Diffusion in a ternary system and the critical mixing point

Abstract

Diffusion coefficients were measured for the ternary system water-chloroformacetic acetic acid at 25°C and at five concentrations approaching the critical mixing point. The relationship D11D22−D12D21=0 holding at the critical mixing point has been proven experimentally. By choosing water as solvent instead of acetic acid, negative main diffusion coefficients were found for chloroform, showing an interesting case of incongruent diffusion.