Microscopic structure and solvation in dry and wet octanol

Area of Science:

• Physical Chemistry
• Environmental Science
• Pharmacology

Background:

• Octanol-water partition coefficients are crucial for predicting environmental and pharmacological processes.
• The 1-octanol phase mimics diverse environments due to its amphiphilic nature.
• The precise structure of the octanol phase and water's effect on it remain unclear.

Purpose of the Study:

• To investigate the structural changes in 1-octanol upon water saturation.
• To reconcile conflicting experimental and theoretical views on 1-octanol's aggregation.
• To quantify the impact of water saturation on partition coefficients.

Main Methods:

• Configurational-bias Monte Carlo simulations using the Gibbs ensemble.
• Analysis of hydrogen-bonded aggregate structures in dry and wet 1-octanol.
• Calculation of partition constants under varying water saturation.

Main Results:

• Diverse hydrogen-bonded aggregates exist in both dry and wet 1-octanol.
• Water saturation transforms 1-octanol from linear aggregates to cylindrical micelles with water cores.
• Simulation results align with and explain previous experimental observations.

Conclusions:

• Water saturation significantly alters the 1-octanol structure and aggregation.
• The study reconciles differing interpretations of 1-octanol's molecular organization.
• Understanding these structural changes is key to accurately predicting partition coefficients.