No abstract

Improvements of an existing method for the calculation of the Gibbs free energy and activity coefficients for binary non‐ideal solutions from total pressure measurements are presented. These improvements are particularly significant whenever the ratio of the vapor pressures of the pure components is greater than 10. The convergence is rapid and the method is well adapted to digital computation.

The following equation Is obtained by substituting Equations 2 and 3 in Equation 1; Amix = 0.1456 eld/n -21.62X10-"] (1097 + 12ß6 '•") (4) For associated liquids, the relationship between log µ and 1/7 becomes slightly curved; in the present case this relationship resulted in straight lines. This may be due to negligible effect of association of n-butanol In the range of temperatures studied.By means of Equation 4, viscosity data at any given temperature and composition of the binary mixture can be predicted. Viscosity data predicted through Equation 4compare well with experimental data (Table II), and the average percent deviation is 2.3. Nomenclature