Preferential solvation of phenol in binary solvent mixtures. A molecular dynamics study

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Solution Chemistry

Background:

• Preferential solvation describes the non-uniform distribution of solvent molecules around a solute.
• Understanding solvation is crucial for predicting chemical reactions and physical properties in solution.
• Binary solvent mixtures offer complex solvation environments due to interactions between different solvent components.

Purpose of the Study:

• To investigate the preferential solvation of phenol in equimolar acetonitrile-water and ethanol-water mixtures using molecular dynamics simulations.
• To assess the influence of different water models on the simulation results.
• To compare simulation findings with experimental data from intermolecular 1H NOESY spectroscopy.

Main Methods:

• Molecular dynamics (MD) computer simulations were employed.
• Two distinct water models were utilized to evaluate model dependence.
• Simulated local mole fractions were compared with experimental intermolecular 1H NOESY data.

Main Results:

• Simulations accurately reproduced experimental results for phenol's preferential solvation in acetonitrile-water mixtures.
• A qualitative difference was observed for ethanol-water mixtures across both water models, diverging from experimental findings.
• Despite the qualitative difference in ethanol-water, the trends in the degree of preferential solvation for both cosolvents (acetonitrile and ethanol) agreed with experimental data.

Conclusions:

• Molecular dynamics simulations are a valuable tool for studying preferential solvation, particularly in systems like acetonitrile-water.
• The choice of water model can influence simulation outcomes, highlighting the need for careful model selection.
• While simulations show good agreement with experiments for acetonitrile-water, further investigation is needed for systems like ethanol-water to fully reconcile discrepancies.