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 volumes , heat capacities , and expansibilities were evaluated. Generally, the temperature dependence of these quantities is rather characteristic of hydrophobic solutes in water. At high concentrations and resemble those of surfactants, suggesting the existence of some microphase separation. At low temperatures 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 for . The and of water in TBA have also been calculated; is in theTBA-rich region 2 to 2.5 cm 3 mol −1 smaller than the molar volume of water, but is of the same order of magnitude as the molar heat capacity of water.