The heat capacities, volumes, and expansibilities of tert-butyl alcohol – water mixtures from 6 to 65 °C

The densities and specific heat capacities of mixtures of tert-butyl alcohol (TBA) and water (W) have been measured at 6, 10, 25, 40, 55, and 65 °C. From these data the apparent molal volumesFormula: see text, heat capacitiesFormula: see text, and expansibilities Formula: see text were evaluated. Generally, the temperature dependence of these quantities is rather characteristic of hydrophobic solutes in water. At high concentrations Formula: see textand Formula: see text resemble those of surfactants, suggesting the existence of some microphase separation. At low temperatures Formula: see text show a significant hump as a function of concentration, which is probably not due to the presence of the —OH group on the TBA molecule. A similar behaviour is observed forFormula: see text. The Formula: see text and Formula: see text of water in TBA have also been calculated; Formula: see text is in theTBA-rich region 2 to 2.5 cm 3 mol −1 smaller than the molar volume of water, but Formula: see text is of the same order of magnitude as the molar heat capacity of water.