p-Cresol

Formula: C₇H₈O
Molecular weight: 108.1378
IUPAC Standard InChI: InChI=1S/C7H8O/c1-6-2-4-7(8)5-3-6/h2-5,8H,1H3
IUPAC Standard InChIKey: IWDCLRJOBJJRNH-UHFFFAOYSA-N
CAS Registry Number: 106-44-5
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.
Other names: Phenol, 4-methyl-; p-Hydroxytoluene; p-Kresol; p-Methylhydroxybenzene; p-Methylphenol; p-Oxytoluene; p-Toluol; p-Tolyl alcohol; 1-Hydroxy-4-methylbenzene; 4-Cresol; 4-Hydroxytoluene; 4-Methylphenol; 1-Methyl-4-hydroxybenzene; Paracresol; Cresol, para; Paramethyl phenol; Rcra waste number U052; p-Cresylic acid; Cresol,p-; Phenol, 4-methyI; NSC 3696; 4-methylphenol ( p-cresol); p-Cresol (4-methylphenol)
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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	-29.94 ± 0.36	kcal/mol	Ccb	Cox, 1961	ALS
Δ_fH°_gas	-29.97 ± 0.36	kcal/mol	Ccb	Andon, Biddiscombe, et al., 1960	ALS

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
9.348	50.	Kudchadker S.A., 1978	Selected entropies and heat capacities are in close agreement with statistical values calculated by [ Green J.H.S., 1962] except for S(298.15 K). This value is 3.1 J/mol*K greater than the calculated by [ Green J.H.S., 1962].; GT
12.26	100.
16.35	150.
20.73	200.
27.522	273.15
29.869	298.15
30.041	300.
38.903	400.
46.372	500.
52.409	600.
57.306	700.
61.348	800.
64.732	900.
67.600	1000.
70.048	1100.
72.149	1200.
73.960	1300.
75.526	1400.
76.886	1500.

Gas phase ion energetics data

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Data evaluated as indicated in comments:
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
MM - Michael M. Meot-Ner (Mautner)
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₇H₈O⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	8.34 ± 0.03	eV	N/A	N/A	L

Proton affinity at 298K

Proton affinity (kcal/mol)	Reference	Comment
195. ± 2.	van Beelen, Koblenz, et al., 2004	T = 298K; PA derived by authors from GB with protonation entropy equated to Rlnσ(B)/σ(BH+); MM

Gas basicity at 298K

Gas basicity (review) (kcal/mol)	Reference	Comment
187. ± 2.	van Beelen, Koblenz, et al., 2004	T = 298K; PA derived by authors from GB with protonation entropy equated to Rlnσ(B)/σ(BH+); MM

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.31 ± 0.08	EI	Selim, Fahmey, et al., 1991	LL
8.13	EI	Russell, Freiser, et al., 1983	LBLHLM
8.34	EI	Johnstone and Mellon, 1973	LLK
8.97	EI	Crable and Kearns, 1962	RDSH
8.35	PE	Palmer, Moyes, et al., 1979	Vertical value; LLK
8.38	PE	Kobayashi and Nagakura, 1974	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C₆H₅⁺	15.69 ± 0.08	?	EI	Selim, Fahmey, et al., 1990	LL
C₆H₇⁺	11.50	?	EI	Russell, Freiser, et al., 1983	LBLHLM
C₇H₇⁺	11.67 ± 0.08	OH	EI	Selim, Fahmey, et al., 1990	LL
C₇H₇O⁺	11.13	H	EI	Russell, Freiser, et al., 1983	LBLHLM
C₇H₇O⁺	12.4 ± 0.1	H	EI	Tait, Shannon, et al., 1962	RDSH

De-protonation reactions

C₇H₇O^- + = p-Cresol

By formula: C₇H₇O^- + H⁺ = C₇H₈O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	350.2 ± 2.1	kcal/mol	G+TS	Fujio, McIver, et al., 1981	gas phase; value altered from reference due to change in acidity scale; B
Δ_rH°	350.2 ± 2.1	kcal/mol	G+TS	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B
Δ_rH°	351.6 ± 2.3	kcal/mol	G+TS	Kebarle and McMahon, 1977	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	343.4 ± 2.0	kcal/mol	IMRE	Fujio, McIver, et al., 1981	gas phase; value altered from reference due to change in acidity scale; B
Δ_rG°	343.4 ± 2.0	kcal/mol	IMRE	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B
Δ_rG°	344.7 ± 2.0	kcal/mol	IMRE	Kebarle and McMahon, 1977	gas phase; B

IR Spectrum

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

Data compiled by: Coblentz Society, Inc.

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

References

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Cox, 1961
Cox, J.D., The heats of combustion of phenol and the three cresols, Pure Appl. Chem., 1961, 2, 125-128. [all data]

Andon, Biddiscombe, et al., 1960
Andon, R.J.L.; Biddiscombe, D.P.; Cox, J.D.; Handley, R.; Harrop, D.; Herington, E.F.G.; Martin, J.F., Thermodynamic properties of organic oxygen compounds. Part I. Preparation and physical properties of pure phenol, cresols, and xylenols, J. Chem. Soc., 1960, 5246-5254. [all data]

Kudchadker S.A., 1978
Kudchadker S.A., Ideal gas thermodynamic properties of phenol and cresols, J. Phys. Chem. Ref. Data, 1978, 7, 417-423. [all data]

Green J.H.S., 1962
Green J.H.S., Normal frequencies, thermodynamic properties and equilibrium of the cresols, Chem. Ind. (London), 1962, 1575-1576. [all data]

van Beelen, Koblenz, et al., 2004
van Beelen, E.S.E.; Koblenz, T.A.; Ingemann, S.; Hammerum, S., Experimental and theoretical evaluation of proton affinities of furan, the methylphenols, and the related anisoles, J. Phys. Chem. A, 2004, 108, 2787. [all data]

Selim, Fahmey, et al., 1991
Selim, E.T.M.; Fahmey, M.A.; Ghonime, H.S., Mass spectrometric study of molecular ions of methyl-phenol isomers using electron impact technique, Indian J. Phys., 1991, 65, 171. [all data]

Russell, Freiser, et al., 1983
Russell, D.H.; Freiser, B.S.; McBay, E.H.; Canada, D.C., The structure of decomposing [C₇H₇O]⁺ ions: Benzyl versus tropylium ion structures, Org. Mass Spectrom., 1983, 18, 474. [all data]

Johnstone and Mellon, 1973
Johnstone, R.A.W.; Mellon, F.A., Effects of induction and resonance in the calculation of ionization potentials of substituted benzenes by perturbation molecular orbital theory, J. Chem. Soc. Faraday Trans. 2, 1973, 69, 36. [all data]

Crable and Kearns, 1962
Crable, G.F.; Kearns, G.L., Effect of substituent groups on the ionization potentials of benzenes, J. Phys. Chem., 1962, 66, 436. [all data]

Palmer, Moyes, et al., 1979
Palmer, M.H.; Moyes, W.; Speirs, M.; Ridyard, J.N.A., The electronic structure of substituted benzenes; ab initio calculations and photoelectron spectra for phenol, the methyl- and fluoro-derivatives, and the dihydroxybenzenes, J. Mol. Struct., 1979, 52, 293. [all data]

Kobayashi and Nagakura, 1974
Kobayashi, T.; Nagakura, S., Photoelectron spectra of substituted benzenes, Bull. Chem. Soc. Jpn., 1974, 47, 2563. [all data]

Selim, Fahmey, et al., 1990
Selim, E.T.M.; Fahmey, M.A.; Ghonime, H.S., [C₇H₇]⁺ and [C₆H₅]⁺ fragment ions produced from methylphenol isomers by electron impact, Org. Mass Spectrom., 1990, 26, 55. [all data]

Tait, Shannon, et al., 1962
Tait, J.M.S.; Shannon, T.W.; Harrison, A.G., The structure of substituted C₇ ions from benzyl derivatives at the appearance potential threshold, J. Am. Chem. Soc., 1962, 84, 4. [all data]

Fujio, McIver, et al., 1981
Fujio, M.; McIver, R.T., Jr.; Taft, R.W., Effects on the acidities of phenols from specific substituent-solvent interactions. Inherent substituent parameters from gas phase acidities, J. Am. Chem. Soc., 1981, 103, 4017. [all data]

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Kebarle and McMahon, 1977
Kebarle, P.; McMahon, T.B., Intrinsic Acidities of Substituted Phenols and Benzoic Acids Determined by Gas Phase Proton Transfer Equilibria, J. Am. Chem. Soc., 1977, 99, 7, 2222, https://doi.org/10.1021/ja00449a032 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, IR Spectrum, References

Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
IE (evaluated)	Recommended ionization energy
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_rG°	Free energy of reaction 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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