Differential heats of dilution of tert-butanol into water-tert-butanol mixtures at 26.90 °C

The differential heats of dilution of tert-butanol into water-tert-butanol mixtures were measured at 26.90 °C. The results in the range where the mole fraction of tert-butanol, x, is less than 0.05 indicate that the hydrophobic interaction is repulsive and of long range; the interaction appears to extend its tail as far as six molecular distances or longer. Above the threshold concentration [Formula: see text], the differential heats of dilution were close to zero and approximately independent of concentration and temperature.