关键词:

定标粒子理论, 加盐排斥萃取, 溶剂化自由能, 盐效应

Abstract:

It is very difficult to select the salt in salt-containing extraction, which has been widely applied in chemical separation processes.In this study, ionic solvation free energies of eight salts in methyl acetate/methanol/water system at 25℃ were calculated by means of selective solvation model and scaled particle model revised by the solubility parameter of salt.The calculated values were verified by extraction separation experiment.The results indicate that the mass fraction of acetate in the organic phase increases linearly with the absolute value of the ionic solvation free energy of salt, while that of water in the organic phase decreases linearly.The electrostatic interaction force is the major factor influencing the effect of salt-containing extraction.When the absolute value of the electrostatic interaction free energy between the salt molecule and water molecule or methanol molecule is larger, the extraction effect of salt on ethyl acetate is better.Furthermore, the method of the ionic solvation free energy can be applied in qualitative selection for proper salt as extractant.

Key words:

定标粒子理论, 加盐排斥萃取, 溶剂化自由能, 盐效应