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
- IUPAC Standard InChIKey: YUWFEBAXEOLKSG-UHFFFAOYSA-N
- 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:
- Other names: Hexamethylbenzene; Mellitene; 1,2,3,4,5,6-Hexamethylbenzene
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, IR Spectrum, 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 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 |
|---|---|---|---|---|---|
| ΔfH°gas | -77.4 ± 2.5 | kJ/mol | Ccb | Colomina, Jimenez, et al., 1989 | see Boned, Colomina, et al., 1964; ALS |
| ΔfH°gas | -78.3 | kJ/mol | N/A | Parks, West, et al., 1946 | Value computed using ΔfHsolid° value of -163.3±3.1 kj/mol from Parks, West, et al., 1946 and ΔsubH° value of 85.0 kj/mol from Parks, West, et al., 1946.; DRB |
Constant pressure heat capacity of gas
| Cp,gas (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 184.4 | 200. | Draeger, 1985 | Recommended values are in close agreement with experimental data on S(T). Discrepancies with earlier statistically calculated values [ Hastings S.H., 1957] amount to 16 and 13 J/mol*K in S(T) and Cp(T), respectively.; GT |
| 227.3 | 273.15 | ||
| 241.5 ± 0.4 | 298.15 | ||
| 242.6 | 300. | ||
| 298.3 | 400. | ||
| 349.3 | 500. | ||
| 393.8 | 600. | ||
| 432.1 | 700. | ||
| 465.0 | 800. | ||
| 493.4 | 900. | ||
| 517.9 | 1000. | ||
| 539.0 | 1100. | ||
| 557.3 | 1200. | ||
| 573.1 | 1300. | ||
| 586.7 | 1400. | ||
| 598.6 | 1500. |
Condensed phase thermochemistry data
Go To: Top, Gas phase thermochemistry data, IR Spectrum, 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 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 | -142.0 | kJ/mol | Ccb | Oth, 1968 | ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°liquid | -7134.6 ± 7.1 | kJ/mol | Ccb | Banse and Parks, 1933 | Reanalyzed by Cox and Pilcher, 1970, Original value = -7129.03 kJ/mol; Corresponding ΔfHºliquid = -160.0 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔfH°solid | -162.4 ± 2.5 | kJ/mol | Ccb | Colomina, Jimenez, et al., 1989 | see Boned, Colomina, et al., 1964; ALS |
| ΔfH°solid | -163.3 ± 3.1 | kJ/mol | Ccb | Parks, West, et al., 1946 | Reanalyzed by Cox and Pilcher, 1970, Original value = -164.0 ± 0.08 kJ/mol; ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°solid | -7132.2 ± 1.9 | kJ/mol | Ccb | Colomina, Jimenez, et al., 1989 | see Boned, Colomina, et al., 1964; Corresponding ΔfHºsolid = -162.4 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| ΔcH°solid | -7113.2 ± 5.2 | kJ/mol | Ccb | Holdiness, 1984 | Hf NR; Corresponding ΔfHºsolid = -181. kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| ΔcH°solid | -7131.3 ± 3.0 | kJ/mol | Ccb | Parks, West, et al., 1946 | Reanalyzed by Cox and Pilcher, 1970, Original value = -7130.7 ± 2.8 kJ/mol; Corresponding ΔfHºsolid = -163.3 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| S°solid,1 bar | 302.81 | J/mol*K | N/A | Atake, Gyoten, et al., 1982 | DH |
| S°solid,1 bar | 306.31 | J/mol*K | N/A | Frankosky and Aston, 1965 | crystaline, I phase; DH |
| S°solid,1 bar | 309.6 | J/mol*K | N/A | Huffman, Parks, et al., 1930 | crystaline, I phase; Extrapolation below 90 K, 82.38 J/mol*K.; DH |
Constant pressure heat capacity of liquid
| Cp,liquid (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 370.7 | 455. | Kurbatov, 1947 | T = 183 to 256°C, mean Cp, two temperatures.; DH |
Constant pressure heat capacity of solid
| Cp,solid (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 243.4 | 298.15 | Colomina, Jimenez, et al., 1989 | DH |
| 252.11 | 300. | Atake, Gyoten, et al., 1982 | T = 3 to 300 K.; DH |
| 245.64 | 298.15 | Frankosky and Aston, 1965 | crystaline, I phase; T = 13 to 340 K.; DH |
| 256.1 | 293.81 | Momotani, Suga, et al., 1956 | T = 273 to 443 K. Unsmoothed experimental datum.; DH |
| 258.5 | 303. | Spaght, Thomas, et al., 1932 | crystaline, II phase; T = 30 to 200°C.; DH |
| 254.8 | 294.6 | Huffman, Parks, et al., 1930 | crystaline, I phase; T = 85 to 294 K. Value is unsmoothed experimental datum.; DH |
IR Spectrum
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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
Gas Phase Spectrum
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Additional Data
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| Owner | NIST Standard Reference Data Program Collection (C) 2018 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
|---|---|
| Origin | Sadtler Research Labs Under US-EPA Contract |
| State | gas |
Mass spectrum (electron ionization)
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, IR Spectrum, 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. |
|---|---|
| Origin | Japan AIST/NIMC Database- Spectrum MS-NW- 223 |
| NIST MS number | 228195 |
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
| Column type | Active phase | Temperature (C) | I | Reference | Comment |
|---|---|---|---|---|---|
| Capillary | HP-5 | 120. | 1452.4 | Pérez-Parajón, Santiuste, et al., 2004 | 60. m/0.25 mm/0.25 μm |
| Capillary | OV-101 | 100. | 1416. | Gerasimenko and Nabivach, 1982 | N2; Column length: 50. m; Column diameter: 0.30 mm |
| Capillary | OV-101 | 120. | 1428. | Gerasimenko and Nabivach, 1982 | N2; Column length: 50. m; Column diameter: 0.30 mm |
| Capillary | OV-101 | 140. | 1442. | Gerasimenko and Nabivach, 1982 | N2; Column length: 50. m; Column diameter: 0.30 mm |
| Capillary | OV-101 | 100. | 1415.6 | Gerasimenko, Kirilenko, et al., 1981 | N2; Column length: 50. m; Column diameter: 0.3 mm |
| Capillary | OV-101 | 120. | 1428.2 | Gerasimenko, Kirilenko, et al., 1981 | N2; Column length: 50. m; Column diameter: 0.3 mm |
| Capillary | OV-101 | 140. | 1441.6 | Gerasimenko, Kirilenko, et al., 1981 | N2; Column length: 50. m; Column diameter: 0.3 mm |
| Capillary | Squalane | 100. | 1415. | Engewald and Wennrich, 1976 | N2; Column length: 100. m; Column diameter: 0.23 mm |
Kovats' RI, non-polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | OV-101 | 1431. | Hayes and Pitzer, 1982 | 110. m/0.25 mm/0.20 μm, He, 1. K/min; Tstart: 35. C; Tend: 200. C |
Kovats' RI, polar column, isothermal
| Column type | Active phase | Temperature (C) | I | Reference | Comment |
|---|---|---|---|---|---|
| Capillary | Carbowax 20M | 100. | 1778.0 | Engewald and Wennrich, 1976 | N2; Column length: 100. m; Column diameter: 0.23 mm |
Van Den Dool and Kratz RI, non-polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | Petrocol DH | 1437. | White, Hackett, et al., 1992 | 100. m/0.25 mm/0.5 μm, He, 1. K/min; Tstart: 30. C; Tend: 220. C |
| Capillary | OV-101 | 1431. | Hayes and Pitzer, 1981 | 108. m/0.25 mm/0.2 μm, 1. K/min; Tstart: 35. C; Tend: 200. C |
Normal alkane RI, non-polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | Petrocol DH | 1437. | Supelco, 2012 | 100. m/0.25 mm/0.50 μm, Helium, 20. C @ 15. min, 15. K/min, 220. C @ 30. min |
Normal alkane RI, non-polar column, custom temperature program
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | OV-1, SE-30, Methyl silicone, SP-2100, OV-101, DB-1, etc. | 1431. | Waggott and Davies, 1984 | Hydrogen; Column length: 50. m; Column diameter: 0.32 mm; Program: not specified |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, IR Spectrum, 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.
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]
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]
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]
Holdiness, 1984
Holdiness, M.R.,
Resonance energy of hexaethylbenzene and hexamethylbenzene,
Thermochim. Acta, 1984, 78, 435-436. [all data]
Atake, Gyoten, et al., 1982
Atake, T.; Gyoten, H.; Chihara, H.,
A concealed anomaly at 117.5 K in the heat capacity of hexamethylbenzene,
J. Chem. Phys., 1982, 76(11), 5535-5540. [all data]
Frankosky and Aston, 1965
Frankosky, M.; Aston, J.G.,
The heat capacity and entropy of hexamethylbenzene from 13 to 340 K. An estimate of the internal rotation barrier,
J. Phys. Chem., 1965, 69, 3126-3132. [all data]
Huffman, Parks, et al., 1930
Huffman, H.M.; Parks, G.S.; Daniels, A.C.,
Thermal data on organic compounds. VII. The heat capacities, entropies and free energies of twelve aromatic hydrocarbons,
J. Am. Chem. Soc., 1930, 52, 1547-1558. [all data]
Kurbatov, 1947
Kurbatov, V.Ya.,
Specific heat of liquids. I. Specific heat of benzenoid hydrocarbons,
Zhur. Obshch. Khim., 1947, 17, 1999-2003. [all data]
Momotani, Suga, et al., 1956
Momotani, M.; Suga, H.; Seki, S.; Nitta, I.,
Phase transitions in crystals composed of organic molecules with methyl groups at the molecular periperies, Proceed. National Academy of Sci. (India), XXV(Section A,
part, 1956, II), 74-82. [all data]
Spaght, Thomas, et al., 1932
Spaght, M.E.; Thomas, S.B.; Parks, G.S.,
Some heat capacity data on organic compounds obtained with a radiation calorimeter,
J. Phys. Chem., 1932, 36, 882-888. [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-C1 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, Condensed phase thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), Gas Chromatography, References
- Symbols used in this document:
Cp,gas Constant pressure heat capacity of gas Cp,liquid Constant pressure heat capacity of liquid Cp,solid Constant pressure heat capacity of solid S°solid,1 bar Entropy of solid at standard conditions (1 bar) ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔcH°solid Enthalpy of combustion of solid at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔfH°solid Enthalpy of formation of solid at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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