A study on carbon dioxide solubility in the deep eutectic solvent (1 sodium bromide+6 ethylene glycol): Experimental and modeling by the SRK and CPA EoS

In this study, carbon dioxide solubilities were measured experimentally in the DES composed of 1 NaBr + 6 ethylene glycol at temperatures ranging from 293.2 to 323.2 K and pressures up to 37 bars. The minimum and maximum measured CO2 solubilities (in mole fraction) within the investigated temperature and pressure ranges were 0.0013 and 0.0526, respectively. The measured data were then used to optimize the values of fitting pa-rameters of the Cubic Plus Association, and the Soave-Redlich-Kwong EoSs equations of state. The AARD% values of 3.37 % and 2.52 % for SRK and CPA EoSs, respectively, showed reliable results for both models. However, the SRK EoS could estimate accurate carbon dioxide solubilities only by much larger binary interaction parameters, as compared to the CPA EoS. Also, using the measured data, the values of Henry's constant, standard enthalpy, standard entropy, and standard Gibbs free energy of dissolution were calculated according to ther-modynamic relations. The stronger interactions in the mixture of carbon dioxide with DES by the establishment of new intermolecular bonds (as compared to the pure DES), leads to the liberating of energy upon dissolution. This also results in less disorder and chaos as indicated by analyzing the above-mentioned thermodynamic properties.

Automated summary

In this study, the solubilities of carbon dioxide in a DES composed of 1 NaBr + 6 ethylene glycol were experimentally measured at different temperatures and pressures. The measured data were used to optimize the fitting parameters of the Cubic Plus Association and the Soave-Redlich-Kwong equations of state. The results showed that both models provided reliable estimations, with the CPA EoS requiring smaller binary interaction parameters compared to the SRK EoS. The study also calculated thermodynamic properties and found that the interactions between carbon dioxide and the DES resulted in the release of energy and reduced disorder.