Abstract: Nomatter for its industrial usefulness or theoretical importance as a very con- vient way to study thermodynamic behavior of the salt in a binary solution, the gas-liquid equilibrium data of tenary system with salt as one of components are of values. Actually a lot of isobaric data has been collected, however the isothermal data are very few. In this paper the isothermal data of CH_3OH-H_2O-LiCl, C_2H_5OH- H_2O-LiCl, CH_3COCH_3-H_2O-LiCl and CH_3COCH_8-H_2O-K_2CO_3 systems has been repor- ted and used to discuss the salt solvation. The equipment was designed by ourselves which the acuracy istested by measuring the data of corresponding binary systems without salt, the results proves to be quite satifactory.
We correlated the data using the three parameter Margules formula, where the parameters are determined by Barker′s method. It is desired that one can get the solvated properties from the gas-liquid equilibrium data, Ohe was the first one who proposed a formulism to get the prefer solvated numbers from the gas-liquid data. However for many organic-water-salt system, the solvated numbers from Ohe′s theory is negative in some region. We developed a similar theory for the isothermal data, the calculated solvated numbers are reasonable.