Excess volumes and excess heat capacities of tetrachloroethene + cyclohexane, + methylcyclohexane, + benzene, and + toluene at 298.15 K

Abstract

Molar excess volumes V m E at 298.15 K were obtained, as a function of mole fraction x, for the four liquid mixtures tetrachloroethene + cyclohexane, + methylcyclohexane, + benzene, and + toluene from measurements of the density with a vibrating-tube densimeter. The excess volumes are positive in all cases, the largest value of V m E being found for { xC 2Cl 4 + (1 − x) c-C 6H 12}: V m E(max) = 0.529 cm 3·mol −1 at x = 0.4540. The maximum values V m E(max)/(cm 3·mol −1) for the other mixtures, in the sequence given above, are: 0.180 at x = 0.4330, 0.405 at x = 0.4538, and 0.131 at x = 0.4532. A Picker flow calorimeter was used to determine molar excess heat capacities at 298.15 K for each of these binaries: C p, m E is negative for all four. In the same sequence, C p, m E(min)/(J·K −1·mol −1) is, respectively, −1.41 at x = 0.5323, −0.92 at x = 0.4899, −2.25 at x = 0.4196, and −0.54 at x = 0.4056.