Hydrogen-bonded networks in alcohol-acetone binary mixtures: molecular dynamics study

Area of Science:

• Physical Chemistry
• Chemical Physics
• Materials Science

Background:

• Anomalous physico-chemical properties observed in hydrogen-bonded binary systems at low volume concentrations (10-30%).
• Previous studies indicated unusual behavior in mixed systems, necessitating further investigation into molecular interactions.

Purpose of the Study:

• To systematically investigate the structural and hydrogen bonding characteristics of binary mixtures of acetone with eight primary alcohols using molecular dynamics.
• To understand the preferential interactions and structural organization within these mixtures at varying concentrations.

Main Methods:

• Molecular dynamics simulations were employed to model binary mixtures of acetone and primary alcohols (R-OH, R=1 to 8).
• Radial distribution functions, hydrogen bond statistics, and graph theory were utilized to analyze system structure and interactions.
• Analysis focused on hydrogen bond characteristics, alcohol-acetone, and alcohol-alcohol bonding.

Main Results:

• Observed distinct clustering in hydrogen bond characteristics for different alcohol groups (R=1,2; R=3,4,6; R=5,7,8) when mixed with acetone.
• Identified preferential bonding: alcohols R=3,4,6 showed more alcohol-acetone hydrogen bonds compared to alcohol-alcohol bonds, unlike other alcohol groups.
• Found that increasing acetone concentration decreased the average degree of association, indicating a reduction in hydrogen bond multimer structures.

Conclusions:

• The study elucidates specific hydrogen bonding behaviors and preferential interactions in acetone-alcohol binary mixtures.
• Molecular dynamics and graph theory provide insights into the structural organization and the impact of alcohol chain length on mixture properties.
• Findings contribute to understanding the fundamental interactions governing anomalous properties in such binary systems.