Predicting the Surface Tension of Deep Eutectic Solvents: A Step Forward in the Use of Greener Solvents

Abstract

Deep eutectic solvents (DES) are an important class of green solvents that have been developed as an alternative to toxic solvents. However, the large-scale industrial application of DESs requires fine-tuning their physicochemical properties. Among others, surface tension is one of such properties that have to be considered while designing novel DESs. In this work, we present the results of a detailed evaluation of Quantitative Structure-Property Relationships (QSPR) modeling efforts designed to predict the surface tension of DESs, following the Organization for Economic Co-operation and Development (OECD) guidelines. The data set used comprises a large number of structurally diverse binary DESs and the models were built systematically through rigorous validation methods, including ‘mixtures-out’- and ‘compounds-out’-based data splitting. The most predictive individual QSPR model found is shown to be statistically robust, besides providing valuable information about the structural and physicochemical features responsible for the surface tension of DESs. Furthermore, the intelligent consensus prediction strategy applied to multiple predictive models led to consensus models with similar statistical robustness to the individual QSPR model. The benefits of the present work stand out also from its reproducibility since it relies on fully specified computational procedures and on publicly available tools. Finally, our results not only guide the future design and screening of novel DESs with a desirable surface tension but also lays out strategies for efficiently setting up silico-based models for binary mixtures.

Unusual Hydration Properties of Choline Fluoride-Based Deep Eutectic Solvents

“…Their model predicted that the lipophilicity, polarizability, and dipole moment of DESs are found to be responsible for ruling their surface tensions. 41 In 2003, Abbott et al reported the first relineF (ChF) DES mixtures (containing 1:2, ChF/Urea), which showed a very low melting temperature of 274 K and strong interactions between fluoride anions and the amino hydrogens of urea. 43 Harmon et al studied the strong OH...F hydrogen bond interactions using ChF in multiple publications.…”

“…utilized quantitative structure–property relationship (QSPR) models for predicting density and viscosity of various hydrophobic eutectic solvents using conductor-like screening model for real solvents (COSMO-RS) based descriptors . The group of Halder also estimate the density, surface tension, and CO 2 uptake capability of DESs using QSPR model. Their model predicted that the lipophilicity, polarizability, and dipole moment of DESs are found to be responsible for ruling their surface tensions …”

“…The group of Halder also estimate the density, surface tension, and CO 2 uptake capability of DESs using QSPR model. Their model predicted that the lipophilicity, polarizability, and dipole moment of DESs are found to be responsible for ruling their surface tensions …”

Importance of the Electrostatic Correlations in Surface Tension of Hydrated Reline Deep Eutectic Solvent from Combined Experiments and Molecular Dynamics Simulations

“…Very recently, Stephens and Smith underlined the importance of interfacial properties and the need for a thorough understanding of them in an interesting review or perspective article . Several studies in the literature have already experimentally measured and theoretically predicted the surface tensions of DESs using techniques, such as quantitative structure–property relationships and machine learning. − However, while these methods are intriguing, predicting surface tension through machine learning and thermodynamic laws does not fully reveal the structure of the interface or establish a connection with surface tension. There have been very few reports on molecular or microscopic insights into the surface tension of both pure and aqueous DESs .…”