Benzene, pentamethyl-

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Gas 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
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity Value Units Method Reference Comment
Δfgas-67.2 ± 2.2kJ/molCcbColomina, Jimenez, et al., 1989see Boned, Colomina, et al., 1964; ALS
Δfgas-57.7kJ/molN/AParks, West, et al., 1946Value computed using ΔfHsolid° value of -135.1±2.6 kj/mol from Parks, West, et al., 1946 and ΔsubH° value of 77.4 kj/mol from Colomina, Jimenez, et al., 1989.; DRB

Constant pressure heat capacity of gas

Cp,gas (J/mol*K) Temperature (K) Reference Comment
162.3200.Draeger, 1985There is an appreciable difference between values of S(T) and Cp(T) for tetra-, penta-, and hexamethylbenzene from earlier statistical thermodynamics calculation [ Hastings S.H., 1957] and those obtained by [ Draeger, 1985] (up to 5, 9, and 16 J/mol*K, respectively). Results [ Draeger, 1985] are more reliable and they agree with experimental data for hexamethylbenzene.; GT
199.7273.15
212.5 ± 0.4298.15
213.4300.
264.4400.
311.4500.
352.3600.
387.4700.
417.5800.
443.4900.
465.61000.
484.81100.
501.31200.
515.61300.
527.91400.
538.71500.

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
Δcliquid-6475.6 ± 6.3kJ/molCcbBanse and Parks, 1933Reanalyzed by Cox and Pilcher, 1970, Original value = -6470.64 kJ/mol; Corresponding Δfliquid = -139.7 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity Value Units Method Reference Comment
Δfsolid-144.6 ± 2.2kJ/molCcbColomina, Jimenez, et al., 1989see Boned, Colomina, et al., 1964; ALS
Δfsolid-135.1 ± 2.6kJ/molCcbParks, West, et al., 1946Reanalyzed by Cox and Pilcher, 1970, Original value = -135.7 ± 0.04 kJ/mol; ALS
Quantity Value Units Method Reference Comment
Δcsolid-6470.6 ± 1.6kJ/molCcbColomina, Jimenez, et al., 1989see Boned, Colomina, et al., 1964; Corresponding Δfsolid = -144.7 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δcsolid-6480.1 ± 2.6kJ/molCcbParks, West, et al., 1946Reanalyzed by Cox and Pilcher, 1970, Original value = -6479.6 ± 2.6 kJ/mol; Corresponding Δfsolid = -135.1 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity Value Units Method Reference Comment
solid,1 bar294.1J/mol*KN/AHuffman, Parks, et al., 1931crystaline, I phase; Extrapolation below 90 K, 102.9 J/mol*K.; DH

Constant pressure heat capacity of solid

Cp,solid (J/mol*K) Temperature (K) Reference Comment
210.5298.15Colomina, Jimenez, et al., 1989DH
270.3298.1Eibert, 1944crystaline, I phase; T = 25 to 200°C, equations only, in t°C. Cp(c) = 0.3914 + 0.001760t cal/g*K (25 to 40°C); Cp(liq) = 0.432 + 0.000425 t cal/g*K (55 to 200°C).; DH
267.3303.Ferry and Thomas, 1933T = 303 to 393 K.; DH
251.0283.8Huffman, Parks, et al., 1931crystaline, I phase; T = 92 to 304 K. Value is unsmoothed experimental datum.; DH

Gas phase ion energetics 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 evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias

Data compiled as indicated in comments:
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess

View reactions leading to C11H16+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
Proton affinity (review)850.7kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity823.5kJ/molN/AHunter and Lias, 1998HL

Electron affinity determinations

EA (eV) Method Reference Comment
<0.182 ± 0.013ECDWojnarovits and Foldiak, 1981EA is an upper limit: Chen and Wentworth, 1989,. G3MP2B3 calculations indicate an EA of ca. -0.5 eV, anion unbound.; B

Ionization energy determinations

IE (eV) Method Reference Comment
7.92PEHowell, Goncalves, et al., 1984LBLHLM
7.92PIBralsford, Harris, et al., 1960RDSH
7.9CTSFoster, 1959RDSH
7.92 ± 0.02PIVilesov and Terenin, 1957RDSH
7.92PEHowell, Goncalves, et al., 1984Vertical value; LBLHLM

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry 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.

Colomina, Jimenez, et al., 1989
Colomina, M.; Jimenez, P.; Roux, M.V.; Turrion, C., Thermochemical properties of 1,2,4,5-tetramethylbenzene, pentamethylbenzene, and hexamethylbenzene, J. Chem. Thermodyn., 1989, 21, 275-281. [all data]

Boned, Colomina, et al., 1964
Boned, M.L.; Colomina, M.; Perez-Ossorio, R.; Turrion, C., Investigaciones termoquimicas sobre los polimetilbencenos superiores, Anal. Fisc. Quim. B, 1964, 60, 459-468. [all data]

Parks, West, et al., 1946
Parks, G.S.; West, T.J.; Naylor, B.F.; Fujii, P.S.; McClaine, L.A., Thermal data on organic compounds. XXIII. Modern combustion data for fourteen hydrocarbons and five polyhydroxy alcohols, J. Am. Chem. Soc., 1946, 68, 2524-2527. [all data]

Draeger, 1985
Draeger, J.A., The methylbenzenes II. Fundamental vibrational shifts, statistical thermodynamic functions, and properties of formation, J. Chem. Thermodyn., 1985, 17, 263-275. [all data]

Hastings S.H., 1957
Hastings S.H., Thermodynamic properties of selected methylbenzenes from 0 to 1000 K, J. Phys. Chem., 1957, 61, 730-735. [all data]

Banse and Parks, 1933
Banse, H.; Parks, G.S., Thermal data on organic compounds. XII. The heats of combustion of nine hydrocarbons, J. Am. Chem. Soc., 1933, 55, 3223-3227. [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]

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]

Eibert, 1944
Eibert, J., Thesis Washington University (St. Louis), 1944. [all data]

Ferry and Thomas, 1933
Ferry, J.D.; Thomas, S.B., Some heat capacity data for durene, pentamethylbenzene, stilbene, and dibenzyl, J. Phys. Chem., 1933, 37, 253-255. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Wojnarovits and Foldiak, 1981
Wojnarovits, L.; Foldiak, G., Electron capture detection of aromatic hydrocarbons, J. Chromatogr. Sci., 1981, 206, 511. [all data]

Chen and Wentworth, 1989
Chen, E.C.M.; Wentworth, W.E., Experimental Determination of Electron Affinities of Organic Molecules, Mol. Cryst. Liq. Cryst., 1989, 171, 271. [all data]

Howell, Goncalves, et al., 1984
Howell, J.O.; Goncalves, J.M.; Amatore, C.; Klasinc, L.; Wightman, R.M.; Kochi, J.K., Electron transfer from aromatic hydrocarbons and their π-complexes with metals. Comparison of the standard oxidation potentials and vertical ionization potentials, J. Am. Chem. Soc., 1984, 106, 3968. [all data]

Bralsford, Harris, et al., 1960
Bralsford, R.; Harris, P.V.; Price, W.C., The effect of fluorine on the electronic spectra and ionization potentials of molecules, Proc. Roy. Soc. (London), 1960, A258, 459. [all data]

Foster, 1959
Foster, R., Ionization potentials of electron donors, Nature (London), 1959, 183, 1253. [all data]

Vilesov and Terenin, 1957
Vilesov, F.I.; Terenin, A.N., The photoionization of the vapors of certain organic compounds, Dokl. Akad. Nauk SSSR, 1957, 115, 744, In original 539. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Gas phase ion energetics data, References