Cyclohexane, ethyl-

Formula: C₈H₁₆
Molecular weight: 112.2126
IUPAC Standard InChI: InChI=1S/C8H16/c1-2-8-6-4-3-5-7-8/h8H,2-7H2,1H3
IUPAC Standard InChIKey: IIEWJVIFRVWJOD-UHFFFAOYSA-N
CAS Registry Number: 1678-91-7
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: Ethylcyclohexane
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Gas phase thermochemistry data

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Data compiled as indicated in comments:
DRB - Donald R. Burgess, Jr.
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	-41.25	kcal/mol	N/A	Baroody and Carpenter, 1972	Value computed using Δ_fH_liquid° value of -213.0 kj/mol from Baroody and Carpenter, 1972 and Δ_vapH° value of 40.4 kj/mol from Prosen, Johnson, et al., 1946.; DRB
Δ_fH°_gas	-41.05 ± 0.37	kcal/mol	Ccb	Prosen, Johnson, et al., 1946	ALS
Quantity	Value	Units	Method	Reference	Comment
S°_gas	91.460	cal/mol*K	N/A	Huffman H.M., 1949	GT

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
9.787	50.	Thermodynamics Research Center, 1997	p=1 bar. There is an appreciable difference, mainly at high temperatures, with values estimated earlier by a method of increments [ Beckett C.W., 1947].; GT
14.98	100.
20.85	150.
26.70	200.
35.85	273.15
39.17	298.15
39.41	300.
52.49	400.
64.10	500.
73.83	600.
81.96	700.
88.81	800.
94.67	900.
99.64	1000.
103.9	1100.
107.6	1200.
110.8	1300.
113.5	1400.
115.9	1500.
120.5	1750.
123.9	2000.
126.3	2250.
128.2	2500.
129.6	2750.
130.7	3000.

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
36.384	298.15	Colgate S.O., 1990	These heat capacities determined from acoustical measurements are significantly lower than statistically calculated values [ Thermodynamics Research Center, 1997] (Cp(298.15 K)=163.9 J/molK) and values estimated by a method of increments [ Beckett C.W., 1947] (Cp(298.15 K)=158.6 J/molK). At the same time, the heat capacities of ethylbenzene determined in this work are only slightly below than calorimetric ones.; GT
40.717	323.15
47.299	373.15
52.015	408.15
57.333	448.15

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_fH°_liquid	-50.8	kcal/mol	Ccb	Baroody and Carpenter, 1972	ALS
Δ_fH°_liquid	-50.72 ± 0.37	kcal/mol	Ccb	Prosen, Johnson, et al., 1946	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1248.23 ± 0.35	kcal/mol	Ccb	Prosen, Johnson, et al., 1946	Corresponding Δ_fHº_liquid = -50.70 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	67.139	cal/mol*K	N/A	Huffman, Todd, et al., 1949	DH
S°_liquid	67.30	cal/mol*K	N/A	Parks, Moore, et al., 1949	Extrapolation below 80 K, 57.74 J/mol*K.; DH

Constant pressure heat capacity of liquid

C_p,liquid (cal/mol*K)	Temperature (K)	Reference	Comment
50.619	298.15	Huffman, Todd, et al., 1949	T = 12 to 310 K.; DH
51.20	298.15	Parks, Moore, et al., 1949	T = 80 to 300 K.; DH

Reaction thermochemistry data

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Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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

+ = Cyclohexane, ethyl-

By formula: C₈H₁₄ + H₂ = C₈H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-26.2 ± 0.3	kcal/mol	Chyd	Rogers and McLafferty, 1971	liquid phase; solvent: Hydrocarbon
Δ_rH°	-26.32 ± 0.04	kcal/mol	Chyd	Turner and Garner, 1958	liquid phase; solvent: Acetic acid
Δ_rH°	-26.32 ± 0.04	kcal/mol	Chyd	Turner and Garner, 1957	liquid phase; solvent: Acetic acid

+ = Cyclohexane, ethyl-

By formula: H₂ + C₈H₁₄ = C₈H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-25.08 ± 0.13	kcal/mol	Chyd	Turner and Garner, 1958	liquid phase; solvent: Acetic acid
Δ_rH°	-25.08 ± 0.13	kcal/mol	Chyd	Turner and Garner, 1957	liquid phase; solvent: Acetic acid

+ 4 = Cyclohexane, ethyl-

By formula: C₈H₈ + 4H₂ = C₈H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-76.50 ± 0.25	kcal/mol	Chyd	Dolliver, Gresham, et al., 1937	gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -77.48 ± 0.20 kcal/mol; At 355 °K

+ 3 = Cyclohexane, ethyl-

By formula: C₈H₁₀ + 3H₂ = C₈H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-48.18 ± 0.10	kcal/mol	Chyd	Dolliver, Gresham, et al., 1937	gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -48.9 ± 0.1 kcal/mol; At 355 °K

+ = Cyclohexane, ethyl-

By formula: H₂ + C₈H₁₄ = C₈H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-27.9 ± 0.8	kcal/mol	Chyd	Rogers and McLafferty, 1971	liquid phase; solvent: Hydrocarbon

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Notes

Baroody and Carpenter, 1972
Baroody, E.E.; Carpenter, G.A., Heats of formation of propellant compounds (U), Rpt. Naval Ordnance Systems Command Task No. 331-003/067-1/UR2402-001 for Naval Ordance Station, Indian Head, MD, 1972, 1-9. [all data]

Prosen, Johnson, et al., 1946
Prosen, E.J.; Johnson, W.H.; Rossini, F.D., Heats of formation and combustion of the normal alkylcyclopentanes and cyclohexanes and the increment per CH₂ group for several homologous series of hydrocarbons, J. Res. NBS, 1946, 37, 51-56. [all data]

Huffman H.M., 1949
Huffman H.M., Low-temperature thermal data on eight C8H16 alkylcyclohexanes, J. Am. Chem. Soc., 1949, 71, 584-592. [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]

Beckett C.W., 1947
Beckett C.W., The thermodynamic properties and molecular structure of cyclohexane, methylcyclohexane, ethylcyclohexane, and seven dimethylcyclohexanes, J. Am. Chem. Soc., 1947, 69, 2488-2495. [all data]

Colgate S.O., 1990
Colgate S.O., Acoustical determination of ideal gas heat capacities of three C-8 compounds, Fluid Phase Equilib., 1990, 60, 191-203. [all data]

Huffman, Todd, et al., 1949
Huffman, H.M.; Todd, S.S.; Oliver, G.D., Low temperature thermal data on eight C₈H₁₆ alkylcyclohexanes, J. Am. Chem. Soc., 1949, 71, 584-592. [all data]

Parks, Moore, et al., 1949
Parks, G.S.; Moore, G.E.; Renquist, M.L.; Naylor, B.F.; McClaine, L.A.; Fujii, P.S.; Hatton, J.A., Thermal data on organic compounds. XXV. Some heat capacity, entropy and free energy data for nine hydrocarbons of high molecular weight, J. Am. Chem. Soc., 1949, 71, 3386-3389. [all data]

Rogers and McLafferty, 1971
Rogers, D.W.; McLafferty, F.J., A new hydrogen calorimeter. Heats of hydrogenation of allyl and vinyl unsaturation adjacent to a ring, Tetrahedron, 1971, 27, 3765-3775. [all data]

Turner and Garner, 1958
Turner, R.B.; Garner, R.H., Heats of hydrogenation. V. Relative stabilities in certain exocyclic-endocyclic olefin pairs, J. Am. Chem. Soc., 1958, 80, 1424-1430. [all data]

Turner and Garner, 1957
Turner, R.B.; Garner, R.H., Heats of hydrogenation. V. Relative stabilities in certain exocyclic-endocyclic olefin pairs, J. Am. Chem. Soc., 1957, 80, 1424-1430. [all data]

Dolliver, Gresham, et al., 1937
Dolliver, M.a.; Gresham, T.L.; Kistiakowsky, G.B.; Vaughan, W.E., Heats of organic reactions. V. Heats of hydrogenation of various hydrocarbons, J. Am. Chem. Soc., 1937, 59, 831-841. [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]

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
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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