Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

A universal form is proposed for the ternary correction to G^E, which is based on the MacLaurin fourth-order expansion, With data on four ternary equilibrium liquid systems of the hydrocarbon-hydrocarbon-polar solvent type, it is demonstrated that a very good reproducibility of equilibrium L-L concentrations can be achieved by using this ternary correction. The ternary correction was applied to the NRTL, modified Wilson and Redlich-Kister equations. The correction parameters were determined from ternary L-L data, binary parameters were found from vapour-liquid (V-L) equlibrium data. For the determination of correction parameters with the help of the activity objective function, it is desirable to use weights from the law of the error propagation. For the determination of correction parameters with the help of the concentration objective function, an approximate expression was derived for calculating the probable value of the mole fraction of the solute in one of the equilibrium phases.