Intermolecular Interactions in 2-Butoxyethanol−DMSO−H2O

Abstract

Excess partial molar enthalpy, HBE, and chemical potential, μBE, of 2-butoxyethanol (B) were determined in ternary mixtures of B, dimethyl sulfoxide (D), and H2O. The data were obtained in small enough mole fraction increments to evaluate the so-called interaction functions, ∂HBE/∂xB, ∂HBE/∂xD, ∂μBE/∂xB, and ∂μBE/∂xD. These interaction functions previously proved useful in elucidating the “mixing schemes” in binary aqueous solutions of B and D. For the binary mixtures, it was found that both B and D influenced H2O in the following manner: in the water-rich composition range (region I) within a certain threshold (xB < 0.0175 and xD < 0.28 at 25 °C), both solutes enhance the hydrogen-bonded network of water in their vicinity, and the mixtures retain the percolated nature of the network. At higher B or D concentrations (region II) a qualitatively different mixing scheme becomes operative. The results from this work suggest that, in the ternary mixtures, solute B and D influences the percolated hydrogen bond...