Carbon Dioxide Solubility in Nonionic Deep Eutectic Solvents Containing Phenolic Alcohols

Abstract

Deep eutectic solvents (DES) are a new class of green solvents that have shown unique properties in several process applications. This study evaluates nonionic DES containing phenolic alcohols as solvents for carbon dioxide (CO2) capture applications. Potential phenolic alcohols and the molar ratio between DES constituents were preselected for experimental investigations based on the conductor-like screening model for realistic solvation (COSMO-RS). CO2 solubility was experimentally determined in two different DES, namely, L-menthol/thymol in 1:2 molar ratio and thymol/2,6-xylenol in 1:1 molar ratio, at various temperatures and pressures. CO2 solubility in the studied systems was higher than that reported in the literature for ionic DES and ionic liquids. This study demonstrates that nonionic DES containing phenolic alcohols can be excellent, inexpensive, and simple solvents for CO2 capture.

Accurate prediction of carbon dioxide capture by deep eutectic solvents using quantum chemistry and a neural network

“…It has also been reported that longer alkyl chain lengths of DESs, or hydrophobic moieties in general, are better solvents for CO 2 . 23,33 Bearing this in mind, novel DES combinations were chosen based on our ML predictions and the following DESs combinations are proposed at different molar ratios and a wide range of pressures: menthol–decanoic acid (1 : 2), menthol–dodecanoic acid (1 : 2), [TBP]Br-TEG, [TOA]Br-TEG, [TOMA]Br-TEG, [ATPP]Br-DECA, [ATPP]Br-EA, [ATPP]Br-MDEA, and [ATPP]Br-ECH. Fig.…”

“…It has also been reported that longer alkyl chain lengths of DESs, or hydrophobic moieties in general, are better solvents for CO 2 . 23,33 Bearing this in mind, novel DES combinations were chosen based on our ML predictions and the following DESs combinations are proposed at different molar ratios and a wide range of pressures: mentholdecanoic acid (1 : 2), menthol-dodecanoic acid 12 shows the calculated solubility of CO 2 in the newly proposed DESs at 298.15 K and different pressures. As the pressure increases, the solubility of CO 2 predicted by the ML model also increases, in accord with Henry's Law.…”

“…The higher solubility in menthol-and phosphonium-based DESs is due to larger free volumes of HBA and HBD and strong interactions with CO 2 through vdW interactions. 23,68 Furthermore, to confirm the molar ratios of newly developed DES combinations, we performed COSMO-RS for menthol and decanoic acid/dodecanoic acid as an example of calculating the eutectic point composition. The eutectic point compositions for [ATPP]Br-based DES were not calculated and validated due to the lack of phase transition properties (i.e., melting point and heat fusion values) in the literature.…”

“…17 In recent years, DESs have been demonstrated as a potential solvent for CO 2 absorption. 5,22,23 However, to date the majority of the research into CO 2 absorption using DESs has relied on experimental methods, which have only been able to address a small fraction of potential DES candidates. 24,25 Because of structural diversity, there are approximately 10 18 DES combinations that can be used to design a solvent with potentially improved CO 2 absorption capabilities.…”

Design of Deep Eutectic Systems: Plastic Crystalline Materials as Constituents

“…To overcome the main drawbacks of ionic DESs, particularly their toxicity and hygroscopicity, natural organic compounds have recently been suggested as constituents of hydrophobic nonionic eutectic systems [ 29 , 30 , 31 , 32 ]. Simple organic compounds have been used to prepare nonionic eutectic systems that were found to be superior to ionic DESs and ionic liquids in terms of viscosity, economy, and performance [ 33 , 34 ]. However, because most nonionic eutectic systems studied in the literature are nearly ideal mixtures, their eutectic temperature is not significantly lower than the melting temperatures of the pure constituents [ 6 , 35 ].…”