Rigorous characterization of static and dynamic apparatus for measuring limiting activity coefficients

In differential ebulliometry the true liquid equilibrium composition is related to the charge composition through an equipment characterization parameter E, which is a function of the vaporization ratio φ. Exact computation of γ1∞ requires an iterative solution of a set of three equations. lar but simpler formulation is possible for differential static apparatus, which accounts exactly for the vapor hold-up. An equipment parameter E is most conveniently resolved in terms of the total equipment volume and involves two new dimensionless groups RT and RG. An iterative procedure involving regula–falsi gave rapid convergence for all systems studied. The flexible one-constant Wilson equation is recommended. For systems of large relative volatility large errors in γ1∞ will result, even at low pressure, if vapor hold-up is not accounted for and if RT⪢1. New values for the self-association constant k are proposed for 2-propanol and ethanol as functions of temperature.