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, Phase change 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 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 |
Phase change data
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 as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
DH - Eugene S. Domalski and Elizabeth D. Hearing
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Tboil | 418. ± 1. | K | AVG | N/A | Average of 18 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 276.8 ± 0.8 | K | AVG | N/A | Average of 9 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 276.800 | K | N/A | Messerly, Todd, et al., 1988 | Crystal phase 1 phase; Uncertainty assigned by TRC = 0.03 K; TRC |
Ttriple | 276.810 | K | N/A | Messerly, Todd, et al., 1988 | Crystal phase 1 phase; Uncertainty assigned by TRC = 0.02 K; TRC |
Ttriple | 276.8 | K | N/A | Soulard, Fillaux, et al., 1986 | Crystal phase 1 phase; Uncertainty assigned by TRC = 1. K; phases identified by Raman spectrum; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 646. | K | N/A | Majer and Svoboda, 1985 | |
Tc | 646.3 | K | N/A | Kobe and Mathews, 1970 | Uncertainty assigned by TRC = 0.5 K; TRC |
Tc | 645.65 | K | N/A | Ambrose and Grant, 1957 | Uncertainty assigned by TRC = 0.5 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 45.99 | atm | N/A | Kobe and Mathews, 1970 | Uncertainty assigned by TRC = 0.5000 atm; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 3.07 | mol/l | N/A | Kobe and Mathews, 1970 | Uncertainty assigned by TRC = 0.21 mol/l; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 10.7 ± 0.1 | kcal/mol | AVG | N/A | Average of 9 values; Individual data points |
Enthalpy of vaporization
ΔvapH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
8.965 | 418.5 | N/A | Majer and Svoboda, 1985 | |
10.4 ± 0.02 | 320. | EB | Chirico, Knipmeyer, et al., 1999 | Based on data from 328. to 459. K.; AC |
9.82 ± 0.02 | 360. | EB | Chirico, Knipmeyer, et al., 1999 | Based on data from 328. to 459. K.; AC |
9.27 ± 0.02 | 400. | EB | Chirico, Knipmeyer, et al., 1999 | Based on data from 328. to 459. K.; AC |
8.65 ± 0.05 | 440. | EB | Chirico, Knipmeyer, et al., 1999 | Based on data from 328. to 459. K.; AC |
9.89 | 363. | A | Stephenson and Malanowski, 1987 | Based on data from 348. to 460. K.; AC |
10.1 | 347. | A | Stephenson and Malanowski, 1987 | Based on data from 348. to 347. K.; AC |
9.56 | 396. | A | Stephenson and Malanowski, 1987 | Based on data from 381. to 460. K.; AC |
9.06 | 467. | A | Stephenson and Malanowski, 1987 | Based on data from 452. to 573. K.; AC |
8.89 | 579. | A | Stephenson and Malanowski, 1987 | Based on data from 564. to 646. K.; AC |
9.89 | 363. | EB,IP | Stephenson and Malanowski, 1987 | Based on data from 348. to 459. K. See also Osborn and Douslin, 1968.; AC |
10.5 ± 0.02 | 313. | C | Majer, Svoboda, et al., 1984 | AC |
10.3 ± 0.02 | 328. | C | Majer, Svoboda, et al., 1984 | AC |
10.1 ± 0.02 | 343. | C | Majer, Svoboda, et al., 1984 | AC |
9.87 | 365. | MG | Herington and Martin, 1953 | Based on data from 350. to 418. K.; AC |
Enthalpy of vaporization
ΔvapH = A exp(-αTr)
(1 − Tr)β
ΔvapH =
Enthalpy of vaporization (at saturation pressure)
(kcal/mol)
Tr = reduced temperature (T / Tc)
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Temperature (K) | 298. to 434. |
---|---|
A (kcal/mol) | 15.3 |
α | 0.5241 |
β | 0.1879 |
Tc (K) | 646. |
Reference | Majer and Svoboda, 1985 |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (atm)
T = temperature (K)
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Temperature (K) | A | B | C | Reference | Comment |
---|---|---|---|---|---|
348.20 to 459.07 | 4.1641 | 1482.84 | -62.407 | Osborn and Douslin, 1968 | |
350.06 to 418.61 | 4.16667 | 1484.484 | -62.229 | Herington and Martin, 1953, 2 | Coefficents calculated by NIST from author's data. |
Enthalpy of sublimation
ΔsubH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
15.0 | 226. | A | Stephenson and Malanowski, 1987 | Based on data from 213. to 239. K.; AC |
Temperature of phase transition
Ttrs (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|
255.010 | crystaline, II | crystaline, I | Steele, Chirico, et al., 1986 | DH |
276.818 | crystaline, I | liquid | Steele, Chirico, et al., 1986 | DH |
Enthalpy of phase transition
ΔHtrs (kcal/mol) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
0.00 | 255.00 | crystaline, II | crystaline, I | Messerly, Todd, et al., 1988, 2 | DH |
3.007238 | 276.818 | crystaline, I | liquid | Messerly, Todd, et al., 1988, 2 | DH |
0.000020 | 255.010 | crystaline, II | crystaline, I | Messerly, Todd, et al., 1987 | DH |
3.0060 | 276.817 | crystaline, I | liquid | Messerly, Todd, et al., 1987 | DH |
Entropy of phase transition
ΔStrs (cal/mol*K) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
10.86 | 276.818 | crystaline, I | liquid | Messerly, Todd, et al., 1988, 2 | DH |
10.86 | 276.817 | crystaline, I | liquid | Messerly, Todd, et al., 1987 | DH |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Phase change data, 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 |
References
Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, 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]
Messerly, Todd, et al., 1988
Messerly, J.F.; Todd, s.S.; Finke, H.L.; Good, W.D.; Gammon, B.E.,
Condensed-phase heat-capacity studies and derived thermodynamic properties for six cyclic nitrogen compounds,
J. Chem. Thermodyn., 1988, 20, 209. [all data]
Soulard, Fillaux, et al., 1986
Soulard, L.; Fillaux, F.; Braathen, G.; Le Calve, N.; Pasquier, B.,
Rotational Dynamics of the Methyl Group in the 4-Methyl pyridine Crystal,
Chem. Phys. Lett., 1986, 125, 41. [all data]
Majer and Svoboda, 1985
Majer, V.; Svoboda, V.,
Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation, Blackwell Scientific Publications, Oxford, 1985, 300. [all data]
Kobe and Mathews, 1970
Kobe, K.A.; Mathews, J.F.,
Critical Properties and Vapor Pressures of Some Organic Nitrogen and Oxygen Compounds,
J. Chem. Eng. Data, 1970, 15, 182. [all data]
Ambrose and Grant, 1957
Ambrose, D.; Grant, D.G.,
The Critical Temperatures of Some Hydrocarbons and Pyridine Bases,
Trans. Faraday Soc., 1957, 53, 771. [all data]
Chirico, Knipmeyer, et al., 1999
Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Steele, W.V.,
Thermodynamic properties of the methylpyridines. Part 2. Vapor pressures, heat capacities, critical properties, derived thermodynamic functions between the temperatures 250 K and 560 K, and equilibrium isomer distributions for all temperatures ≥250 K,
The Journal of Chemical Thermodynamics, 1999, 31, 3, 339-378, https://doi.org/10.1006/jcht.1998.0451
. [all data]
Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw,
Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2
. [all data]
Osborn and Douslin, 1968
Osborn, Ann G.; Douslin, Donald R.,
Vapor pressure relations of 13 nitrogen compounds related to petroleum,
J. Chem. Eng. Data, 1968, 13, 4, 534-537, https://doi.org/10.1021/je60039a024
. [all data]
Majer, Svoboda, et al., 1984
Majer, V.; Svoboda, V.; Lencka, M.,
Enthalpies of vaporization and cohesive energies of pyridine and isomeric methylpyridines,
J. Chem. Thermodyn., 1984, 16, 1019-1024. [all data]
Herington and Martin, 1953
Herington, E.F.G.; Martin, J.F.,
Vapour pressures of pyridine and its homologues,
Trans. Faraday Soc., 1953, 49, 154, https://doi.org/10.1039/tf9534900154
. [all data]
Herington and Martin, 1953, 2
Herington, E.F.G.; Martin, J.F.,
Vapour Pressures of Pyridine and its Homologues,
Trans. Faraday Soc., 1953, 49, 154-162, https://doi.org/10.1039/tf9534900154
. [all data]
Steele, Chirico, et al., 1986
Steele, W.V.; Chirico, R.D.; Collier, W.B.; Hossenlopp, I.A.; Nguyen, A.; Strube, M.M.,
Thermochemical and thermophysical properties of organic nitrogen compounds found in fossil materials,
NIPER Report, 1986, 188, 112p. [all data]
Messerly, Todd, et al., 1988, 2
Messerly, J.F.; Todd, S.S.; Finke, H.L.; Good, W.D.; Gammon, B.E.,
Condensed-phase heat-capacity studies and derived thermodynamic properties for six cyclic nitrogen compounds,
J. Chem. Thermodynam., 1988, 20, 209-224. [all data]
Messerly, Todd, et al., 1987
Messerly, J.F.; Todd, S.S.; Finke, H.L.; Gammon, B.E.,
Thermodynamic properties of organic nitrogen compounds that occur in shale oil and heavy petroleum-topical report,
NIPER Report, 1987, 83, 37p. [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, Phase change data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy Pc Critical pressure Tboil Boiling point Tc Critical temperature Tfus Fusion (melting) point Ttriple Triple point temperature Ttrs Temperature of phase transition ΔHtrs Enthalpy of phase transition ΔStrs Entropy of phase transition 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 ΔsubH Enthalpy of sublimation ΔvapH Enthalpy of vaporization ΔvapH° Enthalpy of vaporization at standard conditions ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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