The thermodynamic properties of ammonium carbamate: An experiment in heterogeneous equilibrium

Converting Carbon Dioxide into Carbamato Derivatives

“…The NH 3 /CO 2 system, see eq 11, has been studied by measuring the dissociation pressure of solid ammonium carbamate at different temperatures, , and the values Δ H 0 ≅ +160 kJ mol -1 and Δ S 0 ≅ +460 J mol -1 K -1 have been reported …”

“…Carbamic acid, NH 2 CO 2 H, although not yet isolated, has been detected by neutralization−reionization mass spectrometry (NRMS) 64 and by IR at low temperature, and some of its properties have been calculated theoretically. , In a thermochemical study,53b the standard enthalpy of formation of gaseous carbamic acid was calculated to be −381 kJ mol -1 (Δ = −317 kJ mol -1 ), and that of solid NH 4 [O 2 CNH 2 ] has been determined ( = −646 kJ mol -1 ; Δ = −459 kJ mol -1 ). According to these figures, it can be calculated that gaseous carbamic acid should be unstable with respect to both NH 4 [O 2 CNH 2 ] (s) + CO 2(g) ( = −277 kJ mol -1 ; = −219 kJ mol -1 ), and to NH 3(g) + CO 2(g) ( = −58 kJ mol -1 ; = −93 kJ mol -1 ).…”

The Use of Ammonium Carbamate as a High Specific Thermal Energy Density Material for the Thermal Management of Low Grade Heat

“…60,61 The dissociation pressure as a function of temperature is shown for four literature sources in Figure 1 and there is excellent agreement among the data. 34,60,62,63 These data give a good indication of the pressures necessary to cause AC to decompose as a function of temperature. A pressure below atmospheric is necessary for rapid decomposition since the desired temperature range for this work is from 30°C to 60°C.…”

“…Table 2. Heat of reaction of ammonium carbamate Source ∆ ° (MJ/kg) Joncich et al 34 2.00 Janjic 71 2.07 Bennett 63 1.96 Egan, Potts and Potts 62 2.01 Clark and Hetherington 72 1.94 Claudel, Brousse, Shehadeh 73 2.05 Patent 4,169,499 69 1.99…”

Empirical Modeling of Urea Synthesis Chemical Equilibria

“…Hamidipour et al [6] assumes the gas is ideal and the liquid properties are modeled using Wilson equations. Other papers related to the thermodynamics of urea synthesis are listed in references [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Reactor models also vary in complexity. Irazoqui et al [23] assume that all components are in liquid phase and there is countercurrent flow between the coil and the bulk of the reactor.…”