Framework for correlating the effect of temperature on nonelectrolyte and ionic liquid activity coefficients

A power‐law expression is proposed for correlating the temperature dependence of infinite‐dilution activity coefficients ( ) for nonelectrolyte solute–solvent binary pairs and for pairs including an ionic liquid: , where θ_ij = 0 for Lewis–Randall ideal solutions, θ_ij = 1 for classic enthalpy‐based Scatchard–Hildebrand regular solution and van Laar models, and ?5 < θ_ij < 5 for most real binaries. The exponent θ_ij is a function of partial molar excess enthalpy ( ) and entropy ( ) such that . Real binaries are classified into seven types corresponding to distinct domains of and θ_ij. The new method provides a framework for correlating phase‐equilibrium driven temperature effects for a wide variety of chemical and environmental applications. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3675–3690, 2014