Thermodynamic Framework for Water in Deep Eutectic Solvents and Ionic Liquids

Prado, Desiree Mae [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000191291648); Gonzaga, Aaron Niño [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0009000103903382); Burda, Clemens [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000273422840)

doi:10.1002/cphc.202500510

DOE OSTI · 3026696

Thermodynamic Framework for Water in Deep Eutectic Solvents and Ionic Liquids

Prado, Desiree Mae [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000191291648)·Gonzaga, Aaron Niño [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0009000103903382)·Burda, Clemens [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000273422840)

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Abstract

Water is widely recognized as critical to the tunability and electrochemical stability of nonaqueous solvents such as deep eutectic solvents (DESs) and ionic liquids (ILs). Traditionally, the water content of these solvents has been controlled by either drying or adding small amounts of water to control their bulk properties to meet specific application requirements. The total water content by itself, does not provide sufficient information about the chemical reactivity and molecular interactions within DES– and IL–water mixtures. In this concept article, water activity is highlighted as a thermodynamically more rigorous descriptor to quantify the influence of the co‐solvent water on DES– and IL–water mixtures. Water activity relates measurable physical properties, such as vapor pressure, density, viscosity, electrochemical stability, and conductivity of DESs and ILs to the underlying molecular interactions between their components. Furthermore, water activity of DESs and ILs correlates with changes in local solvent structures and thermodynamic excess properties, including excess molar volume, enthalpy, and Gibbs energy.

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Prado, Desiree Mae [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000191291648), Gonzaga, Aaron Niño [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0009000103903382), Burda, Clemens [Case Western Reserve Univ., Cleveland, OH (United States)] (ORCID:0000000273422840). 2025-12-16. Thermodynamic Framework for Water in Deep Eutectic Solvents and Ionic Liquids. https://doi.org/10.1002/cphc.202500510

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