The effect of structural feature modifications with respect to those of MEA on the extent of carbamate formation may be explained, allowing us to identify structural factors of alkanolamine molecules that influence the CO The ideal gas contribution to the uncertainty of ∆H carb is much larger than the deprotonation reaction(∆H deprot ) as indicated in Table ranging from 0.1-1.0 pK unit or ≈ 0.57-5.7 kJ at T=298.15 K. The coefficients of -ln K c and ∆H carb obtained from the coefficients of the ideal gas free energy function (A 0 j , B 0 j , C 0 j ) and the residual free energy function (A res , B res , C res ) of the reversion reaction according to Eq. ( ) and Eq. ( ) are given in Tables S8 of Supplementary Information. The reaction enthalpy data at a typical absorption temperature (T = 313.15 K) is given in Table . The ∆H carb and ∆H deprot data maybe used in conjunction with the readily available enthalpy data of reactions R3-R6 to estimate overall heat of CO 2 absorption in these amines. Assuming that the Galvani potential is invariant with respect to temperature, Fig. shows the intrinsic and absolute values of the proton solvation free energies and enthalpies as functions of temperature. We have refined our previously developed 21 general framework for prediction of the equilibrium constants of chemical reactions in solution applied to CO 2 -loaded aqueous amine solutions. The primary aspect of the refinement is the use of isocoulombic reactions to predict the deprotonation and carbamate reversion equilibrium constants and their temperature dependence; this use of such reactions is in concordance with the recent finding that such reactions enable improved estimates of the temperature trend of equilibrium constants. This approach requires the development of a new H 3 O + (hydronium) force field (FF)