Tricritical phenomena in ‘‘quasibinary’’ mixtures of hydrocarbons. I. Methane systems

摘要: Temperature, pressure, and composition measurements are reported for the three coexisting phases in region of tricritical points two ternary mixtures hydrocarbons: methane+n‐pentane+2,3‐dimethylbutane (I) methane+2,2‐dimethylbutane+2,3‐dimethylbutane (II). These systems satisfy a ’’quasibinary’’ approximation which proportions higher hydrocarbons [expressed as Z = xC/(xB+xC)] same each phases, so that phase equilibrium is equivalent to binary system with solute average properties. Least‐squares analysis does not locate point high precision, but all consistent predictions phenomenological theory exponents governing approach ’’classical’’ mean‐field values. If, accord this view, we write difference between upper lower critical‐end‐point temperatures (i.e., extent three‐phase region) Tu−Tl B(Z−Zt)...