Naphthalene, 2-methyl-

Formula: C₁₁H₁₀
Molecular weight: 142.1971
IUPAC Standard InChI: InChI=1S/C11H10/c1-9-6-7-10-4-2-3-5-11(10)8-9/h2-8H,1H3
IUPAC Standard InChIKey: QIMMUPPBPVKWKM-UHFFFAOYSA-N
CAS Registry Number: 91-57-6
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: β-Methylnaphthalene; 2-Methylnaphthalene; 2-methyInaphthalene; Methyl-2-naphthalene
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Other data available:
Data at other public NIST sites:
- Gas Phase Kinetics Database
- NIST Polycyclic Aromatic Hydrocarbon Structure Index
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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
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	27.75 ± 0.62	kcal/mol	Ccb	Speros and Rossini, 1960	Hfusion=2.83±0.01; ALS
Δ_fH°_gas	25.38	kcal/mol	N/A	Richardson and Parks, 1939	Value computed using Δ_fH_solid° value of 35.0±2.2 kj/mol from Richardson and Parks, 1939 and Δ_subH° value of 71.2 kj/mol from Richardson and Parks, 1939.; DRB

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
10.3	50.	Thermodynamics Research Center, 1997	p=1 bar.; GT
14.8	100.
19.3	150.
24.67	200.
33.72	273.15
36.95	298.15
37.19	300.
49.64	400.
60.28	500.
68.95	600.
76.00	700.
81.81	800.
86.64	900.
90.68	1000.
94.2	1100.
97.0	1200.
99.7	1300.
102.	1400.
103.	1500.

Condensed phase thermochemistry data

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Data compiled as indicated in comments:
DH - Eugene S. Domalski and Elizabeth D. Hearing
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity	Value	Units	Method	Reference	Comment
S°_liquid	52.579	cal/mol*K	N/A	McCullough, Finke, et al., 1957	DH
S°_liquid	48.71	cal/mol*K	N/A	Huffman, Parks, et al., 1931	Extrapolation below 90 K, 65.86 J/molK. Value is for crystal. Did not observe transition at 288 K with S= 19.2 J/molK.; DH
Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_solid	10.72 ± 0.35	kcal/mol	Ccb	Speros and Rossini, 1960	Hfusion=2.83±0.01; ALS
Δ_fH°_solid	8.36 ± 0.53	kcal/mol	Ccb	Richardson and Parks, 1939	Reanalyzed by Cox and Pilcher, 1970, Original value = 7.99 kcal/mol; see Richardson, 1939; ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_solid	-1386.88 ± 0.35	kcal/mol	Ccb	Speros and Rossini, 1960	Hfusion=2.83±0.01; Corresponding Δ_fHº_solid = 10.74 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_solid	-1384.50 ± 0.52	kcal/mol	Ccb	Richardson and Parks, 1939	Reanalyzed by Cox and Pilcher, 1970, Original value = -1383.91 kcal/mol; see Richardson, 1939; Corresponding Δ_fHº_solid = 8.36 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS

Constant pressure heat capacity of liquid

C_p,liquid (cal/mol*K)	Temperature (K)	Reference	Comment
46.840	298.15	McCullough, Finke, et al., 1957	T = 10 to 400 K.; DH
54.49	310.4	Huffman, Parks, et al., 1931	T = 94 to 310 K. Value is unsmoothed experimental datum.; DH

Reaction thermochemistry data

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Data compiled by: John E. Bartmess

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

C₁₁H₉^- + = Naphthalene, 2-methyl-

By formula: C₁₁H₉^- + H⁺ = C₁₁H₁₀

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	372.7 ± 2.1	kcal/mol	G+TS	Antol, Glasovac, et al., 2003	gas phase
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	365.2 ± 2.0	kcal/mol	IMRE	Antol, Glasovac, et al., 2003	gas phase

Gas phase ion energetics data

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Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
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 C₁₁H₁₀⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	7.91 ± 0.06	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	198.8	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	191.8	kcal/mol	N/A	Hunter and Lias, 1998	HL

Electron affinity determinations

EA (eV)	Method	Reference	Comment
<0.143 ± 0.069	ECD	Wojnarovits and Foldiak, 1981	EA is an upper limit: Chen and Wentworth, 1989. G3MP2B3 calculations indicate an EA of ca. -0.2 eV, anion unbound.; B

Proton affinity at 298K

Proton affinity (kcal/mol)	Reference	Comment
198.6	Aue, Guidoni, et al., 2000	Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM

Gas basicity at 298K

Gas basicity (review) (kcal/mol)	Reference	Comment
191.7	Aue, Guidoni, et al., 2000	Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM

Ionization energy determinations

IE (eV)	Method	Reference	Comment
7.91 ± 0.02	TRPI	Gotkis and Lifshitz, 1993	LL
7.8	PE	Klasinc, Kovac, et al., 1983	LBLHLM
7.83	PE	Schafer, Schweig, et al., 1975	LLK
8.45 ± 0.05	EI	Loudon and Mazengo, 1974	LLK
8.10 ± 0.03	EI	Bonnier, Gelus, et al., 1965	RDSH
7.96 ± 0.01	PI	Watanabe, Nakayama, et al., 1962	RDSH
7.85	PE	Klasinc, Kovac, et al., 1983	Vertical value; LBLHLM
7.93	PE	Klasinc, Kovac, et al., 1983	Vertical value; LBLHLM
8.01 ± 0.03	PE	Heilbronner, Hoshi, et al., 1976	Vertical value; LLK
7.93	PE	Heilbronner, Hornung, et al., 1972	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C₁₁H₉⁺	13.2 ± 0.2	H	EI	Loudon and Mazengo, 1974	LLK
C₁₁H₉⁺	13.2 ± 0.2	H	EI	Nounou, 1966	RDSH

De-protonation reactions

C₁₁H₉^- + = Naphthalene, 2-methyl-

By formula: C₁₁H₉^- + H⁺ = C₁₁H₁₀

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	372.7 ± 2.1	kcal/mol	G+TS	Antol, Glasovac, et al., 2003	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	365.2 ± 2.0	kcal/mol	IMRE	Antol, Glasovac, et al., 2003	gas phase; B

References

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

Speros and Rossini, 1960
Speros, D.M.; Rossini, F.D., Heats of combustion and formation of naphthalene, the two methylnaphthalenes, cis and trans decahydronaphthalene and related compounds, J. Phys. Chem., 1960, 64, 1723-1727. [all data]

Richardson and Parks, 1939
Richardson, J.W.; Parks, G.S., Thermal data on organic compounds. XIX. Modern combustion data for some non-volatile compounds containing carbon, hydrogen and oxygen, J. Am. Chem. Soc., 1939, 61, 3543-3546. [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]

McCullough, Finke, et al., 1957
McCullough, J.P.; Finke, H.L.; Messerly, J.F.; Kincheloe, T.C.; Waddington, G., The low temperature thermodynamic properties of naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1,2,3,4-tetrahydronaphthalene, trans-decahydronaphthalene and cis-decahydronaphthalene, J. Phys. Chem., 1957, 61, 1105-1116. [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]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Richardson, 1939
Richardson, J.W., Precise determination of the heats of combustion of some representative organic compounds, Ph.D. Thesis for Standford University, 1939, 1-122. [all data]

Antol, Glasovac, et al., 2003
Antol, I.; Glasovac, Z.; Hare, M.C.; Eckert-Maksic, M.; Kass, S.R., On the acidity of cyclopropanaphthalenes - Gas phase and computational studies, Int. J. Mass Spectrom., 2003, 222, 1-3, 11-26, https://doi.org/10.1016/S1387-3806(02)00953-3 . [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Wojnarovits and Foldiak, 1981
Wojnarovits, L.; Foldiak, G., Electron capture detection of aromatic hydrocarbons, J. Chromatogr. Sci., 1981, 206, 511. [all data]

Chen and Wentworth, 1989
Chen, E.C.M.; Wentworth, W.E., Experimental Determination of Electron Affinities of Organic Molecules, Mol. Cryst. Liq. Cryst., 1989, 171, 271. [all data]

Aue, Guidoni, et al., 2000
Aue, D.H.; Guidoni, M.; Betowski, L.D., Ab initio calculated gas-phase basicities of polynuclear aromatic hydrocarbons, Int. J. Mass Spectrom., 2000, 201, 283. [all data]

Gotkis and Lifshitz, 1993
Gotkis, I.; Lifshitz, C., Time-dependent mass spectra and breakdown graphs. 16 - The methylnaphthalenes, Org. Mass Spectrom., 1993, 28, 372. [all data]

Klasinc, Kovac, et al., 1983
Klasinc, L.; Kovac, B.; Gusten, H., Photoelectron spectra of acenes. Electronic structure and substituent effects, Pure Appl. Chem., 1983, 55, 289. [all data]

Schafer, Schweig, et al., 1975
Schafer, W.; Schweig, A.; Vermeer, H.; Bickel-haupt, F.; De Graaf, H., On the nature of the "free electron pair" on phosphorus in aromatic phosphorus compounds: the photoelectron spectrum of 2-phosphanaphthalene, J. Electron Spectrosc. Relat. Phenom., 1975, 6, 91. [all data]

Loudon and Mazengo, 1974
Loudon, A.G.; Mazengo, R.Z., Steric strain and electron-impact. The behaviour of some n, n'-dimethyl- 1,1-binaphthyls, some n, n'-dimethylbiphenyls and model compounds, Org. Mass Spectrom., 1974, 8, 179. [all data]

Bonnier, Gelus, et al., 1965
Bonnier, J.-M.; Gelus, M.; Nounou, P., Contribution a l'etude de l'effet inductif et de l'effet d'hyperconjugaison dans quelques methylaromatiques, J. Chim. Phys., 1965, 10, 1191. [all data]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Heilbronner, Hoshi, et al., 1976
Heilbronner, E.; Hoshi, T.; von Rosenberg, J.L.; Hafner, K., Alkyl-induced, natural hypsochromic shifts of the ²A←²X and ²B←²X transitions of azulene and naphthalene radical cations, Nouv. J. Chim., 1976, 1, 105. [all data]

Heilbronner, Hornung, et al., 1972
Heilbronner, E.; Hornung, V.; Pinkerton, F.H.; Thames, S.F., 31. Photoelectron spectra of azabenzenes and azanaphthalenes: III. The orbital sequence in methyl- and trimethylsilyl- substituted pyridines, Helv. Chim. Acta, 1972, 55, 289. [all data]

Nounou, 1966
Nounou, P., Etude des composes aromatiques par spectrometrie de masse. I. Mesure des potentials d'ionisation et d'apparition par la methode du potential retardateur et interpretation des courbes d'ionisation differentielle, J. Chim. Phys., 1966, 63, 994. [all data]

Notes

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

Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
EA	Electron affinity
IE (evaluated)	Recommended ionization energy
S°_liquid	Entropy of liquid at standard conditions
Δ_cH°_solid	Enthalpy of combustion of solid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_solid	Enthalpy of formation of solid 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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