Benzene, hexamethyl-

• Formula: C₁₂H₁₈
• Molecular weight: 162.2713
• IUPAC Standard InChI: InChI=1S/C12H18/c1-7-8(2)10(4)12(6)11(5)9(7)3/h1-6H3 Copy

  
• IUPAC Standard InChIKey: YUWFEBAXEOLKSG-UHFFFAOYSA-N Copy
• CAS Registry Number: 87-85-4
• 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:
  • Hexamethylbenzene, deuterated
• Other names: Hexamethylbenzene; Mellitene; 1,2,3,4,5,6-Hexamethylbenzene
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • Gas Chromatography
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
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• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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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

Constant pressure heat capacity of gas

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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias

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: C₁₂H₁₈ = C₁₂H₁₈

=

By formula: C₁₂H₁₈ = C₁₂H₁₈

C₆H₇N⁺ +  = (C₆H₇N⁺ • )

By formula: C₆H₇N⁺ + C₁₂H₁₈ = (C₆H₇N⁺ • C₁₂H₁₈)

Bond type: Charge transfer bond (positive ion)

=

By formula: C₁₂H₁₈ = C₁₂H₁₈

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
L - 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
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess

View reactions leading to C₁₂H₁₈⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

Gas Chromatography

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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: NIST Mass Spectrometry Data Center, William E. Wallace, director

Kovats' RI, non-polar column, isothermal

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Kovats' RI, non-polar column, temperature ramp

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Kovats' RI, polar column, isothermal

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Van Den Dool and Kratz RI, non-polar column, temperature ramp

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Normal alkane RI, non-polar column, temperature ramp

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Normal alkane RI, non-polar column, custom temperature program

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References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Gas Chromatography, 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]

Adam and Chang, 1969
Adam, W.; Chang, J.C., Kinetics and thermochemistry of valence isomerization by differential scanning calorimetry: the case of hexamethylprismane and hexamethyldewarbenzene, Int. J. Chem. Kinet., 1969, 1, 487-492. [all data]

Oth, 1968
Oth, J.F.M., The kinetics and thermochemistry of the thermal rearrangement of hexamethylbicyclo[2.2.0]hexa-2,5-diene (hexamethyldewarbenzene) and of hexamethyltetracyclo[2.2.0,0(2,6).0(3,5)]hexane (hexamethylprismane), Chem. Ber., 1968, 47, 1185-1195. [all data]

Oth, 1969
Oth, J.F.M., The kinetics and thermochemistry of the thermal rearrangement of hexamethyl(Dewar benzene) and of hexamethylprismane, Angew. Chem. Int. Ed. Engl., 1969, 7, 646. [all data]

Meot-Ner (Mautner) and El-Shall, 1986
Meot-Ner (Mautner), M.; El-Shall, M.S., Ionic Charge Transfer Complexes. 1. Cationic Complexes with Delocalized and Partially Localized pi Systems, J. Am. Chem. Soc., 1986, 108, 15, 4386, https://doi.org/10.1021/ja00275a026 . [all data]

Childs and Mulholland, 1983
Childs, R.F.; Mulholland, D.L., Thermochemical relationships between some bicyclohexenyl and benzenium cations, J. Am. Chem. Soc., 1983, 105, 96-99. [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]

Kuznesof, Stafford, et al., 1967
Kuznesof, P.M.; Stafford, F.E.; Shriver, D.F., Electron impact ionization potentials of methyl-substituted borazines, J. Phys. Chem., 1967, 71, 1939. [all data]

Vilesov, 1961
Vilesov, F.I., Photoionisation of organic vapours in the vacuum ultra-violet, Zh. Fiz. Khim., 1961, 35, 2010, In original 986. [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]

Briegleb and Czekalla, 1959
Briegleb, G.; Czekalla, J., Die Bestimmung von lonisierungsenergien aus den Spektren von Elektronenubergangskomplexen, Z.Elektrochem., 1959, 63, 6. [all data]

Kovac, Mohraz, et al., 1980
Kovac, B.; Mohraz, M.; Heilbronner, E.; Boekelheide, V.; Hopf, H., Photoelectron spectra of the cyclophanes, J. Am. Chem. Soc., 1980, 102, 4314. [all data]

Pérez-Parajón, Santiuste, et al., 2004
Pérez-Parajón, J.M.; Santiuste, J.M.; Takács, J.M., Sensitivity of the methylbenzenes and chlorobenzenes retention index to column temperature, stationary phase polarity, and number and chemical nature of substituents, J. Chromatogr. A, 2004, 1048, 2, 223-232, https://doi.org/10.1016/j.chroma.2004.07.028 . [all data]

Gerasimenko and Nabivach, 1982
Gerasimenko, V.A.; Nabivach, V.M., Relationship between molecular structure and gas chromatographic retention of alkylbenzenes C₈-C_{1 2} on polydimethylsiloxane, Zh. Anal. Khim., 1982, 37, 110-116. [all data]

Gerasimenko, Kirilenko, et al., 1981
Gerasimenko, V.A.; Kirilenko, A.V.; Nabivach, V.M., Capillary gas chromatography of aromatic compounds found in coal tar fractions, J. Chromatogr., 1981, 208, 1, 9-16, https://doi.org/10.1016/S0021-9673(00)87953-4 . [all data]

Engewald and Wennrich, 1976
Engewald, W.; Wennrich, L., Molekülstruktur und Retentionsverhalten. VIII. Zum Retentionsverhalten höherer Alkylbenzole bei der Gas-Verteilungs-Chromatographie, Chromatographia, 1976, 9, 11, 540-547, https://doi.org/10.1007/BF02275960 . [all data]

Hayes and Pitzer, 1982
Hayes, P.C., Jr.; Pitzer, E.W., Characterizing petroleum- and shale-derived jet fuel distillates via temperature-programmed Kováts indices, J. Chromatogr., 1982, 253, 179-198, https://doi.org/10.1016/S0021-9673(01)88376-X . [all data]

White, Hackett, et al., 1992
White, C.M.; Hackett, J.; Anderson, R.R.; Kail, S.; Spock, P.S., Linear temperature programmed retention indices of gasoline range hydrocarbons and chlorinated hydrocarbons on cross-linked polydimethylsiloxane, J. Hi. Res. Chromatogr., 1992, 15, 2, 105-120, https://doi.org/10.1002/jhrc.1240150211 . [all data]

Hayes and Pitzer, 1981
Hayes, P.C., Jr.; Pitzer, E.W., Kovats indices as a tool in characterizing hydrocarbon fuels in temperature programmed glass capillary gas chromatography. Part 1. Qualitative identification, Inhouse rpt. for Air Force Wright Aeronautical Labs., Air Force Wright Aeronautical Labs., Wright-Patterson AFB, Ohio, 1981, 75. [all data]

Supelco, 2012
Supelco, CatalogNo. 24160-U, Petrocol DH Columns. Catalog No. 24160-U, 2012, retrieved from http://www.sigmaaldrich.com/etc/medialib/docs/Supelco/Datasheet/1/w97949.Par.0001.File.tmp/w97949.pdf. [all data]

Waggott and Davies, 1984
Waggott, A.; Davies, I.W., Identification of organic pollutants using linear temperature programmed retention indices (LTPRIs) - Part II, 1984, retrieved from http://dwi.defra.gov.uk/research/completed-research/reports/dwi0383.pdf. [all data]

Notes

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

• Symbols used in this document:
  

  Cp,gas	Constant pressure heat capacity of gas
  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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