.org/10.1039/b700551b . [all data]

Teixeira, Gonçalves da Silva, et al., 2006
Teixeira, A.C.T.; Gonçalves da Silva, A.M.P.S.; Fernandes, A.C., Phase behaviour of stearic acid--stearonitrile mixtures, Chemistry and Physics of Lipids, 2006, 144, 2, 160-171, https://doi.org/10.1016/j.chemphyslip.2006.09.001 . [all data]

Yu, Meng, et al., 2000
Yu, S.; Meng, S.; Tan, Z.; Li, L.; Zhang, J., Taiyangneng Xuebao, 2000, 21, 2, 171. [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

Eykman, 1889
Eykman, J.F., Zur kryoskopischen Molekulargewichtsbestimmung, Z. Physik. Chem., 1889, 4, 497-519. [all data]

Notes

Go To: Top, Condensed phase thermochemistry data, Phase change data, References

Symbols used in this document:

C_p,solid	Constant pressure heat capacity of solid
P_c	Critical pressure
P_triple	Triple point pressure
S°_{solid,1 bar}	Entropy of solid at standard conditions (1 bar)
T_boil	Boiling point
T_c	Critical temperature
T_fus	Fusion (melting) point
T_triple	Triple point temperature
ΔH_trs	Enthalpy of phase transition
ΔS_trs	Entropy of phase transition
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_cH°_solid	Enthalpy of combustion of solid at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions
Δ_fH°_solid	Enthalpy of formation of solid at standard conditions
Δ_fusH	Enthalpy of fusion
Δ_fusS	Entropy of fusion
Δ_subH	Enthalpy of sublimation
Δ_subH°	Enthalpy of sublimation at standard conditions
Δ_vapH	Enthalpy of vaporization

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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