1H-Imidazole

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Gas phase thermochemistry data

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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:
DRB - Donald R. Burgess, Jr.
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Δfgas30.95kcal/molN/AZaheeruddin and Lodhi, 1991Value computed using ΔfHsolid° value of 60.0 kj/mol from Zaheeruddin and Lodhi, 1991 and ΔsubH° value of 69.5 kj/mol from Jimenez, Roux, et al., 1987.; DRB
Δfgas33.29 ± 0.45kcal/molCmGuthrie and Pike, 1987Heat of hydrolysis; ALS
Δfgas31.8 ± 0.1kcal/molCcbJimenez, Roux, et al., 1987see Jimenez, Roux, et al., 1986; ALS
Δfgas30.6 ± 1.8kcal/molCcbBedford, Edmondson, et al., 1962ALS

Condensed phase thermochemistry data

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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
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Δfsolid  CcbZaheeruddin and Lodhi, 1991uncertain value: 14.33 kcal/mol; ALS
Δfsolid11.9 ± 0.1kcal/molCcbJimenez, Roux, et al., 1987see Jimenez, Roux, et al., 1986; ALS
Δfsolid13.97 ± 0.78kcal/molCcbBedford, Edmondson, et al., 1962Reanalyzed by Cox and Pilcher, 1970, Original value = 14.6 ± 0.8 kcal/mol; ALS
Quantity Value Units Method Reference Comment
Δcsolid  CcbZaheeruddin and Lodhi, 1991uncertain value: -433.119 kcal/mol; ALS
Δcsolid-430.7 ± 0.1kcal/molCcbJimenez, Roux, et al., 1987see Jimenez, Roux, et al., 1986; ALS
Δcsolid-432.75 ± 0.78kcal/molCcbBedford, Edmondson, et al., 1962Reanalyzed by Cox and Pilcher, 1970, Original value = -433.34 ± 0.78 kcal/mol; ALS
Δcsolid-430.8kcal/molCcbZimmerman and Geisenfelder, 1961ALS

Constant pressure heat capacity of solid

Cp,solid (cal/mol*K) Temperature (K) Reference Comment
19.7298.15Jimenez, Roux, et al., 1987Cp given as 1.21 J/g*K.; DH
21.46300.DeWit, DeKruif, et al., 1983T = 90 to 370 K.; DH
22.6310.DeWit, Offringa, et al., 1983T = 300 to 450 K.; DH

Phase change data

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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
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
AC - William E. Acree, Jr., James S. Chickos
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Tboil530.2KN/AWeast and Grasselli, 1989BS
Quantity Value Units Method Reference Comment
Tfus363.7KN/AHilgeman, Mouroux, et al., 1989Uncertainty assigned by TRC = 0.4 K; TRC
Tfus361.9KN/ADe Wit, Offringa, et al., 1983Uncertainty assigned by TRC = 0.2 K; TRC
Quantity Value Units Method Reference Comment
Ttriple362.69KN/ADe Wit, De Kruif, et al., 1983Uncertainty assigned by TRC = 0.02 K; TRC
Quantity Value Units Method Reference Comment
Δsub19. ± 3.kcal/molAVGN/AAverage of 8 values; Individual data points

Enthalpy of sublimation

ΔsubH (kcal/mol) Temperature (K) Method Reference Comment
19.9 ± 0.05300.MEJimenez, Roux, et al., 1987Based on data from 292. - 309. K.; AC
19.3301.ME,TEDe Wit, Van Miltenburg, et al., 1983Based on data from 288. - 310. K.; AC

Enthalpy of fusion

ΔfusH (kcal/mol) Temperature (K) Reference Comment
2.9876363.7Hilgeman, Mouroux, et al., 1989, 2DH
3.0643362.69DeWit, DeKruif, et al., 1983DH
3.0593361.9DeWit, Offringa, et al., 1983DH
3.06361.9Domalski and Hearing, 1996See also De Wit, De Kruif, et al., 1983, 2.; AC

Entropy of fusion

ΔfusS (cal/mol*K) Temperature (K) Reference Comment
8.449362.69DeWit, DeKruif, et al., 1983DH
8.454361.9DeWit, Offringa, et al., 1983DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


Reaction thermochemistry data

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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:
B - John E. Bartmess
RCD - Robert C. Dunbar
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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

imidazolide anion + Hydrogen cation = 1H-Imidazole

By formula: C3H3N2- + H+ = C3H4N2

Quantity Value Units Method Reference Comment
Δr349.93 ± 0.72kcal/molG+TSGianola, Ichino, et al., 2005gas phase; B
Δr350.1 ± 2.1kcal/molG+TSTaft, Anvia, et al., 1986gas phase; value altered from reference due to change in acidity scale; B
Quantity Value Units Method Reference Comment
Δr342.60 ± 0.40kcal/molIMREGianola, Ichino, et al., 2005gas phase; B
Δr342.8 ± 2.0kcal/molIMRETaft, Anvia, et al., 1986gas phase; value altered from reference due to change in acidity scale; B

Sodium ion (1+) + 1H-Imidazole = (Sodium ion (1+) • 1H-Imidazole)

By formula: Na+ + C3H4N2 = (Na+ • C3H4N2)

Quantity Value Units Method Reference Comment
Δr33.4 ± 1.2kcal/molCIDTHuang and Rodgers, 2002RCD
Δr33.4 ± 1.3kcal/molCIDTArmentrout and Rodgers, 2000RCD
Δr33.4 ± 1.2kcal/molCIDTRodgers and Armentrout, 1999RCD

imidazolide anion + 1H-Imidazole = (imidazolide anion • 1H-Imidazole)

By formula: C3H3N2- + C3H4N2 = (C3H3N2- • C3H4N2)

Quantity Value Units Method Reference Comment
Δr26.4kcal/molPHPMSMeot-Ner (Mautner), 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr29.3cal/mol*KPHPMSMeot-Ner (Mautner), 1988gas phase; M

C3H4N2+ + 1H-Imidazole = (C3H4N2+ • 1H-Imidazole)

By formula: C3H4N2+ + C3H4N2 = (C3H4N2+ • C3H4N2)

Quantity Value Units Method Reference Comment
Δr23.7kcal/molPHPMSMeot-Ner (Mautner), 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr21.7cal/mol*KPHPMSMeot-Ner (Mautner), 1988gas phase; M

C4H12N+ + 1H-Imidazole = (C4H12N+ • 1H-Imidazole)

By formula: C4H12N+ + C3H4N2 = (C4H12N+ • C3H4N2)

Quantity Value Units Method Reference Comment
Δr22.6kcal/molPHPMSMeot-Ner (Mautner), 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr21.2cal/mol*KPHPMSMeot-Ner (Mautner), 1988gas phase; M

MeCO2 anion + 1H-Imidazole = (MeCO2 anion • 1H-Imidazole)

By formula: C2H3O2- + C3H4N2 = (C2H3O2- • C3H4N2)

Quantity Value Units Method Reference Comment
Δr27.7kcal/molPHPMSMeot-Ner (Mautner), 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr24.4cal/mol*KPHPMSMeot-Ner (Mautner), 1988gas phase; M

1H-Imidazole, 1-acetyl- + Water = 1H-Imidazole + Acetic acid

By formula: C5H6N2O + H2O = C3H4N2 + C2H4O2

Quantity Value Units Method Reference Comment
Δr-4.83 ± 0.05kcal/molCmWadso, 1960liquid phase; solvent: Aqueous; Heat of hydrolysis; ALS

Acetylimidazole diethyl acetal + Water = Ethyl Acetate + 1H-Imidazole + Ethanol

By formula: C9H16N2O2 + H2O = C4H8O2 + C3H4N2 + C2H6O

Quantity Value Units Method Reference Comment
Δr-10.68 ± 0.16kcal/molCmGuthrie and Pike, 1987liquid phase; Heat of hydrolysis; ALS

1-(Dimethoxy-phenylmethyl)-1H-imidazole + Water = 1H-Imidazole + Methyl Alcohol + Benzoic acid, methyl ester

By formula: C12H14N2O2 + H2O = C3H4N2 + CH4O + C8H8O2

Quantity Value Units Method Reference Comment
Δr-13.26 ± 0.17kcal/molCmGuthrie and Pike, 1987liquid phase; Heat of hydrolysis; ALS

N-Formylimidazole diethyl acetal + Water = Ethyl formate + 1H-Imidazole + Ethanol

By formula: C8H14N2O2 + H2O = C3H6O2 + C3H4N2 + C2H6O

Quantity Value Units Method Reference Comment
Δr-8.28 ± 0.42kcal/molCmGuthrie and Pike, 1987liquid phase; Heat of hydrolysis; ALS

1-Butanamine + 1H-Imidazole, 1-acetyl- = Acetamide, N-butyl- + 1H-Imidazole

By formula: C4H11N + C5H6N2O = C6H13NO + C3H4N2

Quantity Value Units Method Reference Comment
Δr-18.07 ± 0.08kcal/molCmWadso, 1962solid phase; ALS

Lithium ion (1+) + 1H-Imidazole = (Lithium ion (1+) • 1H-Imidazole)

By formula: Li+ + C3H4N2 = (Li+ • C3H4N2)

Quantity Value Units Method Reference Comment
Δr50.4 ± 2.3kcal/molCIDTHuang and Rodgers, 2002RCD

Potassium ion (1+) + 1H-Imidazole = (Potassium ion (1+) • 1H-Imidazole)

By formula: K+ + C3H4N2 = (K+ • C3H4N2)

Quantity Value Units Method Reference Comment
Δr26.0 ± 1.3kcal/molCIDTHuang and Rodgers, 2002RCD

IR Spectrum

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Coblentz Society, Inc.

Condensed Phase Spectrum

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IR spectrum
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Notice: Except where noted, spectra from this collection were measured on dispersive instruments, often in carefully selected solvents, and hence may differ in detail from measurements on FTIR instruments or in other chemical environments. More information on the manner in which spectra in this collection were collected can be found here.

Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived.

Additional Data

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Owner COBLENTZ SOC.
Collection (C) 2018 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
Origin DOW CHEMICAL COMPANY
Source reference COBLENTZ NO. 06436
Date 1963/01/23
Name(s) 1H-imidazole
State SOLID (SPLIT MULL)
SPECTRAL FEATURE AT 1993 CM-1 IS PROBABLY AN ARTIFACT CAUSED BY GRATING CHANGE
Instrument DOW KBr FOREPRISM-GRATING
Instrument parameters BLAZED AT 3.5, 12.0, 20.0 MICRON AND CHANGED AT 5.0, 7.5, 14.9 MICRON
Resolution 2
Sampling procedure TRANSMISSION
Data processing DIGITIZED BY COBLENTZ SOCIETY (BATCH I) FROM HARD COPY

This IR spectrum is from the Coblentz Society's evaluated infrared reference spectra collection.


Mass spectrum (electron ionization)

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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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Mass spectrum
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Additional Data

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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 NIST Mass Spectrometry Data Center
NIST MS number 353138

All mass spectra in this site (plus many more) are available from the NIST/EPA/NIH Mass Spectral Library. Please see the following for information about the library and its accompanying search program.


References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, IR Spectrum, 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.

Zaheeruddin and Lodhi, 1991
Zaheeruddin, M.; Lodhi, Z.H., Enthalpies of formation of some cyclic compounds, Phys. Chem. (Peshawar Pak.), 1991, 10, 111-118. [all data]

Jimenez, Roux, et al., 1987
Jimenez, P.; Roux, M.V.; Turrion, C., Thermochemical properties of N-heterocyclic compounds. I. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of pyrazole, imidazole, indazole, and benzimidazole, J. Chem. Thermodyn., 1987, 19, 985-992. [all data]

Guthrie and Pike, 1987
Guthrie, J.P.; Pike, D.C., Hydration of acylimidazoles: tetrahedral intermediates in acylimidazole hydrolysis and nucleophilic attack by imidazole on esters. The question of concerted mechanisms for acyl transfers, Can. J. Chem., 1987, 65, 1951-1969. [all data]

Jimenez, Roux, et al., 1986
Jimenez, P.; Roux, M.V.; Turrion, C.; Gomis, F., Thermochemical properties of some N-heterocyclic compounds, J. Calorim. Anal. Therm. Thermodyn. Chim., 1986, 17, 469-470. [all data]

Bedford, Edmondson, et al., 1962
Bedford, A.F.; Edmondson, P.B.; Mortimer, C.T., Heats of formation and bond energies. Part VI. n-Butyliso-butyraldimine, n-butylisobutylamine, pyrazole, and imidazole, J. Chem. Soc., 1962, 2927-2931. [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]

Zimmerman and Geisenfelder, 1961
Zimmerman, H.; Geisenfelder, H., Uber die Mesomerieenergie von Azolen, Z. Electrochem., 1961, 65, 368-371. [all data]

DeWit, DeKruif, et al., 1983
DeWit, H.G.M.; DeKruif, C.G.; Van Miltenburg, J.C., Thermodynamic properties of molecular organic crystals containing organic crystals containing nitrogen, oxygen, and sulfur. II. Molar heat capacities of eight compounds by adiabatic calorimetry, J. Chem. Thermodynam., 1983, 15, 891-902. [all data]

DeWit, Offringa, et al., 1983
DeWit, H.G.M.; Offringa, J.C.A.; De Kruif, C.G.; Van Miltenburg, J.C., Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen and sulfur. III. Molar heat capacities measured by differential scanning calorimetry, Thermochim. Acta, 1983, 65, 43-51. [all data]

Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]

Hilgeman, Mouroux, et al., 1989
Hilgeman, F.R.; Mouroux, F.Y.N.; Mok, D.; Holan, M.K., Phase Diagrams of Binary Solid Azole Systems, J. Chem. Eng. Data, 1989, 34, 220. [all data]

De Wit, Offringa, et al., 1983
De Wit, H.G.M.; Offringa, J.C.A.; De Kruif, C.G.; van Miltenburg, J.C., Thremodynamic properties of molecular organic crystals containing nitrogen, oxygen and sulfur. III. molar heat capacities measured by DSC. scanning calorimetry., Thermochim. Acta, 1983, 65, 43. [all data]

De Wit, De Kruif, et al., 1983
De Wit, H.G.M.; De Kruif, C.G.; Van Miltenburg, J.C., Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen, and sulfur II. Molar heat capacities of eight compounds by adiabatic calorimetry, J. Chem. Thermodyn., 1983, 15, 9, 891, https://doi.org/10.1016/0021-9614(83)90095-2 . [all data]

De Wit, Van Miltenburg, et al., 1983
De Wit, H.G.M.; Van Miltenburg, J.C.; De Kruif, C.G., Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen, and sulphur 1. Vapour pressures and enthalpies of sublimation, The Journal of Chemical Thermodynamics, 1983, 15, 7, 651-663, https://doi.org/10.1016/0021-9614(83)90079-4 . [all data]

Hilgeman, Mouroux, et al., 1989, 2
Hilgeman, F.R.; Mouroux, F.Y.N.; Mok, D.; Holan, M.K., Phase diagrams of binary solid azole systems, J. Chem. Eng. Data, 1989, 34, 220-222. [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

De Wit, De Kruif, et al., 1983, 2
De Wit, H.G.M.; De Kruif, C.G.; Van Miltenburg, J.C., Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen, and sulfur II. Molar heat capacities of eight compounds by adiabatic calorimetry, The Journal of Chemical Thermodynamics, 1983, 15, 9, 891-902, https://doi.org/10.1016/0021-9614(83)90095-2 . [all data]

Gianola, Ichino, et al., 2005
Gianola, A.J.; Ichino, T.; Hoenigman, R.L.; Kato, S.; Bierbaum, V.M.; Lineberger, W.C., Photoelectron spectra and ion chemistry of imidazolide, J. Phys. Chem. A, 2005, 109, 50, 11504-11514, https://doi.org/10.1021/jp053566o . [all data]

Taft, Anvia, et al., 1986
Taft, R.W.; Anvia, F.; Taagepera, M.; Catalan, J.; Elgueroy, J., Electrostatic proximity effects in the relative basicities of pyrazole, imidazole, pyridazine, and pyrimidine, J. Am. Chem. Soc., 1986, 108, 3237. [all data]

Huang and Rodgers, 2002
Huang, H.; Rodgers, M.T., Sigma versus Pi interactions in alkali metal ion binding to azoles: Threshold collision-induced dissociation and ab initio theory studies, J. Phys. Chem. A, 2002, 106, 16, 4277, https://doi.org/10.1021/jp013630b . [all data]

Armentrout and Rodgers, 2000
Armentrout, P.B.; Rodgers, M.T., An Absolute Sodium Cation Affinity Scale: Threshold Collision-Induced Dissociation Experiments and ab Initio Theory, J. Phys. Chem A, 2000, 104, 11, 2238, https://doi.org/10.1021/jp991716n . [all data]

Rodgers and Armentrout, 1999
Rodgers, M.T.; Armentrout, P.B., Absolute Alkali Metal Ion Binding Affinities of Several Azoles Determined by Threshold Collision-Induced Dissociation, Int. J. Mass Spectrom. Ion Proc., 1999, 185/186/187, 359. [all data]

Meot-Ner (Mautner), 1988
Meot-Ner (Mautner), M., Models for Strong Interactions in Proteins and Enzymes. 2. Interactions of Ions with the Peptide Link and Imidazole, J. Am. Chem. Soc., 1988, 110, 10, 3075, https://doi.org/10.1021/ja00218a014 . [all data]

Wadso, 1960
Wadso, I., Heats of hydrolysis of N-acetylated imidazole, 1,2,4-triazole and tetrazole, Acta Chem. Scand., 1960, 14, 903-908. [all data]

Wadso, 1962
Wadso, I., Heats of aminolysis and hydrolysis of some N-acetyl compounds and of acetic anhydride, Acta Chem. Scand., 1962, 16, 471-478. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), References