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Benzene, hexamethyl-

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Phase change 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:
BS - Robert L. Brown and Stephen E. Stein
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
DRB - Donald R. Burgess, Jr.
CAL - James S. Chickos, William E. Acree, Jr., Joel F. Liebman, Students of Chem 202 (Introduction to the Literature of Chemistry), University of Missouri -- St. Louis
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Tboil538.2KN/AWeast and Grasselli, 1989BS
Tboil536.85KN/ACooper, Crowne, et al., 1967Uncertainty assigned by TRC = 0.6 K; TRC
Quantity Value Units Method Reference Comment
Tfus438. ± 3.KAVGN/AAverage of 13 values; Individual data points
Quantity Value Units Method Reference Comment
Tc758. ± 1.KN/ATsonopoulos and Ambrose, 1995 
Tc758.KN/AAmbrose, Broderick, et al., 1974Uncertainty assigned by TRC = 2. K; TRC
Tc751.15KN/AGuye and Mallet, 1902Uncertainty assigned by TRC = 10. K; crit. temp. greater than this - sample decomposes at this T; TRC
Quantity Value Units Method Reference Comment
Deltavap68.6kJ/molCGCZhao, Unhannanant, et al., 2008AC
Quantity Value Units Method Reference Comment
Deltasub83. ± 7.kJ/molAVGN/AAverage of 7 values; Individual data points

Enthalpy of vaporization

DeltavapH (kJ/mol) Temperature (K) Method Reference Comment
56.8458.AStephenson and Malanowski, 1987Based on data from 443. - 537. K.; AC

Enthalpy of sublimation

DeltasubH (kJ/mol) Temperature (K) Method Reference Comment
85.2320.AAmbrose, Lawrenson, et al., 1976Based on data from 303. - 338. K.; AC
83.2329.AOverberger, Steele, et al., 1969Based on data from 314. - 364. K.; AC

Enthalpy of fusion

DeltafusH (kJ/mol) Temperature (K) Reference Comment
20.63438.7Domalski and Hearing, 1996See also Spaght, Thomas, et al., 1931.; AC

Entropy of fusion

DeltafusS (J/mol*K) Temperature (K) Reference Comment
4.58383.7Domalski and Hearing, 1996CAL
47.02438.7

Temperature of phase transition

Ttrs (K) Initial Phase Final Phase Reference Comment
382.crystaline, IIIcrystaline, IFujiwara, Inaba, et al., 1992DH
439.crystaline, IliquidFujiwara, Inaba, et al., 1992DH

Enthalpy of phase transition

DeltaHtrs (kJ/mol) Temperature (K) Initial Phase Final Phase Reference Comment
1.100117.5crystaline, IIIcrystaline, IIFujiwara, Inaba, et al., 1992From Atake, Gyoten, et al., 1982; DH
1.500384.0crystaline, IIcrystaline, IPetropavlov, Tsygankova, et al., 1988DH
1.103115.5crystaline, IIcrystaline, IYoshimoto, Fujiwara, et al., 1985DH
0.990117.5crystaline, IIIcrystaline, IIAtake, Gyoten, et al., 1982First order transition.; DH
1.1284116.48crystaline, IIcrystaline, IFrankosky and Aston, 1965Entropy obtained as difference of integral of observed Cp over range 115 to 128 K, and integral of extrapolated Cp data.; DH
1.841383.55crystaline, IIcrystaline, IMomotani, Suga, et al., 1956DH
20.585438.35crystaline, IliquidMomotani, Suga, et al., 1956DH
1.766383.7crystaline, IIcrystaline, ISpaght, Thomas, et al., 1932DH
20.640438.7crystaline, IliquidSpaght, Thomas, et al., 1932DH
1.017108.crystaline, IIIcrystaline, IIHuffman, Parks, et al., 1930DH
0.155151.crystaline, IIcrystaline, IHuffman, Parks, et al., 1930DH

Entropy of phase transition

DeltaStrs (J/mol*K) Temperature (K) Initial Phase Final Phase Reference Comment
9.3117.5crystaline, IIIcrystaline, IIFujiwara, Inaba, et al., 1992From; DH
3.9384.0crystaline, IIcrystaline, IPetropavlov, Tsygankova, et al., 1988DH
9.55115.5crystaline, IIcrystaline, IYoshimoto, Fujiwara, et al., 1985DH
8.3117.5crystaline, IIIcrystaline, IIAtake, Gyoten, et al., 1982First; DH
10.08116.48crystaline, IIcrystaline, IFrankosky and Aston, 1965Entropy; DH
4.81383.55crystaline, IIcrystaline, IMomotani, Suga, et al., 1956DH
46.86438.35crystaline, IliquidMomotani, Suga, et al., 1956DH
4.60383.7crystaline, IIcrystaline, ISpaght, Thomas, et al., 1932DH
47.0438.7crystaline, IliquidSpaght, Thomas, et al., 1932DH
9.5108.crystaline, IIIcrystaline, IIHuffman, Parks, et al., 1930DH
1.0151.crystaline, IIcrystaline, IHuffman, Parks, et al., 1930DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


References

Go To: Top, Phase change data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]

Cooper, Crowne, et al., 1967
Cooper, A.R.; Crowne, C.W.P.; Farrell, P.G., Gas-Liquid Chromatographic Studies of Electron-Donor-Acceptor Systems, Trans. Faraday Soc., 1967, 63, 447. [all data]

Tsonopoulos and Ambrose, 1995
Tsonopoulos, C.; Ambrose, D., Vapor-Liquid Critical Properties of Elements and Compounds. 3. Aromatic Hydrocarbons, J. Chem. Eng. Data, 1995, 40, 547-558. [all data]

Ambrose, Broderick, et al., 1974
Ambrose, D.; Broderick, B.E.; Townsend, R., The Critical Temperatures and Pressures of Thirty Organic Compounds, J. Appl. Chem. Biotechnol., 1974, 24, 359. [all data]

Guye and Mallet, 1902
Guye, P.A.; Mallet, E., Measurement of Critical Constants, Arch. Sci. Phys. Nat., 1902, 13, 274-296. [all data]

Zhao, Unhannanant, et al., 2008
Zhao, Hui; Unhannanant, Patamaporn; Hanshaw, William; Chickos, James S., Enthalpies of Vaporization and Vapor Pressures of Some Deuterated Hydrocarbons. Liquid-Vapor Pressure Isotope Effects, J. Chem. Eng. Data, 2008, 53, 7, 1545-1556, https://doi.org/10.1021/je800091s . [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]

Ambrose, Lawrenson, et al., 1976
Ambrose, D.; Lawrenson, I.J.; Sprake, C.H.S., The vapour pressure of hexamethylbenzene, The Journal of Chemical Thermodynamics, 1976, 8, 5, 503-504, https://doi.org/10.1016/0021-9614(76)90071-9 . [all data]

Overberger, Steele, et al., 1969
Overberger, John E.; Steele, William A.; Aston, John G., The vapor pressure of hexamethylbenzene the standard entropy of hexamethylbenzene vapor and the barrier to internal rotation, The Journal of Chemical Thermodynamics, 1969, 1, 6, 535-542, https://doi.org/10.1016/0021-9614(69)90014-7 . [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]

Spaght, Thomas, et al., 1931
Spaght, M.E.; Thomas, S.B.; Parks, G.S., Some Heat-Capacity Data on Organic Compounds obtained with a Radiation Calorimeter, J. Phys. Chem., 1931, 36, 3, 882-888, https://doi.org/10.1021/j150333a009 . [all data]

Fujiwara, Inaba, et al., 1992
Fujiwara, T.; Inaba, A.; Atake, T.; Chihara, H., Thermodynamic properties of deuterated hexamethylbenzene and of its solid solutions with the hydrogenated analog. A large isotope effect on the phase transition at the temperature 117 K, J. Chem. Thermodynam., 1992, 24, 863-881. [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]

Petropavlov, Tsygankova, et al., 1988
Petropavlov, N.N.; Tsygankova, I.G.; Teslenko, L.A., Microcalorimetric investigation of polymorphic transitions in organic crystals, Sov. Phys. Crystallogr., 1988, 33(6), 853-855. [all data]

Yoshimoto, Fujiwara, et al., 1985
Yoshimoto, Y.; Fujiwara, T.; Atake, T.; Chihara, H., Solid-solid transition in hexamethylbenzene that depends on thermal history, Chem. Lett., 1985, (9), 1347-1350. [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]

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]

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]


Notes

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