“…It was falsely assumed for decades that the unique feasibility rule for the extractive distillation process was the (1.0-1a) class separation, corresponding to the homogeneous extractive distillation of a minT azeotropic mixture with a heavy entrainer or of a maxT azeotropic mixture with a light entrainer (1.0-1a occurrence 21.6% among azeotropic diagrams). But some twenty works published between 1990 and 2013 explored which ternary diagrams would be suited for extractive distillation (Laroche et al, 1991(Laroche et al, , 1992a; Wahnschafft and Westerberg, 1993; Knapp and Doherty, 1994;Petlyuk et al, 1999Petlyuk et al, , 2015Serafimov et al, 2008;Kotai and Lang, 2005;Kotai et al, 2007;Lang, 1992;Lang et al, 1994Lang et al, , 1995Lang et al, , 1999Lang et al, , 2000aLelkes et al, 1998aLelkes et al, ,b,c, 2002Lelkes et al, , 2003aModla et al, 2001Modla et al, , 2003Rev et al, 2003;Stéger et al, 2005Stéger et al, , 2006Varga et al, 2006a,b) until the general feasibility rules discussed in the previous section were enounced (Rodríguez-Donis et al, 2009a,b, 2010, 2012aGerbaud and Rodriguez-donis, 2014;Shen et al, , 2015bShen et al, , 2016 For homogeneous extractive distillation with an entrainer forming no new azeotrope, the feasible diagrams belong to the following classes: (1.0-1a) (separation of minT with E heavy or maxT with E light, occurrence 21.6% among azeotropic diagrams), (1.0-2) (separation of maxT with E heavy or minT with E light, occurrence 8.5%), (1.0-1b) (minT with E light or maxT with E heavy, occurrence 0.4%), and (0.0-1) (low mixture with all type of E, see occurrences in Reshetov and Kravchenko (2007). Besides, when the entrainer forms a new azeotrope, ternary diagrams classes (2.0-1) (occurrence 0.6%), (2.0-2a) (occurrence 0.4%), (2.0-2b) (occurrence 21.0%) and (2.0-2c) (occurrence 0.9%) ...…”