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

Our previous studies on various hydrogen-bonded binary systems have shown anomalous physico-chemical properties at lower (10-30%) volume concentrations of either one or both of the components. In order to have a better understanding of this phenomenon, a systematic molecular dynamics study of binary mixtures of acetone with eight primary alcohols (R-OH, with R = 1 to 8) was undertaken. The structure of the binary systems is studied using radial distribution function, hydrogen bond statistics, and graph theoretical approach. Two distinct features are observed. Firstly, the bunching of R = (1, 2), R = (3, 4, 6), and R = (5, 7, 8)-acetone mixture in their hydrogen bond characteristics. Secondly, the number of alcohol-acetone hydrogen bonds is more for R = (3, 4, 6) and the alcohol-alcohol hydrogen bonds for the rest, indicating a preferential bonding of R = (3, 4, 6) alcohols with acetone when compared to the rest. With an increase in acetone concentration, the average degree of association decreases for all systems, showing an overall decrease in hydrogen bond multimer structures. The hydrogen bond networks are visualized using graph theory.