Benzene, 1,2,4-trimethyl-

Formula: C₉H₁₂
Molecular weight: 120.1916
IUPAC Standard InChI: InChI=1S/C9H12/c1-7-4-5-8(2)9(3)6-7/h4-6H,1-3H3
IUPAC Standard InChIKey: GWHJZXXIDMPWGX-UHFFFAOYSA-N
CAS Registry Number: 95-63-6
Chemical structure:
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Other names: ψ-Cumene; as-Trimethylbenzene; Pseudocumene; Pseudocumol; 1,2,4-Trimethylbenzene; 1,2,5-Trimethylbenzene; 1,3,4-Trimethylbenzene; Psi-cumene; Asymmetrical trimethylbenzene; Benzene, 1,2,5-trimethyl-; NSC 65600; 1,2,4-trimethylbenzene (pseudocumene)
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Gas phase thermochemistry data

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Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-3.33 ± 0.27	kcal/mol	Ccb	Johnson, Prosen, et al., 1945	Hf by Prosen, Johnson, et al., 1946; ALS
Quantity	Value	Units	Method	Reference	Comment
S°_gas	94.59 ± 0.15	cal/mol*K	N/A	Putnam W.E., 1957	GT

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
27.03	200.	Draeger, 1985	Discrepancies with other statistically calculated values [ Taylor W.J., 1946, Hastings S.H., 1957, Thermodynamics Research Center, 1997] amount up to 5 J/mol*K in S(T) and Cp(T).; GT
34.25	273.15
36.83 ± 0.1	298.15
37.05	300.
47.44	400.
56.88	500.
64.94	600.
71.75	700.
77.51	800.
82.41	900.
86.59	1000.
90.18	1100.
93.26	1200.
95.94	1300.
98.23	1400.
100.2	1500.

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, References, Notes

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_fH°_liquid	-14.79 ± 0.27	kcal/mol	Ccb	Johnson, Prosen, et al., 1945	Hf by Prosen, Johnson, et al., 1946; ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1241.58 ± 0.24	kcal/mol	Ccb	Johnson, Prosen, et al., 1945	Hf by Prosen, Johnson, et al., 1946; Corresponding Δ_fHº_liquid = -14.77 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-1240.6	kcal/mol	Ccb	Richards and Barry, 1915	At 291 K; Corresponding Δ_fHº_liquid = -15.8 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	67.729	cal/mol*K	N/A	Putnam and Kilpatrick, 1957	DH
S°_liquid	67.71	cal/mol*K	N/A	Huffman, Parks, et al., 1931	Extrapolation below 90 K, 69.79 J/mol*K.; DH

Constant pressure heat capacity of liquid

C_p,liquid (cal/mol*K)	Temperature (K)	Reference	Comment
50.935	298.15	Wilhelm, Inglese, et al., 1987	DH
50.69	295.99	Andolenko and Grigor'ev, 1979	T = 293 to 430 K. Unsmoothed experimental datum given as 1.765 kJ/kg*K.; DH
51.379	298.15	Putnam and Kilpatrick, 1957	T = 15 to 300 K.; DH
50.289	299.8	Helfrey, Heiser, et al., 1955	T = 80 to 220°F.; DH
50.91	298.	Kurbatov, 1947	T = 15 to 168°C, mean Cp, five temperatures.; DH
50.69	297.3	Huffman, Parks, et al., 1931	T = 94 to 297 K. Value is unsmoothed experimental datum.; DH

References

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Johnson, Prosen, et al., 1945
Johnson, W.H.; Prosen, E.J.; Rossini, F.D., Heats of combustion and isomerization of the eight C₉H₁₂ alkylbenzenes, J. Res. NBS, 1945, 35, 141-146. [all data]

Prosen, Johnson, et al., 1946
Prosen, E.J.; Johnson, W.H.; Rossini, F.D., Heats of combustion and formation at 25°C of the alkylbenzenes through C₁₀H₁₄, and of the higher normal monoalkylbenzenes, J. Res. NBS, 1946, 36, 455-461. [all data]

Putnam W.E., 1957
Putnam W.E., Entropy, heat capacity, and heats of transition of 1,2,4-trimethylbenzene, J. Chem. Phys., 1957, 27, 1075-1080. [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]

Taylor W.J., 1946
Taylor W.J., Heats, equilibrium constants, and free energies of formation of the alkylbenzenes, J. Res. Nat. Bur. Stand., 1946, 37, 95-122. [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]

Thermodynamics Research Center, 1997
Thermodynamics Research Center, Selected Values of Properties of Chemical Compounds., Thermodynamics Research Center, Texas A&M University, College Station, Texas, 1997. [all data]

Richards and Barry, 1915
Richards, T.W.; Barry, F., The heats of combustion of aromatic hydrocarbons and hexamethylene, J. Am. Chem. Soc., 1915, 37, 993-1020. [all data]

Putnam and Kilpatrick, 1957
Putnam, W.E.; Kilpatrick, J.E., Entropy, heat capacity and heats of transition of 1,2,4-trimethylbenzene, J. Chem. Phys., 1957, 27, 1075-1080. [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]

Wilhelm, Inglese, et al., 1987
Wilhelm, E.; Inglese, A.; Roux, A.H.; Grolier, J.-P.E., Excess enthalpy, excess heat capacity and excess volume of 1,2,4-trimethylbenzene +, and 1-methylnaphthalene + an n-alkane, Fluid Phase Equilibria, 1987, 34, 49-67. [all data]

Andolenko and Grigor'ev, 1979
Andolenko, R.A.; Grigor'ev, B.A., Investigation of isobaric heat capacity of aromatic hydrocarbons at atmospheric pressure, Iaz. Vyssh. Ucheb. Zaved., Neft i Gaz (11), 1979, 78, 90. [all data]

Helfrey, Heiser, et al., 1955
Helfrey, P.F.; Heiser, D.A.; Sage, B.H., Isobaric heat capacities at bubble point, Two trimethylbenzenes and n-heptane, Ind. Eng. Chem., 1955, 44, 2385-2388. [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]

Notes

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Symbols used in this document:

C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
S°_gas	Entropy of gas at standard conditions
S°_liquid	Entropy of liquid at standard conditions
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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