Evaluation of COSMO-RS for solid–liquid equilibria prediction of binary eutectic solvent systems

For the design of eutectic solvents (ESs, usually also known as deep eutectic solvents), the prediction of the solid–liquid equilibria (SLE) between candidate components is of primary relevance. In the present work, the SLE prediction of binary eutectic solvent systems by the COSMO-RS model is systematically evaluated, thereby examining the applicability of this method for ES design. Experimental SLE of such systems are first collected exhaustively from the literature, following which COSMO-RS SLE calculations are accordingly carried out. By comparing the experimental and predicted eutectic points (eutectic temperature and eutectic composition) of the involved systems, the effects of salt component conformer and COSMO-RS parameterization as well as the applicability for different types of components (specifically the second component paired with the first salt one) are identified. The distinct performances of COSMO-RS SLE prediction for systems involving different types of components are further interpreted from the non-ideality and fusion enthalpy point of view.

The solid–liquid equilibria prediction by COSMO-RS provides a promising way to the theoretical design of (deep) eutectic solvent. With the identified calculation option and applicability range of COSMO-RS, new eutectic solvents could be readily explored.