Assessment of COSMO-SAC Predictions for Solid–Liquid Equilibrium in Binary Eutectic Systems

As green and sustainable solvents, deep eutectic solvents
(DESs)
have received wide attention in various fields. Predictions of solid–liquid
equilibrium (SLE) make it easier to choose DES constituents from a
large pool of potential compounds. The conductor-like screening model
for segment activity coefficient (COSMO-SAC) predictions for the SLE
of 94 nonsalt and 122 salt-based binary eutectic systems was evaluated
in this study. It was found that the COSMO-SAC model can provide satisfactory
predictions for the eutectic point of most nonsalt eutectic systems.
Similar results were obtained when using the ideal solution model.
The salt was represented in salt-based eutectic systems using one
of two methods: as an ion pair or as fully dissociated ions. COSMO-SAC
predictions for salt-based eutectic systems were unsatisfactory regardless
of the salt representation method used. This inaccuracy in predicting
SLE in the salt-based eutectic systems is not only due to model limitations
but also due to the lack of reliable melting properties for thermally
unstable salts.