Molar volume and speed of sound in the neighborhood of the liquid–liquid critical point of (tetrachloromethane + tetradecafluoromethylcyclohexane)

The universal critical exponents given by the three-dimensional Ising model and derived through renormalization group calculations accurately describe the gas–liquid critical phenomena of pure fluids and the liquid–liquid critical phenomena of binary liquid mixtures. Thus, the behavior of order parameters, such as density or molar volume, along the respective coexistence curve is well represented by the exponent β=0.325. For a binary liquid mixture, along the critical isotherm, the critical anomaly of molar volume shall be described by the exponent (1−α)/β=2.74. The experimental data obtained for the full range of composition for (tetrachloromethane+tetradecafluoromethylcyclohexane) confirm this requirement. of sound, though strictly not a generalized density, should be associated with the same set of exponents that describe the behavior of molar volume. The results on the speed of sound of (tetrachloromethane+tetradecafluoromethylcyclohexane) along the coexistence curve and along the full range of the critical isotherm generally agree with the universality concept.