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 behaviour of order parameters, such as density or molar volume, along the respective coexistence curve is well represented by the exponent = 0.325. For a binary liquid mixture, along the critical isotherm, the critical anomaly of molar volume shall be described by the exponent (1 - )/ = 2.74. The experimental data obtained for the full range of composition for (tetrachloromethane + tetradecafluoromethylcyclohexane) confirm this requirement. Speed of sound, though strictly not a generalized density, should be associated with the same set of exponents that describe the behaviour 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. ########: Critical phenomena; Critical indices; Molar volume; Speed of sound 2 1