As shown in Table 4, the activation barriers are small for the direct reaction, even in the most polar solvent (smaller than 13 kcal mol^-1). Therefore, all reactions must show a fast kinetics. From the viewpoint of CO₂ recovering after capture, it is desirable that the reverse reactions also have a small activation barrier. In this way, the thermodynamics of the reaction is the determinant parameter for the feasibility of the capture process. By selecting from Table 3 the anions with negative value for the Gibbs free energy change (in any solvent) and activation barrier for either the direct or the reverse reaction around 10 kcal mol^-1 or below (Table 4), which would then combine kinetics and thermodynamics features favoring the reaction and its reverse, the following species show up: CH₃S^-, C₂H₅S^-, F^- and CN^-.

Additionally, important cases are those where changing the solvent dielectric constant changes the spontaneity of the reaction. This was found for F^-, CN^-, CH₃S^- and C₂H₅S^-. In these cases, we could think of a capture process in a less polar solvent and thus CO₂ recovering in a more polar one. Therefore, some solvent gradient could be designed to combine the two processes, capture and regeneration.

As an example of such a behavior, Figure 5 shows the profile for the reaction between CN^- and CO₂. Among all systems studied, CN^- is the one which shows a clear dependency of the transition state energy with the solvent polarity. Curiously, as observed before, the effects of THF on the energy values are closer to the effects of water than to those of toluene. In this case, we additionally computed the effect of chloroform, a solvent with a dielectric constant (ɛ = 4.81) intermediary between that of THF and toluene. The results are also shown in Figure 6. The values for chloroform are between those of THF and toluene, but closer to THF.