Octane
- Formula: C8H18
- Molecular weight: 114.2285
- IUPAC Standard InChIKey: TVMXDCGIABBOFY-UHFFFAOYSA-N
- CAS Registry Number: 111-65-9
- 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:
- Other names: n-Octane; n-C8H18; Oktan; Oktanen; Ottani; UN 1262
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Phase change data
Go To: Top, Gas phase ion energetics 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
BS - Robert L. Brown and Stephen E. Stein
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 | 398.7 ± 0.5 | K | AVG | N/A | Average of 75 out of 89 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 216.3 ± 0.3 | K | AVG | N/A | Average of 39 out of 41 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 216.2 ± 0.6 | K | AVG | N/A | Average of 9 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 568.9 ± 0.5 | K | AVG | N/A | Average of 23 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 24.6 ± 0.1 | atm | AVG | N/A | Average of 12 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Vc | 0.492 | l/mol | N/A | Ambrose and Tsonopoulos, 1995 | |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 2.034 ± 0.007 | mol/l | AVG | N/A | Average of 7 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 10. ± 1. | kcal/mol | AVG | N/A | Average of 10 values; Individual data points |
Enthalpy of vaporization
ΔvapH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
8.224 | 398.8 | N/A | Majer and Svoboda, 1985 | |
9.42 | 338. | EB | Ewing and Ochoa, 2003 | Based on data from 323. to 563. K.; AC |
9.80 | 312. | A | Stephenson and Malanowski, 1987 | Based on data from 297. to 400. K.; AC |
10.6 | 263. | A | Stephenson and Malanowski, 1987 | Based on data from 216. to 278. K.; AC |
8.68 | 411. | A | Stephenson and Malanowski, 1987 | Based on data from 396. to 432. K.; AC |
8.48 | 443. | A | Stephenson and Malanowski, 1987 | Based on data from 428. to 510. K.; AC |
8.34 | 521. | A | Stephenson and Malanowski, 1987 | Based on data from 506. to 569. K.; AC |
9.85 | 310. | N/A | Paul, Krug, et al., 1986 | Based on data from 295. to 402. K.; AC |
10.0 | 313. | N/A | Michou-Saucet, Jose, et al., 1984 | Based on data from 298. to 333. K.; AC |
9.68 ± 0.02 | 313. | C | Majer, Svoboda, et al., 1979 | AC |
9.35 ± 0.02 | 333. | C | Majer, Svoboda, et al., 1979 | AC |
9.03 ± 0.02 | 353. | C | Majer, Svoboda, et al., 1979 | AC |
10.3 | 282. | N/A | Carruth and Kobayashi, 1973 | Based on data from 217. to 297. K.; AC |
9.08 ± 0.02 | 311. | C | McKay and Sage, 1960 | AC |
8.77 ± 0.02 | 328. | C | McKay and Sage, 1960 | AC |
8.46 ± 0.02 | 344. | C | McKay and Sage, 1960 | AC |
9.37 | 341. | MM | Willingham, Taylor, et al., 1945 | Based on data from 326. to 400. K.; AC |
Enthalpy of vaporization
ΔvapH = A exp(-αTr)
(1 − Tr)β
ΔvapH =
Enthalpy of vaporization (at saturation pressure)
(kcal/mol)
Tr = reduced temperature (T / Tc)
View plot Requires a JavaScript / HTML 5 canvas capable browser.
Temperature (K) | 298. to 426. |
---|---|
A (kcal/mol) | 13.97 |
α | 0.1834 |
β | 0.3324 |
Tc (K) | 568.8 |
Reference | Majer and Svoboda, 1985 |
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 |
---|---|---|---|---|---|
216.59 to 297.10 | 5.1955 | 1936.281 | -20.143 | Carruth and Kobayashi, 1973 | Coefficents calculated by NIST from author's data. |
326.08 to 399.72 | 4.04296 | 1355.126 | -63.633 | Williamham, Taylor, et al., 1945 |
Enthalpy of sublimation
ΔsubH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
16.3 | 216. | B | Bondi, 1963 | AC |
Enthalpy of fusion
ΔfusH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
4.9570 | 216.38 | N/A | Finke, Gross, et al., 1954 | DH |
5.21 | 216.6 | DSC | Mondieig, Rajabalee, et al., 2004 | AC |
4.957 | 216.4 | N/A | Domalski and Hearing, 1996 | AC |
4.9359 | 215.8 | N/A | Huffman, Parks, et al., 1931 | DH |
4.8021 | 215.6 | N/A | Parks, Huffman, et al., 1930 | DH |
Entropy of fusion
ΔfusS (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
22.91 | 216.38 | Finke, Gross, et al., 1954 | DH |
22.9 | 215.8 | Huffman, Parks, et al., 1931 | DH |
22.27 | 215.6 | Parks, Huffman, et al., 1930 | DH |
Gas phase ion energetics data
Go To: Top, 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 evaluated as indicated in comments:
L - Sharon G. Lias
Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 9.80 ± 0.15 | eV | N/A | N/A | L |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
10.01 | EST | Luo and Pacey, 1992 | LL |
9.80 ± 0.10 | EVAL | Lias, 1982 | LBLHLM |
9.71 ± 0.15 | EQ | Mautner(Meot-Ner), Sieck, et al., 1981 | LLK |
9.79 | EQ | Lias, Ausloos, et al., 1976 | LLK |
10.25 | EI | Potzinger and Bunau, 1969 | RDSH |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
C2H5+ | 13.44 | ? | EI | Potzinger and Bunau, 1969 | RDSH |
C3H7+ | 11.89 | ? | EI | Potzinger and Bunau, 1969 | RDSH |
C4H8+ | 11.19 ± 0.07 | C4H10 | PI | Steiner, Giese, et al., 1961 | RDSH |
C4H9+ | 11.12 | n-C4H9? | EI | Potzinger and Bunau, 1969 | RDSH |
C4H9+ | 11.40 ± 0.07 | n-C4H9? | PI | Steiner, Giese, et al., 1961 | RDSH |
C5H10+ | 11.08 ± 0.03 | C3H8 | PI | Steiner, Giese, et al., 1961 | RDSH |
C5H11+ | 11.03 | C3H7 | EI | Potzinger and Bunau, 1969 | RDSH |
C5H11+ | 11.22 ± 0.085 | C3H7 | PI | Steiner, Giese, et al., 1961 | RDSH |
C6H12+ | 10.29 | C2H6 | EI | Lewis and Hamill, 1970 | RDSH |
C6H12+ | 10.81 ± 0.03 | C2H6 | PI | Steiner, Giese, et al., 1961 | RDSH |
C6H13+ | 10.91 ± 0.035 | C2H5 | PI | Steiner, Giese, et al., 1961 | RDSH |
C7H15+ | ~10.90 ± 0.10 | CH3 | PI | Steiner, Giese, et al., 1961 | RDSH |
References
Go To: Top, Phase change data, Gas phase ion energetics data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
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]
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]
Ewing and Ochoa, 2003
Ewing, M.B.; Ochoa, J.C. Sanchez,
The vapour pressures of n-octane determined using comparative ebulliometry,
Fluid Phase Equilibria, 2003, 210, 2, 277-285, https://doi.org/10.1016/S0378-3812(03)00174-2
. [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]
Paul, Krug, et al., 1986
Paul, Hanns-Ingolf; Krug, Joseph; Knapp, Helmut,
Measurements of VLE, hE and vE for binary mixtures of n-alkanes with n-alkylbenzenes,
Thermochimica Acta, 1986, 108, 9-27, https://doi.org/10.1016/0040-6031(86)85073-0
. [all data]
Michou-Saucet, Jose, et al., 1984
Michou-Saucet, Marie-Annie; Jose, Jacques; Michou-Saucet, Christian; Merlin, J.C.,
Pressions de vapeur et enthalpies libres d'exces de systemes binaires: Hexamethylphosphorotriamide (HMPT) + n-hexane; n-heptane; n-octane: A 298,15 K; 303,15 K; 313,15 K; 323,15 K; 333,15 K,
Thermochimica Acta, 1984, 75, 1-2, 85-106, https://doi.org/10.1016/0040-6031(84)85009-1
. [all data]
Majer, Svoboda, et al., 1979
Majer, Vladimír; Svoboda, Václav; Hála, Slavoj; Pick, Jirí,
Temperature dependence of heats of vaporization of saturated hydrocarbons C5-C8; Experimental data and an estimation method,
Collect. Czech. Chem. Commun., 1979, 44, 3, 637-651, https://doi.org/10.1135/cccc19790637
. [all data]
Carruth and Kobayashi, 1973
Carruth, Grant F.; Kobayashi, Riki,
Vapor pressure of normal paraffins ethane through n-decane from their triple points to about 10 mm mercury,
J. Chem. Eng. Data, 1973, 18, 2, 115-126, https://doi.org/10.1021/je60057a009
. [all data]
McKay and Sage, 1960
McKay, R.A.; Sage, B.H.,
Latent Heat of Vaporization for n-Octane.,
J. Chem. Eng. Data, 1960, 5, 1, 21-24, https://doi.org/10.1021/je60005a005
. [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]
Bondi, 1963
Bondi, A.,
Heat of Siblimation of Molecular Crystals: A Catalog of Molecular Structure Increments.,
J. Chem. Eng. Data, 1963, 8, 3, 371-381, https://doi.org/10.1021/je60018a027
. [all data]
Finke, Gross, et al., 1954
Finke, H.L.; Gross, M.E.; Waddington, G.; Huffman, H.M.,
Low-temperature thermal data for the nine normal paraffin hydrocarbons from octane to hexadecane,
J. Am. Chem. Soc., 1954, 76, 333-341. [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]
Huffman, Parks, et al., 1931
Huffman, H.M.; Parks, G.S.; Barmore, M.,
Thermal data on organic compounds. X. Further studies on the heat capacities, entropies and free energies of hydrocarbons,
J. Am. Chem. Soc., 1931, 53, 3876-3888. [all data]
Parks, Huffman, et al., 1930
Parks, G.S.; Huffman, H.M.; Thomas, S.B.,
Thermal data on organic compounds. VI. The heat capacities, entropies and free energies of some saturated, non-benzenoid hydrocarbons,
J. Am. Chem. Soc., 1930, 52, 1032-1041. [all data]
Luo and Pacey, 1992
Luo, Y.-R.; Pacey, P.D.,
Effects of alkyl substitution on ionization energies of alkanes and haloalkanes and on heats of formation of their molecular cations. Part 2. Alkanes and chloro-, bromo- and iodoalkanes,
Int. J. Mass Spectrom. Ion Processes, 1992, 112, 63. [all data]
Lias, 1982
Lias, S.G.,
Thermochemical information from ion-molecule rate constants,
Ion Cyclotron Reson. Spectrom. 1982, 1982, 409. [all data]
Mautner(Meot-Ner), Sieck, et al., 1981
Mautner(Meot-Ner), M.; Sieck, L.W.; Ausloos, P.,
Ionization of normal alkanes: Enthalpy, entropy, structural, and isotope effects,
J. Am. Chem. Soc., 1981, 103, 5342. [all data]
Lias, Ausloos, et al., 1976
Lias, S.G.; Ausloos, P.; Horvath, Z.,
Charge transfer reactions in alkane and cycloalkane systems. Estimated ionization potentials,
Int. J. Chem. Kinet., 1976, 8, 725. [all data]
Potzinger and Bunau, 1969
Potzinger, P.; Bunau, G.v.,
Empirische Beruksichtigung von Uberschussenergien bei der Auftrittspotentialbestimmung,
Ber. Bunsen-Ges. Phys. Chem., 1969, 73, 466. [all data]
Steiner, Giese, et al., 1961
Steiner, B.; Giese, C.F.; Inghram, M.G.,
Photoionization of alkanes. Dissociation of excited molecular ions,
J. Chem. Phys., 1961, 34, 189. [all data]
Lewis and Hamill, 1970
Lewis, D.; Hamill, W.H.,
Excited states of neutral molecular fragments from appearance potentials by electron impact in a mass spectrometer,
J. Chem. Phys., 1970, 52, 6348. [all data]
Notes
Go To: Top, Phase change data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy IE (evaluated) Recommended ionization energy Pc Critical pressure Tboil Boiling point Tc Critical temperature Tfus Fusion (melting) point Ttriple Triple point temperature Vc Critical volume ΔfusH Enthalpy of fusion ΔfusS Entropy of fusion ΔsubH Enthalpy of sublimation 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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