Clustering and Micro-immiscibility in Alcohol-Water Mixtures: Evidence from Molecular Dynamics Simulations

TL;DR

This study uses molecular dynamics simulations to analyze hydrogen-bonded structures in methanol and water mixtures, revealing chain and ring structures in methanol and micro-immiscibility in the solution, challenging some recent experimental predictions.

Contribution

It provides new molecular-level insights into hydrogen bonding and micro-immiscibility in alcohol-water mixtures using classical simulations.

Findings

Hydrogen-bonded structures in methanol are dominated by chains and small rings.

Evidence of micro-immiscibility in methanol-water solutions.

Contradicts recent X-ray emission predictions about methanol structure.

Abstract

We have investigated the hydrogen-bonded structures in liquid methanol and a 7:3 mole fraction aqueous solution using classical Molecular Dynamics simulations at 298K and ambient pressure. We find that, in contrast to recent predictions from X-ray emission studies, the hydrogen-bonded structure in liquid methanol is dominated by chain and small ring structures. In the methanol-rich solution, we find evidence of micro-immiscibility, supporting recent conclusions derived from neutron diffraction data.