The Solvophobic Solvation and Interaction of Small Apolar Particles in Imidazolium-Based Ionic Liquids is Characterized by Enthalpy-/Entropy-Compensation

TL;DR

This study uses molecular dynamics simulations to explore how small apolar particles interact and are solvated in imidazolium-based ionic liquids, revealing enthalpy-entropy compensation similar to hydrophobic effects.

Contribution

It demonstrates that solvophobic solvation and interactions in ionic liquids are governed by enthalpy-entropy compensation, akin to hydrophobic phenomena in water, supported by simulation data.

Findings

Reproduces temperature dependence of apolar solubility in ILs

Shows enthalpy-entropy compensation governs solvophobic effects

Indicates thermodynamic similarity to hydrophobic interactions

Abstract

We report results of molecular dynamics simulations characterizing the solvation and interaction of small apolar particles such as methane and Xenon in imidazolium-based ionic liquids (ILs). The simulations are able to reproduce semi-quantitatively the anomalous temperature dependence of the solubility of apolar particles in the infinite dilution regime. We observe that the ``solvophobic solvation'' of small apolar particles in ILs is governed by compensating entropic and enthalpic contributions, very much like the hydrophobic hydration of small apolar particles in liquid water. In addition, our simulations clearly indicate that the solvent mediated interaction of apolar particles dissolved in ILs is similarly driven by compensating enthalpic/entropic contributions, making the ``solvophobic interaction'' thermodynamically analogous to the hydrophobic interaction.