Benzene, pentamethyl-

Formula: C₁₁H₁₆
Molecular weight: 148.2447
IUPAC Standard InChI: InChI=1S/C11H16/c1-7-6-8(2)10(4)11(5)9(7)3/h6H,1-5H3
IUPAC Standard InChIKey: BEZDDPMMPIDMGJ-UHFFFAOYSA-N
CAS Registry Number: 700-12-9
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other names: Pentamethylbenzene; 1,2,3,4,5-Pentamethylbenzene; Benzene, 1,2,3,4,5-pentamethyl-
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Condensed phase thermochemistry data

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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
Δ_cH°_liquid	-1547.7 ± 1.5	kcal/mol	Ccb	Banse and Parks, 1933	Reanalyzed by Cox and Pilcher, 1970, Original value = -1546.52 kcal/mol; Corresponding Δ_fHº_liquid = -33.38 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_solid	-34.56 ± 0.53	kcal/mol	Ccb	Colomina, Jimenez, et al., 1989	see Boned, Colomina, et al., 1964; ALS
Δ_fH°_solid	-32.29 ± 0.62	kcal/mol	Ccb	Parks, West, et al., 1946	Reanalyzed by Cox and Pilcher, 1970, Original value = -32.44 ± 0.01 kcal/mol; ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_solid	-1546.5 ± 0.38	kcal/mol	Ccb	Colomina, Jimenez, et al., 1989	see Boned, Colomina, et al., 1964; Corresponding Δ_fHº_solid = -34.58 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_solid	-1548.79 ± 0.61	kcal/mol	Ccb	Parks, West, et al., 1946	Reanalyzed by Cox and Pilcher, 1970, Original value = -1548.67 ± 0.62 kcal/mol; Corresponding Δ_fHº_solid = -32.29 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_{solid,1 bar}	70.29	cal/mol*K	N/A	Huffman, Parks, et al., 1931	crystaline, I phase; Extrapolation below 90 K, 102.9 J/mol*K.; DH

Constant pressure heat capacity of solid

C_p,solid (cal/mol*K)	Temperature (K)	Reference	Comment
50.31	298.15	Colomina, Jimenez, et al., 1989	DH
64.60	298.1	Eibert, 1944	crystaline, I phase; T = 25 to 200°C, equations only, in t°C. Cp(c) = 0.3914 + 0.001760t cal/gK (25 to 40°C); Cp(liq) = 0.432 + 0.000425 t cal/gK (55 to 200°C).; DH
63.89	303.	Ferry and Thomas, 1933	T = 303 to 393 K.; DH
59.99	283.8	Huffman, Parks, et al., 1931	crystaline, I phase; T = 92 to 304 K. Value is unsmoothed experimental datum.; DH

IR Spectrum

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Data compiled by: Coblentz Society, Inc.

Not specified, most likely a prism, grating, or hybrid spectrometer.; (NO SPECTRUM, ONLY SCANNED IMAGE IS AVAILABLE)

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

gas; HP-GC/MS/IRD

References

Go To: Top, Condensed phase thermochemistry data, IR Spectrum, Notes

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]

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]

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]

Notes

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Symbols used in this document:

C_p,solid	Constant pressure heat capacity of solid
S°_{solid,1 bar}	Entropy of solid at standard conditions (1 bar)
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_cH°_solid	Enthalpy of combustion of solid at standard conditions
Δ_fH°_solid	Enthalpy of formation of solid at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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