Pyridine, 4-methyl-

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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
Δfgas24.80 ± 0.22kcal/molCcbGood, 1972ALS
Δfgas24.41 ± 0.15kcal/molCmAndon, Cox, et al., 1957ALS
Δfgas24.43 ± 0.15kcal/molCcbCox, Challoner, et al., 1954ALS
Δfgas22.2kcal/molN/AConstam and White, 1903Value 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)226.4kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity218.8kcal/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
9.46 ± 0.05EIZaretskii, Oren, et al., 1976LLK
9.5 ± 0.1EIStefanovic and Grutzmacher, 1974LLK
9.55 ± 0.05EIDistefano, Foffani, et al., 1971LLK
9.55EIDistefano, Foffani, et al., 1971, 2LLK
9.04 ± 0.03PIWatanabe, Nakayama, et al., 1962RDSH
9.41PEKlasinc, Novak, et al., 1978Vertical value; LLK
9.50 ± 0.05PEHeilbronner, Hornung, et al., 1972Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
C5H6+12.86 ± 0.05HCNEIZaretskii, Oren, et al., 1976LLK
C6H6N+12.2 ± 0.1HEIPalmer and Lossing, 1963RDSH

De-protonation reactions

C6H6N- + Hydrogen cation = Pyridine, 4-methyl-

By formula: C6H6N- + H+ = C6H7N

Quantity Value Units Method Reference Comment
Δr369.7 ± 5.1kcal/molG+TSMeot-ner and Kafafi, 1988gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B
Δr374.8 ± 3.1kcal/molG+TSDePuy, Kass, et al., 1988gas phase; Acid: p-methylpyridine. Between iPrOH, MeCN.; B
Quantity Value Units Method Reference Comment
Δr362.9 ± 5.0kcal/molIMRBMeot-ner and Kafafi, 1988gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B
Δr368.0 ± 3.0kcal/molIMRBDePuy, Kass, et al., 1988gas 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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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

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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