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

Abstract

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[Formula: see text], heat capacities[Formula: 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 text]and [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 for[Formula: 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 cm3 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.