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Urea

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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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Deltafgas-56.29 ± 0.29kcal/molCcbKabo, Miroshnichenko, et al., 1990see Simirsky, Kabo, et al., 1987

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
Deltafsolid-79.62 ± 0.16kcal/molCcbKabo, Miroshnichenko, et al., 1990see Simirsky, Kabo, et al., 1987; ALS
Deltafsolid-76.52 ± 0.48kcal/molCcbContineanu, Wagner, et al., 1982ALS
Deltafsolid-79.682 ± 0.041kcal/molCcbJohnson, 1975ALS
Deltafsolid-79.67 ± 0.05kcal/molCcbHuffman, 1940ALS
Deltafsolid-77.34kcal/molCcbSchmidt and Becker, 1933ALS
Quantity Value Units Method Reference Comment
Deltacsolid-152. ± 2.kcal/molAVGN/AAverage of 8 values; Individual data points
Quantity Value Units Method Reference Comment
solid,1 bar24.919cal/mol*KN/AAndersson, Matsuo, et al., 1993DH
solid,1 bar25.079cal/mol*KN/AKozyro, Dalidovich, et al., 1986DH
solid,1 bar25.19cal/mol*KN/AParks, Huffman, et al., 1933Extrapolation below 90 K, 33.18 J/mol*K.; DH
solid,1 bar41.1cal/mol*KN/AGibson, Latimer, et al., 1920Extrapolation below 86 K, no details.; DH

Constant pressure heat capacity of solid

Cp,solid (cal/mol*K) Temperature (K) Reference Comment
22.18298.15Andersson, Matsuo, et al., 1993T = 15 to 310 K.; DH
22.5304.7Gambino and Bros, 1988T = 303 to 413 K.; DH
22.25298.15Kozyro, Dalidovich, et al., 1986T = 5 to 400 K. Cp = 38.43 + 4.98x10-2T + 7.05x10-4T2 - 8.61x10-7T3 (240 to 400 K).; DH
21.5298.15Sasaki and Yokotake, 1966T = 90 to 298 K.; DH
22.26298.15Ruehrwein and Huffman, 1946T = 19 to 318 K.; DH
16.4293.Campbell and Campbell, 1940DH
22.38298.0Parks, Huffman, et al., 1933T = 93 to 298 K. Value is unsmoothed experimental datum.; DH
27.61298.0Gibson, Latimer, et al., 1920T = 86 to 300 K. Value is unsmoothed experimental datum.; DH

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry 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:
B - John E. Bartmess
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

CH3N2O- + Hydrogen cation = Urea

By formula: CH3N2O- + H+ = CH4N2O

Quantity Value Units Method Reference Comment
Deltar361.8 ± 2.8kcal/molCIDCMa, Wang, et al., 1998gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B
Deltar362.5 ± 2.6kcal/molG+TSTaft, 1987gas phase; value altered from reference due to change in acidity scale; B
Deltar357.4 ± 2.1kcal/molEIAEMuftakhov, Vasil'ev, et al., 1999gas phase; B
Quantity Value Units Method Reference Comment
Deltar355.7 ± 3.2kcal/molH-TSMa, Wang, et al., 1998gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B
Deltar355.5 ± 2.5kcal/molIMRETaft, 1987gas phase; value altered from reference due to change in acidity scale; B

Urea + 2-Oxetanone, 4-methylene- = N-(aminocarbonyl)-3-oxobutyramide

By formula: CH4N2O + C4H4O2 = N-(aminocarbonyl)-3-oxobutyramide

Quantity Value Units Method Reference Comment
Deltar-25.43kcal/molKinLopatin, Popov, et al., 1992liquid phase; solvent: Solution; ALS

6Urea = 1,3,5-Triazine-2,4,6-triamine + 3Carbon dioxide + 6Ammonia

By formula: 6CH4N2O = C3H6N6 + 3CO2 + 6H3N

Quantity Value Units Method Reference Comment
Deltar112.2kcal/molEqkRukevich and Zagranichnyi, 1971liquid phase; ALS

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Notes

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

Kabo, Miroshnichenko, et al., 1990
Kabo, G.Ya.; Miroshnichenko, E.A.; Frenkel, M.L.; Kozyro, A.A.; Simirskii, V.V.; Krasulin, A.P.; Vorob'eva, V.P.; Lebedev, Yu.A., Thermochemistry of urea alkyl derivatives, Bull. Acad. Sci. USSR, Div. Chem. Sci., 1990, 662-667. [all data]

Simirsky, Kabo, et al., 1987
Simirsky, V.V.; Kabo, G.J.; Frenkel, M.L., Additivity of the enthalpies of formation of urea derivatives in the crystalline state, J. Chem. Thermodyn., 1987, 19, 1121-1127. [all data]

Contineanu, Wagner, et al., 1982
Contineanu, I.; Wagner, L.; Stanescu, L.; Marchidan, D.I., Combustion and formation enthalpies of o-phenylenediamine, urea and 2-benzimidazolone, Rev. Roum. Chim., 1982, 27, 205-209. [all data]

Johnson, 1975
Johnson, W.H., The enthalpies of combustion and formation of acetanilide and urea, J. Res. NBS, 1975, 79, 487-491. [all data]

Huffman, 1940
Huffman, H.M., Thermal Data. XII. The heats of combustion of urea and guanidine carbonate and their standard free energies of formation, J. Am. Chem. Soc., 1940, 62, 1009-1011. [all data]

Schmidt and Becker, 1933
Schmidt, V.A.; Becker, F., Die Bildungswarme von Nitrocellulofen, Nitroglycerin und anderen widuigen Beltandteilen von Treibmitteln, Z. Gesamte Schiess Sprengstoffwes., 1933, 33, 280-282. [all data]

Andersson, Matsuo, et al., 1993
Andersson, O.; Matsuo, T.; Suga, H.; Ferloni, P., Low-temperature heat capacity of urea, Int. J. Thermophys., 1993, 14(1), 149-158. [all data]

Kozyro, Dalidovich, et al., 1986
Kozyro, A.A.; Dalidovich, S.V.; Krasulin, A.P., Heat capacity, enthalpy of fusion, and thermodynamic properties of urea, Zhur. Prikl. Khim. (Leningrad), 1986, 59, 1456-1459. [all data]

Parks, Huffman, et al., 1933
Parks, G.S.; Huffman, H.M.; Barmore, M., Thermal data on organic compounds. XI. The heat capacities, entropies and free energies of ten compounds containing oxygen or nitrogen. J. Am. Chem. Soc., 1933, 55, 2733-2740. [all data]

Gibson, Latimer, et al., 1920
Gibson, G.E.; Latimer, W.M.; Parks, G.S., Entropy changes at low temperatures. I. Formic acid and urea. A test of the third law of thermodynamics, J. Am. Chem. Soc., 1920, 42, 1533-1542. [all data]

Gambino and Bros, 1988
Gambino, M.; Bros, J.P., Capacite calorifique de l'uree et de quelques melanges eutectiques a base d'uree entre 30 et 140°C, Thermochim. Acta, 1988, 127, 223-236. [all data]

Sasaki and Yokotake, 1966
Sasaki, K.; Yokotake, T., Thermodynamic properties of the products in SO3-NH3 reaction. II. Specific heats of sulfamide and ammonium sulfamate, Tokyo Kogyo Shikenshi Hokohu, 1966, 61, 309-314. [all data]

Ruehrwein and Huffman, 1946
Ruehrwein, R.A.; Huffman, H.M., Thermal data. XIX. The heat capacity, entropy and free energy of urea, J. Am. Chem. Soc., 1946, 68, 1759-1761. [all data]

Campbell and Campbell, 1940
Campbell, A.N.; Campbell, A.J.R., The heats of solution, heats of formation, specific heats and equilibrium diagrams of certain molecular compounds. J. Am. Chem. Soc., 1940, 62, 291-297. [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]

Lopatin, Popov, et al., 1992
Lopatin, E.B.; Popov, V.V.; Epshtein, N.A.; Mikhaleva, L.M.; Makarov, Yu.N., Kinetic and thermochemical characteristics of diketene-based reactions, Khim.-Farm. Zh., 1992, 26, 76-78. [all data]

Rukevich and Zagranichnyi, 1971
Rukevich, O.S.; Zagranichnyi, V.I., Equilibrium in the reaction of melamine formation from urea, J. Anal. Chem. USSR, 1971, 44, 1616-1620. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, References