Carbon dioxide solubility in hydrophobic natural deep eutectic solvents: An experimental and theoretical investigation

This study aims to assess the efficacy of several hydrophobic natural deep eutectic solvents (HNDESs) as physical solvents in the purification of natural gas and to evaluate their features concerning CO 2 solubility. Thymol (Thy), 1-Decanol (Dec), DL-Menthol (Ment), DL-Camphor (Camp), Octanoic acid (OctA), and Citronellal (Cit) were considered HNDES components. This study involved the characterization of HNDESs utilizing hydrogen nuclear magnetic resonance (1H-NMR) spectroscopy and Fourier-transform infrared spectroscopy (FTIR). In addition, the densities and viscosities of the solvents were determined experimentally. Also, the solubility of CO 2 was assessed utilizing Henry's law constant at 303.15 K and up to 0.5 MPa. Moreover, the reusabilities of the studied HNDESs were also evaluated. The modified Lyderson-Joback-Reid and Lee-Kesler mixing rules were employed to estimate the critical properties of the HNDESs. Furthermore, the pressure swing absorption process was simulated using HNDESs. The findings indicated the viability of employing HNDESs as prospective physical solvents in the petroleum industry for the removal of CO2 from natural gas.