Heptane, 3-methyl-
- Formula: C8H18
- Molecular weight: 114.2285
- IUPAC Standard InChIKey: LAIUFBWHERIJIH-UHFFFAOYSA-N
- CAS Registry Number: 589-81-1
- 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. - Isotopologues:
- Stereoisomers:
- Other names: 3-Methylheptane; 2-Ethylhexane
- Permanent link for this species. Use this link for bookmarking this species for future reference.
- Information on this page:
- Other data available:
- Data at other public NIST sites:
- Options:
Data at NIST subscription sites:
NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.
Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, References, Notes
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
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | -212.6 ± 1.1 | kJ/mol | Ccb | Prosen and Rossini, 1945 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°gas | 465.89 ± 0.84 | J/mol*K | N/A | Finke H.L., 1973 | GT |
Constant pressure heat capacity of gas
Cp,gas (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
132.67 | 200. | Scott D.W., 1974 | Recommended values were obtained from the consistent correlation scheme for alkanes [ Scott D.W., 1974, 2, Scott D.W., 1974]. This approach gives a good agreement with experimental data available for alkanes. However, large uncertainties could be expected at high temperatures.; GT |
172.30 | 273.15 | ||
185.8 ± 0.5 | 298.15 | ||
186.82 | 300. | ||
240.16 | 400. | ||
287.82 | 500. | ||
328.03 | 600. | ||
362.33 | 700. | ||
391.20 | 800. | ||
415.47 | 900. | ||
436.39 | 1000. | ||
454.38 | 1100. | ||
470.28 | 1200. | ||
485.34 | 1300. | ||
497.90 | 1400. | ||
510.45 | 1500. |
Condensed phase thermochemistry data
Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, References, Notes
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 | -252.5 ± 1.1 | kJ/mol | Ccb | Prosen and Rossini, 1945 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°liquid | -5468.2 ± 1.3 | kJ/mol | Ccb | Prosen and Rossini, 1945 | Corresponding ΔfHºliquid = -252.4 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°liquid | 362.6 | J/mol*K | N/A | Finke and Messerly, 1973 | Thermodynamic properties calculated from a Debye function at 10 K.; DH |
Constant pressure heat capacity of liquid
Cp,liquid (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
250.20 | 298.15 | Finke and Messerly, 1973 | T = 10 to 380 K.; DH |
249.66 | 298.15 | Osborne and Ginnings, 1947 | T = 293 to 318 K.; DH |
Phase change data
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, References, Notes
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:
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 | 392. ± 1. | K | AVG | N/A | Average of 27 out of 28 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 152. ± 1. | K | AVG | N/A | Average of 15 out of 16 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 152.65 | K | N/A | Finke and Messerly, 1973, 2 | Uncertainty assigned by TRC = 0.008 K; by exatroplation to 1/f = 0; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 563.6 ± 0.5 | K | N/A | Daubert, 1996 | |
Tc | 563.7 | K | N/A | Majer and Svoboda, 1985 | |
Tc | 563.60 | K | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.4 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 25.5 ± 0.4 | bar | N/A | Daubert, 1996 | |
Pc | 25.460 | bar | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.4053 bar; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Vc | 0.464 | l/mol | N/A | Daubert, 1996 | |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 2.15 ± 0.04 | mol/l | N/A | Daubert, 1996 | |
ρc | 2.15 | mol/l | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.04 mol/l; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 39.88 | kJ/mol | N/A | Majer and Svoboda, 1985 | |
ΔvapH° | 39.8 ± 0.2 | kJ/mol | C | An, Hu, et al., 1987 | AC |
ΔvapH° | 39.8 | kJ/mol | N/A | Reid, 1972 | AC |
ΔvapH° | 39.8 ± 0.1 | kJ/mol | C | Osborne and Ginnings, 1947, 2 | AC |
ΔvapH° | 39.83 | kJ/mol | C | Osborne and Ginnings, 1947 | ALS |
Enthalpy of vaporization
ΔvapH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
33.66 | 392.1 | N/A | Majer and Svoboda, 1985 | |
40.1 | 301. | A | Stephenson and Malanowski, 1987 | Based on data from 286. to 393. K.; AC |
41.6 | 271. | IP | Stephenson and Malanowski, 1987 | Based on data from 238. to 286. K. See also Osborn and Douslin, 1974.; AC |
38.3 | 331. | MM | Willingham, Taylor, et al., 1945 | Based on data from 316. to 393. K.; AC |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (bar)
T = temperature (K)
View plot Requires a JavaScript / HTML 5 canvas capable browser.
Temperature (K) | A | B | C | Reference | Comment |
---|---|---|---|---|---|
238. to 288. | 4.51248 | 1568.919 | -40.686 | Osborn and Douslin, 1974 | Coefficents calculated by NIST from author's data. |
315.82 to 392.96 | 4.02435 | 1331.53 | -60.555 | Williamham, Taylor, et al., 1945 |
Enthalpy of fusion
ΔfusH (kJ/mol) | Temperature (K) | Reference | Comment |
---|---|---|---|
11.67 | 152.6 | Domalski and Hearing, 1996 | AC |
Enthalpy of phase transition
ΔHtrs (kJ/mol) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
11.694 | 152.6574 | crystaline, I | liquid | Finke and Messerly, 1973 | DH |
Entropy of phase transition
ΔStrs (J/mol*K) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
7.665 | 152.6574 | crystaline, I | liquid | Finke and Messerly, 1973 | DH |
Reaction thermochemistry data
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, 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
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: C8H18 = C8H18
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -2.6 ± 0.79 | kJ/mol | Ciso | Prosen and Rossini, 1945, 2 | liquid phase; Calculated from ΔHc |
By formula: C8H16 + H2 = C8H18
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -124.6 ± 0.6 | kJ/mol | Chyd | Rogers, Dejroongruang, et al., 1992 | liquid phase; solvent: Cyclohexane |
By formula: C8H18 = C8H18
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1.86 ± 0.42 | kJ/mol | Eqk | Roganov, Kabo, et al., 1972 | gas phase; At 1368 K |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, 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]
Finke H.L., 1973
Finke H.L.,
3-Methylpentane and 3-methylheptane: low-temperature thermodynamic properties,
J. Chem. Thermodyn., 1973, 5, 247-257. [all data]
Scott D.W., 1974
Scott D.W.,
Chemical Thermodynamic Properties of Hydrocarbons and Related Substances. Properties of the Alkane Hydrocarbons, C1 through C10 in the Ideal Gas State from 0 to 1500 K. U.S. Bureau of Mines, Bulletin 666, 1974. [all data]
Scott D.W., 1974, 2
Scott D.W.,
Correlation of the chemical thermodynamic properties of alkane hydrocarbons,
J. Chem. Phys., 1974, 60, 3144-3165. [all data]
Finke and Messerly, 1973
Finke, H.L.; Messerly, J.F.,
3-Methylpentane and 3-methylheptane: low-temperature thermodynamic properties,
J. Chem. Thermodynam., 1973, 5, 247-257. [all data]
Osborne and Ginnings, 1947
Osborne, N.S.; Ginnings, D.C.,
Measurements of heat of vaporization and heat capacity of a number of hydrocarbons,
J. Res. NBS, 1947, 39, 453-477. [all data]
Finke and Messerly, 1973, 2
Finke, H.L.; Messerly, J.F.,
3-Methylpentane and 3-Methylheptane: Low-temperature Thermo. Properties properties,
J. Chem. Thermodyn., 1973, 5, 247. [all data]
Daubert, 1996
Daubert, T.E.,
Vapor-Liquid Critical Properties of Elements and Compounds. 5. Branched Alkanes and Cycloalkanes,
J. Chem. Eng. Data, 1996, 41, 365-372. [all data]
Majer and Svoboda, 1985
Majer, V.; Svoboda, V.,
Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation, Blackwell Scientific Publications, Oxford, 1985, 300. [all data]
McMicking and Kay, 1965
McMicking, J.H.; Kay, W.B.,
Vapor Pressures and Saturated Liquid and Vapor Densities of The Isomeric Heptanes and Isomeric Octanes,
Proc., Am. Pet. Inst., Sect. 3, 1965, 45, 75-90. [all data]
An, Hu, et al., 1987
An, Xuwu; Hu, Riheng; Wang, Hu; Wu, Mali; Zou, Yongkuang,
Enthalpies of Vaporization of α- and β-Pinene,
Acta Phys. Chim. Sin., 1987, 3, 6, 668-671, https://doi.org/10.3866/PKU.WHXB19870621
. [all data]
Reid, 1972
Reid, Robert C.,
Handbook on vapor pressure and heats of vaporization of hydrocarbons and related compounds, R. C. Wilhort and B. J. Zwolinski, Texas A Research Foundation. College Station, Texas(1971). 329 pages.$10.00,
AIChE J., 1972, 18, 6, 1278-1278, https://doi.org/10.1002/aic.690180637
. [all data]
Osborne and Ginnings, 1947, 2
Osborne, Nathan S.; Ginnings, Defoe C.,
Measurements of heat of vaporization and heat capacity of a number of hydrocarbons,
J. RES. NATL. BUR. STAN., 1947, 39, 5, 453-17, https://doi.org/10.6028/jres.039.031
. [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]
Osborn and Douslin, 1974
Osborn, Ann G.; Douslin, Donald R.,
Vapor-pressure relations for 15 hydrocarbons,
J. Chem. Eng. Data, 1974, 19, 2, 114-117, https://doi.org/10.1021/je60061a022
. [all data]
Willingham, Taylor, et al., 1945
Willingham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D.,
Vapor pressures and boiling points of some paraffin, alkylcyclopentane, alkylcyclohexane, and alkylbenzene hydrocarbons,
J. RES. NATL. BUR. STAN., 1945, 35, 3, 219-17, https://doi.org/10.6028/jres.035.009
. [all data]
Williamham, Taylor, et al., 1945
Williamham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D.,
Vapor Pressures and Boiling Points of Some Paraffin, Alkylcyclopentane, Alkylcyclohexane, and Alkylbenzene Hydrocarbons,
J. Res. Natl. Bur. Stand. (U.S.), 1945, 35, 3, 219-244, https://doi.org/10.6028/jres.035.009
. [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]
Prosen and Rossini, 1945, 2
Prosen, E.J.; Rossini, F.D.,
Heats of isomerization of the 18 octanes,
J. Res. NBS, 1945, 34, 163-174. [all data]
Rogers, Dejroongruang, et al., 1992
Rogers, D.W.; Dejroongruang, K.; Samuel, S.D.; Fang, W.; Zhao, Y.,
Enthalpies of hydrogenation of the octenes and the methylheptenes,
J. Chem. Thermodyn., 1992, 24, 561-565. [all data]
Roganov, Kabo, et al., 1972
Roganov, G.N.; Kabo, G.Ya.; Andreevskii, D.N.,
Thermodynamics of the isomerization of methylpentanes and methylheptanes,
Neftekhimiya, 1972, 12, 495-500. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, References
- Symbols used in this document:
Cp,gas Constant pressure heat capacity of gas Cp,liquid Constant pressure heat capacity of liquid Pc Critical pressure S°gas Entropy of gas at standard conditions S°liquid Entropy of liquid at standard conditions 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 ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔfusH Enthalpy of fusion ΔrH° Enthalpy of reaction 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
- The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.