Octadecane
- Formula: C18H38
- Molecular weight: 254.4943
- IUPAC Standard InChIKey: RZJRJXONCZWCBN-UHFFFAOYSA-N
- CAS Registry Number: 593-45-3
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: n-Octadecane; Octadecan
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Gas phase thermochemistry data
Go To: Top, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), Gas Chromatography, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | -99.08 ± 0.64 | kcal/mol | Ccb | Prosen and Rossini, 1945 |
Phase change 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:
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 |
---|---|---|---|---|---|
Tboil | 589.3 | K | N/A | Weast and Grasselli, 1989 | BS |
Tboil | 581. | K | N/A | Matsui and Arakawa, 1932 | Uncertainty assigned by TRC = 3. K; TRC |
Tboil | 581.65 | K | N/A | Von Braun and Sobecki, 1911 | Uncertainty assigned by TRC = 2.5 K; TRC |
Tboil | 585.65 | K | N/A | Sorabji, 1885 | Uncertainty assigned by TRC = 2. K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 301.0 ± 0.7 | K | AVG | N/A | Average of 35 out of 37 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 301. | K | N/A | Messerly, Guthrie, et al., 1967 | Uncertainty assigned by TRC = 0.04 K; TRC |
Ttriple | 301.3 | K | N/A | Parks, Moore, et al., 1949 | Uncertainty assigned by TRC = 0.2 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 747. ± 3. | K | N/A | Ambrose and Tsonopoulos, 1995 | |
Tc | 745.8 | K | N/A | Anselme, Gude, et al., 1990 | Uncertainty assigned by TRC = 3.4 K; TRC |
Tc | 747.7 | K | N/A | Rosenthal and Teja, 1989 | Uncertainty assigned by TRC = 1. K; TRC |
Tc | 747.2 | K | N/A | Teja, Lee, et al., 1989 | TRC |
Tc | 756.15 | K | N/A | Ambrose, 1963 | Uncertainty assigned by TRC = 0.005 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 13. ± 2. | atm | N/A | Ambrose and Tsonopoulos, 1995 | |
Pc | 12.75 | atm | N/A | Rosenthal and Teja, 1989 | Uncertainty assigned by TRC = 1.09 atm; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Vc | 1.189 | l/mol | N/A | Ambrose and Tsonopoulos, 1995 | |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 0.8 ± 0.2 | mol/l | N/A | Ambrose and Tsonopoulos, 1995 | |
ρc | 0.841 | mol/l | N/A | Anselme, Gude, et al., 1990 | Uncertainty assigned by TRC = 0.02 mol/l; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 21.9 ± 0.3 | kcal/mol | AVG | N/A | Average of 8 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
ΔsubH° | 36.50 | kcal/mol | C | Morawetz, 1972 | AC |
Enthalpy of vaporization
ΔvapH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
17.8 | 428. | N/A | Morgan and Kobayashi, 1994 | Based on data from 413. to 588. K.; AC |
15.5 | 516. | A | Stephenson and Malanowski, 1987 | Based on data from 501. to 548. K.; AC |
20.1 | 333. | A,GS | Stephenson and Malanowski, 1987 | Based on data from 318. to 361. K. See also Macknick and Prausnitz, 1979.; AC |
19.1 | 348. | GS | Allemand, Jose, et al., 1986 | Based on data from 335. to 439. K.; AC |
17.3 | 343. | GC | Nováková and Novák, 1977 | AC |
17.2 | 353. | GC | Nováková and Novák, 1977 | AC |
17.0 | 363. | GC | Nováková and Novák, 1977 | AC |
16.8 | 373. | GC | Nováková and Novák, 1977 | AC |
16.7 | 383. | GC | Nováková and Novák, 1977 | AC |
18.7 | 460. | ME | Ubbelohde, 1938 | Based on data from 447. to 474. K.; AC |
16.6 | 462. | N/A | Krafft, 1882 | Based on data from 447. to 590. K. See also Boublik, Fried, et al., 1984.; AC |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (atm)
T = temperature (K)
View plot Requires a JavaScript / HTML 5 canvas capable browser.
Temperature (K) | A | B | C | Reference | Comment |
---|---|---|---|---|---|
447.7 to 590. | 4.32638 | 2068.963 | -111.927 | Krafft, 1882 | Coefficents calculated by NIST from author's data. |
Enthalpy of sublimation
ΔsubH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
36.6 ± 1.2 | 288. | V | Bradley and Shellard, 1949 | hfusion=14.94±2.0 kcal/mol; ALS |
37. ± 1. | 293. | ME | Bradley and Shellard, 1949 | Based on data from 288. to 298. K. See also Jones, 1960 and Cox and Pilcher, 1970.; AC |
Enthalpy of fusion
ΔfusH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
14.699 | 301.5 | N/A | Barbillon, Schuffenecker, et al., 1991 | DH |
14.522 | 301.0 | N/A | Kolesnikov and Syunyaev, 1985 | DH |
14.748 | 301.33 | N/A | Messerly, Guthrie, et al., 1967, 2 | DH |
14.4 | 301.1 | DSC | Mondieig, Rajabalee, et al., 2004 | AC |
14.7 | 301.3 | N/A | Domalski and Hearing, 1996 | AC |
14.456 | 301.3 | N/A | Parks, Moore, et al., 1949, 2 | DH |
Entropy of fusion
ΔfusS (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
48.26 | 301.0 | Kolesnikov and Syunyaev, 1985 | DH |
48.90 | 301.33 | Messerly, Guthrie, et al., 1967, 2 | DH |
47.97 | 301.3 | Parks, Moore, et al., 1949, 2 | DH |
Enthalpy of phase transition
ΔHtrs (kcal/mol) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
14.500 | 300.7 | crystaline, I | liquid | Claudy and Letoffe, 1991 | DH |
14.670 | 301.35 | crystaline, I | liquid | Schaerer, Busso, et al., 1955 | DH |
Entropy of phase transition
ΔStrs (cal/mol*K) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
48.66 | 301.35 | crystaline, I | liquid | Schaerer, Busso, et al., 1955 | DH |
Reaction 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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.
Individual Reactions
By formula: C18H36 + H2 = C18H38
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -30.08 ± 0.41 | kcal/mol | Chyd | Rogers and Skanupong, 1974 | liquid phase; solvent: Hexane |
Mass spectrum (electron ionization)
Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas Chromatography, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Due to licensing restrictions, this spectrum cannot be downloaded.
Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
NIST MS number | 12337 |
Gas Chromatography
Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Lee's RI, non-polar column, temperature ramp
Column type | Active phase | I | Reference | Comment |
---|---|---|---|---|
Capillary | DB-5MS | 296.84 | Chen, Keeran, et al., 2002 | 30. m/0.25 mm/0.5 μm, 40. C @ 1. min, 10. K/min; Tend: 310. C |
Capillary | DB-5MS | 301.71 | Chen, Keeran, et al., 2002 | 30. m/0.25 mm/0.5 μm, 40. C @ 1. min, 4. K/min; Tend: 310. C |
References
Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), Gas Chromatography, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Prosen and Rossini, 1945
Prosen, E.J.; Rossini, F.D.,
Heats of combustion and formation of the paraffin hydrocarbons at 25° C,
J. Res. NBS, 1945, 263-267. [all data]
Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]
Matsui and Arakawa, 1932
Matsui, M.; Arakawa, S.,
Mem. Coll. Sci., Univ. Kyoto, Ser. A, 1932, 15, 189. [all data]
Von Braun and Sobecki, 1911
Von Braun, J.; Sobecki, W.,
Chem. Ber., 1911, 44, 1470. [all data]
Sorabji, 1885
Sorabji, K.B.B.,
J. Chem. Soc., 1885, 47, 37-41. [all data]
Messerly, Guthrie, et al., 1967
Messerly, J.F.; Guthrie, G.B.; Todd, S.S.; Finke, H.L.,
Low-Temperature Thermal Data for n-Pentane, n-Heptadecane and n-Octadecane. Revised Thermodynamic Functions for ther n-Alkanes, C5 - C18,
J. Chem. Eng. Data, 1967, 12, 338-46. [all data]
Parks, Moore, et al., 1949
Parks, G.S.; Moore, G.E.; Renquist, M.L.; Naylor, B.F.; McClaine, L.A.; Fujii, P.S.; Hatton, J.A.,
Thermal Data on Organic Compounds. XXV. Some Heat Capacity, Entropy and Free Energy Data for Nine Hydrocarbons of High Molecular Weight,
J. Am. Chem. Soc., 1949, 71, 10, 3386, https://doi.org/10.1021/ja01178a034
. [all data]
Ambrose and Tsonopoulos, 1995
Ambrose, D.; Tsonopoulos, C.,
Vapor-Liquid Critical Properties of Elements and Compounds. 2. Normal Alkenes,
J. Chem. Eng. Data, 1995, 40, 531-546. [all data]
Anselme, Gude, et al., 1990
Anselme, M.J.; Gude, M.; Teja, A.S.,
The Critical Temperatures and Densities of the n-Alkanes from Pentane to Octadecane,
Fluid Phase Equilib., 1990, 57, 317-26. [all data]
Rosenthal and Teja, 1989
Rosenthal, D.J.; Teja, A.S.,
The Critical Properties of n-Alkanes Using a Low-Residence Time Flow Apparatus,
AIChE J., 1989, 35, 1829. [all data]
Teja, Lee, et al., 1989
Teja, A.S.; Lee, R.J.; Rosenthal, D.J.; Anselme, M.J.,
Correlation of the Critical Properties of Alkanes and Alkanols
in 5th IUPAC Conference on Alkanes and AlkanolsGradisca, 1989. [all data]
Ambrose, 1963
Ambrose, D.,
Critical Temperatures of Some Phenols and Other Organic Compounds,
Trans. Faraday Soc., 1963, 59, 1988. [all data]
Morawetz, 1972
Morawetz, Ernst,
Correlation of sublimation enthalpies at 298.15 K with molecular structure for planar aromatic hydrocarbons,
The Journal of Chemical Thermodynamics, 1972, 4, 3, 461-467, https://doi.org/10.1016/0021-9614(72)90030-4
. [all data]
Morgan and Kobayashi, 1994
Morgan, David L.; Kobayashi, Riki,
Direct vapor pressure measurements of ten n-alkanes m the 10-C28 range,
Fluid Phase Equilibria, 1994, 97, 211-242, https://doi.org/10.1016/0378-3812(94)85017-8
. [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]
Macknick and Prausnitz, 1979
Macknick, A. Brian; Prausnitz, John M.,
Vapor pressures of high-molecular-weight hydrocarbons,
J. Chem. Eng. Data, 1979, 24, 3, 175-178, https://doi.org/10.1021/je60082a012
. [all data]
Allemand, Jose, et al., 1986
Allemand, Nadine; Jose, Jacques; Merlin, J.C.,
Mesure des pressions de vapeur d'hydrocarbures C10 A C18n-alcanes etn-alkylbenzenes dans le domaine 3-1000 pascal,
Thermochimica Acta, 1986, 105, 79-90, https://doi.org/10.1016/0040-6031(86)85225-X
. [all data]
Nováková and Novák, 1977
Nováková, N.; Novák, J.,
Measurement of heats of vaporization by means of a gas chromatograph,
Journal of Chromatography A, 1977, 135, 1, 13-24, https://doi.org/10.1016/S0021-9673(00)86297-4
. [all data]
Ubbelohde, 1938
Ubbelohde, A.R.,
Structure and thermodynamic properties of long-chain compounds,
Trans. Faraday Soc., 1938, 34, 282, https://doi.org/10.1039/tf9383400282
. [all data]
Krafft, 1882
Krafft, F.,
Ueber neunzehn höhere Normalparaffine Cn H2n + 2 und ein einfaches Volumgesetz für den tropfbar flüssigen Zustand. I,
Ber. Dtsch. Chem. Ges., 1882, 15, 2, 1687-1711, https://doi.org/10.1002/cber.18820150258
. [all data]
Boublik, Fried, et al., 1984
Boublik, T.; Fried, V.; Hala, E.,
The Vapour Pressures of Pure Substances: Selected Values of the Temperature Dependence of the Vapour Pressures of Some Pure Substances in the Normal and Low Pressure Region, 2nd ed., Elsevier, New York, 1984, 972. [all data]
Bradley and Shellard, 1949
Bradley, R.S.; Shellard, A.D.,
The rate of evaporation of droplets. III. Vapour pressures and rates of evaporation of straight-chain paraffin hydrocarbons,
Proc. Roy. Soc. London A, 1949, 198, 239-251. [all data]
Jones, 1960
Jones, A.H.,
Sublimation Pressure Data for Organic Compounds.,
J. Chem. Eng. Data, 1960, 5, 2, 196-200, https://doi.org/10.1021/je60006a019
. [all data]
Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds, Academic Press Inc., London, 1970, 643. [all data]
Barbillon, Schuffenecker, et al., 1991
Barbillon, P.; Schuffenecker, L.; Dellacherie, J.; Balesdent, D.; Dirande, M.,
Variation d'enthalpie subie de 260 K a 340 K par les n-paraffines, comprises entrel'octadecane et l'hexacosane,
J. Chim. Phys. Phys.-Chim. Biol., 1991, 88, 91-113. [all data]
Kolesnikov and Syunyaev, 1985
Kolesnikov, S.I.; Syunyaev, Z.I.,
Phase transitions in the melting and crystallization of n-C18H38 and n-C20H42,
Zhur. Prikl. Khim. (Leningrad), 1985, 58(10), 2267-2271. [all data]
Messerly, Guthrie, et al., 1967, 2
Messerly, J.F.; Guthrie, G.B.; Todd, S.S.; Finke, H.L.,
Low-temperature thermal data for n-pentane, n-heptadecane, and n-octadecane,
J. Chem. Eng. Data, 1967, 12, 338-346. [all data]
Mondieig, Rajabalee, et al., 2004
Mondieig, D.; Rajabalee, F.; Metivaud, V.; Oonk, H.A.J.; Cuevas-Diarte, M.A.,
n -Alkane Binary Molecular Alloys,
Chem. Mater., 2004, 16, 5, 786-798, https://doi.org/10.1021/cm031169p
. [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]
Parks, Moore, et al., 1949, 2
Parks, G.S.; Moore, G.E.; Renquist, M.L.; Naylor, B.F.; McClaine, L.A.; Fujii, P.S.; Hatton, J.A.,
Thermal data on organic compounds. XXV. Some heat capacity, entropy and free energy data for nine hydrocarbons of high molecular weight,
J. Am. Chem. Soc., 1949, 71, 3386-3389. [all data]
Claudy and Letoffe, 1991
Claudy, P.; Letoffe, J.M.,
Phase transitions in even n-alkanes CnH2n+2, n = 16-28. Characterization by differential calorimetric analysis and by thermooptical analysis. Effect of deuteration,
Calorim. Anal. Therm., 1991, 22, 281-290. [all data]
Schaerer, Busso, et al., 1955
Schaerer, A.A.; Busso, C.J.; Smith, A.E.; Skinner, L.B.,
Properties of pure normal alkanes in the C17 to C36 range,
J. Am. Chem. Soc., 1955, 77, 2017-2019. [all data]
Rogers and Skanupong, 1974
Rogers, D.W.; Skanupong, S.,
Heats of hydrogenation of sixteen terminal monoolefins. The alternating effect,
J. Phys. Chem., 1974, 78, 2569-2572. [all data]
Chen, Keeran, et al., 2002
Chen, P.H.; Keeran, W.S.; Van Ausdale, W.A.; Schindler, D.R.; Roberts, D.W.,
Application of Lee retention indices to the confirmation of tentatively identified compounds from GC/MS analysis of environmental samples, Technical paper, Analytical Services Division, Environmental ScienceEngineering, Inc, PO Box 1703, Gainesville, FL 32602, 2002, 11. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), Gas Chromatography, References
- Symbols used in this document:
Pc Critical pressure Tboil Boiling point Tc Critical temperature Tfus Fusion (melting) point Ttriple Triple point temperature Vc Critical volume ΔHtrs Enthalpy of phase transition ΔStrs Entropy of phase transition ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfusH Enthalpy of fusion ΔfusS Entropy of fusion ΔrH° Enthalpy of reaction at standard conditions ΔsubH Enthalpy of sublimation ΔsubH° Enthalpy of sublimation at standard conditions ΔvapH Enthalpy of vaporization ΔvapH° Enthalpy of vaporization at standard conditions ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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