Hydration and Molar Ratio Effects in Choline Chloride-Phenol Deep Eutectic Solvents

Area of Science:

• Physical Chemistry
• Materials Science
• Computational Chemistry

Background:

• Deep eutectic solvents (DESs) like choline chloride and phenol (CCPhe) are gaining attention for their adjustable properties.
• Understanding how water affects DES structure and dynamics is crucial for their application.

Purpose of the Study:

• To investigate the impact of varying hydration levels on the physicochemical properties of CCPhe systems.
• To provide a multiscale understanding of hydration effects using molecular dynamics simulations.

Main Methods:

• Molecular dynamics (MD) simulations were conducted on CCPhe systems with molar ratios of 1:2, 1:3, and 1:4.
• Analyses included energetic, hydrogen-bond, dielectric, transport, and structural properties.

Main Results:

• Hydration shifts stabilization from Phe-Cl and Ch-Cl to water-Cl interactions, increasing water-mediated hydrogen bonding.
• Dielectric constant rises significantly with hydration, reaching 15.93 for the 1:4 system at 30% water.
• Diffusion coefficients increase substantially, and hydration affects choline's solvation shell without changing contact distances.

Conclusions:

• Controlled hydration is an effective tuning parameter for CCPhe systems.
• Hydration modulates energetic balance, hydrogen bonding, polarization, and transport properties in a composition-dependent manner.