Definition of unifac:
(N) :
In statistical thermodynamics, the UNIFAC method (UNIQUAC Functional-group Activity Coefficients)Aage Fredenslund, Russell L. Jones and John M. Prausnitz, "Group-Contribution Estimation of Activity Coefficients in Nonideal Liquid Mixtures", AIChE Journal, vol. 21, p. 1086 is a semi-empirical system for the prediction of non-electrolyte activity in non-ideal mixtures.