Solubility of benzoin in three binary solvent mixtures and investigation of intermolecular interactions by molecular dynamic simulation

Abstract

Solubility of benzoin in three binary solvent systems of acetone+ethanol, acetone+1-butanol, acetone+1-propanol was measured by static analytical method ranging from 283.15K to 318.15K at atmospheric pressure. Density functional theory (DFT) and molecular dynamic (MD) simulation were employed to investigate relationship between solute and solvent molecules. According to results of Solvation free energy and hydrogen bond strength, the solubility of benzoin increases with increasing value of hydrogen bond strength. Radial distribution function (RDF) resulted shows that ethanol, 1-butanol, 1-propanol have an effect on the acetone aggregation in binary mixed solvents, which means it will weaken the interactions between benzoin and acetone molecules. Therefore, solubility behavior was influenced by both solute-solvent and solvent-solvent interactions. The solubility data was correlated with Apelblat equation, CNIBS/R-K equation, and λh model, respectively, and the CNIBS/R-K equation shows the best correlations in three thermodynamic equations. Thermodynamic properties of mixing enthalpy, entropy, and Gibbs energy were further estimated and their implication on dissolution process of benzoin was discussed.