Urea
- Formula: CH4N2O
- Molecular weight: 60.0553
- IUPAC Standard InChIKey: XSQUKJJJFZCRTK-UHFFFAOYSA-N
- CAS Registry Number: 57-13-6
- 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: Carbamide; Carbamimidic acid; Carbonyldiamide; Isourea; Pseudourea; Urea-13C; Ureaphil; Ureophil; Urevert; UR; (NH2)2CO; Carbonyl Diamine; Alphadrate; Aquacare; Aquadrate; B-I-K; Calmurid; Carbaderm; Keratinamin; NCI-C02119; Pastaron; Prespersion, 75 urea; Ultra Mide; Urepearl; Mocovina; Supercel 3000; Varioform II; Benural 70; Harnstoff; Basodexan; Bubber shet; Elaqua xx; Hyanit; Nutraplus; Onychomal; NSC 34375; Uroderm; Panafil (Salt/Mix); Cerovel (Salt/Mix); component of Artra Ashy Skin Cream (Salt/Mix)
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Condensed phase thermochemistry data
Go To: Top, Phase change data, Reaction 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:
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 |
---|---|---|---|---|---|
ΔfH°solid | -79.62 ± 0.16 | kcal/mol | Ccb | Kabo, Miroshnichenko, et al., 1990 | see Simirsky, Kabo, et al., 1987; ALS |
ΔfH°solid | -76.52 ± 0.48 | kcal/mol | Ccb | Contineanu, Wagner, et al., 1982 | ALS |
ΔfH°solid | -79.682 ± 0.041 | kcal/mol | Ccb | Johnson, 1975 | ALS |
ΔfH°solid | -79.67 ± 0.05 | kcal/mol | Ccb | Huffman, 1940 | ALS |
ΔfH°solid | -77.34 | kcal/mol | Ccb | Schmidt and Becker, 1933 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°solid | -152. ± 2. | kcal/mol | AVG | N/A | Average of 8 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
S°solid,1 bar | 24.919 | cal/mol*K | N/A | Andersson, Matsuo, et al., 1993 | DH |
S°solid,1 bar | 25.079 | cal/mol*K | N/A | Kozyro, Dalidovich, et al., 1986 | DH |
S°solid,1 bar | 25.19 | cal/mol*K | N/A | Parks, Huffman, et al., 1933 | Extrapolation below 90 K, 33.18 J/mol*K.; DH |
S°solid,1 bar | 41.1 | cal/mol*K | N/A | Gibson, Latimer, et al., 1920 | Extrapolation below 86 K, no details.; DH |
Constant pressure heat capacity of solid
Cp,solid (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
22.18 | 298.15 | Andersson, Matsuo, et al., 1993 | T = 15 to 310 K.; DH |
22.5 | 304.7 | Gambino and Bros, 1988 | T = 303 to 413 K.; DH |
22.25 | 298.15 | Kozyro, Dalidovich, et al., 1986 | T = 5 to 400 K. Cp = 38.43 + 4.98x10-2T + 7.05x10-4T2 - 8.61x10-7T3 (240 to 400 K).; DH |
21.5 | 298.15 | Sasaki and Yokotake, 1966 | T = 90 to 298 K.; DH |
22.26 | 298.15 | Ruehrwein and Huffman, 1946 | T = 19 to 318 K.; DH |
16.4 | 293. | Campbell and Campbell, 1940 | DH |
22.38 | 298.0 | Parks, Huffman, et al., 1933 | T = 93 to 298 K. Value is unsmoothed experimental datum.; DH |
27.61 | 298.0 | Gibson, Latimer, et al., 1920 | T = 86 to 300 K. Value is unsmoothed experimental datum.; 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:
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
DH - Eugene S. Domalski and Elizabeth D. Hearing
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Tfus | 406. ± 3. | K | AVG | N/A | Average of 8 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 407.9 | K | N/A | Ferloni and DellaGatta, 1995 | Uncertainty assigned by TRC = 0.2 K; TRC |
Ttriple | 408. | K | N/A | Kabo, Miroshnichenko, et al., 1990, 2 | Uncertainty assigned by TRC = 0.00001 K; TRC |
Ttriple | 405.8 | K | N/A | Kozyro, Dalidovich, et al., 1986, 2 | Uncertainty assigned by TRC = 0.1 K; TRC |
Ttriple | 405.8 | K | N/A | Vogel and Schuberth, 1980 | Uncertainty assigned by TRC = 0.2 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔsubH° | 22.8 ± 0.07 | kcal/mol | GS | Emel'yanenko, Kabo, et al., 2006 | Based on data from 358. to 402. K.; AC |
ΔsubH° | 23.6 | kcal/mol | N/A | De Wit, Van Miltenburg, et al., 1983 | AC |
ΔsubH° | 20.95 ± 0.21 | kcal/mol | V | Suzuki, Onishi, et al., 1956 | ALS |
Enthalpy of sublimation
ΔsubH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
22.6 ± 0.53 | 370. | ME | Zaitsau, Kabo, et al., 2003 | Based on data from 329. to 403. K.; AC |
22.7 ± 0.53 | 350. | ME | Zaitsau, Kabo, et al., 2003 | Based on data from 329. to 403. K.; AC |
22.6 ± 0.1 | 350. | C | Zaitsau, Kabo, et al., 2003 | AC |
23.3 ± 0.24 | 354. | C | Kabo, Miroshnichenko, et al., 1990 | see Simirsky, Kabo, et al., 1987; ALS |
21.7 | 381. | N/A | Ferro, Barone, et al., 1987 | AC |
21.0 | 357. | N/A | Stephenson and Malanowski, 1987 | Based on data from 345. to 368. K.; AC |
23.2 | 351. | TE,ME | De Wit, Van Miltenburg, et al., 1983 | Based on data from 338. to 362. K.; AC |
22.8 | 361. | N/A | Trimble and Voorhoeve, 1978 | AC |
21.0 ± 0.50 | 356. | N/A | Suzuki, Onishi, et al., 1956, 2 | Based on data from 345. to 368. K. See also Jones, 1960 and Cox and Pilcher, 1970.; AC |
21.1 | 357. | N/A | Bradley and Cleasby, 1953 | See also De Wit, Van Miltenburg, et al., 1983.; AC |
Enthalpy of fusion
ΔfusH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
3.5349 | 406.5 | N/A | Della Gatta and Ferro, 1987 | DH |
3.3222 | 405.8 | N/A | Kozyro, Dalidovich, et al., 1986 | DH |
3.4656 | 406. | N/A | Gambino and Bros, 1988 | DH |
3.2529 | 405.8 | N/A | Vogel and Schuberth, 1980, 2 | DH |
3.49 | 407.2 | DSC | Rai and Rai, 1999 | AC |
3.25 | 405.2 | DSC | Jamróz, Palczewska-Tulinska, et al., 1998 | AC |
3.49 | 406.7 | DSC | Rai and Rai, 1998 | AC |
3.592 | 407.9 | DSC | Ferloni and Gatta, 1995 | AC |
3.090 | 408.1 | N/A | Kabo, Miroshnichenko, et al., 1990 | AC |
3.32 | 405.8 | N/A | Kozyro, Dalidovich, et al., 1986, 2 | AC |
Entropy of fusion
ΔfusS (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
8.70 | 406.5 | Della Gatta and Ferro, 1987 | DH |
8.186 | 405.8 | Kozyro, Dalidovich, et al., 1986 | DH |
8.53 | 406. | Gambino and Bros, 1988 | DH |
8.016 | 405.8 | Vogel and Schuberth, 1980, 2 | DH |
Reaction thermochemistry data
Go To: Top, Condensed 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 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- + =
By formula: CH3N2O- + H+ = CH4N2O
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 361.8 ± 2.8 | kcal/mol | CIDC | Ma, Wang, et al., 1998 | gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B |
ΔrH° | 362.5 ± 2.6 | kcal/mol | G+TS | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
ΔrH° | 357.4 ± 2.1 | kcal/mol | EIAE | Muftakhov, Vasil'ev, et al., 1999 | gas phase; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 355.7 ± 3.2 | kcal/mol | H-TS | Ma, Wang, et al., 1998 | gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B |
ΔrG° | 355.5 ± 2.5 | kcal/mol | IMRE | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
By formula: CH4N2O + C4H4O2 = N-(aminocarbonyl)-3-oxobutyramide
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -25.43 | kcal/mol | Kin | Lopatin, Popov, et al., 1992 | liquid phase; solvent: Solution; ALS |
By formula: 6CH4N2O = C3H6N6 + 3CO2 + 6H3N
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 112.2 | kcal/mol | Eqk | Rukevich and Zagranichnyi, 1971 | liquid phase; ALS |
References
Go To: Top, Condensed phase thermochemistry data, Phase change 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]
Ferloni and DellaGatta, 1995
Ferloni, P.; DellaGatta, G.,
Heat capacities of urea, N-methylurea, N-ethylurea, N-(n)propylurea, and N- (n)butylurea in the range 200 to 360 K,
Thermochim. Acta, 1995, 266, 203-12. [all data]
Kabo, Miroshnichenko, et al., 1990, 2
Kabo, G.Ya.; Miroshnichenko, E.A.; Frenkel, M.L.; Kozyro, A.A.; Simirsky, V.V.; Krasulin, A.P.; Vorob'eva, V.P.; Lebedev, Yu.A.,
Thermochemistry of Alkyl Derivatives of Urea,
Izv. Akad. Nauk SSSR, Ser. Khim., 1990, No. 4, 750-5. [all data]
Kozyro, Dalidovich, et al., 1986, 2
Kozyro, A.A.; Dalidovich, S.V.; Krausulin, A.P.,
Zh. Prikl. Khim. (S.-Peterburg), 1986, 59, 1456. [all data]
Vogel and Schuberth, 1980
Vogel, L.; Schuberth, H.,
Some physicochemical data of urea near the melting point<,
Chem. Tech. (Leipzig), 1980, 32, 143. [all data]
Emel'yanenko, Kabo, et al., 2006
Emel'yanenko, Vladimir N.; Kabo, Gennady J.; Verevkin, Sergey P.,
Measurement and Prediction of Thermochemical Properties: Improved Increments for the Estimation of Enthalpies of Sublimation and Standard Enthalpies of Formation of Alkyl Derivatives of Urea,
J. Chem. Eng. Data, 2006, 51, 1, 79-87, https://doi.org/10.1021/je050230z
. [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]
Suzuki, Onishi, et al., 1956
Suzuki, K.; Onishi, S.; Koide, T.; Seki, S.,
Vapor pressures of molecular crystals. XI. Vapor pressures of crystalline urea and diformylhydrazine. Energies of hydrogen bonds in these crystals,
Bull. Chem. Soc. Jpn., 1956, 29, 127. [all data]
Zaitsau, Kabo, et al., 2003
Zaitsau, Dz; Kabo, G.J.; Kozyro, A.A.; Sevruk, V.M.,
The effect of the failure of isotropy of a gas in an effusion cell on the vapor pressure and enthalpy of sublimation for alkyl derivatives of carbamide,
Thermochimica Acta, 2003, 406, 1-2, 17-28, https://doi.org/10.1016/S0040-6031(03)00231-4
. [all data]
Ferro, Barone, et al., 1987
Ferro, D.; Barone, G.; Della Gatta, G.; Piacente, V.,
Vapour pressures and sublimation enthalpies of urea and some of its derivatives,
The Journal of Chemical Thermodynamics, 1987, 19, 9, 915-923, https://doi.org/10.1016/0021-9614(87)90038-3
. [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]
Trimble and Voorhoeve, 1978
Trimble, L.E.; Voorhoeve, R.J.H.,
Continuous colorimetric monitoring of vapour-phase urea and cyanates,
Analyst, 1978, 103, 1228, 759, https://doi.org/10.1039/an9780300759
. [all data]
Suzuki, Onishi, et al., 1956, 2
Suzuki, Keisuke; Onishi, Shun-ichi; Koide, Tsutomu; Seki, Syuzo,
Vapor Pressures of Molecular Crystals. XI. Vapor Pressures of Crystalline Urea and Diformylhydrazine. Energies of Hydrogen Bonds in these Crystals,
Bull. Chem. Soc. Jpn., 1956, 29, 1, 127-131, https://doi.org/10.1246/bcsj.29.127
. [all data]
Jones, 1960
Jones, A.H.,
Sublimation Pressure Data for Organic Compounds.,
J. Chem. Eng. Data, 1960, 5, 2, 196-200, https://doi.org/10.1021/je60006a019
. [all data]
Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds, Academic Press Inc., London, 1970, 643. [all data]
Bradley and Cleasby, 1953
Bradley, R.S.; Cleasby, T.G.,
346. The vapour pressure and lattice energy of hydrogen-bonded crystals. Part I. Oxamide, oxamic acid, and rubeanic acid,
J. Chem. Soc., 1953, 1681, https://doi.org/10.1039/jr9530001681
. [all data]
Della Gatta and Ferro, 1987
Della Gatta, G.; Ferro, D.,
Enthalpies of fusion and solid-to-solid transition, entropies of fusion for urea and twelve alkylureas,
Thermochim. Acta, 1987, 122, 143-152. [all data]
Vogel and Schuberth, 1980, 2
Vogel, L.; Schuberth, H.,
Some physicochemical data of urea near the melting point,
Chem. Tech. (Leipzig), 1980, 32, 143-144. [all data]
Rai and Rai, 1999
Rai, U.S.; Rai, R.N.,
Some Physicochemical Studies on Organic Eutectics and Molecular Complex: Urea -- p-nitrophenol System,
J. Mater. Res., 1999, 14, 04, 1299-1305, https://doi.org/10.1557/JMR.1999.0177
. [all data]
Jamróz, Palczewska-Tulinska, et al., 1998
Jamróz, Malgorzata E.; Palczewska-Tulinska, Marcela; Wyrzykowska-Stankiewicz, Danuta; Szafranski, Andrzej M.; Polaczek, Jerzy; Dobrowolski, Jan Cz.; Jamróz, Michal H.; Mazurek, Aleksander P.,
The urea--phenol(s) systems,
Fluid Phase Equilibria, 1998, 152, 2, 307-326, https://doi.org/10.1016/S0378-3812(98)90206-0
. [all data]
Rai and Rai, 1998
Rai, U.S.; Rai, R.N.,
Journal of Thermal Analysis and Calorimetry, 1998, 53, 3, 883-893, https://doi.org/10.1023/A:1010190402954
. [all data]
Ferloni and Gatta, 1995
Ferloni, Paolo; Gatta, Giuseppe Della,
Heat capacities of urea, N-methylurea, N-ethylurea, N-(n)propylurea, and N-(n)butylurea in the range 200 to 360 K,
Thermochimica Acta, 1995, 266, 203-212, https://doi.org/10.1016/0040-6031(95)02453-0
. [all data]
Ma, Wang, et al., 1998
Ma, S.G.; Wang, F.; Cooks, R.G.,
Gas-phase acidity of urea,
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. [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, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, References
- Symbols used in this document:
Cp,solid Constant pressure heat capacity of solid S°solid,1 bar Entropy of solid at standard conditions (1 bar) Tfus Fusion (melting) point Ttriple Triple point temperature ΔcH°solid Enthalpy of combustion of solid at standard conditions ΔfH°solid Enthalpy of formation of solid at standard conditions ΔfusH Enthalpy of fusion ΔfusS Entropy of fusion ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔsubH Enthalpy of sublimation ΔsubH° Enthalpy of sublimation at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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