Phase separation property of a hydrophobic deep eutectic solvent-water binary mixture: A molecular dynamics...

Area of Science:

• Green Chemistry
• Materials Science
• Computational Chemistry

Background:

• Deep eutectic solvents (DESs) are emerging as sustainable alternatives to traditional organic solvents.
• A novel hydrophobic DES, formed by oleic acid and lidocaine, exhibits a lower critical solution temperature in water.
• This thermoreversible phase behavior is key for applications like dye sequestration.

Purpose of the Study:

• To explore the phase separation phenomena of an oleic acid-lidocaine DES in aqueous solutions.
• To elucidate the molecular interactions governing the phase segregation property of this DES-water system.
• To understand the impact of temperature on the DES-water interactions and phase behavior.

Main Methods:

• All-atom molecular dynamics (MD) simulations were employed.
• A 50 wt.% solution of the DES in water was simulated at three temperatures: 253 K, 293 K, and 313 K.
• Analysis focused on hydrogen bonding, non-bonding interactions, and water dynamics near the phase boundary.

Main Results:

• The study identified a competition between hydrogen bonding and non-bonding interactions as the driver for phase separation.
• Increasing temperature leads to unfavorable interactions between the DES components and water, promoting phase segregation.
• Temperature significantly alters the dynamical properties of water molecules at the phase boundary.

Conclusions:

• Molecular insights into the phase separation of this hydrophobic DES are provided.
• The findings highlight the critical role of temperature-dependent interactions in dictating solvent behavior.
• This research aids in designing advanced solvent systems for industrial extraction processes.