Thermal Expansivity, Molar Volume, and Heat Capacity of Liquid Dimethyl Sulfoxide-Water Mixtures at Subzero Temperatures

Abstract

The specific volume, thermal expansivity, and specific heat capacity of liquid binary mixtures of water and dimethyl sulfoxide (DMSO) have been measured at temperatures ranging from approximately -25 o C to room temperature, and at DMSO concentrations from 0 to 85% (w/w). Apparent quantities (apparent molar volume, apparent thermal expansivity, and apparent molar heat capacity) of DMSO were evaluated. Around room temperature, the concentration dependence of these functions show a behavior characteristic for aqueous solutions of molecules with nonpolar moieties. However, at the lowest temperatures the concentration dependence of the apparent molar volume and heat capacity resembled what is observed for strongly hydrophilic nonelectrolytes