Pyridine, 4-methyl-
- Formula: C6H7N
- Molecular weight: 93.1265
- IUPAC Standard InChIKey: FKNQCJSGGFJEIZ-UHFFFAOYSA-N
- CAS Registry Number: 108-89-4
- 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: 4-Picoline; γ-Methylpyridine; γ-Picoline; p-Methylpyridine; p-Picoline; Ba 35846; 4-Methylpyridine; para-Methylpyridine; gamma-Picoline; NSC 18252
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Gas phase thermochemistry data
Go To: Top, Gas phase ion energetics data, Mass spectrum (electron ionization), References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | 24.80 ± 0.22 | kcal/mol | Ccb | Good, 1972 | ALS |
ΔfH°gas | 24.41 ± 0.15 | kcal/mol | Cm | Andon, Cox, et al., 1957 | ALS |
ΔfH°gas | 24.43 ± 0.15 | kcal/mol | Ccb | Cox, Challoner, et al., 1954 | ALS |
ΔfH°gas | 22.2 | kcal/mol | N/A | Constam and White, 1903 | Value computed using ΔfHliquid° value of 48.1 kj/mol from Constam and White, 1903 and ΔvapH° value of 44.6 kj/mol from Good, 1972.; DRB |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Mass spectrum (electron ionization), References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
Data compiled as indicated in comments:
B - John E. Bartmess
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 C6H7N+ (ion structure unspecified)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Proton affinity (review) | 226.4 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 218.8 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
9.46 ± 0.05 | EI | Zaretskii, Oren, et al., 1976 | LLK |
9.5 ± 0.1 | EI | Stefanovic and Grutzmacher, 1974 | LLK |
9.55 ± 0.05 | EI | Distefano, Foffani, et al., 1971 | LLK |
9.55 | EI | Distefano, Foffani, et al., 1971, 2 | LLK |
9.04 ± 0.03 | PI | Watanabe, Nakayama, et al., 1962 | RDSH |
9.41 | PE | Klasinc, Novak, et al., 1978 | Vertical value; LLK |
9.50 ± 0.05 | PE | Heilbronner, Hornung, et al., 1972 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
C5H6+ | 12.86 ± 0.05 | HCN | EI | Zaretskii, Oren, et al., 1976 | LLK |
C6H6N+ | 12.2 ± 0.1 | H | EI | Palmer and Lossing, 1963 | RDSH |
De-protonation reactions
C6H6N- + =
By formula: C6H6N- + H+ = C6H7N
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 369.7 ± 5.1 | kcal/mol | G+TS | Meot-ner and Kafafi, 1988 | gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B |
ΔrH° | 374.8 ± 3.1 | kcal/mol | G+TS | DePuy, Kass, et al., 1988 | gas phase; Acid: p-methylpyridine. Between iPrOH, MeCN.; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 362.9 ± 5.0 | kcal/mol | IMRB | Meot-ner and Kafafi, 1988 | gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B |
ΔrG° | 368.0 ± 3.0 | kcal/mol | IMRB | DePuy, Kass, et al., 1988 | gas phase; Acid: p-methylpyridine. Between iPrOH, MeCN.; B |
Mass spectrum (electron ionization)
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
View image of digitized spectrum (can be printed in landscape orientation).
Due to licensing restrictions, this spectrum cannot be downloaded.
Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
Origin | Japan AIST/NIMC Database- Spectrum MS-NW- 779 |
NIST MS number | 228749 |
References
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Good, 1972
Good, W.D.,
Enthalpies of combustion of nine organic nitrogen compounds related to petroleum,
J. Chem. Eng. Data, 1972, 17, 28-31. [all data]
Andon, Cox, et al., 1957
Andon, R.J.L.; Cox, J.D.; Herington, E.F.G.; Martin, J.F.,
The second virial coefficients of pyridine and benzene, and certain of their methyl homologues,
Trans. Faraday Soc., 1957, 53, 1074. [all data]
Cox, Challoner, et al., 1954
Cox, J.D.; Challoner, A.R.; Meetham, A.R.,
The heats of combustion of pyridine and certain of its derivatives,
J. Chem. Soc., 1954, 265-271. [all data]
Constam and White, 1903
Constam, E.J.; White, J.,
Physico-chemical investigations in the pyridine series,
Am. Chem. J., 1903, 29, 1-49. [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]
Zaretskii, Oren, et al., 1976
Zaretskii, Z.V.I.; Oren, D.; Kelner, L.,
Automatic method for the measurement of the electron impact ionization and appearance potentials,
Appl. Spectrosc., 1976, 30, 366. [all data]
Stefanovic and Grutzmacher, 1974
Stefanovic, D.; Grutzmacher, H.F.,
The ionisation potential of some substituted pyridines,
Org. Mass Spectrom., 1974, 9, 1052. [all data]
Distefano, Foffani, et al., 1971
Distefano, G.; Foffani, A.; Innorta, G.; Pignataro, S.,
Mass spectrometric study of transition metal complexes with ligands having nitrogen or sulphur as donor atom,
Adv. Mass Spectrom., 1971, 5, 696. [all data]
Distefano, Foffani, et al., 1971, 2
Distefano, G.; Foffani, A.; Innorta, G.; Pignataro, S.,
Electron impact ionization potentials of some manganese, chromium and tungsten organometallic derivatives,
Int. J. Mass Spectrom. Ion Phys., 1971, 7, 383. [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]
Klasinc, Novak, et al., 1978
Klasinc, L.; Novak, I.; Scholz, M.; Kluge, G.,
Photoelektronenspektren substituierter Pyridine und Benzole und ihre Interpretation durch die CNDO/SWW-Methode,
Croat. Chem. Acta, 1978, 51, 43. [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]
Palmer and Lossing, 1963
Palmer, T.F.; Lossing, F.P.,
Free radicals by mass spectrometry. XXX. Ionization potentials of anilino and 2-, 3-, and 4-pyridylmethyl radicals,
J. Am. Chem. Soc., 1963, 85, 1733. [all data]
Meot-ner and Kafafi, 1988
Meot-ner, M.; Kafafi, S.A.,
Carbon Acidities of Aromatic Compounds,
J. Am. Chem. Soc., 1988, 110, 19, 6297, https://doi.org/10.1021/ja00227a003
. [all data]
Kiefer, Zhang, et al., 1997
Kiefer, J.H.; Zhang, Q.; Kern, R.D.; Yao, J.; Jursic, B.,
Pyrolysis of Aromatic Azines: Pyrazine, Pyrimidine, and Pyridine,
J. Phys. Chem. A, 1997, 101, 38, 7061, https://doi.org/10.1021/jp970211z
. [all data]
DePuy, Kass, et al., 1988
DePuy, C.H.; Kass, S.R.; Bean, G.P.,
Formation and Reactions of Heteroaromatic Anions in the Gas Phase,
J. Org. Chem., 1988, 53, 19, 4427, https://doi.org/10.1021/jo00254a001
. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), References
- Symbols used in this document:
AE Appearance energy ΔfH°gas Enthalpy of formation of gas at standard conditions ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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