Abstract: The consolute curve of benzene-water-ethanol ternary solutions has been measured by using equal-volume titration, and the coexistence curve near isothermal consolute point at 29.00±0.05 ℃ has also been measured. The obtained order-parameter critical index β = 0.38±0.04, and the order-parameter amplitude K =1.3±0.2. It indicates that near the isothermal consolute point, the critical index of the partly soluble ternary solutions fits Fisher renormalization model well, and it has the character of non-classical critical solution theory.

Key words: Critical phenomena, Order-parameter, Critical index, Isothermal consolute point, 3D-Ising Model, Fisher renormalization model