Urea

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Gas phase ion energetics 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
MM - Michael M. Meot-Ner (Mautner)
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

Proton affinity at 298K

Proton affinity (kJ/mol) Reference Comment
868.4 ± 2.5Zheng and Cooks, 2002MM
873.5 ± 5.0Wang, Ma, et al., 1998m-bromoaniline; p-fluorobenzamide; MM
873.5 ± 5.0Wang, Ma, et al., 1998T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM

Gas basicity at 298K

Gas basicity (review) (kJ/mol) Reference Comment
838.7 ± 3.0Zheng and Cooks, 2002MM
846.1 ± 5.0Wang, Ma, et al., 1998m-bromoaniline; p-fluorobenzamide; MM
841.6 ± 5.0Wang, Ma, et al., 1998T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM

Protonation entropy at 298K

Protonation entropy (J/mol*K) Reference Comment
9.4Zheng and Cooks, 2002MM
-1.9Wang, Ma, et al., 1998T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM

Ionization energy determinations

IE (eV) Method Reference Comment
9.7PEDebies and Rabalais, 1974LLK
10.27 ± 0.05EIBaldwin, Kirkien-Konasiewicz, et al., 1966RDSH
9.8PEBieri, Asbrink, et al., 1982Vertical value; LBLHLM
10.28PEDougherty, Wittel, et al., 1976Vertical value; LLK
10.33PEMines and Thompson, 1975Vertical value; LLK
10.15PEMeeks, Arnett, et al., 1975Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CH2NO+12.90?EILoudon and Webb, 1977LLK

De-protonation reactions

CH3N2O- + Hydrogen cation = Urea

By formula: CH3N2O- + H+ = CH4N2O

Quantity Value Units Method Reference Comment
Δr1514. ± 12.kJ/molCIDCMa, Wang, et al., 1998gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B
Δr1517. ± 11.kJ/molG+TSTaft, 1987gas phase; value altered from reference due to change in acidity scale; B
Δr1495. ± 8.8kJ/molEIAEMuftakhov, Vasil'ev, et al., 1999gas phase; B
Quantity Value Units Method Reference Comment
Δr1488. ± 13.kJ/molH-TSMa, Wang, et al., 1998gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B
Δr1487. ± 10.kJ/molIMRETaft, 1987gas phase; value altered from reference due to change in acidity scale; B

Mass spectrum (electron ionization)

Go To: Top, 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

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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-6843
NIST MS number 229591

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References

Go To: Top, 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.

Zheng and Cooks, 2002
Zheng, X.; Cooks, R.G., Thermochemical determinations by the kinetic method with direct entropy corrrection, J. Phys. Chem. A, 2002, 106, 9939. [all data]

Wang, Ma, et al., 1998
Wang, F.; Ma, S.G.; Zhang, D.X.; Cooks, R.G., Proton affinity and gas-phase basicity of urea, J. Phys. Chem. A., 1998, 102, 2988. [all data]

Debies and Rabalais, 1974
Debies, T.P.; Rabalais, J.W., Electronic structure of amino acids and ureas, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 315. [all data]

Baldwin, Kirkien-Konasiewicz, et al., 1966
Baldwin, M.; Kirkien-Konasiewicz, A.; Loudon, A.G.; Maccoll, A.; Smith, D., Localised or delocalised charges in molecule-ions?, Chem. Commun., 1966, 574. [all data]

Bieri, Asbrink, et al., 1982
Bieri, G.; Asbrink, L.; Von Niessen, W., 30.4-nm He(II) photoelectron spectra of organic molecules, J. Electron Spectrosc. Relat. Phenom., 1982, 27, 129. [all data]

Dougherty, Wittel, et al., 1976
Dougherty, D.; Wittel, K.; Meeks, J.; McGlynn, S.P., Photoelectron spectroscopy of carbonyls. Ureas, uracils, and thymine, J. Am. Chem. Soc., 1976, 98, 3815. [all data]

Mines and Thompson, 1975
Mines, G.W.; Thompson, H.W., The photoelectron spectra of amides, thioamides, ureas and thioureas, Spectrochim. Acta, 1975, 31, 137. [all data]

Meeks, Arnett, et al., 1975
Meeks, J.L.; Arnett, J.F.; Larson, D.B.; McGlynn, S.P., Photoelectron spectroscopy of carbonyls. Urea, oxamide, oxalic acid and oxamic acid, J. Am. Chem. Soc., 1975, 97, 3905. [all data]

Loudon and Webb, 1977
Loudon, A.G.; Webb, K.S., The nature of the [C2H6N]+ and [CH4N]+ ions formed by electron impact on methylated formamides, acetamides, ureas, thioureas and hexamethylphosphoramide, Org. Mass Spectrom., 1977, 12, 283. [all data]

Ma, Wang, et al., 1998
Ma, S.G.; Wang, F.; Cooks, R.G., Gas-phase acidity of urea, J. Mass Spectrom., 1998, 33, 10, 943-949, https://doi.org/10.1002/(SICI)1096-9888(1998100)33:10<943::AID-JMS703>3.0.CO;2-B . [all data]

Taft, 1987
Taft, R.W., The Nature and Analysis of Substitutent Electronic Effects, Personal communication. See also Prog. Phys. Org. Chem., 1987, 16, 1. [all data]

Muftakhov, Vasil'ev, et al., 1999
Muftakhov, M.V.; Vasil'ev, Y.V.; Mazunov, V.A., Determination of electron affinity of carbonyl radicals by means of negative ion mass spectrometry, Rapid Commun. Mass Spectrom., 1999, 13, 12, 1104-1108, https://doi.org/10.1002/(SICI)1097-0231(19990630)13:12<1104::AID-RCM619>3.0.CO;2-C . [all data]


Notes

Go To: Top, Gas phase ion energetics data, Mass spectrum (electron ionization), References