COSMO-RS screening and experimental solid-liquid equilibrium validation of eutectic solvent candidates for CO2 capture

A combined computational -experimental strategy was applied to accelerate the identification of deep eutectic solvent (DES) candidates for CO 2 capture applications. A diverse group of hydrogen bond acceptors (HBA) and hydrogen bond donors (HBD) was selected and screened as potential DES constituents. Subsequently COSMO-RS was used to predict solid-liquid equilibrium (SLE) phase behavior and CO 2 infinite dilution activity coefficients. Based on this screening, selected mixtures were experimentally investigated using differential scanning calorimetry and visual observation of SLE measurements. The experimental results confirmed the formation of stable liquid phases for several systems, including Bet:TEA. In contrast, the Bet:MEA system, predicted to be liquid at ambient conditions, did not form a stable liquid phase experimentally and showed signs of decomposition. For L-tryptophan:MEA, an offset of approximately 2 K between predicted and experimental liquidus temperatures was observed, which is below the experimental uncertainty of 3 K. These findings demonstrate that COSMO-RS is an effective screening tool for identifying promising DES candidates, significantly reducing experimental effort, while highlighting the necessity of experimental validation to account for unexpected effects such as decomposition and metastable behavior. This iterative workflow can offer a time-efficient route for identifying solvents with favorable melting behavior over a broad temperature range and facilitates the development of organic-based DESs for CO 2 capture applications.